blob: 627ed0c593fb4c05dd46e1da9eb75ddf2e6c1269 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics
4 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
Jens Axboe6728cb02008-01-31 13:03:55 +01006 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
7 * - July2000
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
9 */
10
11/*
12 * This handles all read/write requests to block devices
13 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/backing-dev.h>
17#include <linux/bio.h>
18#include <linux/blkdev.h>
Jens Axboe320ae512013-10-24 09:20:05 +010019#include <linux/blk-mq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/highmem.h>
21#include <linux/mm.h>
22#include <linux/kernel_stat.h>
23#include <linux/string.h>
24#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/completion.h>
26#include <linux/slab.h>
27#include <linux/swap.h>
28#include <linux/writeback.h>
Andrew Mortonfaccbd4b2006-12-10 02:19:35 -080029#include <linux/task_io_accounting_ops.h>
Akinobu Mitac17bb492006-12-08 02:39:46 -080030#include <linux/fault-inject.h>
Jens Axboe73c10102011-03-08 13:19:51 +010031#include <linux/list_sort.h>
Tejun Heoe3c78ca2011-10-19 14:32:38 +020032#include <linux/delay.h>
Tejun Heoaaf7c682012-04-19 16:29:22 -070033#include <linux/ratelimit.h>
Lin Ming6c954662013-03-23 11:42:26 +080034#include <linux/pm_runtime.h>
Tejun Heoeea8f412015-05-22 17:13:17 -040035#include <linux/blk-cgroup.h>
Li Zefan55782132009-06-09 13:43:05 +080036
37#define CREATE_TRACE_POINTS
38#include <trace/events/block.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Jens Axboe8324aa92008-01-29 14:51:59 +010040#include "blk.h"
Ming Lei43a5e4e2013-12-26 21:31:35 +080041#include "blk-mq.h"
Jens Axboe8324aa92008-01-29 14:51:59 +010042
Mike Snitzerd07335e2010-11-16 12:52:38 +010043EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
Jun'ichi Nomurab0da3f02009-10-01 21:16:13 +020044EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
Linus Torvalds0a82a8d2013-04-18 09:00:26 -070045EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
Keith Busch3291fa52014-04-28 12:30:52 -060046EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
NeilBrowncbae8d42012-12-14 20:49:27 +010047EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
Ingo Molnar0bfc2452008-11-26 11:59:56 +010048
Tejun Heoa73f7302011-12-14 00:33:37 +010049DEFINE_IDA(blk_queue_ida);
50
Linus Torvalds1da177e2005-04-16 15:20:36 -070051/*
52 * For the allocated request tables
53 */
Jens Axboe320ae512013-10-24 09:20:05 +010054struct kmem_cache *request_cachep = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56/*
57 * For queue allocation
58 */
Jens Axboe6728cb02008-01-31 13:03:55 +010059struct kmem_cache *blk_requestq_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 * Controlling structure to kblockd
63 */
Jens Axboeff856ba2006-01-09 16:02:34 +010064static struct workqueue_struct *kblockd_workqueue;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Tejun Heod40f75a2015-05-22 17:13:42 -040066static void blk_clear_congested(struct request_list *rl, int sync)
67{
Tejun Heod40f75a2015-05-22 17:13:42 -040068#ifdef CONFIG_CGROUP_WRITEBACK
69 clear_wb_congested(rl->blkg->wb_congested, sync);
70#else
Tejun Heo482cf792015-05-22 17:13:43 -040071 /*
72 * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
73 * flip its congestion state for events on other blkcgs.
74 */
75 if (rl == &rl->q->root_rl)
76 clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
Tejun Heod40f75a2015-05-22 17:13:42 -040077#endif
78}
79
80static void blk_set_congested(struct request_list *rl, int sync)
81{
Tejun Heod40f75a2015-05-22 17:13:42 -040082#ifdef CONFIG_CGROUP_WRITEBACK
83 set_wb_congested(rl->blkg->wb_congested, sync);
84#else
Tejun Heo482cf792015-05-22 17:13:43 -040085 /* see blk_clear_congested() */
86 if (rl == &rl->q->root_rl)
87 set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
Tejun Heod40f75a2015-05-22 17:13:42 -040088#endif
89}
90
Jens Axboe8324aa92008-01-29 14:51:59 +010091void blk_queue_congestion_threshold(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
93 int nr;
94
95 nr = q->nr_requests - (q->nr_requests / 8) + 1;
96 if (nr > q->nr_requests)
97 nr = q->nr_requests;
98 q->nr_congestion_on = nr;
99
100 nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
101 if (nr < 1)
102 nr = 1;
103 q->nr_congestion_off = nr;
104}
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106/**
107 * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
108 * @bdev: device
109 *
110 * Locates the passed device's request queue and returns the address of its
Tejun Heoff9ea322014-09-08 08:03:56 +0900111 * backing_dev_info. This function can only be called if @bdev is opened
112 * and the return value is never NULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 */
114struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
115{
Jens Axboe165125e2007-07-24 09:28:11 +0200116 struct request_queue *q = bdev_get_queue(bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
Tejun Heoff9ea322014-09-08 08:03:56 +0900118 return &q->backing_dev_info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120EXPORT_SYMBOL(blk_get_backing_dev_info);
121
FUJITA Tomonori2a4aa302008-04-29 09:54:36 +0200122void blk_rq_init(struct request_queue *q, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123{
FUJITA Tomonori1afb20f2008-04-25 12:26:28 +0200124 memset(rq, 0, sizeof(*rq));
125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 INIT_LIST_HEAD(&rq->queuelist);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700127 INIT_LIST_HEAD(&rq->timeout_list);
Jens Axboec7c22e42008-09-13 20:26:01 +0200128 rq->cpu = -1;
Jens Axboe63a71382008-02-08 12:41:03 +0100129 rq->q = q;
Tejun Heoa2dec7b2009-05-07 22:24:44 +0900130 rq->__sector = (sector_t) -1;
Jens Axboe2e662b62006-07-13 11:55:04 +0200131 INIT_HLIST_NODE(&rq->hash);
132 RB_CLEAR_NODE(&rq->rb_node);
FUJITA Tomonorid7e3c322008-04-29 09:54:39 +0200133 rq->cmd = rq->__cmd;
Li Zefane2494e12009-04-02 13:43:26 +0800134 rq->cmd_len = BLK_MAX_CDB;
Jens Axboe63a71382008-02-08 12:41:03 +0100135 rq->tag = -1;
Tejun Heob243ddc2009-04-23 11:05:18 +0900136 rq->start_time = jiffies;
Divyesh Shah91952912010-04-01 15:01:41 -0700137 set_start_time_ns(rq);
Jerome Marchand09e099d2011-01-05 16:57:38 +0100138 rq->part = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
FUJITA Tomonori2a4aa302008-04-29 09:54:36 +0200140EXPORT_SYMBOL(blk_rq_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
NeilBrown5bb23a62007-09-27 12:46:13 +0200142static void req_bio_endio(struct request *rq, struct bio *bio,
143 unsigned int nbytes, int error)
Tejun Heo797e7db2006-01-06 09:51:03 +0100144{
Mike Snitzer78d8e582015-06-26 10:01:13 -0400145 if (error)
Tejun Heo143a87f2011-01-25 12:43:52 +0100146 clear_bit(BIO_UPTODATE, &bio->bi_flags);
147 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
148 error = -EIO;
Tejun Heo797e7db2006-01-06 09:51:03 +0100149
Tejun Heo143a87f2011-01-25 12:43:52 +0100150 if (unlikely(rq->cmd_flags & REQ_QUIET))
151 set_bit(BIO_QUIET, &bio->bi_flags);
152
Kent Overstreetf79ea412012-09-20 16:38:30 -0700153 bio_advance(bio, nbytes);
Tejun Heo143a87f2011-01-25 12:43:52 +0100154
155 /* don't actually finish bio if it's part of flush sequence */
Mike Snitzer78d8e582015-06-26 10:01:13 -0400156 if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))
Tejun Heo143a87f2011-01-25 12:43:52 +0100157 bio_endio(bio, error);
Tejun Heo797e7db2006-01-06 09:51:03 +0100158}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160void blk_dump_rq_flags(struct request *rq, char *msg)
161{
162 int bit;
163
Jens Axboe59533162013-05-23 12:25:08 +0200164 printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg,
Jens Axboe4aff5e22006-08-10 08:44:47 +0200165 rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
Jens Axboe59533162013-05-23 12:25:08 +0200166 (unsigned long long) rq->cmd_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Tejun Heo83096eb2009-05-07 22:24:39 +0900168 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
169 (unsigned long long)blk_rq_pos(rq),
170 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
Jens Axboeb4f42e22014-04-10 09:46:28 -0600171 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
172 rq->bio, rq->biotail, blk_rq_bytes(rq));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200174 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
Jens Axboe6728cb02008-01-31 13:03:55 +0100175 printk(KERN_INFO " cdb: ");
FUJITA Tomonorid34c87e2008-04-29 14:37:52 +0200176 for (bit = 0; bit < BLK_MAX_CDB; bit++)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 printk("%02x ", rq->cmd[bit]);
178 printk("\n");
179 }
180}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181EXPORT_SYMBOL(blk_dump_rq_flags);
182
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500183static void blk_delay_work(struct work_struct *work)
Jens Axboe6c5e0c42008-08-01 20:31:32 +0200184{
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500185 struct request_queue *q;
Jens Axboe6c5e0c42008-08-01 20:31:32 +0200186
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500187 q = container_of(work, struct request_queue, delay_work.work);
188 spin_lock_irq(q->queue_lock);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200189 __blk_run_queue(q);
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500190 spin_unlock_irq(q->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
193/**
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500194 * blk_delay_queue - restart queueing after defined interval
195 * @q: The &struct request_queue in question
196 * @msecs: Delay in msecs
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 *
198 * Description:
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500199 * Sometimes queueing needs to be postponed for a little while, to allow
200 * resources to come back. This function will make sure that queueing is
Bart Van Assche70460572012-11-28 13:45:56 +0100201 * restarted around the specified time. Queue lock must be held.
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500202 */
203void blk_delay_queue(struct request_queue *q, unsigned long msecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204{
Bart Van Assche70460572012-11-28 13:45:56 +0100205 if (likely(!blk_queue_dead(q)))
206 queue_delayed_work(kblockd_workqueue, &q->delay_work,
207 msecs_to_jiffies(msecs));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500209EXPORT_SYMBOL(blk_delay_queue);
Alan D. Brunelle2ad8b1e2007-11-07 14:26:56 -0500210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211/**
212 * blk_start_queue - restart a previously stopped queue
Jens Axboe165125e2007-07-24 09:28:11 +0200213 * @q: The &struct request_queue in question
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 *
215 * Description:
216 * blk_start_queue() will clear the stop flag on the queue, and call
217 * the request_fn for the queue if it was in a stopped state when
218 * entered. Also see blk_stop_queue(). Queue lock must be held.
219 **/
Jens Axboe165125e2007-07-24 09:28:11 +0200220void blk_start_queue(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
Paolo 'Blaisorblade' Giarrussoa038e252006-06-05 12:09:01 +0200222 WARN_ON(!irqs_disabled());
223
Nick Piggin75ad23b2008-04-29 14:48:33 +0200224 queue_flag_clear(QUEUE_FLAG_STOPPED, q);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200225 __blk_run_queue(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227EXPORT_SYMBOL(blk_start_queue);
228
229/**
230 * blk_stop_queue - stop a queue
Jens Axboe165125e2007-07-24 09:28:11 +0200231 * @q: The &struct request_queue in question
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 *
233 * Description:
234 * The Linux block layer assumes that a block driver will consume all
235 * entries on the request queue when the request_fn strategy is called.
236 * Often this will not happen, because of hardware limitations (queue
237 * depth settings). If a device driver gets a 'queue full' response,
238 * or if it simply chooses not to queue more I/O at one point, it can
239 * call this function to prevent the request_fn from being called until
240 * the driver has signalled it's ready to go again. This happens by calling
241 * blk_start_queue() to restart queue operations. Queue lock must be held.
242 **/
Jens Axboe165125e2007-07-24 09:28:11 +0200243void blk_stop_queue(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
Tejun Heo136b5722012-08-21 13:18:24 -0700245 cancel_delayed_work(&q->delay_work);
Nick Piggin75ad23b2008-04-29 14:48:33 +0200246 queue_flag_set(QUEUE_FLAG_STOPPED, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247}
248EXPORT_SYMBOL(blk_stop_queue);
249
250/**
251 * blk_sync_queue - cancel any pending callbacks on a queue
252 * @q: the queue
253 *
254 * Description:
255 * The block layer may perform asynchronous callback activity
256 * on a queue, such as calling the unplug function after a timeout.
257 * A block device may call blk_sync_queue to ensure that any
258 * such activity is cancelled, thus allowing it to release resources
Michael Opdenacker59c51592007-05-09 08:57:56 +0200259 * that the callbacks might use. The caller must already have made sure
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 * that its ->make_request_fn will not re-add plugging prior to calling
261 * this function.
262 *
Vivek Goyalda527772011-03-02 19:05:33 -0500263 * This function does not cancel any asynchronous activity arising
Masanari Iidada3dae52014-09-09 01:27:23 +0900264 * out of elevator or throttling code. That would require elevator_exit()
Tejun Heo5efd6112012-03-05 13:15:12 -0800265 * and blkcg_exit_queue() to be called with queue lock initialized.
Vivek Goyalda527772011-03-02 19:05:33 -0500266 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 */
268void blk_sync_queue(struct request_queue *q)
269{
Jens Axboe70ed28b2008-11-19 14:38:39 +0100270 del_timer_sync(&q->timeout);
Ming Leif04c1fe2013-12-26 21:31:36 +0800271
272 if (q->mq_ops) {
273 struct blk_mq_hw_ctx *hctx;
274 int i;
275
Christoph Hellwig70f4db62014-04-16 10:48:08 -0600276 queue_for_each_hw_ctx(q, hctx, i) {
277 cancel_delayed_work_sync(&hctx->run_work);
278 cancel_delayed_work_sync(&hctx->delay_work);
279 }
Ming Leif04c1fe2013-12-26 21:31:36 +0800280 } else {
281 cancel_delayed_work_sync(&q->delay_work);
282 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283}
284EXPORT_SYMBOL(blk_sync_queue);
285
286/**
Bart Van Asschec246e802012-12-06 14:32:01 +0100287 * __blk_run_queue_uncond - run a queue whether or not it has been stopped
288 * @q: The queue to run
289 *
290 * Description:
291 * Invoke request handling on a queue if there are any pending requests.
292 * May be used to restart request handling after a request has completed.
293 * This variant runs the queue whether or not the queue has been
294 * stopped. Must be called with the queue lock held and interrupts
295 * disabled. See also @blk_run_queue.
296 */
297inline void __blk_run_queue_uncond(struct request_queue *q)
298{
299 if (unlikely(blk_queue_dead(q)))
300 return;
301
Bart Van Assche24faf6f2012-11-28 13:46:45 +0100302 /*
303 * Some request_fn implementations, e.g. scsi_request_fn(), unlock
304 * the queue lock internally. As a result multiple threads may be
305 * running such a request function concurrently. Keep track of the
306 * number of active request_fn invocations such that blk_drain_queue()
307 * can wait until all these request_fn calls have finished.
308 */
309 q->request_fn_active++;
Bart Van Asschec246e802012-12-06 14:32:01 +0100310 q->request_fn(q);
Bart Van Assche24faf6f2012-11-28 13:46:45 +0100311 q->request_fn_active--;
Bart Van Asschec246e802012-12-06 14:32:01 +0100312}
Christoph Hellwiga7928c12015-04-17 22:37:20 +0200313EXPORT_SYMBOL_GPL(__blk_run_queue_uncond);
Bart Van Asschec246e802012-12-06 14:32:01 +0100314
315/**
Jens Axboe80a4b582008-10-14 09:51:06 +0200316 * __blk_run_queue - run a single device queue
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 * @q: The queue to run
Jens Axboe80a4b582008-10-14 09:51:06 +0200318 *
319 * Description:
320 * See @blk_run_queue. This variant must be called with the queue lock
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200321 * held and interrupts disabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 */
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200323void __blk_run_queue(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324{
Tejun Heoa538cd02009-04-23 11:05:17 +0900325 if (unlikely(blk_queue_stopped(q)))
326 return;
327
Bart Van Asschec246e802012-12-06 14:32:01 +0100328 __blk_run_queue_uncond(q);
Nick Piggin75ad23b2008-04-29 14:48:33 +0200329}
330EXPORT_SYMBOL(__blk_run_queue);
Jens Axboedac07ec2006-05-11 08:20:16 +0200331
Nick Piggin75ad23b2008-04-29 14:48:33 +0200332/**
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200333 * blk_run_queue_async - run a single device queue in workqueue context
334 * @q: The queue to run
335 *
336 * Description:
337 * Tells kblockd to perform the equivalent of @blk_run_queue on behalf
Bart Van Assche70460572012-11-28 13:45:56 +0100338 * of us. The caller must hold the queue lock.
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200339 */
340void blk_run_queue_async(struct request_queue *q)
341{
Bart Van Assche70460572012-11-28 13:45:56 +0100342 if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q)))
Tejun Heoe7c2f962012-08-21 13:18:24 -0700343 mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200344}
Jens Axboec21e6be2011-04-19 13:32:46 +0200345EXPORT_SYMBOL(blk_run_queue_async);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200346
347/**
Nick Piggin75ad23b2008-04-29 14:48:33 +0200348 * blk_run_queue - run a single device queue
349 * @q: The queue to run
Jens Axboe80a4b582008-10-14 09:51:06 +0200350 *
351 * Description:
352 * Invoke request handling on this queue, if it has pending work to do.
Tejun Heoa7f55792009-04-23 11:05:17 +0900353 * May be used to restart queueing when a request has completed.
Nick Piggin75ad23b2008-04-29 14:48:33 +0200354 */
355void blk_run_queue(struct request_queue *q)
356{
357 unsigned long flags;
358
359 spin_lock_irqsave(q->queue_lock, flags);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +0200360 __blk_run_queue(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 spin_unlock_irqrestore(q->queue_lock, flags);
362}
363EXPORT_SYMBOL(blk_run_queue);
364
Jens Axboe165125e2007-07-24 09:28:11 +0200365void blk_put_queue(struct request_queue *q)
Al Viro483f4af2006-03-18 18:34:37 -0500366{
367 kobject_put(&q->kobj);
368}
Jens Axboed86e0e82011-05-27 07:44:43 +0200369EXPORT_SYMBOL(blk_put_queue);
Al Viro483f4af2006-03-18 18:34:37 -0500370
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200371/**
Bart Van Assche807592a2012-11-28 13:43:38 +0100372 * __blk_drain_queue - drain requests from request_queue
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200373 * @q: queue to drain
Tejun Heoc9a929d2011-10-19 14:42:16 +0200374 * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200375 *
Tejun Heoc9a929d2011-10-19 14:42:16 +0200376 * Drain requests from @q. If @drain_all is set, all requests are drained.
377 * If not, only ELVPRIV requests are drained. The caller is responsible
378 * for ensuring that no new requests which need to be drained are queued.
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200379 */
Bart Van Assche807592a2012-11-28 13:43:38 +0100380static void __blk_drain_queue(struct request_queue *q, bool drain_all)
381 __releases(q->queue_lock)
382 __acquires(q->queue_lock)
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200383{
Asias He458f27a2012-06-15 08:45:25 +0200384 int i;
385
Bart Van Assche807592a2012-11-28 13:43:38 +0100386 lockdep_assert_held(q->queue_lock);
387
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200388 while (true) {
Tejun Heo481a7d62011-12-14 00:33:37 +0100389 bool drain = false;
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200390
Tejun Heob855b042012-03-06 21:24:55 +0100391 /*
392 * The caller might be trying to drain @q before its
393 * elevator is initialized.
394 */
395 if (q->elevator)
396 elv_drain_elevator(q);
397
Tejun Heo5efd6112012-03-05 13:15:12 -0800398 blkcg_drain_queue(q);
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200399
Tejun Heo4eabc942011-12-15 20:03:04 +0100400 /*
401 * This function might be called on a queue which failed
Tejun Heob855b042012-03-06 21:24:55 +0100402 * driver init after queue creation or is not yet fully
403 * active yet. Some drivers (e.g. fd and loop) get unhappy
404 * in such cases. Kick queue iff dispatch queue has
405 * something on it and @q has request_fn set.
Tejun Heo4eabc942011-12-15 20:03:04 +0100406 */
Tejun Heob855b042012-03-06 21:24:55 +0100407 if (!list_empty(&q->queue_head) && q->request_fn)
Tejun Heo4eabc942011-12-15 20:03:04 +0100408 __blk_run_queue(q);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200409
Tejun Heo8a5ecdd2012-06-04 20:40:58 -0700410 drain |= q->nr_rqs_elvpriv;
Bart Van Assche24faf6f2012-11-28 13:46:45 +0100411 drain |= q->request_fn_active;
Tejun Heo481a7d62011-12-14 00:33:37 +0100412
413 /*
414 * Unfortunately, requests are queued at and tracked from
415 * multiple places and there's no single counter which can
416 * be drained. Check all the queues and counters.
