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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Christoph Hellwigd2852032014-01-17 12:06:53 +01002 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
5 * SCSI queueing library.
6 * Initial versions: Eric Youngdale (eric@andante.org).
7 * Based upon conversations with large numbers
8 * of people at Linux Expo.
9 */
10
11#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060012#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/blkdev.h>
14#include <linux/completion.h>
15#include <linux/kernel.h>
Paul Gortmaker09703662011-05-27 09:37:25 -040016#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/mempool.h>
18#include <linux/slab.h>
19#include <linux/init.h>
20#include <linux/pci.h>
21#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060022#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020023#include <linux/scatterlist.h>
Christoph Hellwigd2852032014-01-17 12:06:53 +010024#include <linux/blk-mq.h>
Hannes Reineckef1569ff2014-10-24 14:27:07 +020025#include <linux/ratelimit.h>
Hannes Reineckea8aa3972015-12-01 10:16:57 +010026#include <asm/unaligned.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020029#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <scsi/scsi_dbg.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_driver.h>
33#include <scsi/scsi_eh.h>
34#include <scsi/scsi_host.h>
Christoph Hellwigee14c672015-08-27 14:16:59 +020035#include <scsi/scsi_dh.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Christoph Hellwig3b5382c2014-05-06 12:25:40 +020037#include <trace/events/scsi.h>
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include "scsi_priv.h"
40#include "scsi_logging.h"
41
42
Tobias Klauser6391a112006-06-08 22:23:48 -070043#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020044#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
46struct scsi_host_sg_pool {
47 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020048 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080049 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 mempool_t *pool;
51};
52
Mark Rustad037e6d82014-10-14 06:38:53 -070053#define SP(x) { .size = x, "sgpool-" __stringify(x) }
James Bottomleyd3f46f32008-01-15 11:11:46 -060054#if (SCSI_MAX_SG_SEGMENTS < 32)
55#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
56#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070057static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 SP(8),
59 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020060#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060061 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020062#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060063 SP(64),
64#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060066#if (SCSI_MAX_SG_SEGMENTS > 256)
67#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020068#endif
69#endif
70#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060071#endif
72 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020073};
Linus Torvalds1da177e2005-04-16 15:20:36 -070074#undef SP
75
Martin K. Petersen7027ad72008-07-17 17:08:48 -040076struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020077
Jens Axboea488e742010-04-16 21:13:15 +020078/*
79 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
80 * not change behaviour from the previous unplug mechanism, experimentation
81 * may prove this needs changing.
82 */
83#define SCSI_QUEUE_DELAY 3
84
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +010085static void
86scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
Linus Torvalds1da177e2005-04-16 15:20:36 -070087{
88 struct Scsi_Host *host = cmd->device->host;
89 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -050090 struct scsi_target *starget = scsi_target(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
92 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +090093 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 *
95 * If the host/device isn't busy, assume that something actually
96 * completed, and that we should be able to queue a command now.
97 *
98 * Note that the prior mid-layer assumption that any host could
99 * always queue at least one command is now broken. The mid-layer
100 * will implement a user specifiable stall (see
101 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
102 * if a command is requeued with no other commands outstanding
103 * either for the device or for the host.
104 */
Mike Christief0c0a372008-08-17 15:24:38 -0500105 switch (reason) {
106 case SCSI_MLQUEUE_HOST_BUSY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100107 atomic_set(&host->host_blocked, host->max_host_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500108 break;
109 case SCSI_MLQUEUE_DEVICE_BUSY:
James Smart573e5912011-07-06 12:45:17 -0400110 case SCSI_MLQUEUE_EH_RETRY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100111 atomic_set(&device->device_blocked,
112 device->max_device_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500113 break;
114 case SCSI_MLQUEUE_TARGET_BUSY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100115 atomic_set(&starget->target_blocked,
116 starget->max_target_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500117 break;
118 }
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +0100119}
120
Christoph Hellwigd2852032014-01-17 12:06:53 +0100121static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
122{
123 struct scsi_device *sdev = cmd->device;
124 struct request_queue *q = cmd->request->q;
125
126 blk_mq_requeue_request(cmd->request);
127 blk_mq_kick_requeue_list(q);
128 put_device(&sdev->sdev_gendev);
129}
130
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +0100131/**
132 * __scsi_queue_insert - private queue insertion
133 * @cmd: The SCSI command being requeued
134 * @reason: The reason for the requeue
135 * @unbusy: Whether the queue should be unbusied
136 *
137 * This is a private queue insertion. The public interface
138 * scsi_queue_insert() always assumes the queue should be unbusied
139 * because it's always called before the completion. This function is
140 * for a requeue after completion, which should only occur in this
141 * file.
142 */
143static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
144{
145 struct scsi_device *device = cmd->device;
146 struct request_queue *q = device->request_queue;
147 unsigned long flags;
148
149 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
150 "Inserting command %p into mlqueue\n", cmd));
151
152 scsi_set_blocked(cmd, reason);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
154 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 * Decrement the counters, since these commands are no longer
156 * active on the host/device.
157 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600158 if (unbusy)
159 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160
161 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500162 * Requeue this command. It will go before all other commands
Bart Van Asscheb4854622012-06-29 15:36:07 +0000163 * that are already in the queue. Schedule requeue work under
164 * lock such that the kblockd_schedule_work() call happens
165 * before blk_cleanup_queue() finishes.
Jens Axboea488e742010-04-16 21:13:15 +0200166 */
Alan Stern644373a2014-03-28 10:51:15 -0700167 cmd->result = 0;
Christoph Hellwigd2852032014-01-17 12:06:53 +0100168 if (q->mq_ops) {
169 scsi_mq_requeue_cmd(cmd);
170 return;
171 }
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500172 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400173 blk_requeue_request(q, cmd->request);
Jens Axboe59c3d452014-04-08 09:15:35 -0600174 kblockd_schedule_work(&device->requeue_work);
Bart Van Asscheb4854622012-06-29 15:36:07 +0000175 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176}
177
James Bottomley4f5299a2009-01-02 10:42:21 -0600178/*
179 * Function: scsi_queue_insert()
180 *
181 * Purpose: Insert a command in the midlevel queue.
182 *
183 * Arguments: cmd - command that we are adding to queue.
184 * reason - why we are inserting command to queue.
185 *
186 * Lock status: Assumed that lock is not held upon entry.
187 *
188 * Returns: Nothing.
189 *
190 * Notes: We do this for one of two cases. Either the host is busy
191 * and it cannot accept any more commands for the time being,
192 * or the device returned QUEUE_FULL and can accept no more
193 * commands.
194 * Notes: This could be called either from an interrupt context or a
195 * normal process context.
196 */
Bart Van Assche84feb162012-06-29 15:35:05 +0000197void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
James Bottomley4f5299a2009-01-02 10:42:21 -0600198{
Bart Van Assche84feb162012-06-29 15:35:05 +0000199 __scsi_queue_insert(cmd, reason, 1);
James Bottomley4f5299a2009-01-02 10:42:21 -0600200}
James Bottomley39216032005-06-15 18:48:29 -0500201/**
James Bottomley33aa6872005-08-28 11:31:14 -0500202 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500203 * @sdev: scsi device
204 * @cmd: scsi command
205 * @data_direction: data direction
206 * @buffer: data buffer
207 * @bufflen: len of buffer
208 * @sense: optional sense buffer
209 * @timeout: request timeout in seconds
210 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500211 * @flags: or into request flags;
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900212 * @resid: optional residual length
James Bottomley39216032005-06-15 18:48:29 -0500213 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200214 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500215 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500216 */
James Bottomley33aa6872005-08-28 11:31:14 -0500217int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
218 int data_direction, void *buffer, unsigned bufflen,
Martin K. Petersen2bfad212014-04-09 22:20:48 -0400219 unsigned char *sense, int timeout, int retries, u64 flags,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900220 int *resid)
James Bottomley39216032005-06-15 18:48:29 -0500221{
222 struct request *req;
223 int write = (data_direction == DMA_TO_DEVICE);
224 int ret = DRIVER_ERROR << 24;
225
Mel Gorman71baba42015-11-06 16:28:28 -0800226 req = blk_get_request(sdev->request_queue, write, __GFP_RECLAIM);
Joe Lawrencea492f072014-08-28 08:15:21 -0600227 if (IS_ERR(req))
James Bottomleybfe159a2011-07-07 15:45:40 -0500228 return ret;
Jens Axboef27b0872014-06-06 07:57:37 -0600229 blk_rq_set_block_pc(req);
James Bottomley39216032005-06-15 18:48:29 -0500230
231 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
Mel Gorman71baba42015-11-06 16:28:28 -0800232 buffer, bufflen, __GFP_RECLAIM))
James Bottomley39216032005-06-15 18:48:29 -0500233 goto out;
234
235 req->cmd_len = COMMAND_SIZE(cmd[0]);
236 memcpy(req->cmd, cmd, req->cmd_len);
237 req->sense = sense;
238 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600239 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500240 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200241 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500242
243 /*
244 * head injection *required* here otherwise quiesce won't work
245 */
246 blk_execute_rq(req->q, NULL, req, 1);
247
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400248 /*
249 * Some devices (USB mass-storage in particular) may transfer
250 * garbage data together with a residue indicating that the data
251 * is invalid. Prevent the garbage from being misinterpreted
252 * and prevent security leaks by zeroing out the excess data.
253 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900254 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
255 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400256
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900257 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900258 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500259 ret = req->errors;
260 out:
261 blk_put_request(req);
262
263 return ret;
264}
James Bottomley33aa6872005-08-28 11:31:14 -0500265EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500266
Lin Ming9b214932013-03-23 11:42:25 +0800267int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
James Bottomleyea73a9f2005-08-28 11:33:52 -0500268 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900269 struct scsi_sense_hdr *sshdr, int timeout, int retries,
Martin K. Petersen2bfad212014-04-09 22:20:48 -0400270 int *resid, u64 flags)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500271{
272 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700273 int result;
274
James Bottomleyea73a9f2005-08-28 11:33:52 -0500275 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500276 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500277 if (!sense)
278 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500279 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700280 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Lin Ming9b214932013-03-23 11:42:25 +0800281 sense, timeout, retries, flags, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500282 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500283 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500284
285 kfree(sense);
286 return result;
287}
Lin Ming9b214932013-03-23 11:42:25 +0800288EXPORT_SYMBOL(scsi_execute_req_flags);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290/*
291 * Function: scsi_init_cmd_errh()
292 *
293 * Purpose: Initialize cmd fields related to error handling.
294 *
295 * Arguments: cmd - command that is ready to be queued.
296 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 * Notes: This function has the job of initializing a number of
298 * fields related to error handling. Typically this will
299 * be called once for each command, as required.
300 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200301static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200304 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900305 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300307 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308}
309
310void scsi_device_unbusy(struct scsi_device *sdev)
311{
312 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500313 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 unsigned long flags;
315
Christoph Hellwig74665012014-01-22 15:29:29 +0100316 atomic_dec(&shost->host_busy);
Christoph Hellwig2ccbb002014-03-26 10:35:00 +0100317 if (starget->can_queue > 0)
318 atomic_dec(&starget->target_busy);
Christoph Hellwig74665012014-01-22 15:29:29 +0100319
James Bottomley939647e2005-09-18 15:05:20 -0500320 if (unlikely(scsi_host_in_recovery(shost) &&
Christoph Hellwig74665012014-01-22 15:29:29 +0100321 (shost->host_failed || shost->host_eh_scheduled))) {
322 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 scsi_eh_wakeup(shost);
Christoph Hellwig74665012014-01-22 15:29:29 +0100324 spin_unlock_irqrestore(shost->host_lock, flags);
325 }
326
Christoph Hellwig71e75c92014-04-11 19:07:01 +0200327 atomic_dec(&sdev->device_busy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328}
329
Christoph Hellwigd2852032014-01-17 12:06:53 +0100330static void scsi_kick_queue(struct request_queue *q)
331{
332 if (q->mq_ops)
333 blk_mq_start_hw_queues(q);
334 else
335 blk_run_queue(q);
336}
337
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338/*
339 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
340 * and call blk_run_queue for all the scsi_devices on the target -
341 * including current_sdev first.
342 *
343 * Called with *no* scsi locks held.
344 */
345static void scsi_single_lun_run(struct scsi_device *current_sdev)
346{
347 struct Scsi_Host *shost = current_sdev->host;
348 struct scsi_device *sdev, *tmp;
349 struct scsi_target *starget = scsi_target(current_sdev);
350 unsigned long flags;
351
352 spin_lock_irqsave(shost->host_lock, flags);
353 starget->starget_sdev_user = NULL;
354 spin_unlock_irqrestore(shost->host_lock, flags);
355
356 /*
357 * Call blk_run_queue for all LUNs on the target, starting with
358 * current_sdev. We race with others (to set starget_sdev_user),
359 * but in most cases, we will be first. Ideally, each LU on the
360 * target would get some limited time or requests on the target.