417 */
418 if (drain_all) {
Ming Leie97c2932014-09-25 23:23:46 +0800419 struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
Tejun Heo481a7d62011-12-14 00:33:37 +0100420 drain |= !list_empty(&q->queue_head);
421 for (i = 0; i < 2; i++) {
Tejun Heo8a5ecdd2012-06-04 20:40:58 -0700422 drain |= q->nr_rqs[i];
Tejun Heo481a7d62011-12-14 00:33:37 +0100423 drain |= q->in_flight[i];
Ming Lei7c94e1c2014-09-25 23:23:43 +0800424 if (fq)
425 drain |= !list_empty(&fq->flush_queue[i]);
Tejun Heo481a7d62011-12-14 00:33:37 +0100426 }
427 }
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200428
Tejun Heo481a7d62011-12-14 00:33:37 +0100429 if (!drain)
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200430 break;
Bart Van Assche807592a2012-11-28 13:43:38 +0100431
432 spin_unlock_irq(q->queue_lock);
433
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200434 msleep(10);
Bart Van Assche807592a2012-11-28 13:43:38 +0100435
436 spin_lock_irq(q->queue_lock);
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200437 }
Asias He458f27a2012-06-15 08:45:25 +0200438
439 /*
440 * With queue marked dead, any woken up waiter will fail the
441 * allocation path, so the wakeup chaining is lost and we're
442 * left with hung waiters. We need to wake up those waiters.
443 */
444 if (q->request_fn) {
Tejun Heoa0516612012-06-26 15:05:44 -0700445 struct request_list *rl;
446
Tejun Heoa0516612012-06-26 15:05:44 -0700447 blk_queue_for_each_rl(rl, q)
448 for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
449 wake_up_all(&rl->wait[i]);
Asias He458f27a2012-06-15 08:45:25 +0200450 }
Tejun Heoe3c78ca2011-10-19 14:32:38 +0200451}
452
Tejun Heoc9a929d2011-10-19 14:42:16 +0200453/**
Tejun Heod7325802012-03-05 13:14:58 -0800454 * blk_queue_bypass_start - enter queue bypass mode
455 * @q: queue of interest
456 *
457 * In bypass mode, only the dispatch FIFO queue of @q is used. This
458 * function makes @q enter bypass mode and drains all requests which were
Tejun Heo6ecf23a2012-03-05 13:14:59 -0800459 * throttled or issued before. On return, it's guaranteed that no request
Tejun Heo80fd9972012-04-13 14:50:53 -0700460 * is being throttled or has ELVPRIV set and blk_queue_bypass() %true
461 * inside queue or RCU read lock.
Tejun Heod7325802012-03-05 13:14:58 -0800462 */
463void blk_queue_bypass_start(struct request_queue *q)
464{
465 spin_lock_irq(q->queue_lock);
Tejun Heo776687b2014-07-01 10:29:17 -0600466 q->bypass_depth++;
Tejun Heod7325802012-03-05 13:14:58 -0800467 queue_flag_set(QUEUE_FLAG_BYPASS, q);
468 spin_unlock_irq(q->queue_lock);
469
Tejun Heo776687b2014-07-01 10:29:17 -0600470 /*
471 * Queues start drained. Skip actual draining till init is
472 * complete. This avoids lenghty delays during queue init which
473 * can happen many times during boot.
474 */
475 if (blk_queue_init_done(q)) {
Bart Van Assche807592a2012-11-28 13:43:38 +0100476 spin_lock_irq(q->queue_lock);
477 __blk_drain_queue(q, false);
478 spin_unlock_irq(q->queue_lock);
479
Tejun Heob82d4b12012-04-13 13:11:31 -0700480 /* ensure blk_queue_bypass() is %true inside RCU read lock */
481 synchronize_rcu();
482 }
Tejun Heod7325802012-03-05 13:14:58 -0800483}
484EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
485
486/**
487 * blk_queue_bypass_end - leave queue bypass mode
488 * @q: queue of interest
489 *
490 * Leave bypass mode and restore the normal queueing behavior.
491 */
492void blk_queue_bypass_end(struct request_queue *q)
493{
494 spin_lock_irq(q->queue_lock);
495 if (!--q->bypass_depth)
496 queue_flag_clear(QUEUE_FLAG_BYPASS, q);
497 WARN_ON_ONCE(q->bypass_depth < 0);
498 spin_unlock_irq(q->queue_lock);
499}
500EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
501
Jens Axboeaed3ea92014-12-22 14:04:42 -0700502void blk_set_queue_dying(struct request_queue *q)
503{
504 queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
505
506 if (q->mq_ops)
507 blk_mq_wake_waiters(q);
508 else {
509 struct request_list *rl;
510
511 blk_queue_for_each_rl(rl, q) {
512 if (rl->rq_pool) {
513 wake_up(&rl->wait[BLK_RW_SYNC]);
514 wake_up(&rl->wait[BLK_RW_ASYNC]);
515 }
516 }
517 }
518}
519EXPORT_SYMBOL_GPL(blk_set_queue_dying);
520
Tejun Heod7325802012-03-05 13:14:58 -0800521/**
Tejun Heoc9a929d2011-10-19 14:42:16 +0200522 * blk_cleanup_queue - shutdown a request queue
523 * @q: request queue to shutdown
524 *
Bart Van Asschec246e802012-12-06 14:32:01 +0100525 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
526 * put it. All future requests will be failed immediately with -ENODEV.
Vivek Goyalc94a96a2011-03-02 19:04:42 -0500527 */
Jens Axboe6728cb02008-01-31 13:03:55 +0100528void blk_cleanup_queue(struct request_queue *q)
Al Viro483f4af2006-03-18 18:34:37 -0500529{
Tejun Heoc9a929d2011-10-19 14:42:16 +0200530 spinlock_t *lock = q->queue_lock;
Jens Axboee3335de92008-09-18 09:22:54 -0700531
Bart Van Assche3f3299d2012-11-28 13:42:38 +0100532 /* mark @q DYING, no new request or merges will be allowed afterwards */
Al Viro483f4af2006-03-18 18:34:37 -0500533 mutex_lock(&q->sysfs_lock);
Jens Axboeaed3ea92014-12-22 14:04:42 -0700534 blk_set_queue_dying(q);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200535 spin_lock_irq(lock);
Tejun Heo6ecf23a2012-03-05 13:14:59 -0800536
Tejun Heo80fd9972012-04-13 14:50:53 -0700537 /*
Bart Van Assche3f3299d2012-11-28 13:42:38 +0100538 * A dying queue is permanently in bypass mode till released. Note
Tejun Heo80fd9972012-04-13 14:50:53 -0700539 * that, unlike blk_queue_bypass_start(), we aren't performing
540 * synchronize_rcu() after entering bypass mode to avoid the delay
541 * as some drivers create and destroy a lot of queues while
542 * probing. This is still safe because blk_release_queue() will be
543 * called only after the queue refcnt drops to zero and nothing,
544 * RCU or not, would be traversing the queue by then.
545 */
Tejun Heo6ecf23a2012-03-05 13:14:59 -0800546 q->bypass_depth++;
547 queue_flag_set(QUEUE_FLAG_BYPASS, q);
548
Tejun Heoc9a929d2011-10-19 14:42:16 +0200549 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
550 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
Bart Van Assche3f3299d2012-11-28 13:42:38 +0100551 queue_flag_set(QUEUE_FLAG_DYING, q);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200552 spin_unlock_irq(lock);
553 mutex_unlock(&q->sysfs_lock);
554
Bart Van Asschec246e802012-12-06 14:32:01 +0100555 /*
556 * Drain all requests queued before DYING marking. Set DEAD flag to
557 * prevent that q->request_fn() gets invoked after draining finished.
558 */
Ming Lei43a5e4e2013-12-26 21:31:35 +0800559 if (q->mq_ops) {
Tejun Heo780db202014-07-01 10:31:13 -0600560 blk_mq_freeze_queue(q);
Ming Lei43a5e4e2013-12-26 21:31:35 +0800561 spin_lock_irq(lock);
562 } else {
563 spin_lock_irq(lock);
564 __blk_drain_queue(q, true);
565 }
Bart Van Asschec246e802012-12-06 14:32:01 +0100566 queue_flag_set(QUEUE_FLAG_DEAD, q);
Bart Van Assche807592a2012-11-28 13:43:38 +0100567 spin_unlock_irq(lock);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200568
569 /* @q won't process any more request, flush async actions */
570 del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
571 blk_sync_queue(q);
572
Bart Van Assche45a9c9d2014-12-09 16:57:48 +0100573 if (q->mq_ops)
574 blk_mq_free_queue(q);
575
Asias He5e5cfac2012-05-24 23:28:52 +0800576 spin_lock_irq(lock);
577 if (q->queue_lock != &q->__queue_lock)
578 q->queue_lock = &q->__queue_lock;
579 spin_unlock_irq(lock);
580
NeilBrown6cd18e72015-04-27 14:12:22 +1000581 bdi_destroy(&q->backing_dev_info);
582
Tejun Heoc9a929d2011-10-19 14:42:16 +0200583 /* @q is and will stay empty, shutdown and put */
Al Viro483f4af2006-03-18 18:34:37 -0500584 blk_put_queue(q);
585}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586EXPORT_SYMBOL(blk_cleanup_queue);
587
David Rientjes271508d2015-03-24 16:21:16 -0700588/* Allocate memory local to the request queue */
589static void *alloc_request_struct(gfp_t gfp_mask, void *data)
590{
591 int nid = (int)(long)data;
592 return kmem_cache_alloc_node(request_cachep, gfp_mask, nid);
593}
594
595static void free_request_struct(void *element, void *unused)
596{
597 kmem_cache_free(request_cachep, element);
598}
599
Tejun Heo5b788ce2012-06-04 20:40:59 -0700600int blk_init_rl(struct request_list *rl, struct request_queue *q,
601 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602{
Mike Snitzer1abec4f2010-05-25 13:15:15 -0400603 if (unlikely(rl->rq_pool))
604 return 0;
605
Tejun Heo5b788ce2012-06-04 20:40:59 -0700606 rl->q = q;
Jens Axboe1faa16d2009-04-06 14:48:01 +0200607 rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
608 rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
Jens Axboe1faa16d2009-04-06 14:48:01 +0200609 init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
610 init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611
David Rientjes271508d2015-03-24 16:21:16 -0700612 rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct,
613 free_request_struct,
614 (void *)(long)q->node, gfp_mask,
615 q->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (!rl->rq_pool)
617 return -ENOMEM;
618
619 return 0;
620}
621
Tejun Heo5b788ce2012-06-04 20:40:59 -0700622void blk_exit_rl(struct request_list *rl)
623{
624 if (rl->rq_pool)
625 mempool_destroy(rl->rq_pool);
626}
627
Jens Axboe165125e2007-07-24 09:28:11 +0200628struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629{
Ezequiel Garciac304a512012-11-10 10:39:44 +0100630 return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE);
Christoph Lameter19460892005-06-23 00:08:19 -0700631}
632EXPORT_SYMBOL(blk_alloc_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633
Jens Axboe165125e2007-07-24 09:28:11 +0200634struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
Christoph Lameter19460892005-06-23 00:08:19 -0700635{
Jens Axboe165125e2007-07-24 09:28:11 +0200636 struct request_queue *q;
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700637 int err;
Christoph Lameter19460892005-06-23 00:08:19 -0700638
Jens Axboe8324aa92008-01-29 14:51:59 +0100639 q = kmem_cache_alloc_node(blk_requestq_cachep,
Christoph Lameter94f60302007-07-17 04:03:29 -0700640 gfp_mask | __GFP_ZERO, node_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 if (!q)
642 return NULL;
643
Dan Carpenter00380a42012-03-23 09:58:54 +0100644 q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
Tejun Heoa73f7302011-12-14 00:33:37 +0100645 if (q->id < 0)
Ming Lei3d2936f2014-05-27 23:35:14 +0800646 goto fail_q;
Tejun Heoa73f7302011-12-14 00:33:37 +0100647
Jens Axboe0989a022009-06-12 14:42:56 +0200648 q->backing_dev_info.ra_pages =
649 (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
Tejun Heo89e9b9e2015-05-22 17:13:36 -0400650 q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
Jens Axboed9938312009-06-12 14:45:52 +0200651 q->backing_dev_info.name = "block";
Mike Snitzer51514122011-11-23 10:59:13 +0100652 q->node = node_id;
Jens Axboe0989a022009-06-12 14:42:56 +0200653
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700654 err = bdi_init(&q->backing_dev_info);
Tejun Heoa73f7302011-12-14 00:33:37 +0100655 if (err)
656 goto fail_id;
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700657
Matthew Garrett31373d02010-04-06 14:25:14 +0200658 setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
659 laptop_mode_timer_fn, (unsigned long) q);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700660 setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
Tejun Heob855b042012-03-06 21:24:55 +0100661 INIT_LIST_HEAD(&q->queue_head);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700662 INIT_LIST_HEAD(&q->timeout_list);
Tejun Heoa612fdd2011-12-14 00:33:41 +0100663 INIT_LIST_HEAD(&q->icq_list);
Tejun Heo4eef3042012-03-05 13:15:18 -0800664#ifdef CONFIG_BLK_CGROUP
Tejun Heoe8989fa2012-03-05 13:15:20 -0800665 INIT_LIST_HEAD(&q->blkg_list);
Tejun Heo4eef3042012-03-05 13:15:18 -0800666#endif
Jens Axboe3cca6dc2011-03-02 11:08:00 -0500667 INIT_DELAYED_WORK(&q->delay_work, blk_delay_work);
Al Viro483f4af2006-03-18 18:34:37 -0500668
Jens Axboe8324aa92008-01-29 14:51:59 +0100669 kobject_init(&q->kobj, &blk_queue_ktype);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670
Al Viro483f4af2006-03-18 18:34:37 -0500671 mutex_init(&q->sysfs_lock);
Neil Browne7e72bf2008-05-14 16:05:54 -0700672 spin_lock_init(&q->__queue_lock);
Al Viro483f4af2006-03-18 18:34:37 -0500673
Vivek Goyalc94a96a2011-03-02 19:04:42 -0500674 /*
675 * By default initialize queue_lock to internal lock and driver can
676 * override it later if need be.
677 */
678 q->queue_lock = &q->__queue_lock;
679
Tejun Heob82d4b12012-04-13 13:11:31 -0700680 /*
681 * A queue starts its life with bypass turned on to avoid
682 * unnecessary bypass on/off overhead and nasty surprises during
Tejun Heo749fefe2012-09-20 14:08:52 -0700683 * init. The initial bypass will be finished when the queue is
684 * registered by blk_register_queue().
Tejun Heob82d4b12012-04-13 13:11:31 -0700685 */
686 q->bypass_depth = 1;
687 __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
688
Jens Axboe320ae512013-10-24 09:20:05 +0100689 init_waitqueue_head(&q->mq_freeze_wq);
690
Tejun Heo5efd6112012-03-05 13:15:12 -0800691 if (blkcg_init_queue(q))
Mikulas Patockafff49962013-10-14 12:11:36 -0400692 goto fail_bdi;
Tejun Heof51b8022012-03-05 13:15:05 -0800693
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 return q;
Tejun Heoa73f7302011-12-14 00:33:37 +0100695
Mikulas Patockafff49962013-10-14 12:11:36 -0400696fail_bdi:
697 bdi_destroy(&q->backing_dev_info);
Tejun Heoa73f7302011-12-14 00:33:37 +0100698fail_id:
699 ida_simple_remove(&blk_queue_ida, q->id);
700fail_q:
701 kmem_cache_free(blk_requestq_cachep, q);
702 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703}
Christoph Lameter19460892005-06-23 00:08:19 -0700704EXPORT_SYMBOL(blk_alloc_queue_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705
706/**
707 * blk_init_queue - prepare a request queue for use with a block device
708 * @rfn: The function to be called to process requests that have been
709 * placed on the queue.
710 * @lock: Request queue spin lock
711 *
712 * Description:
713 * If a block device wishes to use the standard request handling procedures,
714 * which sorts requests and coalesces adjacent requests, then it must
715 * call blk_init_queue(). The function @rfn will be called when there
716 * are requests on the queue that need to be processed. If the device
717 * supports plugging, then @rfn may not be called immediately when requests
718 * are available on the queue, but may be called at some time later instead.
719 * Plugged queues are generally unplugged when a buffer belonging to one
720 * of the requests on the queue is needed, or due to memory pressure.
721 *
722 * @rfn is not required, or even expected, to remove all requests off the
723 * queue, but only as many as it can handle at a time. If it does leave
724 * requests on the queue, it is responsible for arranging that the requests
725 * get dealt with eventually.
726 *
727 * The queue spin lock must be held while manipulating the requests on the
Paolo 'Blaisorblade' Giarrussoa038e252006-06-05 12:09:01 +0200728 * request queue; this lock will be taken also from interrupt context, so irq
729 * disabling is needed for it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 *
Randy Dunlap710027a2008-08-19 20:13:11 +0200731 * Function returns a pointer to the initialized request queue, or %NULL if
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 * it didn't succeed.
733 *
734 * Note:
735 * blk_init_queue() must be paired with a blk_cleanup_queue() call
736 * when the block device is deactivated (such as at module unload).
737 **/
Christoph Lameter19460892005-06-23 00:08:19 -0700738
Jens Axboe165125e2007-07-24 09:28:11 +0200739struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740{
Ezequiel Garciac304a512012-11-10 10:39:44 +0100741 return blk_init_queue_node(rfn, lock, NUMA_NO_NODE);
Christoph Lameter19460892005-06-23 00:08:19 -0700742}
743EXPORT_SYMBOL(blk_init_queue);
744
Jens Axboe165125e2007-07-24 09:28:11 +0200745struct request_queue *
Christoph Lameter19460892005-06-23 00:08:19 -0700746blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
747{
Mike Snitzerc86d1b82010-06-03 11:34:52 -0600748 struct request_queue *uninit_q, *q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749
Mike Snitzerc86d1b82010-06-03 11:34:52 -0600750 uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
751 if (!uninit_q)
752 return NULL;
753
Mike Snitzer51514122011-11-23 10:59:13 +0100754 q = blk_init_allocated_queue(uninit_q, rfn, lock);
Mike Snitzerc86d1b82010-06-03 11:34:52 -0600755 if (!q)
Mike Snitzer7982e902014-03-08 17:20:01 -0700756 blk_cleanup_queue(uninit_q);
Christoph Hellwig18741982014-02-10 09:29:00 -0700757
Mike Snitzer7982e902014-03-08 17:20:01 -0700758 return q;
Mike Snitzer01effb02010-05-11 08:57:42 +0200759}
760EXPORT_SYMBOL(blk_init_queue_node);
761
Mike Snitzer336b7e12015-05-11 14:06:32 -0400762static void blk_queue_bio(struct request_queue *q, struct bio *bio);
763
Mike Snitzer01effb02010-05-11 08:57:42 +0200764struct request_queue *
765blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
766 spinlock_t *lock)
767{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 if (!q)
769 return NULL;
770
Ming Leif70ced02014-09-25 23:23:47 +0800771 q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0);
Ming Leiba483382014-09-25 23:23:44 +0800772 if (!q->fq)
Mike Snitzer7982e902014-03-08 17:20:01 -0700773 return NULL;
774
Tejun Heoa0516612012-06-26 15:05:44 -0700775 if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
Dave Jones708f04d2014-03-20 15:03:58 -0600776 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778 q->request_fn = rfn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 q->prep_rq_fn = NULL;
James Bottomley28018c22010-07-01 19:49:17 +0900780 q->unprep_rq_fn = NULL;
Tejun Heo60ea8222012-09-20 14:09:30 -0700781 q->queue_flags |= QUEUE_FLAG_DEFAULT;
Vivek Goyalc94a96a2011-03-02 19:04:42 -0500782
783 /* Override internal queue lock with supplied lock pointer */
784 if (lock)
785 q->queue_lock = lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786
Jens Axboef3b144a2009-03-06 08:48:33 +0100787 /*
788 * This also sets hw/phys segments, boundary and size
789 */
Jens Axboec20e8de2011-09-12 12:03:37 +0200790 blk_queue_make_request(q, blk_queue_bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791
Alan Stern44ec9542007-02-20 11:01:57 -0500792 q->sg_reserved_size = INT_MAX;
793
Tomoki Sekiyamaeb1c1602013-10-15 16:42:16 -0600794 /* Protect q->elevator from elevator_change */
795 mutex_lock(&q->sysfs_lock);
796
Tejun Heob82d4b12012-04-13 13:11:31 -0700797 /* init elevator */
Tomoki Sekiyamaeb1c1602013-10-15 16:42:16 -0600798 if (elevator_init(q, NULL)) {
799 mutex_unlock(&q->sysfs_lock);
Dave Jones708f04d2014-03-20 15:03:58 -0600800 goto fail;
Tomoki Sekiyamaeb1c1602013-10-15 16:42:16 -0600801 }
802
803 mutex_unlock(&q->sysfs_lock);
804
Tejun Heob82d4b12012-04-13 13:11:31 -0700805 return q;
Dave Jones708f04d2014-03-20 15:03:58 -0600806
807fail:
Ming Leiba483382014-09-25 23:23:44 +0800808 blk_free_flush_queue(q->fq);
Dave Jones708f04d2014-03-20 15:03:58 -0600809 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810}
Mike Snitzer51514122011-11-23 10:59:13 +0100811EXPORT_SYMBOL(blk_init_allocated_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812
Tejun Heo09ac46c2011-12-14 00:33:38 +0100813bool blk_get_queue(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814{
Bart Van Assche3f3299d2012-11-28 13:42:38 +0100815 if (likely(!blk_queue_dying(q))) {
Tejun Heo09ac46c2011-12-14 00:33:38 +0100816 __blk_get_queue(q);
817 return true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 }
819
Tejun Heo09ac46c2011-12-14 00:33:38 +0100820 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821}
Jens Axboed86e0e82011-05-27 07:44:43 +0200822EXPORT_SYMBOL(blk_get_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823
Tejun Heo5b788ce2012-06-04 20:40:59 -0700824static inline void blk_free_request(struct request_list *rl, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825{
Tejun Heof1f8cc92011-12-14 00:33:42 +0100826 if (rq->cmd_flags & REQ_ELVPRIV) {
Tejun Heo5b788ce2012-06-04 20:40:59 -0700827 elv_put_request(rl->q, rq);
Tejun Heof1f8cc92011-12-14 00:33:42 +0100828 if (rq->elv.icq)
Tejun Heo11a31222012-02-07 07:51:30 +0100829 put_io_context(rq->elv.icq->ioc);
Tejun Heof1f8cc92011-12-14 00:33:42 +0100830 }
831
Tejun Heo5b788ce2012-06-04 20:40:59 -0700832 mempool_free(rq, rl->rq_pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833}
834
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835/*
836 * ioc_batching returns true if the ioc is a valid batching request and
837 * should be given priority access to a request.