361 */
Christoph Hellwigd2852032014-01-17 12:06:53 +0100362 scsi_kick_queue(current_sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
364 spin_lock_irqsave(shost->host_lock, flags);
365 if (starget->starget_sdev_user)
366 goto out;
367 list_for_each_entry_safe(sdev, tmp, &starget->devices,
368 same_target_siblings) {
369 if (sdev == current_sdev)
370 continue;
371 if (scsi_device_get(sdev))
372 continue;
373
374 spin_unlock_irqrestore(shost->host_lock, flags);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100375 scsi_kick_queue(sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 spin_lock_irqsave(shost->host_lock, flags);
377
378 scsi_device_put(sdev);
379 }
380 out:
381 spin_unlock_irqrestore(shost->host_lock, flags);
382}
383
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100384static inline bool scsi_device_is_busy(struct scsi_device *sdev)
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400385{
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100386 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
387 return true;
388 if (atomic_read(&sdev->device_blocked) > 0)
389 return true;
390 return false;
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400391}
392
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100393static inline bool scsi_target_is_busy(struct scsi_target *starget)
Mike Christief0c0a372008-08-17 15:24:38 -0500394{
Christoph Hellwig2ccbb002014-03-26 10:35:00 +0100395 if (starget->can_queue > 0) {
396 if (atomic_read(&starget->target_busy) >= starget->can_queue)
397 return true;
398 if (atomic_read(&starget->target_blocked) > 0)
399 return true;
400 }
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100401 return false;
Mike Christief0c0a372008-08-17 15:24:38 -0500402}
403
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100404static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400405{
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100406 if (shost->can_queue > 0 &&
407 atomic_read(&shost->host_busy) >= shost->can_queue)
408 return true;
409 if (atomic_read(&shost->host_blocked) > 0)
410 return true;
411 if (shost->host_self_blocked)
412 return true;
413 return false;
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400414}
415
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800416static void scsi_starved_list_run(struct Scsi_Host *shost)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600418 LIST_HEAD(starved_list);
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800419 struct scsi_device *sdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 unsigned long flags;
421
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600423 list_splice_init(&shost->starved_list, &starved_list);
424
425 while (!list_empty(&starved_list)) {
James Bottomleye2eb7242013-07-02 15:05:26 +0200426 struct request_queue *slq;
427
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 /*
429 * As long as shost is accepting commands and we have
430 * starved queues, call blk_run_queue. scsi_request_fn
431 * drops the queue_lock and can add us back to the
432 * starved_list.
433 *
434 * host_lock protects the starved_list and starved_entry.
435 * scsi_request_fn must get the host_lock before checking
436 * or modifying starved_list or starved_entry.
437 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600438 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500439 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500440
Mike Christie2a3a59e2008-11-11 13:42:35 -0600441 sdev = list_entry(starved_list.next,
442 struct scsi_device, starved_entry);
443 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500444 if (scsi_target_is_busy(scsi_target(sdev))) {
445 list_move_tail(&sdev->starved_entry,
446 &shost->starved_list);
447 continue;
448 }
449
James Bottomleye2eb7242013-07-02 15:05:26 +0200450 /*
451 * Once we drop the host lock, a racing scsi_remove_device()
452 * call may remove the sdev from the starved list and destroy
453 * it and the queue. Mitigate by taking a reference to the
454 * queue and never touching the sdev again after we drop the
455 * host lock. Note: if __scsi_remove_device() invokes
456 * blk_cleanup_queue() before the queue is run from this
457 * function then blk_run_queue() will return immediately since
458 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
459 */
460 slq = sdev->request_queue;
461 if (!blk_get_queue(slq))
462 continue;
463 spin_unlock_irqrestore(shost->host_lock, flags);
464
Christoph Hellwigd2852032014-01-17 12:06:53 +0100465 scsi_kick_queue(slq);
James Bottomleye2eb7242013-07-02 15:05:26 +0200466 blk_put_queue(slq);
467
468 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600470 /* put any unprocessed entries back */
471 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 spin_unlock_irqrestore(shost->host_lock, flags);
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800473}
474
475/*
476 * Function: scsi_run_queue()
477 *
478 * Purpose: Select a proper request queue to serve next
479 *
480 * Arguments: q - last request's queue
481 *
482 * Returns: Nothing
483 *
484 * Notes: The previous command was completely finished, start
485 * a new one if possible.
486 */
487static void scsi_run_queue(struct request_queue *q)
488{
489 struct scsi_device *sdev = q->queuedata;
490
491 if (scsi_target(sdev)->single_lun)
492 scsi_single_lun_run(sdev);
493 if (!list_empty(&sdev->host->starved_list))
494 scsi_starved_list_run(sdev->host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
Christoph Hellwigd2852032014-01-17 12:06:53 +0100496 if (q->mq_ops)
497 blk_mq_start_stopped_hw_queues(q, false);
498 else
499 blk_run_queue(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500}
501
Jens Axboe9937a5e2011-05-17 11:04:44 +0200502void scsi_requeue_run_queue(struct work_struct *work)
503{
504 struct scsi_device *sdev;
505 struct request_queue *q;
506
507 sdev = container_of(work, struct scsi_device, requeue_work);
508 q = sdev->request_queue;
509 scsi_run_queue(q);
510}
511
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512/*
513 * Function: scsi_requeue_command()
514 *
515 * Purpose: Handle post-processing of completed commands.
516 *
517 * Arguments: q - queue to operate on
518 * cmd - command that may need to be requeued.
519 *
520 * Returns: Nothing
521 *
522 * Notes: After command completion, there may be blocks left
523 * over which weren't finished by the previous command
524 * this can be for a number of reasons - the main one is
525 * I/O errors in the middle of the request, in which case
526 * we need to request the blocks that come after the bad
527 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500528 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 */
530static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
531{
Bart Van Assche940f5d42012-06-29 15:34:26 +0000532 struct scsi_device *sdev = cmd->device;
James Bottomleye91442b2005-09-09 10:44:16 -0500533 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500534 unsigned long flags;
535
Tejun Heo 283369c2005-04-24 02:06:36 -0500536 spin_lock_irqsave(q->queue_lock, flags);
Christoph Hellwig134997a2014-02-20 14:20:58 -0800537 blk_unprep_request(req);
538 req->special = NULL;
539 scsi_put_command(cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500540 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500541 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
543 scsi_run_queue(q);
Bart Van Assche940f5d42012-06-29 15:34:26 +0000544
545 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546}
547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548void scsi_run_host_queues(struct Scsi_Host *shost)
549{
550 struct scsi_device *sdev;
551
552 shost_for_each_device(sdev, shost)
553 scsi_run_queue(sdev->request_queue);
554}
555
Jens Axboea8474ce2007-08-07 09:02:51 +0200556static inline unsigned int scsi_sgtable_index(unsigned short nents)
557{
558 unsigned int index;
559
James Bottomleyd3f46f32008-01-15 11:11:46 -0600560 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
561
562 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200563 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600564 else
565 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200566
567 return index;
568}
569
Jens Axboe5ed79592007-11-15 09:13:11 +0100570static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571{
572 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100573
574 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
575 mempool_free(sgl, sgp->pool);
576}
577
578static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
579{
580 struct scsi_host_sg_pool *sgp;
581
582 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
583 return mempool_alloc(sgp->pool, gfp_mask);
584}
585
Christoph Hellwigd2852032014-01-17 12:06:53 +0100586static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
Christoph Hellwigc53c6d62014-04-15 14:38:31 +0200587{
Tony Battersby0c958ec2015-07-16 11:40:41 -0400588 if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
Christoph Hellwigd2852032014-01-17 12:06:53 +0100589 return;
590 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
Christoph Hellwigc53c6d62014-04-15 14:38:31 +0200591}
592
Christoph Hellwig3c356bd2014-09-05 18:20:23 -0700593static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
Jens Axboe5ed79592007-11-15 09:13:11 +0100594{
Christoph Hellwigd2852032014-01-17 12:06:53 +0100595 struct scatterlist *first_chunk = NULL;
Jens Axboe5ed79592007-11-15 09:13:11 +0100596 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200598 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
Christoph Hellwigd2852032014-01-17 12:06:53 +0100600 if (mq) {
601 if (nents <= SCSI_MAX_SG_SEGMENTS) {
Tony Battersby0c958ec2015-07-16 11:40:41 -0400602 sdb->table.nents = sdb->table.orig_nents = nents;
603 sg_init_table(sdb->table.sgl, nents);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100604 return 0;
605 }
606 first_chunk = sdb->table.sgl;
607 }
608
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200609 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
Christoph Hellwig70a0f2c2015-01-05 20:29:38 +0100610 first_chunk, GFP_ATOMIC, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100611 if (unlikely(ret))
Christoph Hellwigd2852032014-01-17 12:06:53 +0100612 scsi_free_sgtable(sdb, mq);
Jens Axboea8474ce2007-08-07 09:02:51 +0200613 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614}
615
Christoph Hellwigd2852032014-01-17 12:06:53 +0100616static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
617{
618 if (cmd->request->cmd_type == REQ_TYPE_FS) {
619 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
620
621 if (drv->uninit_command)
622 drv->uninit_command(cmd);
623 }
624}
625
626static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
627{
628 if (cmd->sdb.table.nents)
629 scsi_free_sgtable(&cmd->sdb, true);
630 if (cmd->request->next_rq && cmd->request->next_rq->special)
631 scsi_free_sgtable(cmd->request->next_rq->special, true);
632 if (scsi_prot_sg_count(cmd))
633 scsi_free_sgtable(cmd->prot_sdb, true);
634}
635
636static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
637{
638 struct scsi_device *sdev = cmd->device;
Kashyap.Desai@avagotech.com64bdcbc2014-08-20 19:24:33 +0530639 struct Scsi_Host *shost = sdev->host;
Christoph Hellwigd2852032014-01-17 12:06:53 +0100640 unsigned long flags;
641
Christoph Hellwigd2852032014-01-17 12:06:53 +0100642 scsi_mq_free_sgtables(cmd);
643 scsi_uninit_cmd(cmd);
644
Kashyap.Desai@avagotech.com64bdcbc2014-08-20 19:24:33 +0530645 if (shost->use_cmd_list) {
646 BUG_ON(list_empty(&cmd->list));
647 spin_lock_irqsave(&sdev->list_lock, flags);
648 list_del_init(&cmd->list);
649 spin_unlock_irqrestore(&sdev->list_lock, flags);
650 }
Christoph Hellwigd2852032014-01-17 12:06:53 +0100651}
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653/*
654 * Function: scsi_release_buffers()
655 *
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200656 * Purpose: Free resources allocate for a scsi_command.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 *
658 * Arguments: cmd - command that we are bailing.
659 *
660 * Lock status: Assumed that no lock is held upon entry.
661 *
662 * Returns: Nothing
663 *
664 * Notes: In the event that an upper level driver rejects a
665 * command, we must release resources allocated during
666 * the __init_io() function. Primarily this would involve
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200667 * the scatter-gather table.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 */
Christoph Hellwigf1bea552014-04-15 12:26:54 +0200669static void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670{
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200671 if (cmd->sdb.table.nents)
Christoph Hellwigd2852032014-01-17 12:06:53 +0100672 scsi_free_sgtable(&cmd->sdb, false);
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200673
674 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
675
676 if (scsi_prot_sg_count(cmd))
Christoph Hellwigd2852032014-01-17 12:06:53 +0100677 scsi_free_sgtable(cmd->prot_sdb, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678}
679
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200680static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
681{
682 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
683
Christoph Hellwigd2852032014-01-17 12:06:53 +0100684 scsi_free_sgtable(bidi_sdb, false);
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200685 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
686 cmd->request->next_rq->special = NULL;
687}
688
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800689static bool scsi_end_request(struct request *req, int error,
690 unsigned int bytes, unsigned int bidi_bytes)
691{
692 struct scsi_cmnd *cmd = req->special;
693 struct scsi_device *sdev = cmd->device;
694 struct request_queue *q = sdev->request_queue;
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800695
696 if (blk_update_request(req, error, bytes))
697 return true;
698
699 /* Bidi request must be completed as a whole */
700 if (unlikely(bidi_bytes) &&
701 blk_update_request(req->next_rq, error, bidi_bytes))
702 return true;
703
704 if (blk_queue_add_random(q))
705 add_disk_randomness(req->rq_disk);
706
Christoph Hellwigd2852032014-01-17 12:06:53 +0100707 if (req->mq_ctx) {
708 /*
Christoph Hellwigc8a446a2014-09-13 16:40:10 -0700709 * In the MQ case the command gets freed by __blk_mq_end_request,
Christoph Hellwigd2852032014-01-17 12:06:53 +0100710 * so we have to do all cleanup that depends on it earlier.
711 *
712 * We also can't kick the queues from irq context, so we
713 * will have to defer it to a workqueue.