838 */
Jens Axboe165125e2007-07-24 09:28:11 +0200839static inline int ioc_batching(struct request_queue *q, struct io_context *ioc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840{
841 if (!ioc)
842 return 0;
843
844 /*
845 * Make sure the process is able to allocate at least 1 request
846 * even if the batch times out, otherwise we could theoretically
847 * lose wakeups.
848 */
849 return ioc->nr_batch_requests == q->nr_batching ||
850 (ioc->nr_batch_requests > 0
851 && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
852}
853
854/*
855 * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
856 * will cause the process to be a "batcher" on all queues in the system. This
857 * is the behaviour we want though - once it gets a wakeup it should be given
858 * a nice run.
859 */
Jens Axboe165125e2007-07-24 09:28:11 +0200860static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861{
862 if (!ioc || ioc_batching(q, ioc))
863 return;
864
865 ioc->nr_batch_requests = q->nr_batching;
866 ioc->last_waited = jiffies;
867}
868
Tejun Heo5b788ce2012-06-04 20:40:59 -0700869static void __freed_request(struct request_list *rl, int sync)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870{
Tejun Heo5b788ce2012-06-04 20:40:59 -0700871 struct request_queue *q = rl->q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872
Tejun Heod40f75a2015-05-22 17:13:42 -0400873 if (rl->count[sync] < queue_congestion_off_threshold(q))
874 blk_clear_congested(rl, sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875
Jens Axboe1faa16d2009-04-06 14:48:01 +0200876 if (rl->count[sync] + 1 <= q->nr_requests) {
877 if (waitqueue_active(&rl->wait[sync]))
878 wake_up(&rl->wait[sync]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879
Tejun Heo5b788ce2012-06-04 20:40:59 -0700880 blk_clear_rl_full(rl, sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 }
882}
883
884/*
885 * A request has just been released. Account for it, update the full and
886 * congestion status, wake up any waiters. Called under q->queue_lock.
887 */
Tejun Heo5b788ce2012-06-04 20:40:59 -0700888static void freed_request(struct request_list *rl, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889{
Tejun Heo5b788ce2012-06-04 20:40:59 -0700890 struct request_queue *q = rl->q;
Tejun Heo75eb6c32011-10-19 14:31:22 +0200891 int sync = rw_is_sync(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892
Tejun Heo8a5ecdd2012-06-04 20:40:58 -0700893 q->nr_rqs[sync]--;
Jens Axboe1faa16d2009-04-06 14:48:01 +0200894 rl->count[sync]--;
Tejun Heo75eb6c32011-10-19 14:31:22 +0200895 if (flags & REQ_ELVPRIV)
Tejun Heo8a5ecdd2012-06-04 20:40:58 -0700896 q->nr_rqs_elvpriv--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
Tejun Heo5b788ce2012-06-04 20:40:59 -0700898 __freed_request(rl, sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899
Jens Axboe1faa16d2009-04-06 14:48:01 +0200900 if (unlikely(rl->starved[sync ^ 1]))
Tejun Heo5b788ce2012-06-04 20:40:59 -0700901 __freed_request(rl, sync ^ 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902}
903
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600904int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
905{
906 struct request_list *rl;
Tejun Heod40f75a2015-05-22 17:13:42 -0400907 int on_thresh, off_thresh;
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600908
909 spin_lock_irq(q->queue_lock);
910 q->nr_requests = nr;
911 blk_queue_congestion_threshold(q);
Tejun Heod40f75a2015-05-22 17:13:42 -0400912 on_thresh = queue_congestion_on_threshold(q);
913 off_thresh = queue_congestion_off_threshold(q);
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600914
915 blk_queue_for_each_rl(rl, q) {
Tejun Heod40f75a2015-05-22 17:13:42 -0400916 if (rl->count[BLK_RW_SYNC] >= on_thresh)
917 blk_set_congested(rl, BLK_RW_SYNC);
918 else if (rl->count[BLK_RW_SYNC] < off_thresh)
919 blk_clear_congested(rl, BLK_RW_SYNC);
920
921 if (rl->count[BLK_RW_ASYNC] >= on_thresh)
922 blk_set_congested(rl, BLK_RW_ASYNC);
923 else if (rl->count[BLK_RW_ASYNC] < off_thresh)
924 blk_clear_congested(rl, BLK_RW_ASYNC);
925
Jens Axboee3a2b3f2014-05-20 11:49:02 -0600926 if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
927 blk_set_rl_full(rl, BLK_RW_SYNC);
928 } else {
929 blk_clear_rl_full(rl, BLK_RW_SYNC);
930 wake_up(&rl->wait[BLK_RW_SYNC]);
931 }
932
933 if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
934 blk_set_rl_full(rl, BLK_RW_ASYNC);
935 } else {
936 blk_clear_rl_full(rl, BLK_RW_ASYNC);
937 wake_up(&rl->wait[BLK_RW_ASYNC]);
938 }
939 }
940
941 spin_unlock_irq(q->queue_lock);
942 return 0;
943}
944
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945/*
Mike Snitzer9d5a4e92011-02-11 11:05:46 +0100946 * Determine if elevator data should be initialized when allocating the
947 * request associated with @bio.
948 */
949static bool blk_rq_should_init_elevator(struct bio *bio)
950{
951 if (!bio)
952 return true;
953
954 /*
955 * Flush requests do not use the elevator so skip initialization.
956 * This allows a request to share the flush and elevator data.
957 */
958 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA))
959 return false;
960
961 return true;
962}
963
Tejun Heoda8303c2011-10-19 14:33:05 +0200964/**
Tejun Heo852c7882012-03-05 13:15:27 -0800965 * rq_ioc - determine io_context for request allocation
966 * @bio: request being allocated is for this bio (can be %NULL)
967 *
968 * Determine io_context to use for request allocation for @bio. May return
969 * %NULL if %current->io_context doesn't exist.
970 */
971static struct io_context *rq_ioc(struct bio *bio)
972{
973#ifdef CONFIG_BLK_CGROUP
974 if (bio && bio->bi_ioc)
975 return bio->bi_ioc;
976#endif
977 return current->io_context;
978}
979
980/**
Tejun Heoa06e05e2012-06-04 20:40:55 -0700981 * __get_request - get a free request
Tejun Heo5b788ce2012-06-04 20:40:59 -0700982 * @rl: request list to allocate from
Tejun Heoda8303c2011-10-19 14:33:05 +0200983 * @rw_flags: RW and SYNC flags
984 * @bio: bio to allocate request for (can be %NULL)
985 * @gfp_mask: allocation mask
986 *
987 * Get a free request from @q. This function may fail under memory
988 * pressure or if @q is dead.
989 *
Masanari Iidada3dae52014-09-09 01:27:23 +0900990 * Must be called with @q->queue_lock held and,
Joe Lawrencea492f072014-08-28 08:15:21 -0600991 * Returns ERR_PTR on failure, with @q->queue_lock held.
992 * Returns request pointer on success, with @q->queue_lock *not held*.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 */
Tejun Heo5b788ce2012-06-04 20:40:59 -0700994static struct request *__get_request(struct request_list *rl, int rw_flags,
Tejun Heoa06e05e2012-06-04 20:40:55 -0700995 struct bio *bio, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996{
Tejun Heo5b788ce2012-06-04 20:40:59 -0700997 struct request_queue *q = rl->q;
Tejun Heob6792812012-03-05 13:15:23 -0800998 struct request *rq;
Tejun Heo7f4b35d2012-06-04 20:40:56 -0700999 struct elevator_type *et = q->elevator->type;
1000 struct io_context *ioc = rq_ioc(bio);
Tejun Heof1f8cc92011-12-14 00:33:42 +01001001 struct io_cq *icq = NULL;
Jens Axboe1faa16d2009-04-06 14:48:01 +02001002 const bool is_sync = rw_is_sync(rw_flags) != 0;
Tejun Heo75eb6c32011-10-19 14:31:22 +02001003 int may_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004
Bart Van Assche3f3299d2012-11-28 13:42:38 +01001005 if (unlikely(blk_queue_dying(q)))
Joe Lawrencea492f072014-08-28 08:15:21 -06001006 return ERR_PTR(-ENODEV);
Tejun Heoda8303c2011-10-19 14:33:05 +02001007
Jens Axboe7749a8d2006-12-13 13:02:26 +01001008 may_queue = elv_may_queue(q, rw_flags);
Jens Axboe88ee5ef2005-11-12 11:09:12 +01001009 if (may_queue == ELV_MQUEUE_NO)
1010 goto rq_starved;
1011
Jens Axboe1faa16d2009-04-06 14:48:01 +02001012 if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
1013 if (rl->count[is_sync]+1 >= q->nr_requests) {
Tejun Heof2dbd762011-12-14 00:33:40 +01001014 /*
Jens Axboe88ee5ef2005-11-12 11:09:12 +01001015 * The queue will fill after this allocation, so set
1016 * it as full, and mark this process as "batching".
1017 * This process will be allowed to complete a batch of
1018 * requests, others will be blocked.
1019 */
Tejun Heo5b788ce2012-06-04 20:40:59 -07001020 if (!blk_rl_full(rl, is_sync)) {
Jens Axboe88ee5ef2005-11-12 11:09:12 +01001021 ioc_set_batching(q, ioc);
Tejun Heo5b788ce2012-06-04 20:40:59 -07001022 blk_set_rl_full(rl, is_sync);
Jens Axboe88ee5ef2005-11-12 11:09:12 +01001023 } else {
1024 if (may_queue != ELV_MQUEUE_MUST
1025 && !ioc_batching(q, ioc)) {
1026 /*
1027 * The queue is full and the allocating
1028 * process is not a "batcher", and not
1029 * exempted by the IO scheduler
1030 */
Joe Lawrencea492f072014-08-28 08:15:21 -06001031 return ERR_PTR(-ENOMEM);
Jens Axboe88ee5ef2005-11-12 11:09:12 +01001032 }
1033 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 }
Tejun Heod40f75a2015-05-22 17:13:42 -04001035 blk_set_congested(rl, is_sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 }
1037
Jens Axboe082cf692005-06-28 16:35:11 +02001038 /*
1039 * Only allow batching queuers to allocate up to 50% over the defined
1040 * limit of requests, otherwise we could have thousands of requests
1041 * allocated with any setting of ->nr_requests
1042 */
Jens Axboe1faa16d2009-04-06 14:48:01 +02001043 if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
Joe Lawrencea492f072014-08-28 08:15:21 -06001044 return ERR_PTR(-ENOMEM);
Hugh Dickinsfd782a42005-06-29 15:15:40 +01001045
Tejun Heo8a5ecdd2012-06-04 20:40:58 -07001046 q->nr_rqs[is_sync]++;
Jens Axboe1faa16d2009-04-06 14:48:01 +02001047 rl->count[is_sync]++;
1048 rl->starved[is_sync] = 0;
Tejun Heocb98fc82005-10-28 08:29:39 +02001049
Tejun Heof1f8cc92011-12-14 00:33:42 +01001050 /*
1051 * Decide whether the new request will be managed by elevator. If
1052 * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will
1053 * prevent the current elevator from being destroyed until the new
1054 * request is freed. This guarantees icq's won't be destroyed and
1055 * makes creating new ones safe.
1056 *
1057 * Also, lookup icq while holding queue_lock. If it doesn't exist,
1058 * it will be created after releasing queue_lock.
1059 */
Tejun Heod7325802012-03-05 13:14:58 -08001060 if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
Tejun Heo75eb6c32011-10-19 14:31:22 +02001061 rw_flags |= REQ_ELVPRIV;
Tejun Heo8a5ecdd2012-06-04 20:40:58 -07001062 q->nr_rqs_elvpriv++;
Tejun Heof1f8cc92011-12-14 00:33:42 +01001063 if (et->icq_cache && ioc)
1064 icq = ioc_lookup_icq(ioc, q);
Mike Snitzer9d5a4e92011-02-11 11:05:46 +01001065 }
Tejun Heocb98fc82005-10-28 08:29:39 +02001066
Jens Axboef253b862010-10-24 22:06:02 +02001067 if (blk_queue_io_stat(q))
1068 rw_flags |= REQ_IO_STAT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 spin_unlock_irq(q->queue_lock);
1070
Tejun Heo29e2b092012-04-19 16:29:21 -07001071 /* allocate and init request */
Tejun Heo5b788ce2012-06-04 20:40:59 -07001072 rq = mempool_alloc(rl->rq_pool, gfp_mask);
Tejun Heo29e2b092012-04-19 16:29:21 -07001073 if (!rq)
Tejun Heob6792812012-03-05 13:15:23 -08001074 goto fail_alloc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075
Tejun Heo29e2b092012-04-19 16:29:21 -07001076 blk_rq_init(q, rq);
Tejun Heoa0516612012-06-26 15:05:44 -07001077 blk_rq_set_rl(rq, rl);
Tejun Heo29e2b092012-04-19 16:29:21 -07001078 rq->cmd_flags = rw_flags | REQ_ALLOCED;
1079
Tejun Heoaaf7c682012-04-19 16:29:22 -07001080 /* init elvpriv */
Tejun Heo29e2b092012-04-19 16:29:21 -07001081 if (rw_flags & REQ_ELVPRIV) {
Tejun Heoaaf7c682012-04-19 16:29:22 -07001082 if (unlikely(et->icq_cache && !icq)) {
Tejun Heo7f4b35d2012-06-04 20:40:56 -07001083 if (ioc)
1084 icq = ioc_create_icq(ioc, q, gfp_mask);
Tejun Heoaaf7c682012-04-19 16:29:22 -07001085 if (!icq)
1086 goto fail_elvpriv;
Tejun Heo29e2b092012-04-19 16:29:21 -07001087 }
Tejun Heoaaf7c682012-04-19 16:29:22 -07001088
1089 rq->elv.icq = icq;
1090 if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
1091 goto fail_elvpriv;
1092
1093 /* @rq->elv.icq holds io_context until @rq is freed */
Tejun Heo29e2b092012-04-19 16:29:21 -07001094 if (icq)
1095 get_io_context(icq->ioc);
1096 }
Tejun Heoaaf7c682012-04-19 16:29:22 -07001097out:
Jens Axboe88ee5ef2005-11-12 11:09:12 +01001098 /*
1099 * ioc may be NULL here, and ioc_batching will be false. That's
1100 * OK, if the queue is under the request limit then requests need
1101 * not count toward the nr_batch_requests limit. There will always
1102 * be some limit enforced by BLK_BATCH_TIME.
1103 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 if (ioc_batching(q, ioc))
1105 ioc->nr_batch_requests--;
Jens Axboe6728cb02008-01-31 13:03:55 +01001106
Jens Axboe1faa16d2009-04-06 14:48:01 +02001107 trace_block_getrq(q, bio, rw_flags & 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 return rq;
Tejun Heob6792812012-03-05 13:15:23 -08001109
Tejun Heoaaf7c682012-04-19 16:29:22 -07001110fail_elvpriv:
1111 /*
1112 * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
1113 * and may fail indefinitely under memory pressure and thus
1114 * shouldn't stall IO. Treat this request as !elvpriv. This will
1115 * disturb iosched and blkcg but weird is bettern than dead.
1116 */
Robert Elliott7b2b10e2014-08-27 10:50:36 -05001117 printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n",
1118 __func__, dev_name(q->backing_dev_info.dev));
Tejun Heoaaf7c682012-04-19 16:29:22 -07001119
1120 rq->cmd_flags &= ~REQ_ELVPRIV;
1121 rq->elv.icq = NULL;
1122
1123 spin_lock_irq(q->queue_lock);
Tejun Heo8a5ecdd2012-06-04 20:40:58 -07001124 q->nr_rqs_elvpriv--;
Tejun Heoaaf7c682012-04-19 16:29:22 -07001125 spin_unlock_irq(q->queue_lock);
1126 goto out;
1127
Tejun Heob6792812012-03-05 13:15:23 -08001128fail_alloc:
1129 /*
1130 * Allocation failed presumably due to memory. Undo anything we
1131 * might have messed up.
1132 *
1133 * Allocating task should really be put onto the front of the wait
1134 * queue, but this is pretty rare.
1135 */
1136 spin_lock_irq(q->queue_lock);
Tejun Heo5b788ce2012-06-04 20:40:59 -07001137 freed_request(rl, rw_flags);
Tejun Heob6792812012-03-05 13:15:23 -08001138
1139 /*
1140 * in the very unlikely event that allocation failed and no
1141 * requests for this direction was pending, mark us starved so that
1142 * freeing of a request in the other direction will notice
1143 * us. another possible fix would be to split the rq mempool into
1144 * READ and WRITE
1145 */
1146rq_starved:
1147 if (unlikely(rl->count[is_sync] == 0))
1148 rl->starved[is_sync] = 1;
Joe Lawrencea492f072014-08-28 08:15:21 -06001149 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150}
1151
Tejun Heoda8303c2011-10-19 14:33:05 +02001152/**
Tejun Heoa06e05e2012-06-04 20:40:55 -07001153 * get_request - get a free request
Tejun Heoda8303c2011-10-19 14:33:05 +02001154 * @q: request_queue to allocate request from
1155 * @rw_flags: RW and SYNC flags
1156 * @bio: bio to allocate request for (can be %NULL)
Tejun Heoa06e05e2012-06-04 20:40:55 -07001157 * @gfp_mask: allocation mask
Nick Piggind6344532005-06-28 20:45:14 -07001158 *
Tejun Heoa06e05e2012-06-04 20:40:55 -07001159 * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this
1160 * function keeps retrying under memory pressure and fails iff @q is dead.
Tejun Heoda8303c2011-10-19 14:33:05 +02001161 *
Masanari Iidada3dae52014-09-09 01:27:23 +09001162 * Must be called with @q->queue_lock held and,
Joe Lawrencea492f072014-08-28 08:15:21 -06001163 * Returns ERR_PTR on failure, with @q->queue_lock held.
1164 * Returns request pointer on success, with @q->queue_lock *not held*.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 */
Tejun Heoa06e05e2012-06-04 20:40:55 -07001166static struct request *get_request(struct request_queue *q, int rw_flags,
1167 struct bio *bio, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168{
Jens Axboe1faa16d2009-04-06 14:48:01 +02001169 const bool is_sync = rw_is_sync(rw_flags) != 0;
Tejun Heoa06e05e2012-06-04 20:40:55 -07001170 DEFINE_WAIT(wait);
Tejun Heoa0516612012-06-26 15:05:44 -07001171 struct request_list *rl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 struct request *rq;
Tejun Heoa0516612012-06-26 15:05:44 -07001173
1174 rl = blk_get_rl(q, bio); /* transferred to @rq on success */
Tejun Heoa06e05e2012-06-04 20:40:55 -07001175retry:
Tejun Heoa0516612012-06-26 15:05:44 -07001176 rq = __get_request(rl, rw_flags, bio, gfp_mask);
Joe Lawrencea492f072014-08-28 08:15:21 -06001177 if (!IS_ERR(rq))
Tejun Heoa06e05e2012-06-04 20:40:55 -07001178 return rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179
Bart Van Assche3f3299d2012-11-28 13:42:38 +01001180 if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) {
Tejun Heoa0516612012-06-26 15:05:44 -07001181 blk_put_rl(rl);
Joe Lawrencea492f072014-08-28 08:15:21 -06001182 return rq;
Tejun Heoa0516612012-06-26 15:05:44 -07001183 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184
Tejun Heoa06e05e2012-06-04 20:40:55 -07001185 /* wait on @rl and retry */
1186 prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
1187 TASK_UNINTERRUPTIBLE);
Tejun Heoda8303c2011-10-19 14:33:05 +02001188
Tejun Heoa06e05e2012-06-04 20:40:55 -07001189 trace_block_sleeprq(q, bio, rw_flags & 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
Tejun Heoa06e05e2012-06-04 20:40:55 -07001191 spin_unlock_irq(q->queue_lock);
1192 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193
Tejun Heoa06e05e2012-06-04 20:40:55 -07001194 /*
1195 * After sleeping, we become a "batching" process and will be able
1196 * to allocate at least one request, and up to a big batch of them
1197 * for a small period time. See ioc_batching, ioc_set_batching
1198 */
Tejun Heoa06e05e2012-06-04 20:40:55 -07001199 ioc_set_batching(q, current->io_context);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200
Tejun Heoa06e05e2012-06-04 20:40:55 -07001201 spin_lock_irq(q->queue_lock);
1202 finish_wait(&rl->wait[is_sync], &wait);
Jens Axboe2056a782006-03-23 20:00:26 +01001203
Tejun Heoa06e05e2012-06-04 20:40:55 -07001204 goto retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205}
1206
Jens Axboe320ae512013-10-24 09:20:05 +01001207static struct request *blk_old_get_request(struct request_queue *q, int rw,
1208 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209{
1210 struct request *rq;
1211
1212 BUG_ON(rw != READ && rw != WRITE);
1213
Tejun Heo7f4b35d2012-06-04 20:40:56 -07001214 /* create ioc upfront */
1215 create_io_context(gfp_mask, q->node);
1216
Nick Piggind6344532005-06-28 20:45:14 -07001217 spin_lock_irq(q->queue_lock);
Tejun Heoa06e05e2012-06-04 20:40:55 -07001218 rq = get_request(q, rw, NULL, gfp_mask);
Joe Lawrencea492f072014-08-28 08:15:21 -06001219 if (IS_ERR(rq))
Tejun Heoda8303c2011-10-19 14:33:05 +02001220 spin_unlock_irq(q->queue_lock);
Nick Piggind6344532005-06-28 20:45:14 -07001221 /* q->queue_lock is unlocked at this point */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222
1223 return rq;
1224}
Jens Axboe320ae512013-10-24 09:20:05 +01001225
1226struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
1227{
1228 if (q->mq_ops)
Christoph Hellwig4ce01dd2014-05-27 20:59:46 +02001229 return blk_mq_alloc_request(q, rw, gfp_mask, false);
Jens Axboe320ae512013-10-24 09:20:05 +01001230 else
1231 return blk_old_get_request(q, rw, gfp_mask);
1232}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233EXPORT_SYMBOL(blk_get_request);
1234
1235/**
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001236 * blk_make_request - given a bio, allocate a corresponding struct request.
Randy Dunlap8ebf9752009-06-11 20:00:41 -07001237 * @q: target request queue
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001238 * @bio: The bio describing the memory mappings that will be submitted for IO.
1239 * It may be a chained-bio properly constructed by block/bio layer.
Randy Dunlap8ebf9752009-06-11 20:00:41 -07001240 * @gfp_mask: gfp flags to be used for memory allocation
Jens Axboedc72ef42006-07-20 14:54:05 +02001241 *
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001242 * blk_make_request is the parallel of generic_make_request for BLOCK_PC
1243 * type commands. Where the struct request needs to be farther initialized by
1244 * the caller. It is passed a &struct bio, which describes the memory info of
1245 * the I/O transfer.
1246 *
1247 * The caller of blk_make_request must make sure that bi_io_vec
1248 * are set to describe the memory buffers. That bio_data_dir() will return
1249 * the needed direction of the request. (And all bio's in the passed bio-chain
1250 * are properly set accordingly)
1251 *
1252 * If called under none-sleepable conditions, mapped bio buffers must not
1253 * need bouncing, by calling the appropriate masked or flagged allocator,
1254 * suitable for the target device. Otherwise the call to blk_queue_bounce will
1255 * BUG.
Jens Axboe53674ac2009-05-19 19:52:35 +02001256 *
1257 * WARNING: When allocating/cloning a bio-chain, careful consideration should be
1258 * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for
1259 * anything but the first bio in the chain. Otherwise you risk waiting for IO
1260 * completion of a bio that hasn't been submitted yet, thus resulting in a
1261 * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead
1262 * of bio_alloc(), as that avoids the mempool deadlock.
1263 * If possible a big IO should be split into smaller parts when allocation
1264 * fails. Partial allocation should not be an error, or you risk a live-lock.
Jens Axboedc72ef42006-07-20 14:54:05 +02001265 */
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001266struct request *blk_make_request(struct request_queue *q, struct bio *bio,
1267 gfp_t gfp_mask)
Jens Axboedc72ef42006-07-20 14:54:05 +02001268{
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001269 struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);
1270
Joe Lawrencea492f072014-08-28 08:15:21 -06001271 if (IS_ERR(rq))
1272 return rq;
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001273
Jens Axboef27b0872014-06-06 07:57:37 -06001274 blk_rq_set_block_pc(rq);
1275
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001276 for_each_bio(bio) {
1277 struct bio *bounce_bio = bio;
1278 int ret;
1279
1280 blk_queue_bounce(q, &bounce_bio);
1281 ret = blk_rq_append_bio(q, rq, bounce_bio);
1282 if (unlikely(ret)) {
1283 blk_put_request(rq);
1284 return ERR_PTR(ret);
1285 }
1286 }
1287
1288 return rq;
Jens Axboedc72ef42006-07-20 14:54:05 +02001289}
Boaz Harrosh79eb63e2009-05-17 18:57:15 +03001290EXPORT_SYMBOL(blk_make_request);
Jens Axboedc72ef42006-07-20 14:54:05 +02001291
1292/**
Masanari Iidada3dae52014-09-09 01:27:23 +09001293 * blk_rq_set_block_pc - initialize a request to type BLOCK_PC
Jens Axboef27b0872014-06-06 07:57:37 -06001294 * @rq: request to be initialized
1295 *
1296 */
1297void blk_rq_set_block_pc(struct request *rq)
1298{
1299 rq->cmd_type = REQ_TYPE_BLOCK_PC;
1300 rq->__data_len = 0;
1301 rq->__sector = (sector_t) -1;
1302 rq->bio = rq->biotail = NULL;
1303 memset(rq->__cmd, 0, sizeof(rq->__cmd));
Jens Axboef27b0872014-06-06 07:57:37 -06001304}
1305EXPORT_SYMBOL(blk_rq_set_block_pc);
1306
1307/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308 * blk_requeue_request - put a request back on queue
1309 * @q: request queue where request should be inserted
1310 * @rq: request to be inserted
1311 *
1312 * Description:
1313 * Drivers often keep queueing requests until the hardware cannot accept
1314 * more, when that condition happens we need to put the request back
1315 * on the queue. Must be called with queue lock held.
1316 */
Jens Axboe165125e2007-07-24 09:28:11 +02001317void blk_requeue_request(struct request_queue *q, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001319 blk_delete_timer(rq);
1320 blk_clear_rq_complete(rq);
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +01001321 trace_block_rq_requeue(q, rq);
Jens Axboe2056a782006-03-23 20:00:26 +01001322
Christoph Hellwig125c99b2014-11-03 12:47:47 +01001323 if (rq->cmd_flags & REQ_QUEUED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324 blk_queue_end_tag(q, rq);
1325
James Bottomleyba396a62009-05-27 14:17:08 +02001326 BUG_ON(blk_queued_rq(rq));
1327
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 elv_requeue_request(q, rq);
1329}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330EXPORT_SYMBOL(blk_requeue_request);
1331
Jens Axboe73c10102011-03-08 13:19:51 +01001332static void add_acct_request(struct request_queue *q, struct request *rq,
1333 int where)
1334{
Jens Axboe320ae512013-10-24 09:20:05 +01001335 blk_account_io_start(rq, true);
Jens Axboe7eaceac2011-03-10 08:52:07 +01001336 __elv_add_request(q, rq, where);
Jens Axboe73c10102011-03-08 13:19:51 +01001337}
1338
Tejun Heo074a7ac2008-08-25 19:56:14 +09001339static void part_round_stats_single(int cpu, struct hd_struct *part,
1340 unsigned long now)
1341{
Jens Axboe7276d022014-05-09 15:48:23 -06001342 int inflight;
1343
Tejun Heo074a7ac2008-08-25 19:56:14 +09001344 if (now == part->stamp)
1345 return;
1346
Jens Axboe7276d022014-05-09 15:48:23 -06001347 inflight = part_in_flight(part);
1348 if (inflight) {
Tejun Heo074a7ac2008-08-25 19:56:14 +09001349 __part_stat_add(cpu, part, time_in_queue,
Jens Axboe7276d022014-05-09 15:48:23 -06001350 inflight * (now - part->stamp));
Tejun Heo074a7ac2008-08-25 19:56:14 +09001351 __part_stat_add(cpu, part, io_ticks, (now - part->stamp));
1352 }
1353 part->stamp = now;
1354}
1355
1356/**
Randy Dunlap496aa8a2008-10-16 07:46:23 +02001357 * part_round_stats() - Round off the performance stats on a struct disk_stats.
1358 * @cpu: cpu number for stats access
1359 * @part: target partition
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 *
1361 * The average IO queue length and utilisation statistics are maintained
1362 * by observing the current state of the queue length and the amount of
1363 * time it has been in this state for.
1364 *
1365 * Normally, that accounting is done on IO completion, but that can result
1366 * in more than a second's worth of IO being accounted for within any one
1367 * second, leading to >100% utilisation. To deal with that, we call this
1368 * function to do a round-off before returning the results when reading
1369 * /proc/diskstats. This accounts immediately for all queue usage up to
1370 * the current jiffies and restarts the counters again.
1371 */
Tejun Heoc9959052008-08-25 19:47:21 +09001372void part_round_stats(int cpu, struct hd_struct *part)
Jerome Marchand6f2576a2008-02-08 11:04:35 +01001373{
1374 unsigned long now = jiffies;
1375
Tejun Heo074a7ac2008-08-25 19:56:14 +09001376 if (part->partno)
1377 part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
1378 part_round_stats_single(cpu, part, now);
Jerome Marchand6f2576a2008-02-08 11:04:35 +01001379}
Tejun Heo074a7ac2008-08-25 19:56:14 +09001380EXPORT_SYMBOL_GPL(part_round_stats);
Jerome Marchand6f2576a2008-02-08 11:04:35 +01001381
Rafael J. Wysocki47fafbc2014-12-04 01:00:23 +01001382#ifdef CONFIG_PM
Lin Mingc8158812013-03-23 11:42:27 +08001383static void blk_pm_put_request(struct request *rq)
1384{
1385 if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending)
1386 pm_runtime_mark_last_busy(rq->q->dev);
1387}
1388#else
1389static inline void blk_pm_put_request(struct request *rq) {}
1390#endif
1391
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392/*
1393 * queue lock must be held
1394 */
Jens Axboe165125e2007-07-24 09:28:11 +02001395void __blk_put_request(struct request_queue *q, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 if (unlikely(!q))
1398 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399
Christoph Hellwig6f5ba582014-02-07 10:22:37 -08001400 if (q->mq_ops) {
1401 blk_mq_free_request(req);
1402 return;
1403 }
1404
Lin Mingc8158812013-03-23 11:42:27 +08001405 blk_pm_put_request(req);
1406
Tejun Heo8922e162005-10-20 16:23:44 +02001407 elv_completed_request(q, req);
1408
Boaz Harrosh1cd96c22009-03-24 12:35:07 +01001409 /* this is a bio leak */
1410 WARN_ON(req->bio != NULL);
1411
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 /*
1413 * Request may not have originated from ll_rw_blk. if not,
1414 * it didn't come out of our reserved rq pools
1415 */
Jens Axboe49171e52006-08-10 08:59:11 +02001416 if (req->cmd_flags & REQ_ALLOCED) {
Tejun Heo75eb6c32011-10-19 14:31:22 +02001417 unsigned int flags = req->cmd_flags;
Tejun Heoa0516612012-06-26 15:05:44 -07001418 struct request_list *rl = blk_rq_rl(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420 BUG_ON(!list_empty(&req->queuelist));
Jens Axboe360f92c2014-04-09 20:27:01 -06001421 BUG_ON(ELV_ON_HASH(req));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422
Tejun Heoa0516612012-06-26 15:05:44 -07001423 blk_free_request(rl, req);
1424 freed_request(rl, flags);
1425 blk_put_rl(rl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 }
1427}
Mike Christie6e39b69e2005-11-11 05:30:24 -06001428EXPORT_SYMBOL_GPL(__blk_put_request);
1429
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430void blk_put_request(struct request *req)
1431{
Jens Axboe165125e2007-07-24 09:28:11 +02001432 struct request_queue *q = req->q;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001433
Jens Axboe320ae512013-10-24 09:20:05 +01001434 if (q->mq_ops)
1435 blk_mq_free_request(req);
1436 else {
1437 unsigned long flags;
1438
1439 spin_lock_irqsave(q->queue_lock, flags);
1440 __blk_put_request(q, req);
1441 spin_unlock_irqrestore(q->queue_lock, flags);
1442 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444EXPORT_SYMBOL(blk_put_request);
1445
Christoph Hellwig66ac0282010-06-18 16:59:42 +02001446/**
1447 * blk_add_request_payload - add a payload to a request
1448 * @rq: request to update
1449 * @page: page backing the payload
1450 * @len: length of the payload.
1451 *
1452 * This allows to later add a payload to an already submitted request by
1453 * a block driver. The driver needs to take care of freeing the payload
1454 * itself.
1455 *
1456 * Note that this is a quite horrible hack and nothing but handling of
1457 * discard requests should ever use it.
1458 */
1459void blk_add_request_payload(struct request *rq, struct page *page,
1460 unsigned int len)
1461{
1462 struct bio *bio = rq->bio;
1463
1464 bio->bi_io_vec->bv_page = page;
1465 bio->bi_io_vec->bv_offset = 0;
1466 bio->bi_io_vec->bv_len = len;
1467
Kent Overstreet4f024f32013-10-11 15:44:27 -07001468 bio->bi_iter.bi_size = len;
Christoph Hellwig66ac0282010-06-18 16:59:42 +02001469 bio->bi_vcnt = 1;
1470 bio->bi_phys_segments = 1;
1471
1472 rq->__data_len = rq->resid_len = len;
1473 rq->nr_phys_segments = 1;
Christoph Hellwig66ac0282010-06-18 16:59:42 +02001474}
1475EXPORT_SYMBOL_GPL(blk_add_request_payload);
1476
Jens Axboe320ae512013-10-24 09:20:05 +01001477bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
1478 struct bio *bio)
Jens Axboe73c10102011-03-08 13:19:51 +01001479{
1480 const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
1481
Jens Axboe73c10102011-03-08 13:19:51 +01001482 if (!ll_back_merge_fn(q, req, bio))
1483 return false;
1484
Tejun Heo8c1cf6b2013-01-11 13:06:34 -08001485 trace_block_bio_backmerge(q, req, bio);
Jens Axboe73c10102011-03-08 13:19:51 +01001486
1487 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
1488 blk_rq_set_mixed_merge(req);
1489
1490 req->biotail->bi_next = bio;
1491 req->biotail = bio;
Kent Overstreet4f024f32013-10-11 15:44:27 -07001492 req->__data_len += bio->bi_iter.bi_size;
Jens Axboe73c10102011-03-08 13:19:51 +01001493 req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
1494
Jens Axboe320ae512013-10-24 09:20:05 +01001495 blk_account_io_start(req, false);
Jens Axboe73c10102011-03-08 13:19:51 +01001496 return true;
1497}
1498
Jens Axboe320ae512013-10-24 09:20:05 +01001499bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
1500 struct bio *bio)
Jens Axboe73c10102011-03-08 13:19:51 +01001501{
1502 const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
Jens Axboe73c10102011-03-08 13:19:51 +01001503
Jens Axboe73c10102011-03-08 13:19:51 +01001504 if (!ll_front_merge_fn(q, req, bio))
1505 return false;
1506
Tejun Heo8c1cf6b2013-01-11 13:06:34 -08001507 trace_block_bio_frontmerge(q, req, bio);
Jens Axboe73c10102011-03-08 13:19:51 +01001508
1509 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
1510 blk_rq_set_mixed_merge(req);
1511
Jens Axboe73c10102011-03-08 13:19:51 +01001512 bio->bi_next = req->bio;
1513 req->bio = bio;
1514
Kent Overstreet4f024f32013-10-11 15:44:27 -07001515 req->__sector = bio->bi_iter.bi_sector;
1516 req->__data_len += bio->bi_iter.bi_size;
Jens Axboe73c10102011-03-08 13:19:51 +01001517 req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
1518
Jens Axboe320ae512013-10-24 09:20:05 +01001519 blk_account_io_start(req, false);
Jens Axboe73c10102011-03-08 13:19:51 +01001520 return true;
1521}
1522
Tejun Heobd87b582011-10-19 14:33:08 +02001523/**
Jens Axboe320ae512013-10-24 09:20:05 +01001524 * blk_attempt_plug_merge - try to merge with %current's plugged list
Tejun Heobd87b582011-10-19 14:33:08 +02001525 * @q: request_queue new bio is being queued at
1526 * @bio: new bio being queued
1527 * @request_count: out parameter for number of traversed plugged requests
1528 *
1529 * Determine whether @bio being queued on @q can be merged with a request
1530 * on %current's plugged list. Returns %true if merge was successful,
1531 * otherwise %false.
1532 *
Tejun Heo07c2bd32012-02-08 09:19:42 +01001533 * Plugging coalesces IOs from the same issuer for the same purpose without
1534 * going through @q->queue_lock. As such it's more of an issuing mechanism
1535 * than scheduling, and the request, while may have elvpriv data, is not
1536 * added on the elevator at this point. In addition, we don't have
1537 * reliable access to the elevator outside queue lock. Only check basic
1538 * merging parameters without querying the elevator.
Robert Elliottda41a582014-05-20 16:46:26 -05001539 *
1540 * Caller must ensure !blk_queue_nomerges(q) beforehand.
Jens Axboe73c10102011-03-08 13:19:51 +01001541 */
Jens Axboe320ae512013-10-24 09:20:05 +01001542bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
Shaohua Li5b3f3412015-05-08 10:51:33 -07001543 unsigned int *request_count,
1544 struct request **same_queue_rq)
Jens Axboe73c10102011-03-08 13:19:51 +01001545{
1546 struct blk_plug *plug;
1547 struct request *rq;
1548 bool ret = false;
Shaohua Li92f399c2013-10-29 12:01:03 -06001549 struct list_head *plug_list;
Jens Axboe73c10102011-03-08 13:19:51 +01001550
Tejun Heobd87b582011-10-19 14:33:08 +02001551 plug = current->plug;
Jens Axboe73c10102011-03-08 13:19:51 +01001552 if (!plug)
1553 goto out;
Shaohua Li56ebdaf2011-08-24 16:04:34 +02001554 *request_count = 0;
Jens Axboe73c10102011-03-08 13:19:51 +01001555
Shaohua Li92f399c2013-10-29 12:01:03 -06001556 if (q->mq_ops)
1557 plug_list = &plug->mq_list;
1558 else
1559 plug_list = &plug->list;
1560
1561 list_for_each_entry_reverse(rq, plug_list, queuelist) {
Jens Axboe73c10102011-03-08 13:19:51 +01001562 int el_ret;
1563
Shaohua Li5b3f3412015-05-08 10:51:33 -07001564 if (rq->q == q) {
Shaohua Li1b2e19f2012-04-06 11:37:47 -06001565 (*request_count)++;
Shaohua Li5b3f3412015-05-08 10:51:33 -07001566 /*
1567 * Only blk-mq multiple hardware queues case checks the
1568 * rq in the same queue, there should be only one such
1569 * rq in a queue
1570 **/
1571 if (same_queue_rq)
1572 *same_queue_rq = rq;
1573 }
Shaohua Li56ebdaf2011-08-24 16:04:34 +02001574
Tejun Heo07c2bd32012-02-08 09:19:42 +01001575 if (rq->q != q || !blk_rq_merge_ok(rq, bio))
Jens Axboe73c10102011-03-08 13:19:51 +01001576 continue;
1577
Tejun Heo050c8ea2012-02-08 09:19:38 +01001578 el_ret = blk_try_merge(rq, bio);
Jens Axboe73c10102011-03-08 13:19:51 +01001579 if (el_ret == ELEVATOR_BACK_MERGE) {
1580 ret = bio_attempt_back_merge(q, rq, bio);
1581 if (ret)
1582 break;
1583 } else if (el_ret == ELEVATOR_FRONT_MERGE) {
1584 ret = bio_attempt_front_merge(q, rq, bio);
1585 if (ret)
1586 break;
1587 }
1588 }
1589out:
1590 return ret;
1591}
1592
Jens Axboe86db1e22008-01-29 14:53:40 +01001593void init_request_from_bio(struct request *req, struct bio *bio)
Tejun Heo52d9e672006-01-06 09:49:58 +01001594{
Jens Axboe4aff5e22006-08-10 08:44:47 +02001595 req->cmd_type = REQ_TYPE_FS;
Tejun Heo52d9e672006-01-06 09:49:58 +01001596
Christoph Hellwig7b6d91d2010-08-07 18:20:39 +02001597 req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK;
1598 if (bio->bi_rw & REQ_RAHEAD)
Tejun Heoa82afdf2009-07-03 17:48:16 +09001599 req->cmd_flags |= REQ_FAILFAST_MASK;
Jens Axboeb31dc662006-06-13 08:26:10 +02001600
Tejun Heo52d9e672006-01-06 09:49:58 +01001601 req->errors = 0;
Kent Overstreet4f024f32013-10-11 15:44:27 -07001602 req->__sector = bio->bi_iter.bi_sector;
Tejun Heo52d9e672006-01-06 09:49:58 +01001603 req->ioprio = bio_prio(bio);
NeilBrownbc1c56f2007-08-16 13:31:30 +02001604 blk_rq_bio_prep(req->q, req, bio);
Tejun Heo52d9e672006-01-06 09:49:58 +01001605}
1606
Mike Snitzer336b7e12015-05-11 14:06:32 -04001607static void blk_queue_bio(struct request_queue *q, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608{
Jiri Slaby5e00d1b2010-08-12 14:31:06 +02001609 const bool sync = !!(bio->bi_rw & REQ_SYNC);
Jens Axboe73c10102011-03-08 13:19:51 +01001610 struct blk_plug *plug;
1611 int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT;
1612 struct request *req;
Shaohua Li56ebdaf2011-08-24 16:04:34 +02001613 unsigned int request_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615 /*
1616 * low level driver can indicate that it wants pages above a
1617 * certain limit bounced to low memory (ie for highmem, or even
1618 * ISA dma in theory)
1619 */
1620 blk_queue_bounce(q, &bio);
1621
Darrick J. Wongffecfd12013-02-21 16:42:55 -08001622 if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
1623 bio_endio(bio, -EIO);
1624 return;
1625 }
1626
Tejun Heo4fed9472010-09-03 11:56:17 +02001627 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
Jens Axboe73c10102011-03-08 13:19:51 +01001628 spin_lock_irq(q->queue_lock);
Tejun Heoae1b1532011-01-25 12:43:54 +01001629 where = ELEVATOR_INSERT_FLUSH;
Tejun Heo28e7d182010-09-03 11:56:16 +02001630 goto get_rq;
1631 }
1632
Jens Axboe73c10102011-03-08 13:19:51 +01001633 /*
1634 * Check if we can merge with the plugged list before grabbing
1635 * any locks.