714 */
715 scsi_mq_uninit_cmd(cmd);
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800716
Christoph Hellwigc8a446a2014-09-13 16:40:10 -0700717 __blk_mq_end_request(req, error);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100718
719 if (scsi_target(sdev)->single_lun ||
720 !list_empty(&sdev->host->starved_list))
721 kblockd_schedule_work(&sdev->requeue_work);
722 else
723 blk_mq_start_stopped_hw_queues(q, true);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100724 } else {
725 unsigned long flags;
726
Daniel Gryniewiczf81426a2014-09-16 10:41:13 -0400727 if (bidi_bytes)
728 scsi_release_bidi_buffers(cmd);
729
Christoph Hellwigd2852032014-01-17 12:06:53 +0100730 spin_lock_irqsave(q->queue_lock, flags);
731 blk_finish_request(req, error);
732 spin_unlock_irqrestore(q->queue_lock, flags);
733
Christoph Hellwigd2852032014-01-17 12:06:53 +0100734 scsi_release_buffers(cmd);
Christoph Hellwigbb3ec622014-09-05 18:02:09 -0700735
736 scsi_put_command(cmd);
737 scsi_run_queue(q);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100738 }
739
Christoph Hellwigbb3ec622014-09-05 18:02:09 -0700740 put_device(&sdev->sdev_gendev);
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800741 return false;
742}
743
Hannes Reinecke0f7f6232013-07-01 15:16:23 +0200744/**
745 * __scsi_error_from_host_byte - translate SCSI error code into errno
746 * @cmd: SCSI command (unused)
747 * @result: scsi error code
748 *
749 * Translate SCSI error code into standard UNIX errno.
750 * Return values:
751 * -ENOLINK temporary transport failure
752 * -EREMOTEIO permanent target failure, do not retry
753 * -EBADE permanent nexus failure, retry on other path
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +0200754 * -ENOSPC No write space available
Hannes Reinecke7e782af2013-07-01 15:16:26 +0200755 * -ENODATA Medium error
Hannes Reinecke0f7f6232013-07-01 15:16:23 +0200756 * -EIO unspecified I/O error
757 */
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100758static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
759{
760 int error = 0;
761
762 switch(host_byte(result)) {
763 case DID_TRANSPORT_FAILFAST:
764 error = -ENOLINK;
765 break;
766 case DID_TARGET_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000767 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100768 error = -EREMOTEIO;
769 break;
770 case DID_NEXUS_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000771 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100772 error = -EBADE;
773 break;
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +0200774 case DID_ALLOC_FAILURE:
775 set_host_byte(cmd, DID_OK);
776 error = -ENOSPC;
777 break;
Hannes Reinecke7e782af2013-07-01 15:16:26 +0200778 case DID_MEDIUM_ERROR:
779 set_host_byte(cmd, DID_OK);
780 error = -ENODATA;
781 break;
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100782 default:
783 error = -EIO;
784 break;
785 }
786
787 return error;
788}
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790/*
791 * Function: scsi_io_completion()
792 *
793 * Purpose: Completion processing for block device I/O requests.
794 *
795 * Arguments: cmd - command that is finished.
796 *
797 * Lock status: Assumed that no lock is held upon entry.
798 *
799 * Returns: Nothing
800 *
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200801 * Notes: We will finish off the specified number of sectors. If we
802 * are done, the command block will be released and the queue
803 * function will be goosed. If we are not done then we have to
Alan Sternb60af5b2008-11-03 15:56:47 -0500804 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500806 * a) We can call scsi_requeue_command(). The request
807 * will be unprepared and put back on the queue. Then
808 * a new command will be created for it. This should
809 * be used if we made forward progress, or if we want
810 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 *
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200812 * b) We can call __scsi_queue_insert(). The request will
Alan Sternb60af5b2008-11-03 15:56:47 -0500813 * be put back on the queue and retried using the same
814 * command as before, possibly after a delay.
815 *
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800816 * c) We can call scsi_end_request() with -EIO to fail
Alan Sternb60af5b2008-11-03 15:56:47 -0500817 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700819void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820{
821 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200822 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500824 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 struct scsi_sense_hdr sshdr;
Hannes Reinecke4753cbc2014-10-24 14:26:52 +0200826 bool sense_valid = false;
Hannes Reineckec11c0042014-10-24 14:27:01 +0200827 int sense_deferred = 0, level = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500828 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
829 ACTION_DELAYED_RETRY} action;
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +0900830 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 if (result) {
833 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
834 if (sense_valid)
835 sense_deferred = scsi_sense_is_deferred(&sshdr);
836 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200837
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200838 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 if (sense_valid && req->sense) {
841 /*
842 * SG_IO wants current and deferred errors
843 */
844 int len = 8 + cmd->sense_buffer[7];
845
846 if (len > SCSI_SENSE_BUFFERSIZE)
847 len = SCSI_SENSE_BUFFERSIZE;
848 memcpy(req->sense, cmd->sense_buffer, len);
849 req->sense_len = len;
850 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500851 if (!sense_deferred)
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100852 error = __scsi_error_from_host_byte(cmd, result);
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400853 }
Mike Snitzer27c41972012-05-31 15:05:33 -0400854 /*
855 * __scsi_error_from_host_byte may have reset the host_byte
856 */
857 req->errors = cmd->result;
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900858
859 req->resid_len = scsi_get_resid(cmd);
860
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200861 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900862 /*
863 * Bidi commands Must be complete as a whole,
864 * both sides at once.
865 */
866 req->next_rq->resid_len = scsi_in(cmd)->resid;
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800867 if (scsi_end_request(req, 0, blk_rq_bytes(req),
868 blk_rq_bytes(req->next_rq)))
869 BUG();
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200870 return;
871 }
James Bottomley89fb4cd2014-07-03 19:17:34 +0200872 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
873 /*
874 * Certain non BLOCK_PC requests are commands that don't
875 * actually transfer anything (FLUSH), so cannot use
876 * good_bytes != blk_rq_bytes(req) as the signal for an error.
877 * This sets the error explicitly for the problem case.
878 */
879 error = __scsi_error_from_host_byte(cmd, result);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 }
881
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200882 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
883 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200884
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 * Next deal with any sectors which we were able to correctly
887 * handle.
888 */
Hannes Reinecke91921e02014-06-25 16:39:59 +0200889 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
890 "%u sectors total, %d bytes done.\n",
891 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892
James Bottomleya9bddd72009-03-30 16:55:51 +0000893 /*
894 * Recovered errors need reporting, but they're always treated
895 * as success, so fiddle the result code here. For BLOCK_PC
896 * we already took a copy of the original into rq->errors which
897 * is what gets returned to the user
898 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500899 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
900 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
901 * print since caller wants ATA registers. Only occurs on
902 * SCSI ATA PASS_THROUGH commands when CK_COND=1
903 */
904 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
905 ;
906 else if (!(req->cmd_flags & REQ_QUIET))
Hannes Reinecked811b842014-10-24 14:26:45 +0200907 scsi_print_sense(cmd);
James Bottomleya9bddd72009-03-30 16:55:51 +0000908 result = 0;
909 /* BLOCK_PC may have set error */
910 error = 0;
911 }
912
913 /*
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200914 * If we finished all bytes in the request we are done now.
James Bottomleyd6b0c532006-07-02 10:06:28 -0500915 */
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800916 if (!scsi_end_request(req, error, good_bytes, 0))
917 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200918
919 /*
920 * Kill remainder if no retrys.
921 */
922 if (error && scsi_noretry_cmd(cmd)) {
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800923 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
924 BUG();
925 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200926 }
927
928 /*
929 * If there had been no error, but we have leftover bytes in the
930 * requeues just queue the command up again.
931 */
932 if (result == 0)
933 goto requeue;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700934
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100935 error = __scsi_error_from_host_byte(cmd, result);
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500936
Alan Sternb60af5b2008-11-03 15:56:47 -0500937 if (host_byte(result) == DID_RESET) {
938 /* Third party bus reset or reset for error recovery
939 * reasons. Just retry the command and see what
940 * happens.
941 */
942 action = ACTION_RETRY;
943 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 switch (sshdr.sense_key) {
945 case UNIT_ATTENTION:
946 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700947 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 * and quietly refuse further access.
949 */
950 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500951 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700953 /* Must have been a power glitch, or a
954 * bus reset. Could not have been a
955 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500956 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700957 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500958 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 }
960 break;
961 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700962 /* If we had an ILLEGAL REQUEST returned, then
963 * we may have performed an unsupported
964 * command. The only thing this should be
965 * would be a ten byte read where only a six
966 * byte read was supported. Also, on a system
967 * where READ CAPACITY failed, we may have
968 * read past the end of the disk.
969 */
Jens Axboe26a68012005-11-29 21:03:34 +0100970 if ((cmd->device->use_10_for_rw &&
971 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 (cmd->cmnd[0] == READ_10 ||
973 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500974 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500976 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500977 } else if (sshdr.asc == 0x10) /* DIX */ {
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500978 action = ACTION_FAIL;
979 error = -EILSEQ;
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500980 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
Martin K. Petersen5db44862012-09-18 12:19:32 -0400981 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500982 action = ACTION_FAIL;
Martin K. Petersen66a651a2012-02-13 15:38:22 -0500983 error = -EREMOTEIO;
Alan Sternb60af5b2008-11-03 15:56:47 -0500984 } else
985 action = ACTION_FAIL;
986 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400987 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000988 action = ACTION_FAIL;
Maurizio Lombardie6c11db2014-07-10 09:41:53 +0200989 if (sshdr.asc == 0x10) /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500990 error = -EILSEQ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 break;
992 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700993 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500994 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500996 if (sshdr.asc == 0x04) {
997 switch (sshdr.ascq) {
998 case 0x01: /* becoming ready */
999 case 0x04: /* format in progress */
1000 case 0x05: /* rebuild in progress */
1001 case 0x06: /* recalculation in progress */
1002 case 0x07: /* operation in progress */
1003 case 0x08: /* Long write in progress */
1004 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -05001005 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -05001006 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -05001007 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -05001008 default:
Alan Stern3dbf6a52008-12-15 10:31:28 -05001009 action = ACTION_FAIL;
1010 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -05001011 }
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001012 } else
Alan Sternb60af5b2008-11-03 15:56:47 -05001013 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -05001014 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -07001016 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -05001017 action = ACTION_FAIL;
1018 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 default:
Alan Sternb60af5b2008-11-03 15:56:47 -05001020 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 break;
1022 }
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001023 } else
Alan Sternb60af5b2008-11-03 15:56:47 -05001024 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -05001025
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001026 if (action != ACTION_FAIL &&
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001027 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001028 action = ACTION_FAIL;
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001029
Alan Sternb60af5b2008-11-03 15:56:47 -05001030 switch (action) {
1031 case ACTION_FAIL:
1032 /* Give up and fail the remainder of the request */
Hannes Reineckef1569ff2014-10-24 14:27:07 +02001033 if (!(req->cmd_flags & REQ_QUIET)) {
1034 static DEFINE_RATELIMIT_STATE(_rs,
1035 DEFAULT_RATELIMIT_INTERVAL,
1036 DEFAULT_RATELIMIT_BURST);
1037
1038 if (unlikely(scsi_logging_level))
1039 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
1040 SCSI_LOG_MLCOMPLETE_BITS);
1041
1042 /*
1043 * if logging is enabled the failure will be printed
1044 * in scsi_log_completion(), so avoid duplicate messages
1045 */
1046 if (!level && __ratelimit(&_rs)) {
1047 scsi_print_result(cmd, NULL, FAILED);
1048 if (driver_byte(result) & DRIVER_SENSE)
1049 scsi_print_sense(cmd);
1050 scsi_print_command(cmd);
1051 }
James Bottomley3173d8c2005-09-04 11:32:05 -05001052 }
Christoph Hellwigf6d47e72014-02-16 06:16:13 -08001053 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1054 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +02001055 /*FALLTHRU*/
Alan Sternb60af5b2008-11-03 15:56:47 -05001056 case ACTION_REPREP:
Christoph Hellwigbc85dc52014-05-01 16:51:03 +02001057 requeue:
Alan Sternb60af5b2008-11-03 15:56:47 -05001058 /* Unprep the request and put it back at the head of the queue.
1059 * A new command will be prepared and issued.
1060 */
Christoph Hellwigd2852032014-01-17 12:06:53 +01001061 if (q->mq_ops) {
1062 cmd->request->cmd_flags &= ~REQ_DONTPREP;
1063 scsi_mq_uninit_cmd(cmd);
1064 scsi_mq_requeue_cmd(cmd);
1065 } else {
1066 scsi_release_buffers(cmd);
1067 scsi_requeue_command(q, cmd);
1068 }
Alan Sternb60af5b2008-11-03 15:56:47 -05001069 break;
1070 case ACTION_RETRY:
1071 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -06001072 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001073 break;
1074 case ACTION_DELAYED_RETRY:
1075 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -06001076 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001077 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 }
1079}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001081static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001083 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084
1085 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001086 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001088 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001089 req->mq_ctx != NULL)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 return BLKPREP_DEFER;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 /*
1093 * Next, walk the list, and fill in the addresses and sizes of
1094 * each segment.
1095 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001096 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1097 BUG_ON(count > sdb->table.nents);
1098 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +09001099 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +11001100 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001102
1103/*
1104 * Function: scsi_init_io()
1105 *
1106 * Purpose: SCSI I/O initialize function.
1107 *
1108 * Arguments: cmd - Command descriptor we wish to initialize
1109 *
1110 * Returns: 0 on success
1111 * BLKPREP_DEFER if the failure is retryable
1112 * BLKPREP_KILL if the failure is fatal
1113 */
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001114int scsi_init_io(struct scsi_cmnd *cmd)
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001115{
Christoph Hellwig5e012aa2014-04-15 12:24:55 +02001116 struct scsi_device *sdev = cmd->device;
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001117 struct request *rq = cmd->request;
Christoph Hellwigd2852032014-01-17 12:06:53 +01001118 bool is_mq = (rq->mq_ctx != NULL);
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001119 int error;
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001120
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001121 BUG_ON(!rq->nr_phys_segments);
1122
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001123 error = scsi_init_sgtable(rq, &cmd->sdb);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001124 if (error)
1125 goto err_exit;
1126
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001127 if (blk_bidi_rq(rq)) {
Christoph Hellwigd2852032014-01-17 12:06:53 +01001128 if (!rq->q->mq_ops) {
1129 struct scsi_data_buffer *bidi_sdb =
1130 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1131 if (!bidi_sdb) {
1132 error = BLKPREP_DEFER;
1133 goto err_exit;
1134 }
1135
1136 rq->next_rq->special = bidi_sdb;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001137 }
1138
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001139 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001140 if (error)
1141 goto err_exit;
1142 }
1143
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001144 if (blk_integrity_rq(rq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001145 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1146 int ivecs, count;
1147
Ewan D. Milne91724c22015-01-15 10:02:12 -05001148 if (prot_sdb == NULL) {
1149 /*
1150 * This can happen if someone (e.g. multipath)
1151 * queues a command to a device on an adapter
1152 * that does not support DIX.
1153 */
1154 WARN_ON_ONCE(1);
1155 error = BLKPREP_KILL;
1156 goto err_exit;
1157 }
1158
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001159 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001160
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001161 if (scsi_alloc_sgtable(prot_sdb, ivecs, is_mq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001162 error = BLKPREP_DEFER;
1163 goto err_exit;
1164 }
1165
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001166 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001167 prot_sdb->table.sgl);
1168 BUG_ON(unlikely(count > ivecs));
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001169 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001170
1171 cmd->prot_sdb = prot_sdb;
1172 cmd->prot_sdb->table.nents = count;
1173 }
1174
Christoph Hellwigd2852032014-01-17 12:06:53 +01001175 return BLKPREP_OK;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001176err_exit:
Christoph Hellwigd2852032014-01-17 12:06:53 +01001177 if (is_mq) {
1178 scsi_mq_free_sgtables(cmd);
1179 } else {
1180 scsi_release_buffers(cmd);
1181 cmd->request->special = NULL;
1182 scsi_put_command(cmd);
1183 put_device(&sdev->sdev_gendev);
1184 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001185 return error;
1186}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001187EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188
Christoph Hellwig3b003152006-11-04 20:10:55 +01001189static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1190 struct request *req)
1191{
1192 struct scsi_cmnd *cmd;
1193
1194 if (!req->special) {
Christoph Hellwig04796332014-02-20 14:20:55 -08001195 /* Bail if we can't get a reference to the device */
1196 if (!get_device(&sdev->sdev_gendev))
Christoph Hellwig3b003152006-11-04 20:10:55 +01001197 return NULL;
Christoph Hellwig04796332014-02-20 14:20:55 -08001198
1199 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1200 if (unlikely(!cmd)) {
1201 put_device(&sdev->sdev_gendev);
1202 return NULL;
1203 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001204 req->special = cmd;
1205 } else {
1206 cmd = req->special;
1207 }
1208
1209 /* pull a tag out of the request if we have one */
1210 cmd->tag = req->tag;
1211 cmd->request = req;
1212
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001213 cmd->cmnd = req->cmd;
Martin K. Petersen72f7d322011-03-08 02:03:59 -05001214 cmd->prot_op = SCSI_PROT_NORMAL;
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001215
Christoph Hellwig3b003152006-11-04 20:10:55 +01001216 return cmd;
1217}
1218
Christoph Hellwig4f1e5762014-06-28 12:36:28 +02001219static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001220{
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001221 struct scsi_cmnd *cmd = req->special;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001222
1223 /*
1224 * BLOCK_PC requests may transfer data, in which case they must
1225 * a bio attached to them. Or they might contain a SCSI command
1226 * that does not transfer data, in which case they may optionally
1227 * submit a request without an attached bio.
1228 */
1229 if (req->bio) {
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001230 int ret = scsi_init_io(cmd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001231 if (unlikely(ret))
1232 return ret;
1233 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001234 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001235
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001236 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001237 }
James Bottomley7b163182005-12-15 20:17:02 -06001238
James Bottomley7b163182005-12-15 20:17:02 -06001239 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001240 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001241 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001242 return BLKPREP_OK;
1243}
1244
1245/*
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001246 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1247 * that still need to be translated to SCSI CDBs from the ULD.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001248 */
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001249static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001250{
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001251 struct scsi_cmnd *cmd = req->special;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001252
Christoph Hellwigee14c672015-08-27 14:16:59 +02001253 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1254 int ret = sdev->handler->prep_fn(sdev, req);
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001255 if (ret != BLKPREP_OK)
1256 return ret;
1257 }
1258
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001259 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001260 return scsi_cmd_to_driver(cmd)->init_command(cmd);
James Bottomley7b163182005-12-15 20:17:02 -06001261}
James Bottomley7b163182005-12-15 20:17:02 -06001262
Christoph Hellwig6af7a4f2014-07-08 13:16:17 +02001263static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1264{
1265 struct scsi_cmnd *cmd = req->special;
1266
1267 if (!blk_rq_bytes(req))
1268 cmd->sc_data_direction = DMA_NONE;
1269 else if (rq_data_dir(req) == WRITE)
1270 cmd->sc_data_direction = DMA_TO_DEVICE;
1271 else
1272 cmd->sc_data_direction = DMA_FROM_DEVICE;
1273
1274 switch (req->cmd_type) {
1275 case REQ_TYPE_FS:
1276 return scsi_setup_fs_cmnd(sdev, req);
1277 case REQ_TYPE_BLOCK_PC:
1278 return scsi_setup_blk_pc_cmnd(sdev, req);
1279 default:
1280 return BLKPREP_KILL;
1281 }
1282}
1283
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001284static int
1285scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001287 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288
1289 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001290 * If the device is not in running state we will reject some
1291 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001294 switch (sdev->sdev_state) {
1295 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05001296 case SDEV_TRANSPORT_OFFLINE:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001297 /*
1298 * If the device is offline we refuse to process any
1299 * commands. The device must be brought online
1300 * before trying any recovery commands.
1301 */
1302 sdev_printk(KERN_ERR, sdev,
1303 "rejecting I/O to offline device\n");
1304 ret = BLKPREP_KILL;
1305 break;
1306 case SDEV_DEL:
1307 /*
1308 * If the device is fully deleted, we refuse to
1309 * process any commands as well.
1310 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001311 sdev_printk(KERN_ERR, sdev,
1312 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001313 ret = BLKPREP_KILL;
1314 break;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001315 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001316 case SDEV_CREATED_BLOCK:
Bart Van Asschebba0bdd2015-03-04 10:31:47 +01001317 ret = BLKPREP_DEFER;
1318 break;
1319 case SDEV_QUIESCE:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001320 /*
1321 * If the devices is blocked we defer normal commands.
1322 */
1323 if (!(req->cmd_flags & REQ_PREEMPT))
1324 ret = BLKPREP_DEFER;
1325 break;
1326 default:
1327 /*
1328 * For any other not fully online state we only allow
1329 * special commands. In particular any user initiated
1330 * command is not allowed.
1331 */
1332 if (!(req->cmd_flags & REQ_PREEMPT))
1333 ret = BLKPREP_KILL;
1334 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001337 return ret;
1338}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001340static int
1341scsi_prep_return(struct request_queue *q, struct request *req, int ret)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001342{
1343 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344
Christoph Hellwig3b003152006-11-04 20:10:55 +01001345 switch (ret) {
1346 case BLKPREP_KILL:
1347 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001348 /* release the command and kill it */
1349 if (req->special) {
1350 struct scsi_cmnd *cmd = req->special;
1351 scsi_release_buffers(cmd);
1352 scsi_put_command(cmd);
Christoph Hellwig68c03d92014-04-15 12:24:56 +02001353 put_device(&sdev->sdev_gendev);
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001354 req->special = NULL;
1355 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001356 break;
1357 case BLKPREP_DEFER:
1358 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001359 * If we defer, the blk_peek_request() returns NULL, but the
Jens Axboea488e742010-04-16 21:13:15 +02001360 * queue must be restarted, so we schedule a callback to happen
1361 * shortly.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001362 */
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001363 if (atomic_read(&sdev->device_busy) == 0)
Jens Axboea488e742010-04-16 21:13:15 +02001364 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001365 break;
1366 default:
1367 req->cmd_flags |= REQ_DONTPREP;
1368 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369
Christoph Hellwig3b003152006-11-04 20:10:55 +01001370 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001372
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001373static int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001374{
1375 struct scsi_device *sdev = q->queuedata;
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001376 struct scsi_cmnd *cmd;
1377 int ret;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001378
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001379 ret = scsi_prep_state_check(sdev, req);
1380 if (ret != BLKPREP_OK)
1381 goto out;
1382
1383 cmd = scsi_get_cmd_from_req(sdev, req);
1384 if (unlikely(!cmd)) {
1385 ret = BLKPREP_DEFER;
1386 goto out;
1387 }
1388
Christoph Hellwig6af7a4f2014-07-08 13:16:17 +02001389 ret = scsi_setup_cmnd(sdev, req);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001390out:
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001391 return scsi_prep_return(q, req, ret);
1392}
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001393
1394static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1395{
Christoph Hellwigd2852032014-01-17 12:06:53 +01001396 scsi_uninit_cmd(req->special);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001397}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398
1399/*
1400 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1401 * return 0.
1402 *
1403 * Called with the queue_lock held.
1404 */
1405static inline int scsi_dev_queue_ready(struct request_queue *q,
1406 struct scsi_device *sdev)
1407{
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001408 unsigned int busy;
1409
1410 busy = atomic_inc_return(&sdev->device_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001411 if (atomic_read(&sdev->device_blocked)) {
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001412 if (busy)
1413 goto out_dec;
1414
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415 /*
1416 * unblock after device_blocked iterates to zero
1417 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001418 if (atomic_dec_return(&sdev->device_blocked) > 0) {
Christoph Hellwigd2852032014-01-17 12:06:53 +01001419 /*
1420 * For the MQ case we take care of this in the caller.
1421 */
1422 if (!q->mq_ops)
1423 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001424 goto out_dec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425 }
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001426 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1427 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428 }
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001429
1430 if (busy >= sdev->queue_depth)
1431 goto out_dec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432
1433 return 1;
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001434out_dec:
1435 atomic_dec(&sdev->device_busy);
1436 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437}
1438
Mike Christief0c0a372008-08-17 15:24:38 -05001439/*
1440 * scsi_target_queue_ready: checks if there we can send commands to target
1441 * @sdev: scsi device on starget to check.
Mike Christief0c0a372008-08-17 15:24:38 -05001442 */
1443static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1444 struct scsi_device *sdev)
1445{
1446 struct scsi_target *starget = scsi_target(sdev);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001447 unsigned int busy;
Mike Christief0c0a372008-08-17 15:24:38 -05001448
1449 if (starget->single_lun) {
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001450 spin_lock_irq(shost->host_lock);
Mike Christief0c0a372008-08-17 15:24:38 -05001451 if (starget->starget_sdev_user &&
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001452 starget->starget_sdev_user != sdev) {
1453 spin_unlock_irq(shost->host_lock);
1454 return 0;
1455 }
Mike Christief0c0a372008-08-17 15:24:38 -05001456 starget->starget_sdev_user = sdev;
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001457 spin_unlock_irq(shost->host_lock);
Mike Christief0c0a372008-08-17 15:24:38 -05001458 }
1459
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001460 if (starget->can_queue <= 0)
1461 return 1;
1462
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001463 busy = atomic_inc_return(&starget->target_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001464 if (atomic_read(&starget->target_blocked) > 0) {
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001465 if (busy)
1466 goto starved;
1467
Mike Christief0c0a372008-08-17 15:24:38 -05001468 /*
1469 * unblock after target_blocked iterates to zero
1470 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001471 if (atomic_dec_return(&starget->target_blocked) > 0)
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001472 goto out_dec;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001473
1474 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1475 "unblocking target at zero depth\n"));
Mike Christief0c0a372008-08-17 15:24:38 -05001476 }
1477
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001478 if (busy >= starget->can_queue)
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001479 goto starved;
Mike Christief0c0a372008-08-17 15:24:38 -05001480
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001481 return 1;
1482
1483starved:
1484 spin_lock_irq(shost->host_lock);
1485 list_move_tail(&sdev->starved_entry, &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001486 spin_unlock_irq(shost->host_lock);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001487out_dec:
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001488 if (starget->can_queue > 0)
1489 atomic_dec(&starget->target_busy);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001490 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001491}
1492
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493/*
1494 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1495 * return 0. We must end up running the queue again whenever 0 is
1496 * returned, else IO can hang.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 */
1498static inline int scsi_host_queue_ready(struct request_queue *q,
1499 struct Scsi_Host *shost,
1500 struct scsi_device *sdev)
1501{
Christoph Hellwig74665012014-01-22 15:29:29 +01001502 unsigned int busy;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001503
James Bottomley939647e2005-09-18 15:05:20 -05001504 if (scsi_host_in_recovery(shost))
Christoph Hellwig74665012014-01-22 15:29:29 +01001505 return 0;
1506
1507 busy = atomic_inc_return(&shost->host_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001508 if (atomic_read(&shost->host_blocked) > 0) {
Christoph Hellwig74665012014-01-22 15:29:29 +01001509 if (busy)
1510 goto starved;
1511
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512 /*
1513 * unblock after host_blocked iterates to zero
1514 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001515 if (atomic_dec_return(&shost->host_blocked) > 0)
Christoph Hellwig74665012014-01-22 15:29:29 +01001516 goto out_dec;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001517
1518 SCSI_LOG_MLQUEUE(3,
1519 shost_printk(KERN_INFO, shost,
1520 "unblocking host at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521 }
Christoph Hellwig74665012014-01-22 15:29:29 +01001522
1523 if (shost->can_queue > 0 && busy >= shost->can_queue)
1524 goto starved;
1525 if (shost->host_self_blocked)
1526 goto starved;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527
1528 /* We're OK to process the command, so we can't be starved */
Christoph Hellwig74665012014-01-22 15:29:29 +01001529 if (!list_empty(&sdev->starved_entry)) {
1530 spin_lock_irq(shost->host_lock);
1531 if (!list_empty(&sdev->starved_entry))
1532 list_del_init(&sdev->starved_entry);
1533 spin_unlock_irq(shost->host_lock);
1534 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535
Christoph Hellwig74665012014-01-22 15:29:29 +01001536 return 1;
1537
1538starved:
1539 spin_lock_irq(shost->host_lock);
1540 if (list_empty(&sdev->starved_entry))
1541 list_add_tail(&sdev->starved_entry, &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001542 spin_unlock_irq(shost->host_lock);
Christoph Hellwig74665012014-01-22 15:29:29 +01001543out_dec:
1544 atomic_dec(&shost->host_busy);
1545 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546}
1547
1548/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001549 * Busy state exporting function for request stacking drivers.