1636 */
Robert Elliottda41a582014-05-20 16:46:26 -05001637 if (!blk_queue_nomerges(q) &&
Shaohua Li5b3f3412015-05-08 10:51:33 -07001638 blk_attempt_plug_merge(q, bio, &request_count, NULL))
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001639 return;
Jens Axboe73c10102011-03-08 13:19:51 +01001640
1641 spin_lock_irq(q->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642
1643 el_ret = elv_merge(q, &req, bio);
Jens Axboe73c10102011-03-08 13:19:51 +01001644 if (el_ret == ELEVATOR_BACK_MERGE) {
Jens Axboe73c10102011-03-08 13:19:51 +01001645 if (bio_attempt_back_merge(q, req, bio)) {
Tejun Heo07c2bd32012-02-08 09:19:42 +01001646 elv_bio_merged(q, req, bio);
Jens Axboe73c10102011-03-08 13:19:51 +01001647 if (!attempt_back_merge(q, req))
1648 elv_merged_request(q, req, el_ret);
1649 goto out_unlock;
Tejun Heo80a761f2009-07-03 17:48:17 +09001650 }
Jens Axboe73c10102011-03-08 13:19:51 +01001651 } else if (el_ret == ELEVATOR_FRONT_MERGE) {
Jens Axboe73c10102011-03-08 13:19:51 +01001652 if (bio_attempt_front_merge(q, req, bio)) {
Tejun Heo07c2bd32012-02-08 09:19:42 +01001653 elv_bio_merged(q, req, bio);
Jens Axboe73c10102011-03-08 13:19:51 +01001654 if (!attempt_front_merge(q, req))
1655 elv_merged_request(q, req, el_ret);
1656 goto out_unlock;
1657 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 }
1659
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660get_rq:
Nick Piggin450991b2005-06-28 20:45:13 -07001661 /*
Jens Axboe7749a8d2006-12-13 13:02:26 +01001662 * This sync check and mask will be re-done in init_request_from_bio(),
1663 * but we need to set it earlier to expose the sync flag to the
1664 * rq allocator and io schedulers.
1665 */
1666 rw_flags = bio_data_dir(bio);
1667 if (sync)
Christoph Hellwig7b6d91d2010-08-07 18:20:39 +02001668 rw_flags |= REQ_SYNC;
Jens Axboe7749a8d2006-12-13 13:02:26 +01001669
1670 /*
Nick Piggin450991b2005-06-28 20:45:13 -07001671 * Grab a free request. This is might sleep but can not fail.
Nick Piggind6344532005-06-28 20:45:14 -07001672 * Returns with the queue unlocked.
Nick Piggin450991b2005-06-28 20:45:13 -07001673 */
Tejun Heoa06e05e2012-06-04 20:40:55 -07001674 req = get_request(q, rw_flags, bio, GFP_NOIO);
Joe Lawrencea492f072014-08-28 08:15:21 -06001675 if (IS_ERR(req)) {
1676 bio_endio(bio, PTR_ERR(req)); /* @q is dead */
Tejun Heoda8303c2011-10-19 14:33:05 +02001677 goto out_unlock;
1678 }
Nick Piggind6344532005-06-28 20:45:14 -07001679
Nick Piggin450991b2005-06-28 20:45:13 -07001680 /*
1681 * After dropping the lock and possibly sleeping here, our request
1682 * may now be mergeable after it had proven unmergeable (above).
1683 * We don't worry about that case for efficiency. It won't happen
1684 * often, and the elevators are able to handle it.
1685 */
Tejun Heo52d9e672006-01-06 09:49:58 +01001686 init_request_from_bio(req, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687
Tao Ma9562ad92011-10-24 16:11:30 +02001688 if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags))
Jens Axboe11ccf112011-07-26 15:01:15 +02001689 req->cpu = raw_smp_processor_id();
Tejun Heodd831002010-09-03 11:56:16 +02001690
Jens Axboe73c10102011-03-08 13:19:51 +01001691 plug = current->plug;
Jens Axboe721a9602011-03-09 11:56:30 +01001692 if (plug) {
Jens Axboedc6d36c2011-04-12 10:28:28 +02001693 /*
1694 * If this is the first request added after a plug, fire
Jianpeng Ma7aef2e72013-09-11 13:21:07 -06001695 * of a plug trace.
Jens Axboedc6d36c2011-04-12 10:28:28 +02001696 */
Jianpeng Ma7aef2e72013-09-11 13:21:07 -06001697 if (!request_count)
Jens Axboedc6d36c2011-04-12 10:28:28 +02001698 trace_block_plug(q);
Shaohua Li3540d5e2011-11-16 09:21:50 +01001699 else {
Shaohua Li019ceb72011-11-16 09:21:50 +01001700 if (request_count >= BLK_MAX_REQUEST_COUNT) {
Shaohua Li3540d5e2011-11-16 09:21:50 +01001701 blk_flush_plug_list(plug, false);
Shaohua Li019ceb72011-11-16 09:21:50 +01001702 trace_block_plug(q);
1703 }
Jens Axboe73c10102011-03-08 13:19:51 +01001704 }
Shaohua Lia6327162011-08-24 16:04:32 +02001705 list_add_tail(&req->queuelist, &plug->list);
Jens Axboe320ae512013-10-24 09:20:05 +01001706 blk_account_io_start(req, true);
Jens Axboe73c10102011-03-08 13:19:51 +01001707 } else {
1708 spin_lock_irq(q->queue_lock);
1709 add_acct_request(q, req, where);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +02001710 __blk_run_queue(q);
Jens Axboe73c10102011-03-08 13:19:51 +01001711out_unlock:
1712 spin_unlock_irq(q->queue_lock);
1713 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714}
1715
1716/*
1717 * If bio->bi_dev is a partition, remap the location
1718 */
1719static inline void blk_partition_remap(struct bio *bio)
1720{
1721 struct block_device *bdev = bio->bi_bdev;
1722
Jens Axboebf2de6f2007-09-27 13:01:25 +02001723 if (bio_sectors(bio) && bdev != bdev->bd_contains) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724 struct hd_struct *p = bdev->bd_part;
Jens Axboea3623572005-11-01 09:26:16 +01001725
Kent Overstreet4f024f32013-10-11 15:44:27 -07001726 bio->bi_iter.bi_sector += p->start_sect;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727 bio->bi_bdev = bdev->bd_contains;
Alan D. Brunellec7149d62007-08-07 15:30:23 +02001728
Mike Snitzerd07335e2010-11-16 12:52:38 +01001729 trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
1730 bdev->bd_dev,
Kent Overstreet4f024f32013-10-11 15:44:27 -07001731 bio->bi_iter.bi_sector - p->start_sect);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 }
1733}
1734
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735static void handle_bad_sector(struct bio *bio)
1736{
1737 char b[BDEVNAME_SIZE];
1738
1739 printk(KERN_INFO "attempt to access beyond end of device\n");
1740 printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
1741 bdevname(bio->bi_bdev, b),
1742 bio->bi_rw,
Kent Overstreetf73a1c72012-09-25 15:05:12 -07001743 (unsigned long long)bio_end_sector(bio),
Mike Snitzer77304d22010-11-08 14:39:12 +01001744 (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745}
1746
Akinobu Mitac17bb492006-12-08 02:39:46 -08001747#ifdef CONFIG_FAIL_MAKE_REQUEST
1748
1749static DECLARE_FAULT_ATTR(fail_make_request);
1750
1751static int __init setup_fail_make_request(char *str)
1752{
1753 return setup_fault_attr(&fail_make_request, str);
1754}
1755__setup("fail_make_request=", setup_fail_make_request);
1756
Akinobu Mitab2c9cd32011-07-26 16:09:03 -07001757static bool should_fail_request(struct hd_struct *part, unsigned int bytes)
Akinobu Mitac17bb492006-12-08 02:39:46 -08001758{
Akinobu Mitab2c9cd32011-07-26 16:09:03 -07001759 return part->make_it_fail && should_fail(&fail_make_request, bytes);
Akinobu Mitac17bb492006-12-08 02:39:46 -08001760}
1761
1762static int __init fail_make_request_debugfs(void)
1763{
Akinobu Mitadd48c082011-08-03 16:21:01 -07001764 struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
1765 NULL, &fail_make_request);
1766
Duan Jiong21f9fcd2014-04-11 15:58:56 +08001767 return PTR_ERR_OR_ZERO(dir);
Akinobu Mitac17bb492006-12-08 02:39:46 -08001768}
1769
1770late_initcall(fail_make_request_debugfs);
1771
1772#else /* CONFIG_FAIL_MAKE_REQUEST */
1773
Akinobu Mitab2c9cd32011-07-26 16:09:03 -07001774static inline bool should_fail_request(struct hd_struct *part,
1775 unsigned int bytes)
Akinobu Mitac17bb492006-12-08 02:39:46 -08001776{
Akinobu Mitab2c9cd32011-07-26 16:09:03 -07001777 return false;
Akinobu Mitac17bb492006-12-08 02:39:46 -08001778}
1779
1780#endif /* CONFIG_FAIL_MAKE_REQUEST */
1781
Jens Axboec07e2b42007-07-18 13:27:58 +02001782/*
1783 * Check whether this bio extends beyond the end of the device.
1784 */
1785static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
1786{
1787 sector_t maxsector;
1788
1789 if (!nr_sectors)
1790 return 0;
1791
1792 /* Test device or partition size, when known. */
Mike Snitzer77304d22010-11-08 14:39:12 +01001793 maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
Jens Axboec07e2b42007-07-18 13:27:58 +02001794 if (maxsector) {
Kent Overstreet4f024f32013-10-11 15:44:27 -07001795 sector_t sector = bio->bi_iter.bi_sector;
Jens Axboec07e2b42007-07-18 13:27:58 +02001796
1797 if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
1798 /*
1799 * This may well happen - the kernel calls bread()
1800 * without checking the size of the device, e.g., when
1801 * mounting a device.
1802 */
1803 handle_bad_sector(bio);
1804 return 1;
1805 }
1806 }
1807
1808 return 0;
1809}
1810
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001811static noinline_for_stack bool
1812generic_make_request_checks(struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813{
Jens Axboe165125e2007-07-24 09:28:11 +02001814 struct request_queue *q;
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001815 int nr_sectors = bio_sectors(bio);
Jens Axboe51fd77b2007-11-02 08:49:08 +01001816 int err = -EIO;
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001817 char b[BDEVNAME_SIZE];
1818 struct hd_struct *part;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819
1820 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821
Jens Axboec07e2b42007-07-18 13:27:58 +02001822 if (bio_check_eod(bio, nr_sectors))
1823 goto end_io;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001825 q = bdev_get_queue(bio->bi_bdev);
1826 if (unlikely(!q)) {
1827 printk(KERN_ERR
1828 "generic_make_request: Trying to access "
1829 "nonexistent block-device %s (%Lu)\n",
1830 bdevname(bio->bi_bdev, b),
Kent Overstreet4f024f32013-10-11 15:44:27 -07001831 (long long) bio->bi_iter.bi_sector);
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001832 goto end_io;
1833 }
1834
Martin K. Petersene2a60da2012-09-18 12:19:25 -04001835 if (likely(bio_is_rw(bio) &&
1836 nr_sectors > queue_max_hw_sectors(q))) {
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001837 printk(KERN_ERR "bio too big device %s (%u > %u)\n",
1838 bdevname(bio->bi_bdev, b),
1839 bio_sectors(bio),
1840 queue_max_hw_sectors(q));
1841 goto end_io;
1842 }
1843
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001844 part = bio->bi_bdev->bd_part;
Kent Overstreet4f024f32013-10-11 15:44:27 -07001845 if (should_fail_request(part, bio->bi_iter.bi_size) ||
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001846 should_fail_request(&part_to_disk(part)->part0,
Kent Overstreet4f024f32013-10-11 15:44:27 -07001847 bio->bi_iter.bi_size))
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001848 goto end_io;
1849
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 /*
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001851 * If this device has partitions, remap block n
1852 * of partition p to block n+start(p) of the disk.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853 */
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001854 blk_partition_remap(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001856 if (bio_check_eod(bio, nr_sectors))
1857 goto end_io;
1858
1859 /*
1860 * Filter flush bio's early so that make_request based
1861 * drivers without flush support don't have to worry
1862 * about them.
1863 */
1864 if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) {
1865 bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA);
1866 if (!nr_sectors) {
1867 err = 0;
Tejun Heoa7384672008-11-28 13:32:03 +09001868 goto end_io;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869 }
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001870 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001872 if ((bio->bi_rw & REQ_DISCARD) &&
1873 (!blk_queue_discard(q) ||
Martin K. Petersene2a60da2012-09-18 12:19:25 -04001874 ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) {
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001875 err = -EOPNOTSUPP;
1876 goto end_io;
1877 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878
Martin K. Petersen4363ac72012-09-18 12:19:27 -04001879 if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 err = -EOPNOTSUPP;
1881 goto end_io;
1882 }
1883
Tejun Heo7f4b35d2012-06-04 20:40:56 -07001884 /*
1885 * Various block parts want %current->io_context and lazy ioc
1886 * allocation ends up trading a lot of pain for a small amount of
1887 * memory. Just allocate it upfront. This may fail and block
1888 * layer knows how to live with it.
1889 */
1890 create_io_context(GFP_ATOMIC, q->node);
1891
Tejun Heobc16a4f2011-10-19 14:33:01 +02001892 if (blk_throtl_bio(q, bio))
1893 return false; /* throttled, will be resubmitted later */
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001894
Christoph Hellwig5a7bbad2011-09-12 12:12:01 +02001895 trace_block_bio_queue(q, bio);
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001896 return true;
Tejun Heoa7384672008-11-28 13:32:03 +09001897
1898end_io:
1899 bio_endio(bio, err);
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001900 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901}
1902
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001903/**
1904 * generic_make_request - hand a buffer to its device driver for I/O
1905 * @bio: The bio describing the location in memory and on the device.
1906 *
1907 * generic_make_request() is used to make I/O requests of block
1908 * devices. It is passed a &struct bio, which describes the I/O that needs
1909 * to be done.
1910 *
1911 * generic_make_request() does not return any status. The
1912 * success/failure status of the request, along with notification of
1913 * completion, is delivered asynchronously through the bio->bi_end_io
1914 * function described (one day) else where.
1915 *
1916 * The caller of generic_make_request must make sure that bi_io_vec
1917 * are set to describe the memory buffer, and that bi_dev and bi_sector are
1918 * set to describe the device address, and the
1919 * bi_end_io and optionally bi_private are set to describe how
1920 * completion notification should be signaled.
1921 *
1922 * generic_make_request and the drivers it calls may use bi_next if this
1923 * bio happens to be merged with someone else, and may resubmit the bio to
1924 * a lower device by calling into generic_make_request recursively, which
1925 * means the bio should NOT be touched after the call to ->make_request_fn.
Neil Brownd89d8792007-05-01 09:53:42 +02001926 */
1927void generic_make_request(struct bio *bio)
1928{
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001929 struct bio_list bio_list_on_stack;
1930
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001931 if (!generic_make_request_checks(bio))
1932 return;
1933
1934 /*
1935 * We only want one ->make_request_fn to be active at a time, else
1936 * stack usage with stacked devices could be a problem. So use
1937 * current->bio_list to keep a list of requests submited by a
1938 * make_request_fn function. current->bio_list is also used as a
1939 * flag to say if generic_make_request is currently active in this
1940 * task or not. If it is NULL, then no make_request is active. If
1941 * it is non-NULL, then a make_request is active, and new requests
1942 * should be added at the tail
1943 */
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001944 if (current->bio_list) {
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001945 bio_list_add(current->bio_list, bio);
Neil Brownd89d8792007-05-01 09:53:42 +02001946 return;
1947 }
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001948
Neil Brownd89d8792007-05-01 09:53:42 +02001949 /* following loop may be a bit non-obvious, and so deserves some
1950 * explanation.
1951 * Before entering the loop, bio->bi_next is NULL (as all callers
1952 * ensure that) so we have a list with a single bio.
1953 * We pretend that we have just taken it off a longer list, so
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001954 * we assign bio_list to a pointer to the bio_list_on_stack,
1955 * thus initialising the bio_list of new bios to be
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001956 * added. ->make_request() may indeed add some more bios
Neil Brownd89d8792007-05-01 09:53:42 +02001957 * through a recursive call to generic_make_request. If it
1958 * did, we find a non-NULL value in bio_list and re-enter the loop
1959 * from the top. In this case we really did just take the bio
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001960 * of the top of the list (no pretending) and so remove it from
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001961 * bio_list, and call into ->make_request() again.
Neil Brownd89d8792007-05-01 09:53:42 +02001962 */
1963 BUG_ON(bio->bi_next);
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001964 bio_list_init(&bio_list_on_stack);
1965 current->bio_list = &bio_list_on_stack;
Neil Brownd89d8792007-05-01 09:53:42 +02001966 do {
Christoph Hellwig27a84d52011-09-15 14:01:40 +02001967 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1968
1969 q->make_request_fn(q, bio);
1970
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001971 bio = bio_list_pop(current->bio_list);
Neil Brownd89d8792007-05-01 09:53:42 +02001972 } while (bio);
Akinobu Mitabddd87c2010-02-23 08:55:42 +01001973 current->bio_list = NULL; /* deactivate */
Neil Brownd89d8792007-05-01 09:53:42 +02001974}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975EXPORT_SYMBOL(generic_make_request);
1976
1977/**
Randy Dunlap710027a2008-08-19 20:13:11 +02001978 * submit_bio - submit a bio to the block device layer for I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
1980 * @bio: The &struct bio which describes the I/O
1981 *
1982 * submit_bio() is very similar in purpose to generic_make_request(), and
1983 * uses that function to do most of the work. Both are fairly rough
Randy Dunlap710027a2008-08-19 20:13:11 +02001984 * interfaces; @bio must be presetup and ready for I/O.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 *
1986 */
1987void submit_bio(int rw, struct bio *bio)
1988{
Jens Axboe22e2c502005-06-27 10:55:12 +02001989 bio->bi_rw |= rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990
Jens Axboebf2de6f2007-09-27 13:01:25 +02001991 /*
1992 * If it's a regular read/write or a barrier with data attached,
1993 * go through the normal accounting stuff before submission.