1550 *
1551 * For efficiency, no lock is taken to check the busy state of
1552 * shost/starget/sdev, since the returned value is not guaranteed and
1553 * may be changed after request stacking drivers call the function,
1554 * regardless of taking lock or not.
1555 *
Bart Van Assche67bd9412012-06-29 15:33:22 +00001556 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1557 * needs to return 'not busy'. Otherwise, request stacking drivers
1558 * may hold requests forever.
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001559 */
1560static int scsi_lld_busy(struct request_queue *q)
1561{
1562 struct scsi_device *sdev = q->queuedata;
1563 struct Scsi_Host *shost;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001564
Bart Van Assche3f3299d2012-11-28 13:42:38 +01001565 if (blk_queue_dying(q))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001566 return 0;
1567
1568 shost = sdev->host;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001569
Jun'ichi Nomurab7e94a12012-05-22 18:57:17 +09001570 /*
1571 * Ignore host/starget busy state.
1572 * Since block layer does not have a concept of fairness across
1573 * multiple queues, congestion of host/starget needs to be handled
1574 * in SCSI layer.
1575 */
1576 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001577 return 1;
1578
1579 return 0;
1580}
1581
1582/*
James Bottomleye91442b2005-09-09 10:44:16 -05001583 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584 */
Jens Axboe165125e2007-07-24 09:28:11 +02001585static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586{
James Bottomleye91442b2005-09-09 10:44:16 -05001587 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001588 struct scsi_device *sdev;
1589 struct scsi_target *starget;
1590 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001591
Tejun Heo9934c8c2009-05-08 11:54:16 +09001592 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001593
Hannes Reinecke74571812011-11-09 08:39:24 +01001594 scmd_printk(KERN_INFO, cmd, "killing request\n");
1595
Jiri Slaby03b14702009-09-23 16:15:35 +02001596 sdev = cmd->device;
1597 starget = scsi_target(sdev);
1598 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001599 scsi_init_cmd_errh(cmd);
1600 cmd->result = DID_NO_CONNECT << 16;
1601 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001602
1603 /*
1604 * SCSI request completion path will do scsi_device_unbusy(),
1605 * bump busy counts. To bump the counters, we need to dance
1606 * with the locks as normal issue path does.
1607 */
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001608 atomic_inc(&sdev->device_busy);
Christoph Hellwig74665012014-01-22 15:29:29 +01001609 atomic_inc(&shost->host_busy);
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001610 if (starget->can_queue > 0)
1611 atomic_inc(&starget->target_busy);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001612
Jens Axboe242f9dc2008-09-14 05:55:09 -07001613 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614}
1615
Jens Axboe1aea6432006-01-09 16:03:03 +01001616static void scsi_softirq_done(struct request *rq)
1617{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001618 struct scsi_cmnd *cmd = rq->special;
1619 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001620 int disposition;
1621
1622 INIT_LIST_HEAD(&cmd->eh_entry);
1623
Jens Axboe242f9dc2008-09-14 05:55:09 -07001624 atomic_inc(&cmd->device->iodone_cnt);
1625 if (cmd->result)
1626 atomic_inc(&cmd->device->ioerr_cnt);
1627
Jens Axboe1aea6432006-01-09 16:03:03 +01001628 disposition = scsi_decide_disposition(cmd);
1629 if (disposition != SUCCESS &&
1630 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1631 sdev_printk(KERN_ERR, cmd->device,
1632 "timing out command, waited %lus\n",
1633 wait_for/HZ);
1634 disposition = SUCCESS;
1635 }
Hannes Reinecke91921e02014-06-25 16:39:59 +02001636
Jens Axboe1aea6432006-01-09 16:03:03 +01001637 scsi_log_completion(cmd, disposition);
1638
1639 switch (disposition) {
1640 case SUCCESS:
1641 scsi_finish_command(cmd);
1642 break;
1643 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001644 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001645 break;
1646 case ADD_TO_MLQUEUE:
1647 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1648 break;
1649 default:
1650 if (!scsi_eh_scmd_add(cmd, 0))
1651 scsi_finish_command(cmd);
1652 }
1653}
1654
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001655/**
Christoph Hellwig82042a22014-09-05 18:23:07 -07001656 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1657 * @cmd: command block we are dispatching.
1658 *
1659 * Return: nonzero return request was rejected and device's queue needs to be
1660 * plugged.
1661 */
1662static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1663{
1664 struct Scsi_Host *host = cmd->device->host;
1665 int rtn = 0;
1666
1667 atomic_inc(&cmd->device->iorequest_cnt);
1668
1669 /* check if the device is still usable */
1670 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1671 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1672 * returns an immediate error upwards, and signals
1673 * that the device is no longer present */
1674 cmd->result = DID_NO_CONNECT << 16;
1675 goto done;
1676 }
1677
1678 /* Check to see if the scsi lld made this device blocked. */
1679 if (unlikely(scsi_device_blocked(cmd->device))) {
1680 /*
1681 * in blocked state, the command is just put back on
1682 * the device queue. The suspend state has already
1683 * blocked the queue so future requests should not
1684 * occur until the device transitions out of the
1685 * suspend state.
1686 */
1687 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1688 "queuecommand : device blocked\n"));
1689 return SCSI_MLQUEUE_DEVICE_BUSY;
1690 }
1691
1692 /* Store the LUN value in cmnd, if needed. */
1693 if (cmd->device->lun_in_cdb)
1694 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1695 (cmd->device->lun << 5 & 0xe0);
1696
1697 scsi_log_send(cmd);
1698
1699 /*
1700 * Before we queue this command, check if the command
1701 * length exceeds what the host adapter can handle.
1702 */
1703 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1704 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1705 "queuecommand : command too long. "
1706 "cdb_size=%d host->max_cmd_len=%d\n",
1707 cmd->cmd_len, cmd->device->host->max_cmd_len));
1708 cmd->result = (DID_ABORT << 16);
1709 goto done;
1710 }
1711
1712 if (unlikely(host->shost_state == SHOST_DEL)) {
1713 cmd->result = (DID_NO_CONNECT << 16);
1714 goto done;
1715
1716 }
1717
1718 trace_scsi_dispatch_cmd_start(cmd);
1719 rtn = host->hostt->queuecommand(host, cmd);
1720 if (rtn) {
1721 trace_scsi_dispatch_cmd_error(cmd, rtn);
1722 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1723 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1724 rtn = SCSI_MLQUEUE_HOST_BUSY;
1725
1726 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1727 "queuecommand : request rejected\n"));
1728 }
1729
1730 return rtn;
1731 done:
1732 cmd->scsi_done(cmd);
1733 return 0;
1734}
1735
1736/**
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001737 * scsi_done - Invoke completion on finished SCSI command.
1738 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1739 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1740 *
1741 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1742 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1743 * calls blk_complete_request() for further processing.
1744 *
1745 * This function is interrupt context safe.
1746 */
1747static void scsi_done(struct scsi_cmnd *cmd)
1748{
1749 trace_scsi_dispatch_cmd_done(cmd);
1750 blk_complete_request(cmd->request);
1751}
1752
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753/*
1754 * Function: scsi_request_fn()
1755 *
1756 * Purpose: Main strategy routine for SCSI.
1757 *
1758 * Arguments: q - Pointer to actual queue.
1759 *
1760 * Returns: Nothing
1761 *
1762 * Lock status: IO request lock assumed to be held when called.
1763 */
1764static void scsi_request_fn(struct request_queue *q)
Bart Van Assche613be1f2014-02-20 14:20:56 -08001765 __releases(q->queue_lock)
1766 __acquires(q->queue_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767{
1768 struct scsi_device *sdev = q->queuedata;
1769 struct Scsi_Host *shost;
1770 struct scsi_cmnd *cmd;
1771 struct request *req;
1772
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 /*
1774 * To start with, we keep looping until the queue is empty, or until
1775 * the host is no longer able to accept any more requests.
1776 */
1777 shost = sdev->host;
Jens Axboea488e742010-04-16 21:13:15 +02001778 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 int rtn;
1780 /*
1781 * get next queueable request. We do this early to make sure
Hannes Reinecke91921e02014-06-25 16:39:59 +02001782 * that the request is fully prepared even if we cannot
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 * accept it.
1784 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001785 req = blk_peek_request(q);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001786 if (!req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787 break;
1788
1789 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001790 sdev_printk(KERN_ERR, sdev,
1791 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001792 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001793 continue;
1794 }
1795
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001796 if (!scsi_dev_queue_ready(q, sdev))
1797 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798
1799 /*
1800 * Remove the request from the request list.
1801 */
1802 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001803 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001805 spin_unlock_irq(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001806 cmd = req->special;
1807 if (unlikely(cmd == NULL)) {
1808 printk(KERN_CRIT "impossible request in %s.\n"
1809 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001810 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001811 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001812 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001813 BUG();
1814 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815
Mike Christieecefe8a2008-07-11 19:50:35 -05001816 /*
1817 * We hit this when the driver is using a host wide
1818 * tag map. For device level tag maps the queue_depth check
1819 * in the device ready fn would prevent us from trying
1820 * to allocate a tag. Since the map is a shared host resource
1821 * we add the dev to the starved list so it eventually gets
1822 * a run when a tag is freed.
1823 */
Christoph Hellwig125c99b2014-11-03 12:47:47 +01001824 if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001825 spin_lock_irq(shost->host_lock);
Mike Christieecefe8a2008-07-11 19:50:35 -05001826 if (list_empty(&sdev->starved_entry))
1827 list_add_tail(&sdev->starved_entry,
1828 &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001829 spin_unlock_irq(shost->host_lock);
Mike Christieecefe8a2008-07-11 19:50:35 -05001830 goto not_ready;
1831 }
1832
Mike Christief0c0a372008-08-17 15:24:38 -05001833 if (!scsi_target_queue_ready(shost, sdev))
1834 goto not_ready;
1835
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836 if (!scsi_host_queue_ready(q, shost, sdev))
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001837 goto host_not_ready;
Christoph Hellwig125c99b2014-11-03 12:47:47 +01001838
1839 if (sdev->simple_tags)
1840 cmd->flags |= SCMD_TAGGED;
1841 else
1842 cmd->flags &= ~SCMD_TAGGED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 /*
1845 * Finally, initialize any error handling parameters, and set up
1846 * the timers for timeouts.
1847 */
1848 scsi_init_cmd_errh(cmd);
1849
1850 /*
1851 * Dispatch the command to the low-level driver.
1852 */
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001853 cmd->scsi_done = scsi_done;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 rtn = scsi_dispatch_cmd(cmd);
Christoph Hellwigd0d3bbf2014-01-22 18:39:04 +01001855 if (rtn) {
1856 scsi_queue_insert(cmd, rtn);
1857 spin_lock_irq(q->queue_lock);
Jens Axboea488e742010-04-16 21:13:15 +02001858 goto out_delay;
Christoph Hellwigd0d3bbf2014-01-22 18:39:04 +01001859 }
1860 spin_lock_irq(q->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 }
1862
Bart Van Assche613be1f2014-02-20 14:20:56 -08001863 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001864
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001865 host_not_ready:
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001866 if (scsi_target(sdev)->can_queue > 0)
1867 atomic_dec(&scsi_target(sdev)->target_busy);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001868 not_ready:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869 /*
1870 * lock q, handle tag, requeue req, and decrement device_busy. We
1871 * must return with queue_lock held.