1994 */
Martin K. Petersene2a60da2012-09-18 12:19:25 -04001995 if (bio_has_data(bio)) {
Martin K. Petersen4363ac72012-09-18 12:19:27 -04001996 unsigned int count;
1997
1998 if (unlikely(rw & REQ_WRITE_SAME))
1999 count = bdev_logical_block_size(bio->bi_bdev) >> 9;
2000 else
2001 count = bio_sectors(bio);
2002
Jens Axboebf2de6f2007-09-27 13:01:25 +02002003 if (rw & WRITE) {
2004 count_vm_events(PGPGOUT, count);
2005 } else {
Kent Overstreet4f024f32013-10-11 15:44:27 -07002006 task_io_account_read(bio->bi_iter.bi_size);
Jens Axboebf2de6f2007-09-27 13:01:25 +02002007 count_vm_events(PGPGIN, count);
2008 }
2009
2010 if (unlikely(block_dump)) {
2011 char b[BDEVNAME_SIZE];
San Mehat8dcbdc72010-09-14 08:48:01 +02002012 printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07002013 current->comm, task_pid_nr(current),
Jens Axboebf2de6f2007-09-27 13:01:25 +02002014 (rw & WRITE) ? "WRITE" : "READ",
Kent Overstreet4f024f32013-10-11 15:44:27 -07002015 (unsigned long long)bio->bi_iter.bi_sector,
San Mehat8dcbdc72010-09-14 08:48:01 +02002016 bdevname(bio->bi_bdev, b),
2017 count);
Jens Axboebf2de6f2007-09-27 13:01:25 +02002018 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002019 }
2020
2021 generic_make_request(bio);
2022}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023EXPORT_SYMBOL(submit_bio);
2024
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002025/**
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002026 * blk_rq_check_limits - Helper function to check a request for the queue limit
2027 * @q: the queue
2028 * @rq: the request being checked
2029 *
2030 * Description:
2031 * @rq may have been made based on weaker limitations of upper-level queues
2032 * in request stacking drivers, and it may violate the limitation of @q.
2033 * Since the block layer and the underlying device driver trust @rq
2034 * after it is inserted to @q, it should be checked against @q before
2035 * the insertion using this generic function.
2036 *
2037 * This function should also be useful for request stacking drivers
Stefan Weileef35c22010-08-06 21:11:15 +02002038 * in some cases below, so export this function.
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002039 * Request stacking drivers like request-based dm may change the queue
2040 * limits while requests are in the queue (e.g. dm's table swapping).
Masanari Iidae2278672014-02-18 22:54:36 +09002041 * Such request stacking drivers should check those requests against
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002042 * the new queue limits again when they dispatch those requests,
2043 * although such checkings are also done against the old queue limits
2044 * when submitting requests.
2045 */
2046int blk_rq_check_limits(struct request_queue *q, struct request *rq)
2047{
Martin K. Petersene2a60da2012-09-18 12:19:25 -04002048 if (!rq_mergeable(rq))
ike Snitzer33839772010-08-08 12:11:33 -04002049 return 0;
2050
Martin K. Petersenf31dc1c2012-09-18 12:19:26 -04002051 if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) {
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002052 printk(KERN_ERR "%s: over max size limit.\n", __func__);
2053 return -EIO;
2054 }
2055
2056 /*
2057 * queue's settings related to segment counting like q->bounce_pfn
2058 * may differ from that of other stacking queues.
2059 * Recalculate it to check the request correctly on this queue's
2060 * limitation.
2061 */
2062 blk_recalc_rq_segments(rq);
Martin K. Petersen8a783622010-02-26 00:20:39 -05002063 if (rq->nr_phys_segments > queue_max_segments(q)) {
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002064 printk(KERN_ERR "%s: over max segments limit.\n", __func__);
2065 return -EIO;
2066 }
2067
2068 return 0;
2069}
2070EXPORT_SYMBOL_GPL(blk_rq_check_limits);
2071
2072/**
2073 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
2074 * @q: the queue to submit the request
2075 * @rq: the request being queued
2076 */
2077int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
2078{
2079 unsigned long flags;
Jeff Moyer4853aba2011-08-15 21:37:25 +02002080 int where = ELEVATOR_INSERT_BACK;
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002081
2082 if (blk_rq_check_limits(q, rq))
2083 return -EIO;
2084
Akinobu Mitab2c9cd32011-07-26 16:09:03 -07002085 if (rq->rq_disk &&
2086 should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002087 return -EIO;
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002088
Keith Busch7fb48982014-10-17 17:46:38 -06002089 if (q->mq_ops) {
2090 if (blk_queue_io_stat(q))
2091 blk_account_io_start(rq, true);
2092 blk_mq_insert_request(rq, false, true, true);
2093 return 0;
2094 }
2095
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002096 spin_lock_irqsave(q->queue_lock, flags);
Bart Van Assche3f3299d2012-11-28 13:42:38 +01002097 if (unlikely(blk_queue_dying(q))) {
Tejun Heo8ba61432011-12-14 00:33:37 +01002098 spin_unlock_irqrestore(q->queue_lock, flags);
2099 return -ENODEV;
2100 }
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002101
2102 /*
2103 * Submitting request must be dequeued before calling this function
2104 * because it will be linked to another request_queue
2105 */
2106 BUG_ON(blk_queued_rq(rq));
2107
Jeff Moyer4853aba2011-08-15 21:37:25 +02002108 if (rq->cmd_flags & (REQ_FLUSH|REQ_FUA))
2109 where = ELEVATOR_INSERT_FLUSH;
2110
2111 add_acct_request(q, rq, where);
Jeff Moyere67b77c2011-10-17 12:57:23 +02002112 if (where == ELEVATOR_INSERT_FLUSH)
2113 __blk_run_queue(q);
Kiyoshi Ueda82124d62008-09-18 10:45:38 -04002114 spin_unlock_irqrestore(q->queue_lock, flags);
2115
2116 return 0;
2117}
2118EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
2119
Tejun Heo80a761f2009-07-03 17:48:17 +09002120/**
2121 * blk_rq_err_bytes - determine number of bytes till the next failure boundary
2122 * @rq: request to examine
2123 *
2124 * Description:
2125 * A request could be merge of IOs which require different failure
2126 * handling. This function determines the number of bytes which
2127 * can be failed from the beginning of the request without
2128 * crossing into area which need to be retried further.
2129 *
2130 * Return:
2131 * The number of bytes to fail.
2132 *
2133 * Context:
2134 * queue_lock must be held.
2135 */
2136unsigned int blk_rq_err_bytes(const struct request *rq)
2137{
2138 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
2139 unsigned int bytes = 0;
2140 struct bio *bio;
2141
2142 if (!(rq->cmd_flags & REQ_MIXED_MERGE))
2143 return blk_rq_bytes(rq);
2144
2145 /*
2146 * Currently the only 'mixing' which can happen is between
2147 * different fastfail types. We can safely fail portions
2148 * which have all the failfast bits that the first one has -
2149 * the ones which are at least as eager to fail as the first
2150 * one.
2151 */
2152 for (bio = rq->bio; bio; bio = bio->bi_next) {
2153 if ((bio->bi_rw & ff) != ff)
2154 break;
Kent Overstreet4f024f32013-10-11 15:44:27 -07002155 bytes += bio->bi_iter.bi_size;
Tejun Heo80a761f2009-07-03 17:48:17 +09002156 }
2157
2158 /* this could lead to infinite loop */
2159 BUG_ON(blk_rq_bytes(rq) && !bytes);
2160 return bytes;
2161}
2162EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
2163
Jens Axboe320ae512013-10-24 09:20:05 +01002164void blk_account_io_completion(struct request *req, unsigned int bytes)
Jens Axboebc58ba92009-01-23 10:54:44 +01002165{
Jens Axboec2553b52009-04-24 08:10:11 +02002166 if (blk_do_io_stat(req)) {
Jens Axboebc58ba92009-01-23 10:54:44 +01002167 const int rw = rq_data_dir(req);
2168 struct hd_struct *part;
2169 int cpu;
2170
2171 cpu = part_stat_lock();
Jerome Marchand09e099d2011-01-05 16:57:38 +01002172 part = req->part;
Jens Axboebc58ba92009-01-23 10:54:44 +01002173 part_stat_add(cpu, part, sectors[rw], bytes >> 9);
2174 part_stat_unlock();
2175 }
2176}
2177
Jens Axboe320ae512013-10-24 09:20:05 +01002178void blk_account_io_done(struct request *req)
Jens Axboebc58ba92009-01-23 10:54:44 +01002179{
Jens Axboebc58ba92009-01-23 10:54:44 +01002180 /*
Tejun Heodd4c1332010-09-03 11:56:16 +02002181 * Account IO completion. flush_rq isn't accounted as a
2182 * normal IO on queueing nor completion. Accounting the
2183 * containing request is enough.
Jens Axboebc58ba92009-01-23 10:54:44 +01002184 */
Tejun Heo414b4ff2011-01-25 12:43:49 +01002185 if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) {
Jens Axboebc58ba92009-01-23 10:54:44 +01002186 unsigned long duration = jiffies - req->start_time;
2187 const int rw = rq_data_dir(req);
2188 struct hd_struct *part;
2189 int cpu;
2190
2191 cpu = part_stat_lock();
Jerome Marchand09e099d2011-01-05 16:57:38 +01002192 part = req->part;
Jens Axboebc58ba92009-01-23 10:54:44 +01002193
2194 part_stat_inc(cpu, part, ios[rw]);
2195 part_stat_add(cpu, part, ticks[rw], duration);
2196 part_round_stats(cpu, part);
Nikanth Karthikesan316d3152009-10-06 20:16:55 +02002197 part_dec_in_flight(part, rw);
Jens Axboebc58ba92009-01-23 10:54:44 +01002198
Jens Axboe6c23a962011-01-07 08:43:37 +01002199 hd_struct_put(part);
Jens Axboebc58ba92009-01-23 10:54:44 +01002200 part_stat_unlock();
2201 }
2202}
2203
Rafael J. Wysocki47fafbc2014-12-04 01:00:23 +01002204#ifdef CONFIG_PM
Lin Mingc8158812013-03-23 11:42:27 +08002205/*
2206 * Don't process normal requests when queue is suspended
2207 * or in the process of suspending/resuming
2208 */
2209static struct request *blk_pm_peek_request(struct request_queue *q,
2210 struct request *rq)
2211{
2212 if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
2213 (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM))))
2214 return NULL;
2215 else
2216 return rq;
2217}
2218#else
2219static inline struct request *blk_pm_peek_request(struct request_queue *q,
2220 struct request *rq)
2221{
2222 return rq;
2223}
2224#endif
2225
Jens Axboe320ae512013-10-24 09:20:05 +01002226void blk_account_io_start(struct request *rq, bool new_io)
2227{
2228 struct hd_struct *part;
2229 int rw = rq_data_dir(rq);
2230 int cpu;
2231
2232 if (!blk_do_io_stat(rq))
2233 return;
2234
2235 cpu = part_stat_lock();
2236
2237 if (!new_io) {
2238 part = rq->part;
2239 part_stat_inc(cpu, part, merges[rw]);
2240 } else {
2241 part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
2242 if (!hd_struct_try_get(part)) {
2243 /*
2244 * The partition is already being removed,
2245 * the request will be accounted on the disk only
2246 *
2247 * We take a reference on disk->part0 although that
2248 * partition will never be deleted, so we can treat
2249 * it as any other partition.
2250 */
2251 part = &rq->rq_disk->part0;
2252 hd_struct_get(part);
2253 }
2254 part_round_stats(cpu, part);
2255 part_inc_in_flight(part, rw);
2256 rq->part = part;
2257 }
2258
2259 part_stat_unlock();
2260}
2261
Tejun Heo53a08802008-12-03 12:41:26 +01002262/**
Tejun Heo9934c8c2009-05-08 11:54:16 +09002263 * blk_peek_request - peek at the top of a request queue
2264 * @q: request queue to peek at
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002265 *
2266 * Description:
Tejun Heo9934c8c2009-05-08 11:54:16 +09002267 * Return the request at the top of @q. The returned request
2268 * should be started using blk_start_request() before LLD starts
2269 * processing it.
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002270 *
2271 * Return:
Tejun Heo9934c8c2009-05-08 11:54:16 +09002272 * Pointer to the request at the top of @q if available. Null
2273 * otherwise.
2274 *
2275 * Context:
2276 * queue_lock must be held.
2277 */
2278struct request *blk_peek_request(struct request_queue *q)
Tejun Heo158dbda2009-04-23 11:05:18 +09002279{
2280 struct request *rq;
2281 int ret;
2282
2283 while ((rq = __elv_next_request(q)) != NULL) {
Lin Mingc8158812013-03-23 11:42:27 +08002284
2285 rq = blk_pm_peek_request(q, rq);
2286 if (!rq)
2287 break;
2288
Tejun Heo158dbda2009-04-23 11:05:18 +09002289 if (!(rq->cmd_flags & REQ_STARTED)) {
2290 /*
2291 * This is the first time the device driver
2292 * sees this request (possibly after
2293 * requeueing). Notify IO scheduler.
2294 */
Christoph Hellwig33659eb2010-08-07 18:17:56 +02002295 if (rq->cmd_flags & REQ_SORTED)
Tejun Heo158dbda2009-04-23 11:05:18 +09002296 elv_activate_rq(q, rq);
2297
2298 /*
2299 * just mark as started even if we don't start
2300 * it, a request that has been delayed should
2301 * not be passed by new incoming requests
2302 */
2303 rq->cmd_flags |= REQ_STARTED;
2304 trace_block_rq_issue(q, rq);
2305 }
2306
2307 if (!q->boundary_rq || q->boundary_rq == rq) {
2308 q->end_sector = rq_end_sector(rq);
2309 q->boundary_rq = NULL;
2310 }
2311
2312 if (rq->cmd_flags & REQ_DONTPREP)
2313 break;
2314
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002315 if (q->dma_drain_size && blk_rq_bytes(rq)) {
Tejun Heo158dbda2009-04-23 11:05:18 +09002316 /*
2317 * make sure space for the drain appears we
2318 * know we can do this because max_hw_segments
2319 * has been adjusted to be one fewer than the
2320 * device can handle
2321 */
2322 rq->nr_phys_segments++;
2323 }
2324
2325 if (!q->prep_rq_fn)
2326 break;
2327
2328 ret = q->prep_rq_fn(q, rq);
2329 if (ret == BLKPREP_OK) {
2330 break;
2331 } else if (ret == BLKPREP_DEFER) {
2332 /*
2333 * the request may have been (partially) prepped.
2334 * we need to keep this request in the front to
2335 * avoid resource deadlock. REQ_STARTED will
2336 * prevent other fs requests from passing this one.
2337 */
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002338 if (q->dma_drain_size && blk_rq_bytes(rq) &&
Tejun Heo158dbda2009-04-23 11:05:18 +09002339 !(rq->cmd_flags & REQ_DONTPREP)) {
2340 /*
2341 * remove the space for the drain we added
2342 * so that we don't add it again
2343 */
2344 --rq->nr_phys_segments;
2345 }
2346
2347 rq = NULL;
2348 break;
2349 } else if (ret == BLKPREP_KILL) {
2350 rq->cmd_flags |= REQ_QUIET;
James Bottomleyc143dc92009-05-30 06:43:49 +02002351 /*
2352 * Mark this request as started so we don't trigger
2353 * any debug logic in the end I/O path.
2354 */
2355 blk_start_request(rq);
Tejun Heo40cbbb72009-04-23 11:05:19 +09002356 __blk_end_request_all(rq, -EIO);
Tejun Heo158dbda2009-04-23 11:05:18 +09002357 } else {
2358 printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
2359 break;
2360 }
2361 }
2362
2363 return rq;
2364}
Tejun Heo9934c8c2009-05-08 11:54:16 +09002365EXPORT_SYMBOL(blk_peek_request);
Tejun Heo158dbda2009-04-23 11:05:18 +09002366
Tejun Heo9934c8c2009-05-08 11:54:16 +09002367void blk_dequeue_request(struct request *rq)
Tejun Heo158dbda2009-04-23 11:05:18 +09002368{
Tejun Heo9934c8c2009-05-08 11:54:16 +09002369 struct request_queue *q = rq->q;
2370
Tejun Heo158dbda2009-04-23 11:05:18 +09002371 BUG_ON(list_empty(&rq->queuelist));
2372 BUG_ON(ELV_ON_HASH(rq));
2373
2374 list_del_init(&rq->queuelist);
2375
2376 /*
2377 * the time frame between a request being removed from the lists
2378 * and to it is freed is accounted as io that is in progress at
2379 * the driver side.
2380 */
Divyesh Shah91952912010-04-01 15:01:41 -07002381 if (blk_account_rq(rq)) {
Jens Axboe0a7ae2f2009-05-20 08:54:31 +02002382 q->in_flight[rq_is_sync(rq)]++;
Divyesh Shah91952912010-04-01 15:01:41 -07002383 set_io_start_time_ns(rq);
2384 }
Tejun Heo158dbda2009-04-23 11:05:18 +09002385}
2386
Tejun Heo5efccd12009-04-23 11:05:18 +09002387/**
Tejun Heo9934c8c2009-05-08 11:54:16 +09002388 * blk_start_request - start request processing on the driver
2389 * @req: request to dequeue
2390 *
2391 * Description:
2392 * Dequeue @req and start timeout timer on it. This hands off the
2393 * request to the driver.
2394 *
2395 * Block internal functions which don't want to start timer should
2396 * call blk_dequeue_request().
2397 *
2398 * Context:
2399 * queue_lock must be held.
2400 */
2401void blk_start_request(struct request *req)
2402{
2403 blk_dequeue_request(req);
2404
2405 /*
Tejun Heo5f49f632009-05-19 18:33:05 +09002406 * We are now handing the request to the hardware, initialize
2407 * resid_len to full count and add the timeout handler.
Tejun Heo9934c8c2009-05-08 11:54:16 +09002408 */
Tejun Heo5f49f632009-05-19 18:33:05 +09002409 req->resid_len = blk_rq_bytes(req);
FUJITA Tomonoridbb66c42009-06-09 05:47:10 +02002410 if (unlikely(blk_bidi_rq(req)))
2411 req->next_rq->resid_len = blk_rq_bytes(req->next_rq);
2412
Jeff Moyer4912aa62013-10-08 14:36:41 -04002413 BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
Tejun Heo9934c8c2009-05-08 11:54:16 +09002414 blk_add_timer(req);
2415}
2416EXPORT_SYMBOL(blk_start_request);
2417
2418/**
2419 * blk_fetch_request - fetch a request from a request queue
2420 * @q: request queue to fetch a request from
2421 *
2422 * Description:
2423 * Return the request at the top of @q. The request is started on
2424 * return and LLD can start processing it immediately.
2425 *
2426 * Return:
2427 * Pointer to the request at the top of @q if available. Null
2428 * otherwise.
2429 *
2430 * Context:
2431 * queue_lock must be held.
2432 */
2433struct request *blk_fetch_request(struct request_queue *q)
2434{
2435 struct request *rq;
2436
2437 rq = blk_peek_request(q);
2438 if (rq)
2439 blk_start_request(rq);
2440 return rq;
2441}
2442EXPORT_SYMBOL(blk_fetch_request);
2443
2444/**
Tejun Heo2e60e022009-04-23 11:05:18 +09002445 * blk_update_request - Special helper function for request stacking drivers
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002446 * @req: the request being processed
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002447 * @error: %0 for success, < %0 for error
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002448 * @nr_bytes: number of bytes to complete @req
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002449 *
2450 * Description:
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002451 * Ends I/O on a number of bytes attached to @req, but doesn't complete
2452 * the request structure even if @req doesn't have leftover.
2453 * If @req has leftover, sets it up for the next range of segments.
Tejun Heo2e60e022009-04-23 11:05:18 +09002454 *
2455 * This special helper function is only for request stacking drivers
2456 * (e.g. request-based dm) so that they can handle partial completion.
2457 * Actual device drivers should use blk_end_request instead.
2458 *
2459 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
2460 * %false return from this function.
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002461 *
2462 * Return:
Tejun Heo2e60e022009-04-23 11:05:18 +09002463 * %false - this request doesn't have any more data
2464 * %true - this request has more data
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -05002465 **/
Tejun Heo2e60e022009-04-23 11:05:18 +09002466bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002467{
Kent Overstreetf79ea412012-09-20 16:38:30 -07002468 int total_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002469
Hannes Reinecke4a0efdc2014-10-01 14:32:31 +02002470 trace_block_rq_complete(req->q, req, nr_bytes);
2471
Tejun Heo2e60e022009-04-23 11:05:18 +09002472 if (!req->bio)
2473 return false;
2474
Linus Torvalds1da177e2005-04-16 15:20:36 -07002475 /*
Tejun Heo6f414692009-04-19 07:00:41 +09002476 * For fs requests, rq is just carrier of independent bio's
2477 * and each partial completion should be handled separately.
2478 * Reset per-request error on each partial completion.
2479 *
2480 * TODO: tj: This is too subtle. It would be better to let
2481 * low level drivers do what they see fit.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002482 */
Christoph Hellwig33659eb2010-08-07 18:17:56 +02002483 if (req->cmd_type == REQ_TYPE_FS)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002484 req->errors = 0;
2485
Christoph Hellwig33659eb2010-08-07 18:17:56 +02002486 if (error && req->cmd_type == REQ_TYPE_FS &&
2487 !(req->cmd_flags & REQ_QUIET)) {
Hannes Reinecke79775562011-01-18 10:13:13 +01002488 char *error_type;
2489
2490 switch (error) {
2491 case -ENOLINK:
2492 error_type = "recoverable transport";
2493 break;
2494 case -EREMOTEIO:
2495 error_type = "critical target";
2496 break;
2497 case -EBADE:
2498 error_type = "critical nexus";
2499 break;
Hannes Reinecked1ffc1f2013-01-30 09:26:16 +00002500 case -ETIMEDOUT:
2501 error_type = "timeout";
2502 break;
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +02002503 case -ENOSPC:
2504 error_type = "critical space allocation";
2505 break;
Hannes Reinecke7e782af2013-07-01 15:16:26 +02002506 case -ENODATA:
2507 error_type = "critical medium";
2508 break;
Hannes Reinecke79775562011-01-18 10:13:13 +01002509 case -EIO:
2510 default:
2511 error_type = "I/O";
2512 break;
2513 }
Robert Elliottef3ecb62014-08-27 10:50:31 -05002514 printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n",
2515 __func__, error_type, req->rq_disk ?
Yi Zou37d7b342012-08-30 16:26:25 -07002516 req->rq_disk->disk_name : "?",
2517 (unsigned long long)blk_rq_pos(req));
2518
Linus Torvalds1da177e2005-04-16 15:20:36 -07002519 }
2520
Jens Axboebc58ba92009-01-23 10:54:44 +01002521 blk_account_io_completion(req, nr_bytes);
Jens Axboed72d9042005-11-01 08:35:42 +01002522
Kent Overstreetf79ea412012-09-20 16:38:30 -07002523 total_bytes = 0;
2524 while (req->bio) {
2525 struct bio *bio = req->bio;
Kent Overstreet4f024f32013-10-11 15:44:27 -07002526 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002527
Kent Overstreet4f024f32013-10-11 15:44:27 -07002528 if (bio_bytes == bio->bi_iter.bi_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529 req->bio = bio->bi_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530
Kent Overstreetf79ea412012-09-20 16:38:30 -07002531 req_bio_endio(req, bio, bio_bytes, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002532
Kent Overstreetf79ea412012-09-20 16:38:30 -07002533 total_bytes += bio_bytes;
2534 nr_bytes -= bio_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002535
Kent Overstreetf79ea412012-09-20 16:38:30 -07002536 if (!nr_bytes)
2537 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002538 }
2539
2540 /*
2541 * completely done
2542 */
Tejun Heo2e60e022009-04-23 11:05:18 +09002543 if (!req->bio) {
2544 /*
2545 * Reset counters so that the request stacking driver
2546 * can find how many bytes remain in the request
2547 * later.
2548 */
Tejun Heoa2dec7b2009-05-07 22:24:44 +09002549 req->__data_len = 0;
Tejun Heo2e60e022009-04-23 11:05:18 +09002550 return false;
2551 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002552
Tejun Heoa2dec7b2009-05-07 22:24:44 +09002553 req->__data_len -= total_bytes;
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002554
2555 /* update sector only for requests with clear definition of sector */
Martin K. Petersene2a60da2012-09-18 12:19:25 -04002556 if (req->cmd_type == REQ_TYPE_FS)
Tejun Heoa2dec7b2009-05-07 22:24:44 +09002557 req->__sector += total_bytes >> 9;
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002558
Tejun Heo80a761f2009-07-03 17:48:17 +09002559 /* mixed attributes always follow the first bio */
2560 if (req->cmd_flags & REQ_MIXED_MERGE) {
2561 req->cmd_flags &= ~REQ_FAILFAST_MASK;
2562 req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK;
2563 }
2564
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002565 /*
2566 * If total number of sectors is less than the first segment
2567 * size, something has gone terribly wrong.
2568 */
2569 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
Jens Axboe81829242011-03-30 09:51:33 +02002570 blk_dump_rq_flags(req, "request botched");
Tejun Heoa2dec7b2009-05-07 22:24:44 +09002571 req->__data_len = blk_rq_cur_bytes(req);
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002572 }
2573
2574 /* recalculate the number of segments */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002575 blk_recalc_rq_segments(req);
Tejun Heo2e46e8b2009-05-07 22:24:41 +09002576
Tejun Heo2e60e022009-04-23 11:05:18 +09002577 return true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002578}
Tejun Heo2e60e022009-04-23 11:05:18 +09002579EXPORT_SYMBOL_GPL(blk_update_request);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002580
Tejun Heo2e60e022009-04-23 11:05:18 +09002581static bool blk_update_bidi_request(struct request *rq, int error,
2582 unsigned int nr_bytes,
2583 unsigned int bidi_bytes)
Tejun Heo5efccd12009-04-23 11:05:18 +09002584{
Tejun Heo2e60e022009-04-23 11:05:18 +09002585 if (blk_update_request(rq, error, nr_bytes))
2586 return true;
Tejun Heo5efccd12009-04-23 11:05:18 +09002587
Tejun Heo2e60e022009-04-23 11:05:18 +09002588 /* Bidi request must be completed as a whole */
2589 if (unlikely(blk_bidi_rq(rq)) &&
2590 blk_update_request(rq->next_rq, error, bidi_bytes))
2591 return true;
Tejun Heo5efccd12009-04-23 11:05:18 +09002592
Jens Axboee2e1a142010-06-09 10:42:09 +02002593 if (blk_queue_add_random(rq->q))
2594 add_disk_randomness(rq->rq_disk);
Tejun Heo2e60e022009-04-23 11:05:18 +09002595
2596 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002597}
2598
James Bottomley28018c22010-07-01 19:49:17 +09002599/**
2600 * blk_unprep_request - unprepare a request
2601 * @req: the request
2602 *
2603 * This function makes a request ready for complete resubmission (or
2604 * completion). It happens only after all error handling is complete,
2605 * so represents the appropriate moment to deallocate any resources
2606 * that were allocated to the request in the prep_rq_fn. The queue
2607 * lock is held when calling this.
2608 */
2609void blk_unprep_request(struct request *req)
2610{
2611 struct request_queue *q = req->q;
2612
2613 req->cmd_flags &= ~REQ_DONTPREP;
2614 if (q->unprep_rq_fn)
2615 q->unprep_rq_fn(q, req);
2616}
2617EXPORT_SYMBOL_GPL(blk_unprep_request);
2618
Linus Torvalds1da177e2005-04-16 15:20:36 -07002619/*
2620 * queue lock must be held
2621 */
Christoph Hellwig12120072014-04-16 09:44:59 +02002622void blk_finish_request(struct request *req, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002623{
Christoph Hellwig125c99b2014-11-03 12:47:47 +01002624 if (req->cmd_flags & REQ_QUEUED)
Kiyoshi Uedab8286232007-12-11 17:53:24 -05002625 blk_queue_end_tag(req->q, req);
2626
James Bottomleyba396a62009-05-27 14:17:08 +02002627 BUG_ON(blk_queued_rq(req));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002628
Christoph Hellwig33659eb2010-08-07 18:17:56 +02002629 if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS)
Matthew Garrett31373d02010-04-06 14:25:14 +02002630 laptop_io_completion(&req->q->backing_dev_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631
Mike Andersone78042e2008-10-30 02:16:20 -07002632 blk_delete_timer(req);
2633
James Bottomley28018c22010-07-01 19:49:17 +09002634 if (req->cmd_flags & REQ_DONTPREP)
2635 blk_unprep_request(req);
2636
Jens Axboebc58ba92009-01-23 10:54:44 +01002637 blk_account_io_done(req);
Kiyoshi Uedab8286232007-12-11 17:53:24 -05002638
Linus Torvalds1da177e2005-04-16 15:20:36 -07002639 if (req->end_io)
Tejun Heo8ffdc652006-01-06 09:49:03 +01002640 req->end_io(req, error);
Kiyoshi Uedab8286232007-12-11 17:53:24 -05002641 else {
2642 if (blk_bidi_rq(req))
2643 __blk_put_request(req->next_rq->q, req->next_rq);
2644
Linus Torvalds1da177e2005-04-16 15:20:36 -07002645 __blk_put_request(req->q, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646 }
2647}
Christoph Hellwig12120072014-04-16 09:44:59 +02002648EXPORT_SYMBOL(blk_finish_request);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649
Kiyoshi Ueda3b113132007-12-11 17:41:17 -05002650/**
Tejun Heo2e60e022009-04-23 11:05:18 +09002651 * blk_end_bidi_request - Complete a bidi request
2652 * @rq: the request to complete
Randy Dunlap710027a2008-08-19 20:13:11 +02002653 * @error: %0 for success, < %0 for error
Kiyoshi Uedae3a04fe2007-12-11 17:51:46 -05002654 * @nr_bytes: number of bytes to complete @rq
2655 * @bidi_bytes: number of bytes to complete @rq->next_rq
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002656 *
2657 * Description:
2658 * Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
Tejun Heo2e60e022009-04-23 11:05:18 +09002659 * Drivers that supports bidi can safely call this member for any
2660 * type of request, bidi or uni. In the later case @bidi_bytes is
2661 * just ignored.
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002662 *
2663 * Return:
Tejun Heo2e60e022009-04-23 11:05:18 +09002664 * %false - we are done with this request
2665 * %true - still buffers pending for this request
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002666 **/
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002667static bool blk_end_bidi_request(struct request *rq, int error,
2668 unsigned int nr_bytes, unsigned int bidi_bytes)
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002669{
2670 struct request_queue *q = rq->q;
Tejun Heo2e60e022009-04-23 11:05:18 +09002671 unsigned long flags;
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002672
Tejun Heo2e60e022009-04-23 11:05:18 +09002673 if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
2674 return true;
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002675
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002676 spin_lock_irqsave(q->queue_lock, flags);
Tejun Heo2e60e022009-04-23 11:05:18 +09002677 blk_finish_request(rq, error);
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002678 spin_unlock_irqrestore(q->queue_lock, flags);
2679
Tejun Heo2e60e022009-04-23 11:05:18 +09002680 return false;
Kiyoshi Uedae3a04fe2007-12-11 17:51:46 -05002681}
Kiyoshi Uedae3a04fe2007-12-11 17:51:46 -05002682
2683/**
Tejun Heo2e60e022009-04-23 11:05:18 +09002684 * __blk_end_bidi_request - Complete a bidi request with queue lock held
2685 * @rq: the request to complete
2686 * @error: %0 for success, < %0 for error
2687 * @nr_bytes: number of bytes to complete @rq
2688 * @bidi_bytes: number of bytes to complete @rq->next_rq
Tejun Heo5efccd12009-04-23 11:05:18 +09002689 *
2690 * Description:
Tejun Heo2e60e022009-04-23 11:05:18 +09002691 * Identical to blk_end_bidi_request() except that queue lock is
2692 * assumed to be locked on entry and remains so on return.
Tejun Heo5efccd12009-04-23 11:05:18 +09002693 *
Tejun Heo2e60e022009-04-23 11:05:18 +09002694 * Return:
2695 * %false - we are done with this request
2696 * %true - still buffers pending for this request
Tejun Heo5efccd12009-04-23 11:05:18 +09002697 **/
Jeff Moyer4853aba2011-08-15 21:37:25 +02002698bool __blk_end_bidi_request(struct request *rq, int error,
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002699 unsigned int nr_bytes, unsigned int bidi_bytes)
Tejun Heo5efccd12009-04-23 11:05:18 +09002700{
Tejun Heo2e60e022009-04-23 11:05:18 +09002701 if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
2702 return true;
Tejun Heo5efccd12009-04-23 11:05:18 +09002703
Tejun Heo2e60e022009-04-23 11:05:18 +09002704 blk_finish_request(rq, error);
Tejun Heo5efccd12009-04-23 11:05:18 +09002705
Tejun Heo2e60e022009-04-23 11:05:18 +09002706 return false;
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002707}
2708
2709/**
2710 * blk_end_request - Helper function for drivers to complete the request.
2711 * @rq: the request being processed
2712 * @error: %0 for success, < %0 for error
2713 * @nr_bytes: number of bytes to complete
2714 *
2715 * Description:
2716 * Ends I/O on a number of bytes attached to @rq.
2717 * If @rq has leftover, sets it up for the next range of segments.
2718 *
2719 * Return:
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002720 * %false - we are done with this request
2721 * %true - still buffers pending for this request
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002722 **/
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002723bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002724{
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002725 return blk_end_bidi_request(rq, error, nr_bytes, 0);
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002726}
Jens Axboe56ad1742009-07-28 22:11:24 +02002727EXPORT_SYMBOL(blk_end_request);
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002728
2729/**
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002730 * blk_end_request_all - Helper function for drives to finish the request.
2731 * @rq: the request to finish
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002732 * @error: %0 for success, < %0 for error
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002733 *
2734 * Description:
2735 * Completely finish @rq.
2736 */
2737void blk_end_request_all(struct request *rq, int error)
2738{
2739 bool pending;
2740 unsigned int bidi_bytes = 0;
2741
2742 if (unlikely(blk_bidi_rq(rq)))
2743 bidi_bytes = blk_rq_bytes(rq->next_rq);
2744
2745 pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
2746 BUG_ON(pending);
2747}
Jens Axboe56ad1742009-07-28 22:11:24 +02002748EXPORT_SYMBOL(blk_end_request_all);
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002749
2750/**
2751 * blk_end_request_cur - Helper function to finish the current request chunk.
2752 * @rq: the request to finish the current chunk for
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002753 * @error: %0 for success, < %0 for error
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002754 *
2755 * Description:
2756 * Complete the current consecutively mapped chunk from @rq.
2757 *
2758 * Return:
2759 * %false - we are done with this request
2760 * %true - still buffers pending for this request
2761 */
2762bool blk_end_request_cur(struct request *rq, int error)
2763{
2764 return blk_end_request(rq, error, blk_rq_cur_bytes(rq));
2765}
Jens Axboe56ad1742009-07-28 22:11:24 +02002766EXPORT_SYMBOL(blk_end_request_cur);
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002767
2768/**
Tejun Heo80a761f2009-07-03 17:48:17 +09002769 * blk_end_request_err - Finish a request till the next failure boundary.
2770 * @rq: the request to finish till the next failure boundary for
2771 * @error: must be negative errno
2772 *
2773 * Description:
2774 * Complete @rq till the next failure boundary.
2775 *
2776 * Return:
2777 * %false - we are done with this request
2778 * %true - still buffers pending for this request
2779 */
2780bool blk_end_request_err(struct request *rq, int error)
2781{
2782 WARN_ON(error >= 0);
2783 return blk_end_request(rq, error, blk_rq_err_bytes(rq));
2784}
2785EXPORT_SYMBOL_GPL(blk_end_request_err);
2786
2787/**
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002788 * __blk_end_request - Helper function for drivers to complete the request.
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002789 * @rq: the request being processed
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002790 * @error: %0 for success, < %0 for error
2791 * @nr_bytes: number of bytes to complete
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002792 *
2793 * Description:
2794 * Must be called with queue lock held unlike blk_end_request().
2795 *
2796 * Return:
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002797 * %false - we are done with this request
2798 * %true - still buffers pending for this request
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002799 **/
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002800bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002801{
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002802 return __blk_end_bidi_request(rq, error, nr_bytes, 0);
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002803}
Jens Axboe56ad1742009-07-28 22:11:24 +02002804EXPORT_SYMBOL(__blk_end_request);
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002805
2806/**
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002807 * __blk_end_request_all - Helper function for drives to finish the request.
2808 * @rq: the request to finish
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002809 * @error: %0 for success, < %0 for error
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -05002810 *
2811 * Description:
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002812 * Completely finish @rq. Must be called with queue lock held.
Kiyoshi Ueda32fab442008-09-18 10:45:09 -04002813 */
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002814void __blk_end_request_all(struct request *rq, int error)
Kiyoshi Ueda32fab442008-09-18 10:45:09 -04002815{
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002816 bool pending;
2817 unsigned int bidi_bytes = 0;
2818
2819 if (unlikely(blk_bidi_rq(rq)))
2820 bidi_bytes = blk_rq_bytes(rq->next_rq);
2821
2822 pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
2823 BUG_ON(pending);
Kiyoshi Ueda32fab442008-09-18 10:45:09 -04002824}
Jens Axboe56ad1742009-07-28 22:11:24 +02002825EXPORT_SYMBOL(__blk_end_request_all);
Kiyoshi Ueda32fab442008-09-18 10:45:09 -04002826
2827/**
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002828 * __blk_end_request_cur - Helper function to finish the current request chunk.
2829 * @rq: the request to finish the current chunk for
Randy Dunlap8ebf9752009-06-11 20:00:41 -07002830 * @error: %0 for success, < %0 for error
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002831 *
2832 * Description:
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002833 * Complete the current consecutively mapped chunk from @rq. Must
2834 * be called with queue lock held.
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002835 *
2836 * Return:
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002837 * %false - we are done with this request
2838 * %true - still buffers pending for this request
2839 */
2840bool __blk_end_request_cur(struct request *rq, int error)
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002841{
FUJITA Tomonorib1f74492009-05-11 17:56:09 +09002842 return __blk_end_request(rq, error, blk_rq_cur_bytes(rq));
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002843}
Jens Axboe56ad1742009-07-28 22:11:24 +02002844EXPORT_SYMBOL(__blk_end_request_cur);
Kiyoshi Uedae19a3ab2007-12-11 17:51:02 -05002845
Tejun Heo80a761f2009-07-03 17:48:17 +09002846/**
2847 * __blk_end_request_err - Finish a request till the next failure boundary.
2848 * @rq: the request to finish till the next failure boundary for
2849 * @error: must be negative errno
2850 *
2851 * Description:
2852 * Complete @rq till the next failure boundary. Must be called
2853 * with queue lock held.
2854 *
2855 * Return:
2856 * %false - we are done with this request
2857 * %true - still buffers pending for this request
2858 */
2859bool __blk_end_request_err(struct request *rq, int error)
2860{
2861 WARN_ON(error >= 0);
2862 return __blk_end_request(rq, error, blk_rq_err_bytes(rq));
2863}
2864EXPORT_SYMBOL_GPL(__blk_end_request_err);
2865
Jens Axboe86db1e22008-01-29 14:53:40 +01002866void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
2867 struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002868{
Tejun Heoa82afdf2009-07-03 17:48:16 +09002869 /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */
Christoph Hellwig7b6d91d2010-08-07 18:20:39 +02002870 rq->cmd_flags |= bio->bi_rw & REQ_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002871
Jens Axboeb4f42e22014-04-10 09:46:28 -06002872 if (bio_has_data(bio))
David Woodhousefb2dce82008-08-05 18:01:53 +01002873 rq->nr_phys_segments = bio_phys_segments(q, bio);
Jens Axboeb4f42e22014-04-10 09:46:28 -06002874
Kent Overstreet4f024f32013-10-11 15:44:27 -07002875 rq->__data_len = bio->bi_iter.bi_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002876 rq->bio = rq->biotail = bio;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002877
NeilBrown66846572007-08-16 13:31:28 +02002878 if (bio->bi_bdev)
2879 rq->rq_disk = bio->bi_bdev->bd_disk;
2880}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002881
Ilya Loginov2d4dc892009-11-26 09:16:19 +01002882#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
2883/**
2884 * rq_flush_dcache_pages - Helper function to flush all pages in a request
2885 * @rq: the request to be flushed
2886 *
2887 * Description:
2888 * Flush all pages in @rq.
2889 */
2890void rq_flush_dcache_pages(struct request *rq)
2891{
2892 struct req_iterator iter;
Kent Overstreet79886132013-11-23 17:19:00 -08002893 struct bio_vec bvec;
Ilya Loginov2d4dc892009-11-26 09:16:19 +01002894
2895 rq_for_each_segment(bvec, rq, iter)
Kent Overstreet79886132013-11-23 17:19:00 -08002896 flush_dcache_page(bvec.bv_page);
Ilya Loginov2d4dc892009-11-26 09:16:19 +01002897}
2898EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
2899#endif
2900
Kiyoshi Uedaef9e3fa2008-10-01 16:12:15 +02002901/**
2902 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
2903 * @q : the queue of the device being checked
2904 *
2905 * Description:
2906 * Check if underlying low-level drivers of a device are busy.
2907 * If the drivers want to export their busy state, they must set own
2908 * exporting function using blk_queue_lld_busy() first.
2909 *
2910 * Basically, this function is used only by request stacking drivers
2911 * to stop dispatching requests to underlying devices when underlying
2912 * devices are busy. This behavior helps more I/O merging on the queue
2913 * of the request stacking driver and prevents I/O throughput regression
2914 * on burst I/O load.
2915 *
2916 * Return:
2917 * 0 - Not busy (The request stacking driver should dispatch request)
2918 * 1 - Busy (The request stacking driver should stop dispatching request)
2919 */
2920int blk_lld_busy(struct request_queue *q)
2921{
2922 if (q->lld_busy_fn)
2923 return q->lld_busy_fn(q);
2924
2925 return 0;
2926}
2927EXPORT_SYMBOL_GPL(blk_lld_busy);
2928
Mike Snitzer78d8e582015-06-26 10:01:13 -04002929/**
2930 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
2931 * @rq: the clone request to be cleaned up
2932 *
2933 * Description:
2934 * Free all bios in @rq for a cloned request.