1872 *
1873 * Decrementing device_busy without checking it is OK, as all such
1874 * cases (host limits or settings) should run the queue at some
1875 * later time.
1876 */
1877 spin_lock_irq(q->queue_lock);
1878 blk_requeue_request(q, req);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001879 atomic_dec(&sdev->device_busy);
Jens Axboea488e742010-04-16 21:13:15 +02001880out_delay:
Guenter Roeck480cadc2014-08-10 05:54:25 -07001881 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
Jens Axboea488e742010-04-16 21:13:15 +02001882 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883}
1884
Christoph Hellwigd2852032014-01-17 12:06:53 +01001885static inline int prep_to_mq(int ret)
1886{
1887 switch (ret) {
1888 case BLKPREP_OK:
1889 return 0;
1890 case BLKPREP_DEFER:
1891 return BLK_MQ_RQ_QUEUE_BUSY;
1892 default:
1893 return BLK_MQ_RQ_QUEUE_ERROR;
1894 }
1895}
1896
1897static int scsi_mq_prep_fn(struct request *req)
1898{
1899 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1900 struct scsi_device *sdev = req->q->queuedata;
1901 struct Scsi_Host *shost = sdev->host;
1902 unsigned char *sense_buf = cmd->sense_buffer;
1903 struct scatterlist *sg;
1904
1905 memset(cmd, 0, sizeof(struct scsi_cmnd));
1906
1907 req->special = cmd;
1908
1909 cmd->request = req;
1910 cmd->device = sdev;
1911 cmd->sense_buffer = sense_buf;
1912
1913 cmd->tag = req->tag;
1914
Christoph Hellwigd2852032014-01-17 12:06:53 +01001915 cmd->cmnd = req->cmd;
1916 cmd->prot_op = SCSI_PROT_NORMAL;
1917
1918 INIT_LIST_HEAD(&cmd->list);
1919 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1920 cmd->jiffies_at_alloc = jiffies;
1921
Kashyap.Desai@avagotech.com64bdcbc2014-08-20 19:24:33 +05301922 if (shost->use_cmd_list) {
1923 spin_lock_irq(&sdev->list_lock);
1924 list_add_tail(&cmd->list, &sdev->cmd_list);
1925 spin_unlock_irq(&sdev->list_lock);
1926 }
Christoph Hellwigd2852032014-01-17 12:06:53 +01001927
1928 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1929 cmd->sdb.table.sgl = sg;
1930
1931 if (scsi_host_get_prot(shost)) {
1932 cmd->prot_sdb = (void *)sg +
Tony Battersby120bb3e2014-12-08 17:20:52 -05001933 min_t(unsigned int,
1934 shost->sg_tablesize, SCSI_MAX_SG_SEGMENTS) *
1935 sizeof(struct scatterlist);
Christoph Hellwigd2852032014-01-17 12:06:53 +01001936 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1937
1938 cmd->prot_sdb->table.sgl =
1939 (struct scatterlist *)(cmd->prot_sdb + 1);
1940 }
1941
1942 if (blk_bidi_rq(req)) {
1943 struct request *next_rq = req->next_rq;
1944 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1945
1946 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1947 bidi_sdb->table.sgl =
1948 (struct scatterlist *)(bidi_sdb + 1);
1949
1950 next_rq->special = bidi_sdb;
1951 }
1952
Christoph Hellwigfe052522014-09-22 15:59:31 +02001953 blk_mq_start_request(req);
1954
Christoph Hellwigd2852032014-01-17 12:06:53 +01001955 return scsi_setup_cmnd(sdev, req);
1956}
1957
1958static void scsi_mq_done(struct scsi_cmnd *cmd)
1959{
1960 trace_scsi_dispatch_cmd_done(cmd);
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001961 blk_mq_complete_request(cmd->request, cmd->request->errors);
Christoph Hellwigd2852032014-01-17 12:06:53 +01001962}
1963
Jens Axboe74c45052014-10-29 11:14:52 -06001964static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1965 const struct blk_mq_queue_data *bd)
Christoph Hellwigd2852032014-01-17 12:06:53 +01001966{
Jens Axboe74c45052014-10-29 11:14:52 -06001967 struct request *req = bd->rq;
Christoph Hellwigd2852032014-01-17 12:06:53 +01001968 struct request_queue *q = req->q;
1969 struct scsi_device *sdev = q->queuedata;
1970 struct Scsi_Host *shost = sdev->host;
1971 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1972 int ret;
1973 int reason;
1974
1975 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1976 if (ret)
1977 goto out;
1978
1979 ret = BLK_MQ_RQ_QUEUE_BUSY;
1980 if (!get_device(&sdev->sdev_gendev))
1981 goto out;
1982
1983 if (!scsi_dev_queue_ready(q, sdev))
1984 goto out_put_device;
1985 if (!scsi_target_queue_ready(shost, sdev))
1986 goto out_dec_device_busy;
1987 if (!scsi_host_queue_ready(q, shost, sdev))
1988 goto out_dec_target_busy;
1989
Christoph Hellwigfe052522014-09-22 15:59:31 +02001990
Christoph Hellwigd2852032014-01-17 12:06:53 +01001991 if (!(req->cmd_flags & REQ_DONTPREP)) {
1992 ret = prep_to_mq(scsi_mq_prep_fn(req));
1993 if (ret)
1994 goto out_dec_host_busy;
1995 req->cmd_flags |= REQ_DONTPREP;
Christoph Hellwigfe052522014-09-22 15:59:31 +02001996 } else {
1997 blk_mq_start_request(req);
Christoph Hellwigd2852032014-01-17 12:06:53 +01001998 }
1999
Christoph Hellwig125c99b2014-11-03 12:47:47 +01002000 if (sdev->simple_tags)
2001 cmd->flags |= SCMD_TAGGED;
Christoph Hellwigb1dd2aa2014-10-19 17:13:58 +02002002 else
Christoph Hellwig125c99b2014-11-03 12:47:47 +01002003 cmd->flags &= ~SCMD_TAGGED;
Christoph Hellwigb1dd2aa2014-10-19 17:13:58 +02002004
Christoph Hellwigd2852032014-01-17 12:06:53 +01002005 scsi_init_cmd_errh(cmd);
2006 cmd->scsi_done = scsi_mq_done;
2007
2008 reason = scsi_dispatch_cmd(cmd);
2009 if (reason) {
2010 scsi_set_blocked(cmd, reason);
2011 ret = BLK_MQ_RQ_QUEUE_BUSY;
2012 goto out_dec_host_busy;
2013 }
2014
2015 return BLK_MQ_RQ_QUEUE_OK;
2016
2017out_dec_host_busy:
2018 atomic_dec(&shost->host_busy);
2019out_dec_target_busy:
2020 if (scsi_target(sdev)->can_queue > 0)
2021 atomic_dec(&scsi_target(sdev)->target_busy);
2022out_dec_device_busy:
2023 atomic_dec(&sdev->device_busy);
2024out_put_device:
2025 put_device(&sdev->sdev_gendev);
2026out:
2027 switch (ret) {
2028 case BLK_MQ_RQ_QUEUE_BUSY:
2029 blk_mq_stop_hw_queue(hctx);
2030 if (atomic_read(&sdev->device_busy) == 0 &&
2031 !scsi_device_blocked(sdev))
2032 blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
2033 break;
2034 case BLK_MQ_RQ_QUEUE_ERROR:
2035 /*
2036 * Make sure to release all allocated ressources when
2037 * we hit an error, as we will never see this command
2038 * again.
2039 */
2040 if (req->cmd_flags & REQ_DONTPREP)
2041 scsi_mq_uninit_cmd(cmd);
2042 break;
2043 default:
2044 break;
2045 }
2046 return ret;
2047}
2048
Christoph Hellwig0152fb62014-09-13 16:40:13 -07002049static enum blk_eh_timer_return scsi_timeout(struct request *req,
2050 bool reserved)
2051{
2052 if (reserved)
2053 return BLK_EH_RESET_TIMER;
2054 return scsi_times_out(req);
2055}
2056
Christoph Hellwigd2852032014-01-17 12:06:53 +01002057static int scsi_init_request(void *data, struct request *rq,
2058 unsigned int hctx_idx, unsigned int request_idx,
2059 unsigned int numa_node)
2060{
2061 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2062
2063 cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
2064 numa_node);
2065 if (!cmd->sense_buffer)
2066 return -ENOMEM;
2067 return 0;
2068}
2069
2070static void scsi_exit_request(void *data, struct request *rq,
2071 unsigned int hctx_idx, unsigned int request_idx)
2072{
2073 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2074
2075 kfree(cmd->sense_buffer);
2076}
2077
Christoph Hellwigf1bea552014-04-15 12:26:54 +02002078static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002079{
2080 struct device *host_dev;
2081 u64 bounce_limit = 0xffffffff;
2082
2083 if (shost->unchecked_isa_dma)
2084 return BLK_BOUNCE_ISA;
2085 /*
2086 * Platforms with virtual-DMA translation
2087 * hardware have no practical limit.
2088 */
2089 if (!PCI_DMA_BUS_IS_PHYS)
2090 return BLK_BOUNCE_ANY;
2091
2092 host_dev = scsi_get_device(shost);
2093 if (host_dev && host_dev->dma_mask)
Russell Kinge83b3662014-02-11 17:11:04 +00002094 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095
2096 return bounce_limit;
2097}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002098
Christoph Hellwigd2852032014-01-17 12:06:53 +01002099static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100{
Lin Ming6f381fa2012-04-12 13:50:38 +08002101 struct device *dev = shost->dma_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102
Jens Axboea8474ce2007-08-07 09:02:51 +02002103 /*
2104 * this limit is imposed by hardware restrictions
2105 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05002106 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2107 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02002108
Martin K. Petersen13f05c82010-09-10 20:50:10 +02002109 if (scsi_host_prot_dma(shost)) {
2110 shost->sg_prot_tablesize =
2111 min_not_zero(shost->sg_prot_tablesize,
2112 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2113 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2114 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2115 }
2116
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05002117 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2119 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08002120 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121
FUJITA Tomonori860ac562008-02-04 22:28:05 -08002122 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2123
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 if (!shost->use_clustering)
Martin K. Petersene692cb62010-12-01 19:41:49 +01002125 q->limits.cluster = 0;
James Bottomley465ff312008-01-01 10:00:10 -06002126
2127 /*
2128 * set a reasonable default alignment on word boundaries: the
2129 * host and device may alter it using
2130 * blk_queue_update_dma_alignment() later.
2131 */
2132 blk_queue_dma_alignment(q, 0x03);
Christoph Hellwigd2852032014-01-17 12:06:53 +01002133}
James Bottomley465ff312008-01-01 10:00:10 -06002134
Christoph Hellwigd2852032014-01-17 12:06:53 +01002135struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2136 request_fn_proc *request_fn)
2137{
2138 struct request_queue *q;
2139
2140 q = blk_init_queue(request_fn, NULL);
2141 if (!q)
2142 return NULL;
2143 __scsi_init_queue(shost, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002144 return q;
2145}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002146EXPORT_SYMBOL(__scsi_alloc_queue);
2147
2148struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2149{
2150 struct request_queue *q;
2151
2152 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2153 if (!q)
2154 return NULL;
2155
2156 blk_queue_prep_rq(q, scsi_prep_fn);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02002157 blk_queue_unprep_rq(q, scsi_unprep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002158 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07002159 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04002160 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002161 return q;
2162}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002163
Christoph Hellwigd2852032014-01-17 12:06:53 +01002164static struct blk_mq_ops scsi_mq_ops = {
2165 .map_queue = blk_mq_map_queue,
2166 .queue_rq = scsi_queue_rq,
2167 .complete = scsi_softirq_done,
Christoph Hellwig0152fb62014-09-13 16:40:13 -07002168 .timeout = scsi_timeout,
Christoph Hellwigd2852032014-01-17 12:06:53 +01002169 .init_request = scsi_init_request,
2170 .exit_request = scsi_exit_request,
2171};
2172
2173struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2174{
2175 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2176 if (IS_ERR(sdev->request_queue))
2177 return NULL;
2178
2179 sdev->request_queue->queuedata = sdev;
2180 __scsi_init_queue(sdev->host, sdev->request_queue);
2181 return sdev->request_queue;
2182}
2183
2184int scsi_mq_setup_tags(struct Scsi_Host *shost)
2185{
2186 unsigned int cmd_size, sgl_size, tbl_size;
2187
2188 tbl_size = shost->sg_tablesize;
2189 if (tbl_size > SCSI_MAX_SG_SEGMENTS)
2190 tbl_size = SCSI_MAX_SG_SEGMENTS;
2191 sgl_size = tbl_size * sizeof(struct scatterlist);
2192 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2193 if (scsi_host_get_prot(shost))
2194 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2195
2196 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2197 shost->tag_set.ops = &scsi_mq_ops;
Bart Van Asscheefec4b92014-10-30 14:45:36 +01002198 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
Christoph Hellwigd2852032014-01-17 12:06:53 +01002199 shost->tag_set.queue_depth = shost->can_queue;
2200 shost->tag_set.cmd_size = cmd_size;
2201 shost->tag_set.numa_node = NUMA_NO_NODE;
2202 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
Shaohua Li24391c02015-01-23 14:18:00 -07002203 shost->tag_set.flags |=
2204 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
Christoph Hellwigd2852032014-01-17 12:06:53 +01002205 shost->tag_set.driver_data = shost;
2206
2207 return blk_mq_alloc_tag_set(&shost->tag_set);
2208}
2209
2210void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2211{
2212 blk_mq_free_tag_set(&shost->tag_set);
2213}
2214
Linus Torvalds1da177e2005-04-16 15:20:36 -07002215/*
2216 * Function: scsi_block_requests()
2217 *
2218 * Purpose: Utility function used by low-level drivers to prevent further
2219 * commands from being queued to the device.