2935 */
2936void blk_rq_unprep_clone(struct request *rq)
2937{
2938 struct bio *bio;
2939
2940 while ((bio = rq->bio) != NULL) {
2941 rq->bio = bio->bi_next;
2942
2943 bio_put(bio);
2944 }
2945}
2946EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
2947
2948/*
2949 * Copy attributes of the original request to the clone request.
2950 * The actual data parts (e.g. ->cmd, ->sense) are not copied.
2951 */
2952static void __blk_rq_prep_clone(struct request *dst, struct request *src)
Kiyoshi Uedab0fd2712009-06-11 13:10:16 +02002953{
2954 dst->cpu = src->cpu;
Mike Snitzer78d8e582015-06-26 10:01:13 -04002955 dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE;
Kiyoshi Uedab0fd2712009-06-11 13:10:16 +02002956 dst->cmd_type = src->cmd_type;
2957 dst->__sector = blk_rq_pos(src);
2958 dst->__data_len = blk_rq_bytes(src);
2959 dst->nr_phys_segments = src->nr_phys_segments;
2960 dst->ioprio = src->ioprio;
2961 dst->extra_len = src->extra_len;
Mike Snitzer78d8e582015-06-26 10:01:13 -04002962}
2963
2964/**
2965 * blk_rq_prep_clone - Helper function to setup clone request
2966 * @rq: the request to be setup
2967 * @rq_src: original request to be cloned
2968 * @bs: bio_set that bios for clone are allocated from
2969 * @gfp_mask: memory allocation mask for bio
2970 * @bio_ctr: setup function to be called for each clone bio.
2971 * Returns %0 for success, non %0 for failure.
2972 * @data: private data to be passed to @bio_ctr
2973 *
2974 * Description:
2975 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
2976 * The actual data parts of @rq_src (e.g. ->cmd, ->sense)
2977 * are not copied, and copying such parts is the caller's responsibility.
2978 * Also, pages which the original bios are pointing to are not copied
2979 * and the cloned bios just point same pages.
2980 * So cloned bios must be completed before original bios, which means
2981 * the caller must complete @rq before @rq_src.
2982 */
2983int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
2984 struct bio_set *bs, gfp_t gfp_mask,
2985 int (*bio_ctr)(struct bio *, struct bio *, void *),
2986 void *data)
2987{
2988 struct bio *bio, *bio_src;
2989
2990 if (!bs)
2991 bs = fs_bio_set;
2992
2993 __rq_for_each_bio(bio_src, rq_src) {
2994 bio = bio_clone_fast(bio_src, gfp_mask, bs);
2995 if (!bio)
2996 goto free_and_out;
2997
2998 if (bio_ctr && bio_ctr(bio, bio_src, data))
2999 goto free_and_out;
3000
3001 if (rq->bio) {
3002 rq->biotail->bi_next = bio;
3003 rq->biotail = bio;
3004 } else
3005 rq->bio = rq->biotail = bio;
3006 }
3007
3008 __blk_rq_prep_clone(rq, rq_src);
3009
3010 return 0;
3011
3012free_and_out:
3013 if (bio)
3014 bio_put(bio);
3015 blk_rq_unprep_clone(rq);
3016
3017 return -ENOMEM;
Kiyoshi Uedab0fd2712009-06-11 13:10:16 +02003018}
3019EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3020
Jens Axboe59c3d452014-04-08 09:15:35 -06003021int kblockd_schedule_work(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003022{
3023 return queue_work(kblockd_workqueue, work);
3024}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003025EXPORT_SYMBOL(kblockd_schedule_work);
3026
Jens Axboe59c3d452014-04-08 09:15:35 -06003027int kblockd_schedule_delayed_work(struct delayed_work *dwork,
3028 unsigned long delay)
Vivek Goyale43473b2010-09-15 17:06:35 -04003029{
3030 return queue_delayed_work(kblockd_workqueue, dwork, delay);
3031}
3032EXPORT_SYMBOL(kblockd_schedule_delayed_work);
3033
Jens Axboe8ab14592014-04-08 09:17:40 -06003034int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
3035 unsigned long delay)
3036{
3037 return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
3038}
3039EXPORT_SYMBOL(kblockd_schedule_delayed_work_on);
3040
Suresh Jayaraman75df7132011-09-21 10:00:16 +02003041/**
3042 * blk_start_plug - initialize blk_plug and track it inside the task_struct
3043 * @plug: The &struct blk_plug that needs to be initialized
3044 *
3045 * Description:
3046 * Tracking blk_plug inside the task_struct will help with auto-flushing the
3047 * pending I/O should the task end up blocking between blk_start_plug() and
3048 * blk_finish_plug(). This is important from a performance perspective, but
3049 * also ensures that we don't deadlock. For instance, if the task is blocking
3050 * for a memory allocation, memory reclaim could end up wanting to free a
3051 * page belonging to that request that is currently residing in our private
3052 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
3053 * this kind of deadlock.
3054 */
Jens Axboe73c10102011-03-08 13:19:51 +01003055void blk_start_plug(struct blk_plug *plug)
3056{
3057 struct task_struct *tsk = current;
3058
Shaohua Lidd6cf3e2015-05-08 10:51:28 -07003059 /*
3060 * If this is a nested plug, don't actually assign it.
3061 */
3062 if (tsk->plug)
3063 return;
3064
Jens Axboe73c10102011-03-08 13:19:51 +01003065 INIT_LIST_HEAD(&plug->list);
Jens Axboe320ae512013-10-24 09:20:05 +01003066 INIT_LIST_HEAD(&plug->mq_list);
NeilBrown048c9372011-04-18 09:52:22 +02003067 INIT_LIST_HEAD(&plug->cb_list);
Jens Axboe73c10102011-03-08 13:19:51 +01003068 /*
Shaohua Lidd6cf3e2015-05-08 10:51:28 -07003069 * Store ordering should not be needed here, since a potential
3070 * preempt will imply a full memory barrier
Jens Axboe73c10102011-03-08 13:19:51 +01003071 */
Shaohua Lidd6cf3e2015-05-08 10:51:28 -07003072 tsk->plug = plug;
Jens Axboe73c10102011-03-08 13:19:51 +01003073}
3074EXPORT_SYMBOL(blk_start_plug);
3075
3076static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
3077{
3078 struct request *rqa = container_of(a, struct request, queuelist);
3079 struct request *rqb = container_of(b, struct request, queuelist);
3080
Jianpeng Ma975927b2012-10-25 21:58:17 +02003081 return !(rqa->q < rqb->q ||
3082 (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb)));
Jens Axboe73c10102011-03-08 13:19:51 +01003083}
3084
Jens Axboe49cac012011-04-16 13:51:05 +02003085/*
3086 * If 'from_schedule' is true, then postpone the dispatch of requests
3087 * until a safe kblockd context. We due this to avoid accidental big
3088 * additional stack usage in driver dispatch, in places where the originally
3089 * plugger did not intend it.
3090 */
Jens Axboef6603782011-04-15 15:49:07 +02003091static void queue_unplugged(struct request_queue *q, unsigned int depth,
Jens Axboe49cac012011-04-16 13:51:05 +02003092 bool from_schedule)
Jens Axboe99e22592011-04-18 09:59:55 +02003093 __releases(q->queue_lock)
Jens Axboe94b5eb22011-04-12 10:12:19 +02003094{
Jens Axboe49cac012011-04-16 13:51:05 +02003095 trace_block_unplug(q, depth, !from_schedule);
Jens Axboe99e22592011-04-18 09:59:55 +02003096
Bart Van Assche70460572012-11-28 13:45:56 +01003097 if (from_schedule)
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +02003098 blk_run_queue_async(q);
Bart Van Assche70460572012-11-28 13:45:56 +01003099 else
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +02003100 __blk_run_queue(q);
Bart Van Assche70460572012-11-28 13:45:56 +01003101 spin_unlock(q->queue_lock);
Jens Axboe94b5eb22011-04-12 10:12:19 +02003102}
3103
NeilBrown74018dc2012-07-31 09:08:15 +02003104static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
NeilBrown048c9372011-04-18 09:52:22 +02003105{
3106 LIST_HEAD(callbacks);
3107
Shaohua Li2a7d5552012-07-31 09:08:15 +02003108 while (!list_empty(&plug->cb_list)) {
3109 list_splice_init(&plug->cb_list, &callbacks);
NeilBrown048c9372011-04-18 09:52:22 +02003110
Shaohua Li2a7d5552012-07-31 09:08:15 +02003111 while (!list_empty(&callbacks)) {
3112 struct blk_plug_cb *cb = list_first_entry(&callbacks,
NeilBrown048c9372011-04-18 09:52:22 +02003113 struct blk_plug_cb,
3114 list);
Shaohua Li2a7d5552012-07-31 09:08:15 +02003115 list_del(&cb->list);
NeilBrown74018dc2012-07-31 09:08:15 +02003116 cb->callback(cb, from_schedule);
Shaohua Li2a7d5552012-07-31 09:08:15 +02003117 }
NeilBrown048c9372011-04-18 09:52:22 +02003118 }
3119}
3120
NeilBrown9cbb1752012-07-31 09:08:14 +02003121struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
3122 int size)
3123{
3124 struct blk_plug *plug = current->plug;
3125 struct blk_plug_cb *cb;
3126
3127 if (!plug)
3128 return NULL;
3129
3130 list_for_each_entry(cb, &plug->cb_list, list)
3131 if (cb->callback == unplug && cb->data == data)
3132 return cb;
3133
3134 /* Not currently on the callback list */
3135 BUG_ON(size < sizeof(*cb));
3136 cb = kzalloc(size, GFP_ATOMIC);
3137 if (cb) {
3138 cb->data = data;
3139 cb->callback = unplug;
3140 list_add(&cb->list, &plug->cb_list);
3141 }
3142 return cb;
3143}
3144EXPORT_SYMBOL(blk_check_plugged);
3145
Jens Axboe49cac012011-04-16 13:51:05 +02003146void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
Jens Axboe73c10102011-03-08 13:19:51 +01003147{
3148 struct request_queue *q;
3149 unsigned long flags;
3150 struct request *rq;
NeilBrown109b8122011-04-11 14:13:10 +02003151 LIST_HEAD(list);
Jens Axboe94b5eb22011-04-12 10:12:19 +02003152 unsigned int depth;
Jens Axboe73c10102011-03-08 13:19:51 +01003153
NeilBrown74018dc2012-07-31 09:08:15 +02003154 flush_plug_callbacks(plug, from_schedule);
Jens Axboe320ae512013-10-24 09:20:05 +01003155
3156 if (!list_empty(&plug->mq_list))
3157 blk_mq_flush_plug_list(plug, from_schedule);
3158
Jens Axboe73c10102011-03-08 13:19:51 +01003159 if (list_empty(&plug->list))
3160 return;
3161
NeilBrown109b8122011-04-11 14:13:10 +02003162 list_splice_init(&plug->list, &list);
3163
Jianpeng Ma422765c2013-01-11 14:46:09 +01003164 list_sort(NULL, &list, plug_rq_cmp);
Jens Axboe73c10102011-03-08 13:19:51 +01003165
3166 q = NULL;
Jens Axboe94b5eb22011-04-12 10:12:19 +02003167 depth = 0;
Jens Axboe18811272011-04-12 10:11:24 +02003168
3169 /*
3170 * Save and disable interrupts here, to avoid doing it for every
3171 * queue lock we have to take.
3172 */
Jens Axboe73c10102011-03-08 13:19:51 +01003173 local_irq_save(flags);
NeilBrown109b8122011-04-11 14:13:10 +02003174 while (!list_empty(&list)) {
3175 rq = list_entry_rq(list.next);
Jens Axboe73c10102011-03-08 13:19:51 +01003176 list_del_init(&rq->queuelist);
Jens Axboe73c10102011-03-08 13:19:51 +01003177 BUG_ON(!rq->q);
3178 if (rq->q != q) {
Jens Axboe99e22592011-04-18 09:59:55 +02003179 /*
3180 * This drops the queue lock
3181 */
3182 if (q)
Jens Axboe49cac012011-04-16 13:51:05 +02003183 queue_unplugged(q, depth, from_schedule);
Jens Axboe73c10102011-03-08 13:19:51 +01003184 q = rq->q;
Jens Axboe94b5eb22011-04-12 10:12:19 +02003185 depth = 0;
Jens Axboe73c10102011-03-08 13:19:51 +01003186 spin_lock(q->queue_lock);
3187 }
Tejun Heo8ba61432011-12-14 00:33:37 +01003188
3189 /*
3190 * Short-circuit if @q is dead
3191 */
Bart Van Assche3f3299d2012-11-28 13:42:38 +01003192 if (unlikely(blk_queue_dying(q))) {
Tejun Heo8ba61432011-12-14 00:33:37 +01003193 __blk_end_request_all(rq, -ENODEV);
3194 continue;
3195 }
3196
Jens Axboe73c10102011-03-08 13:19:51 +01003197 /*
3198 * rq is already accounted, so use raw insert
3199 */
Jens Axboe401a18e2011-03-25 16:57:52 +01003200 if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA))
3201 __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH);
3202 else
3203 __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);
Jens Axboe94b5eb22011-04-12 10:12:19 +02003204
3205 depth++;
Jens Axboe73c10102011-03-08 13:19:51 +01003206 }
3207
Jens Axboe99e22592011-04-18 09:59:55 +02003208 /*
3209 * This drops the queue lock
3210 */
3211 if (q)
Jens Axboe49cac012011-04-16 13:51:05 +02003212 queue_unplugged(q, depth, from_schedule);
Jens Axboe73c10102011-03-08 13:19:51 +01003213
Jens Axboe73c10102011-03-08 13:19:51 +01003214 local_irq_restore(flags);
3215}
Jens Axboe73c10102011-03-08 13:19:51 +01003216
3217void blk_finish_plug(struct blk_plug *plug)
3218{
Shaohua Lidd6cf3e2015-05-08 10:51:28 -07003219 if (plug != current->plug)
3220 return;
Jens Axboef6603782011-04-15 15:49:07 +02003221 blk_flush_plug_list(plug, false);
Christoph Hellwig88b996c2011-04-15 15:20:10 +02003222
Shaohua Lidd6cf3e2015-05-08 10:51:28 -07003223 current->plug = NULL;
Jens Axboe73c10102011-03-08 13:19:51 +01003224}
3225EXPORT_SYMBOL(blk_finish_plug);
3226
Rafael J. Wysocki47fafbc2014-12-04 01:00:23 +01003227#ifdef CONFIG_PM
Lin Ming6c954662013-03-23 11:42:26 +08003228/**
3229 * blk_pm_runtime_init - Block layer runtime PM initialization routine
3230 * @q: the queue of the device
3231 * @dev: the device the queue belongs to
3232 *
3233 * Description:
3234 * Initialize runtime-PM-related fields for @q and start auto suspend for
3235 * @dev. Drivers that want to take advantage of request-based runtime PM
3236 * should call this function after @dev has been initialized, and its
3237 * request queue @q has been allocated, and runtime PM for it can not happen
3238 * yet(either due to disabled/forbidden or its usage_count > 0). In most
3239 * cases, driver should call this function before any I/O has taken place.
3240 *
3241 * This function takes care of setting up using auto suspend for the device,
3242 * the autosuspend delay is set to -1 to make runtime suspend impossible
3243 * until an updated value is either set by user or by driver. Drivers do
3244 * not need to touch other autosuspend settings.
3245 *
3246 * The block layer runtime PM is request based, so only works for drivers
3247 * that use request as their IO unit instead of those directly use bio's.
3248 */
3249void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
3250{
3251 q->dev = dev;
3252 q->rpm_status = RPM_ACTIVE;
3253 pm_runtime_set_autosuspend_delay(q->dev, -1);
3254 pm_runtime_use_autosuspend(q->dev);
3255}
3256EXPORT_SYMBOL(blk_pm_runtime_init);
3257
3258/**
3259 * blk_pre_runtime_suspend - Pre runtime suspend check
3260 * @q: the queue of the device
3261 *
3262 * Description:
3263 * This function will check if runtime suspend is allowed for the device
3264 * by examining if there are any requests pending in the queue. If there
3265 * are requests pending, the device can not be runtime suspended; otherwise,
3266 * the queue's status will be updated to SUSPENDING and the driver can
3267 * proceed to suspend the device.
3268 *
3269 * For the not allowed case, we mark last busy for the device so that
3270 * runtime PM core will try to autosuspend it some time later.
3271 *
3272 * This function should be called near the start of the device's
3273 * runtime_suspend callback.
3274 *
3275 * Return:
3276 * 0 - OK to runtime suspend the device
3277 * -EBUSY - Device should not be runtime suspended
3278 */
3279int blk_pre_runtime_suspend(struct request_queue *q)
3280{
3281 int ret = 0;
3282
3283 spin_lock_irq(q->queue_lock);
3284 if (q->nr_pending) {
3285 ret = -EBUSY;
3286 pm_runtime_mark_last_busy(q->dev);
3287 } else {
3288 q->rpm_status = RPM_SUSPENDING;
3289 }
3290 spin_unlock_irq(q->queue_lock);
3291 return ret;
3292}
3293EXPORT_SYMBOL(blk_pre_runtime_suspend);
3294
3295/**
3296 * blk_post_runtime_suspend - Post runtime suspend processing
3297 * @q: the queue of the device
3298 * @err: return value of the device's runtime_suspend function
3299 *
3300 * Description:
3301 * Update the queue's runtime status according to the return value of the
3302 * device's runtime suspend function and mark last busy for the device so
3303 * that PM core will try to auto suspend the device at a later time.
3304 *
3305 * This function should be called near the end of the device's
3306 * runtime_suspend callback.
3307 */
3308void blk_post_runtime_suspend(struct request_queue *q, int err)
3309{
3310 spin_lock_irq(q->queue_lock);
3311 if (!err) {
3312 q->rpm_status = RPM_SUSPENDED;
3313 } else {
3314 q->rpm_status = RPM_ACTIVE;
3315 pm_runtime_mark_last_busy(q->dev);
3316 }
3317 spin_unlock_irq(q->queue_lock);
3318}
3319EXPORT_SYMBOL(blk_post_runtime_suspend);
3320
3321/**
3322 * blk_pre_runtime_resume - Pre runtime resume processing
3323 * @q: the queue of the device
3324 *
3325 * Description:
3326 * Update the queue's runtime status to RESUMING in preparation for the
3327 * runtime resume of the device.
3328 *
3329 * This function should be called near the start of the device's
3330 * runtime_resume callback.
3331 */
3332void blk_pre_runtime_resume(struct request_queue *q)
3333{
3334 spin_lock_irq(q->queue_lock);
3335 q->rpm_status = RPM_RESUMING;
3336 spin_unlock_irq(q->queue_lock);
3337}
3338EXPORT_SYMBOL(blk_pre_runtime_resume);
3339
3340/**
3341 * blk_post_runtime_resume - Post runtime resume processing
3342 * @q: the queue of the device
3343 * @err: return value of the device's runtime_resume function
3344 *
3345 * Description:
3346 * Update the queue's runtime status according to the return value of the
3347 * device's runtime_resume function. If it is successfully resumed, process
3348 * the requests that are queued into the device's queue when it is resuming
3349 * and then mark last busy and initiate autosuspend for it.
3350 *
3351 * This function should be called near the end of the device's
3352 * runtime_resume callback.
3353 */
3354void blk_post_runtime_resume(struct request_queue *q, int err)
3355{
3356 spin_lock_irq(q->queue_lock);
3357 if (!err) {
3358 q->rpm_status = RPM_ACTIVE;
3359 __blk_run_queue(q);
3360 pm_runtime_mark_last_busy(q->dev);
Aaron Luc60855c2013-05-17 15:47:20 +08003361 pm_request_autosuspend(q->dev);
Lin Ming6c954662013-03-23 11:42:26 +08003362 } else {
3363 q->rpm_status = RPM_SUSPENDED;
3364 }
3365 spin_unlock_irq(q->queue_lock);
3366}
3367EXPORT_SYMBOL(blk_post_runtime_resume);
3368#endif
3369
Linus Torvalds1da177e2005-04-16 15:20:36 -07003370int __init blk_dev_init(void)
3371{
Nikanth Karthikesan9eb55b02009-04-27 14:53:54 +02003372 BUILD_BUG_ON(__REQ_NR_BITS > 8 *
Maninder Singh0762b232015-07-07 12:41:07 +05303373 FIELD_SIZEOF(struct request, cmd_flags));
Nikanth Karthikesan9eb55b02009-04-27 14:53:54 +02003374
Tejun Heo89b90be2011-01-03 15:01:47 +01003375 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
3376 kblockd_workqueue = alloc_workqueue("kblockd",
Matias Bjørling28747fc2014-06-11 23:43:54 +02003377 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003378 if (!kblockd_workqueue)
3379 panic("Failed to create kblockd\n");
3380
3381 request_cachep = kmem_cache_create("blkdev_requests",
Paul Mundt20c2df82007-07-20 10:11:58 +09003382 sizeof(struct request), 0, SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003383
Jens Axboe8324aa92008-01-29 14:51:59 +01003384 blk_requestq_cachep = kmem_cache_create("blkdev_queue",
Jens Axboe165125e2007-07-24 09:28:11 +02003385 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003386
Linus Torvalds1da177e2005-04-16 15:20:36 -07003387 return 0;
3388}