2220 *
2221 * Arguments: shost - Host in question
2222 *
2223 * Returns: Nothing
2224 *
2225 * Lock status: No locks are assumed held.
2226 *
2227 * Notes: There is no timer nor any other means by which the requests
2228 * get unblocked other than the low-level driver calling
2229 * scsi_unblock_requests().
2230 */
2231void scsi_block_requests(struct Scsi_Host *shost)
2232{
2233 shost->host_self_blocked = 1;
2234}
2235EXPORT_SYMBOL(scsi_block_requests);
2236
2237/*
2238 * Function: scsi_unblock_requests()
2239 *
2240 * Purpose: Utility function used by low-level drivers to allow further
2241 * commands from being queued to the device.
2242 *
2243 * Arguments: shost - Host in question
2244 *
2245 * Returns: Nothing
2246 *
2247 * Lock status: No locks are assumed held.
2248 *
2249 * Notes: There is no timer nor any other means by which the requests
2250 * get unblocked other than the low-level driver calling
2251 * scsi_unblock_requests().
2252 *
2253 * This is done as an API function so that changes to the
2254 * internals of the scsi mid-layer won't require wholesale
2255 * changes to drivers that use this feature.
2256 */
2257void scsi_unblock_requests(struct Scsi_Host *shost)
2258{
2259 shost->host_self_blocked = 0;
2260 scsi_run_host_queues(shost);
2261}
2262EXPORT_SYMBOL(scsi_unblock_requests);
2263
2264int __init scsi_init_queue(void)
2265{
2266 int i;
2267
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002268 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2269 sizeof(struct scsi_data_buffer),
2270 0, 0, NULL);
2271 if (!scsi_sdb_cache) {
2272 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09002273 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02002274 }
2275
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2277 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2278 int size = sgp->size * sizeof(struct scatterlist);
2279
2280 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09002281 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282 if (!sgp->slab) {
2283 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
2284 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002285 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286 }
2287
Matthew Dobson93d23412006-03-26 01:37:50 -08002288 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
2289 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002290 if (!sgp->pool) {
2291 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
2292 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002293 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 }
2295 }
2296
2297 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002298
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002299cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002300 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2301 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2302 if (sgp->pool)
2303 mempool_destroy(sgp->pool);
2304 if (sgp->slab)
2305 kmem_cache_destroy(sgp->slab);
2306 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002307 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002308
2309 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310}
2311
2312void scsi_exit_queue(void)
2313{
2314 int i;
2315
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002316 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06002317
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2319 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2320 mempool_destroy(sgp->pool);
2321 kmem_cache_destroy(sgp->slab);
2322 }
2323}
James Bottomley5baba832006-03-18 14:10:35 -06002324
2325/**
2326 * scsi_mode_select - issue a mode select
2327 * @sdev: SCSI device to be queried
2328 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2329 * @sp: Save page bit (0 == don't save, 1 == save)
2330 * @modepage: mode page being requested
2331 * @buffer: request buffer (may not be smaller than eight bytes)
2332 * @len: length of request buffer.
2333 * @timeout: command timeout
2334 * @retries: number of retries before failing
2335 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05002336 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06002337 * must be SCSI_SENSE_BUFFERSIZE big.
2338 *
2339 * Returns zero if successful; negative error number or scsi
2340 * status on error
2341 *
2342 */
2343int
2344scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2345 unsigned char *buffer, int len, int timeout, int retries,
2346 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2347{
2348 unsigned char cmd[10];
2349 unsigned char *real_buffer;
2350 int ret;
2351
2352 memset(cmd, 0, sizeof(cmd));
2353 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2354
2355 if (sdev->use_10_for_ms) {
2356 if (len > 65535)
2357 return -EINVAL;
2358 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2359 if (!real_buffer)
2360 return -ENOMEM;
2361 memcpy(real_buffer + 8, buffer, len);
2362 len += 8;
2363 real_buffer[0] = 0;
2364 real_buffer[1] = 0;
2365 real_buffer[2] = data->medium_type;
2366 real_buffer[3] = data->device_specific;
2367 real_buffer[4] = data->longlba ? 0x01 : 0;
2368 real_buffer[5] = 0;
2369 real_buffer[6] = data->block_descriptor_length >> 8;
2370 real_buffer[7] = data->block_descriptor_length;
2371
2372 cmd[0] = MODE_SELECT_10;
2373 cmd[7] = len >> 8;
2374 cmd[8] = len;
2375 } else {
2376 if (len > 255 || data->block_descriptor_length > 255 ||
2377 data->longlba)
2378 return -EINVAL;
2379
2380 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2381 if (!real_buffer)
2382 return -ENOMEM;
2383 memcpy(real_buffer + 4, buffer, len);
2384 len += 4;
2385 real_buffer[0] = 0;
2386 real_buffer[1] = data->medium_type;
2387 real_buffer[2] = data->device_specific;
2388 real_buffer[3] = data->block_descriptor_length;
2389
2390
2391 cmd[0] = MODE_SELECT;
2392 cmd[4] = len;
2393 }
2394
2395 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002396 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06002397 kfree(real_buffer);
2398 return ret;
2399}
2400EXPORT_SYMBOL_GPL(scsi_mode_select);
2401
Linus Torvalds1da177e2005-04-16 15:20:36 -07002402/**
Rob Landleyeb448202007-11-03 13:30:39 -05002403 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05002404 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07002405 * @dbd: set if mode sense will allow block descriptors to be returned
2406 * @modepage: mode page being requested
2407 * @buffer: request buffer (may not be smaller than eight bytes)
2408 * @len: length of request buffer.
2409 * @timeout: command timeout
2410 * @retries: number of retries before failing
2411 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05002412 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05002413 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002414 *
2415 * Returns zero if unsuccessful, or the header offset (either 4
2416 * or 8 depending on whether a six or ten byte command was
2417 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05002418 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002419int
James Bottomley1cf72692005-08-28 11:27:01 -05002420scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002421 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06002422 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2423{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424 unsigned char cmd[12];
2425 int use_10_for_ms;
2426 int header_length;
Hannes Reinecke0ae80ba2015-06-12 16:12:48 +02002427 int result, retry_count = retries;
James Bottomleyea73a9f2005-08-28 11:33:52 -05002428 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002429
2430 memset(data, 0, sizeof(*data));
2431 memset(&cmd[0], 0, 12);
2432 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2433 cmd[2] = modepage;
2434
James Bottomleyea73a9f2005-08-28 11:33:52 -05002435 /* caller might not be interested in sense, but we need it */
2436 if (!sshdr)
2437 sshdr = &my_sshdr;
2438
Linus Torvalds1da177e2005-04-16 15:20:36 -07002439 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05002440 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002441
2442 if (use_10_for_ms) {
2443 if (len < 8)
2444 len = 8;
2445
2446 cmd[0] = MODE_SENSE_10;
2447 cmd[8] = len;
2448 header_length = 8;
2449 } else {
2450 if (len < 4)
2451 len = 4;
2452
2453 cmd[0] = MODE_SENSE;
2454 cmd[4] = len;
2455 header_length = 4;
2456 }
2457
Linus Torvalds1da177e2005-04-16 15:20:36 -07002458 memset(buffer, 0, len);
2459
James Bottomley1cf72692005-08-28 11:27:01 -05002460 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002461 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002462
2463 /* This code looks awful: what it's doing is making sure an
2464 * ILLEGAL REQUEST sense return identifies the actual command
2465 * byte as the problem. MODE_SENSE commands can return
2466 * ILLEGAL REQUEST if the code page isn't supported */
2467
James Bottomley1cf72692005-08-28 11:27:01 -05002468 if (use_10_for_ms && !scsi_status_is_good(result) &&
2469 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05002470 if (scsi_sense_valid(sshdr)) {
2471 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2472 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002473 /*
2474 * Invalid command operation code
2475 */
James Bottomley1cf72692005-08-28 11:27:01 -05002476 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002477 goto retry;
2478 }
2479 }
2480 }
2481
James Bottomley1cf72692005-08-28 11:27:01 -05002482 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01002483 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2484 (modepage == 6 || modepage == 8))) {
2485 /* Initio breakage? */
2486 header_length = 0;
2487 data->length = 13;
2488 data->medium_type = 0;
2489 data->device_specific = 0;
2490 data->longlba = 0;
2491 data->block_descriptor_length = 0;
2492 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002493 data->length = buffer[0]*256 + buffer[1] + 2;
2494 data->medium_type = buffer[2];
2495 data->device_specific = buffer[3];
2496 data->longlba = buffer[4] & 0x01;
2497 data->block_descriptor_length = buffer[6]*256
2498 + buffer[7];
2499 } else {
2500 data->length = buffer[0] + 1;
2501 data->medium_type = buffer[1];
2502 data->device_specific = buffer[2];
2503 data->block_descriptor_length = buffer[3];
2504 }
Al Viro6d73c852006-02-23 02:03:16 +01002505 data->header_length = header_length;
Hannes Reinecke0ae80ba2015-06-12 16:12:48 +02002506 } else if ((status_byte(result) == CHECK_CONDITION) &&
2507 scsi_sense_valid(sshdr) &&
2508 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2509 retry_count--;
2510 goto retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002511 }
2512
James Bottomley1cf72692005-08-28 11:27:01 -05002513 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002514}
2515EXPORT_SYMBOL(scsi_mode_sense);
2516
James Bottomley001aac22007-12-02 19:10:40 +02002517/**
2518 * scsi_test_unit_ready - test if unit is ready
2519 * @sdev: scsi device to change the state of.
2520 * @timeout: command timeout
2521 * @retries: number of retries before failing
2522 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2523 * returning sense. Make sure that this is cleared before passing
2524 * in.
2525 *
2526 * Returns zero if unsuccessful or an error if TUR failed. For
Tejun Heo9f8a2c22010-12-08 20:57:40 +01002527 * removable media, UNIT_ATTENTION sets ->changed flag.
James Bottomley001aac22007-12-02 19:10:40 +02002528 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529int
James Bottomley001aac22007-12-02 19:10:40 +02002530scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2531 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002532{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002533 char cmd[] = {
2534 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2535 };
James Bottomley001aac22007-12-02 19:10:40 +02002536 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002537 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002538
2539 if (!sshdr_external)
2540 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2541 else
2542 sshdr = sshdr_external;
2543
2544 /* try to eat the UNIT_ATTENTION if there are enough retries */
2545 do {
2546 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002547 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002548 if (sdev->removable && scsi_sense_valid(sshdr) &&
2549 sshdr->sense_key == UNIT_ATTENTION)
2550 sdev->changed = 1;
2551 } while (scsi_sense_valid(sshdr) &&
2552 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002553
James Bottomley001aac22007-12-02 19:10:40 +02002554 if (!sshdr_external)
2555 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002556 return result;
2557}
2558EXPORT_SYMBOL(scsi_test_unit_ready);
2559
2560/**
Rob Landleyeb448202007-11-03 13:30:39 -05002561 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002562 * @sdev: scsi device to change the state of.
2563 * @state: state to change to.
2564 *
2565 * Returns zero if unsuccessful or an error if the requested
2566 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002567 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002568int
2569scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2570{
2571 enum scsi_device_state oldstate = sdev->sdev_state;
2572
2573 if (state == oldstate)
2574 return 0;
2575
2576 switch (state) {
2577 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002578 switch (oldstate) {
2579 case SDEV_CREATED_BLOCK:
2580 break;
2581 default:
2582 goto illegal;
2583 }
2584 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002585
2586 case SDEV_RUNNING:
2587 switch (oldstate) {
2588 case SDEV_CREATED:
2589 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002590 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002591 case SDEV_QUIESCE:
2592 case SDEV_BLOCK:
2593 break;
2594 default:
2595 goto illegal;
2596 }
2597 break;
2598
2599 case SDEV_QUIESCE:
2600 switch (oldstate) {
2601 case SDEV_RUNNING:
2602 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002603 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002604 break;
2605 default:
2606 goto illegal;
2607 }
2608 break;
2609
2610 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002611 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002612 switch (oldstate) {
2613 case SDEV_CREATED:
2614 case SDEV_RUNNING:
2615 case SDEV_QUIESCE:
2616 case SDEV_BLOCK:
2617 break;
2618 default:
2619 goto illegal;
2620 }
2621 break;
2622
2623 case SDEV_BLOCK:
2624 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002625 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002626 case SDEV_CREATED_BLOCK:
2627 break;
2628 default:
2629 goto illegal;
2630 }
2631 break;
2632
2633 case SDEV_CREATED_BLOCK:
2634 switch (oldstate) {
2635 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002636 break;
2637 default:
2638 goto illegal;
2639 }
2640 break;
2641
2642 case SDEV_CANCEL:
2643 switch (oldstate) {
2644 case SDEV_CREATED:
2645 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002646 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002648 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 case SDEV_BLOCK:
2650 break;
2651 default:
2652 goto illegal;
2653 }
2654 break;
2655
2656 case SDEV_DEL:
2657 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002658 case SDEV_CREATED:
2659 case SDEV_RUNNING:
2660 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002661 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002662 case SDEV_CANCEL:
Bart Van Assche0516c082013-07-02 15:06:33 +02002663 case SDEV_CREATED_BLOCK:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002664 break;
2665 default:
2666 goto illegal;
2667 }
2668 break;
2669
2670 }
2671 sdev->sdev_state = state;
2672 return 0;
2673
2674 illegal:
Hannes Reinecke91921e02014-06-25 16:39:59 +02002675 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002676 sdev_printk(KERN_ERR, sdev,
Hannes Reinecke91921e02014-06-25 16:39:59 +02002677 "Illegal state transition %s->%s",
James Bottomley9ccfc752005-10-02 11:45:08 -05002678 scsi_device_state_name(oldstate),
2679 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680 );
2681 return -EINVAL;
2682}
2683EXPORT_SYMBOL(scsi_device_set_state);
2684
2685/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002686 * sdev_evt_emit - emit a single SCSI device uevent
2687 * @sdev: associated SCSI device
2688 * @evt: event to emit
2689 *
2690 * Send a single uevent (scsi_event) to the associated scsi_device.
2691 */
2692static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2693{
2694 int idx = 0;
2695 char *envp[3];
2696
2697 switch (evt->evt_type) {
2698 case SDEV_EVT_MEDIA_CHANGE:
2699 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2700 break;
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002701 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2702 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2703 break;
2704 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2705 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2706 break;
2707 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2708 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2709 break;
2710 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2711 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2712 break;
2713 case SDEV_EVT_LUN_CHANGE_REPORTED:
2714 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2715 break;
Hannes Reinecke14c3e672015-07-06 13:41:53 +02002716 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2717 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2718 break;
Jeff Garzika341cd02007-10-29 17:15:22 -04002719 default:
2720 /* do nothing */
2721 break;
2722 }
2723
2724 envp[idx++] = NULL;
2725
2726 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2727}
2728
2729/**
2730 * sdev_evt_thread - send a uevent for each scsi event
2731 * @work: work struct for scsi_device
2732 *
2733 * Dispatch queued events to their associated scsi_device kobjects
2734 * as uevents.
2735 */
2736void scsi_evt_thread(struct work_struct *work)
2737{
2738 struct scsi_device *sdev;
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002739 enum scsi_device_event evt_type;
Jeff Garzika341cd02007-10-29 17:15:22 -04002740 LIST_HEAD(event_list);
2741
2742 sdev = container_of(work, struct scsi_device, event_work);
2743
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002744 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2745 if (test_and_clear_bit(evt_type, sdev->pending_events))
2746 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2747
Jeff Garzika341cd02007-10-29 17:15:22 -04002748 while (1) {
2749 struct scsi_event *evt;
2750 struct list_head *this, *tmp;
2751 unsigned long flags;
2752
2753 spin_lock_irqsave(&sdev->list_lock, flags);
2754 list_splice_init(&sdev->event_list, &event_list);
2755 spin_unlock_irqrestore(&sdev->list_lock, flags);
2756
2757 if (list_empty(&event_list))
2758 break;
2759
2760 list_for_each_safe(this, tmp, &event_list) {
2761 evt = list_entry(this, struct scsi_event, node);
2762 list_del(&evt->node);
2763 scsi_evt_emit(sdev, evt);
2764 kfree(evt);
2765 }
2766 }
2767}
2768
2769/**
2770 * sdev_evt_send - send asserted event to uevent thread
2771 * @sdev: scsi_device event occurred on
2772 * @evt: event to send
2773 *
2774 * Assert scsi device event asynchronously.
2775 */
2776void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2777{
2778 unsigned long flags;
2779
Kay Sievers4d1566e2008-03-19 13:04:47 +01002780#if 0
2781 /* FIXME: currently this check eliminates all media change events
2782 * for polled devices. Need to update to discriminate between AN
2783 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002784 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2785 kfree(evt);
2786 return;
2787 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002788#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002789
2790 spin_lock_irqsave(&sdev->list_lock, flags);
2791 list_add_tail(&evt->node, &sdev->event_list);
2792 schedule_work(&sdev->event_work);
2793 spin_unlock_irqrestore(&sdev->list_lock, flags);
2794}
2795EXPORT_SYMBOL_GPL(sdev_evt_send);
2796
2797/**
2798 * sdev_evt_alloc - allocate a new scsi event
2799 * @evt_type: type of event to allocate
2800 * @gfpflags: GFP flags for allocation
2801 *
2802 * Allocates and returns a new scsi_event.
2803 */
2804struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2805 gfp_t gfpflags)
2806{
2807 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2808 if (!evt)
2809 return NULL;
2810
2811 evt->evt_type = evt_type;
2812 INIT_LIST_HEAD(&evt->node);
2813
2814 /* evt_type-specific initialization, if any */
2815 switch (evt_type) {
2816 case SDEV_EVT_MEDIA_CHANGE:
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002817 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2818 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2819 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2820 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2821 case SDEV_EVT_LUN_CHANGE_REPORTED:
Hannes Reinecke14c3e672015-07-06 13:41:53 +02002822 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
Jeff Garzika341cd02007-10-29 17:15:22 -04002823 default:
2824 /* do nothing */
2825 break;
2826 }
2827
2828 return evt;
2829}
2830EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2831
2832/**
2833 * sdev_evt_send_simple - send asserted event to uevent thread
2834 * @sdev: scsi_device event occurred on
2835 * @evt_type: type of event to send
2836 * @gfpflags: GFP flags for allocation
2837 *
2838 * Assert scsi device event asynchronously, given an event type.
2839 */
2840void sdev_evt_send_simple(struct scsi_device *sdev,
2841 enum scsi_device_event evt_type, gfp_t gfpflags)
2842{
2843 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2844 if (!evt) {
2845 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2846 evt_type);
2847 return;
2848 }
2849
2850 sdev_evt_send(sdev, evt);
2851}
2852EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2853
2854/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002855 * scsi_device_quiesce - Block user issued commands.
2856 * @sdev: scsi device to quiesce.
2857 *
2858 * This works by trying to transition to the SDEV_QUIESCE state
2859 * (which must be a legal transition). When the device is in this
2860 * state, only special requests will be accepted, all others will
2861 * be deferred. Since special requests may also be requeued requests,
2862 * a successful return doesn't guarantee the device will be
2863 * totally quiescent.
2864 *
2865 * Must be called with user context, may sleep.
2866 *
2867 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002868 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002869int
2870scsi_device_quiesce(struct scsi_device *sdev)
2871{
2872 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2873 if (err)
2874 return err;
2875
2876 scsi_run_queue(sdev->request_queue);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02002877 while (atomic_read(&sdev->device_busy)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002878 msleep_interruptible(200);
2879 scsi_run_queue(sdev->request_queue);
2880 }
2881 return 0;
2882}
2883EXPORT_SYMBOL(scsi_device_quiesce);
2884
2885/**
2886 * scsi_device_resume - Restart user issued commands to a quiesced device.
2887 * @sdev: scsi device to resume.
2888 *
2889 * Moves the device from quiesced back to running and restarts the
2890 * queues.
2891 *
2892 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002893 */
Dan Williamsa7a20d12012-03-22 17:05:11 -07002894void scsi_device_resume(struct scsi_device *sdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002895{
Dan Williamsa7a20d12012-03-22 17:05:11 -07002896 /* check if the device state was mutated prior to resume, and if
2897 * so assume the state is being managed elsewhere (for example
2898 * device deleted during suspend)
2899 */
2900 if (sdev->sdev_state != SDEV_QUIESCE ||
2901 scsi_device_set_state(sdev, SDEV_RUNNING))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002902 return;
2903 scsi_run_queue(sdev->request_queue);
2904}
2905EXPORT_SYMBOL(scsi_device_resume);
2906
2907static void
2908device_quiesce_fn(struct scsi_device *sdev, void *data)
2909{
2910 scsi_device_quiesce(sdev);
2911}
2912
2913void
2914scsi_target_quiesce(struct scsi_target *starget)
2915{
2916 starget_for_each_device(starget, NULL, device_quiesce_fn);
2917}
2918EXPORT_SYMBOL(scsi_target_quiesce);
2919
2920static void
2921device_resume_fn(struct scsi_device *sdev, void *data)
2922{
2923 scsi_device_resume(sdev);
2924}
2925
2926void
2927scsi_target_resume(struct scsi_target *starget)
2928{
2929 starget_for_each_device(starget, NULL, device_resume_fn);
2930}
2931EXPORT_SYMBOL(scsi_target_resume);
2932
2933/**
Rob Landleyeb448202007-11-03 13:30:39 -05002934 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002935 * @sdev: device to block
2936 *
2937 * Block request made by scsi lld's to temporarily stop all
2938 * scsi commands on the specified device. Called from interrupt
2939 * or normal process context.
2940 *
2941 * Returns zero if successful or error if not
2942 *
2943 * Notes:
2944 * This routine transitions the device to the SDEV_BLOCK state
2945 * (which must be a legal transition). When the device is in this
2946 * state, all commands are deferred until the scsi lld reenables
2947 * the device with scsi_device_unblock or device_block_tmo fires.
Rob Landleyeb448202007-11-03 13:30:39 -05002948 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002949int
2950scsi_internal_device_block(struct scsi_device *sdev)
2951{
Jens Axboe165125e2007-07-24 09:28:11 +02002952 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002953 unsigned long flags;
2954 int err = 0;
2955
2956 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002957 if (err) {
2958 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2959
2960 if (err)
2961 return err;
2962 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002963
2964 /*
2965 * The device has transitioned to SDEV_BLOCK. Stop the
2966 * block layer from calling the midlayer with this device's
2967 * request queue.
2968 */
Christoph Hellwigd2852032014-01-17 12:06:53 +01002969 if (q->mq_ops) {
2970 blk_mq_stop_hw_queues(q);
2971 } else {
2972 spin_lock_irqsave(q->queue_lock, flags);
2973 blk_stop_queue(q);
2974 spin_unlock_irqrestore(q->queue_lock, flags);
2975 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002976
2977 return 0;
2978}
2979EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2980
2981/**
2982 * scsi_internal_device_unblock - resume a device after a block request
2983 * @sdev: device to resume
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002984 * @new_state: state to set devices to after unblocking
Linus Torvalds1da177e2005-04-16 15:20:36 -07002985 *
2986 * Called by scsi lld's or the midlayer to restart the device queue
2987 * for the previously suspended scsi device. Called from interrupt or
2988 * normal process context.
2989 *
2990 * Returns zero if successful or error if not.
2991 *
2992 * Notes:
2993 * This routine transitions the device to the SDEV_RUNNING state
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002994 * or to one of the offline states (which must be a legal transition)
Mike Christied0754982012-05-17 23:56:58 -05002995 * allowing the midlayer to goose the queue for this device.
Rob Landleyeb448202007-11-03 13:30:39 -05002996 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002997int
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002998scsi_internal_device_unblock(struct scsi_device *sdev,
2999 enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003000{
Jens Axboe165125e2007-07-24 09:28:11 +02003001 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003002 unsigned long flags;
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003003
3004 /*
3005 * Try to transition the scsi device to SDEV_RUNNING or one of the
3006 * offlined states and goose the device queue if successful.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003007 */
Vikas Chaudhary0e580762012-08-09 04:51:30 -04003008 if ((sdev->sdev_state == SDEV_BLOCK) ||
3009 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003010 sdev->sdev_state = new_state;
3011 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
3012 if (new_state == SDEV_TRANSPORT_OFFLINE ||
3013 new_state == SDEV_OFFLINE)
3014 sdev->sdev_state = new_state;
3015 else
3016 sdev->sdev_state = SDEV_CREATED;
3017 } else if (sdev->sdev_state != SDEV_CANCEL &&
Mike Christie986fe6c2010-10-06 03:10:59 -05003018 sdev->sdev_state != SDEV_OFFLINE)
Takahiro Yasui5c10e632009-04-29 12:13:02 -04003019 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003020
Christoph Hellwigd2852032014-01-17 12:06:53 +01003021 if (q->mq_ops) {
3022 blk_mq_start_stopped_hw_queues(q, false);
3023 } else {
3024 spin_lock_irqsave(q->queue_lock, flags);
3025 blk_start_queue(q);
3026 spin_unlock_irqrestore(q->queue_lock, flags);
3027 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003028
3029 return 0;
3030}
3031EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
3032
3033static void
3034device_block(struct scsi_device *sdev, void *data)
3035{
3036 scsi_internal_device_block(sdev);
3037}
3038
3039static int
3040target_block(struct device *dev, void *data)
3041{
3042 if (scsi_is_target_device(dev))
3043 starget_for_each_device(to_scsi_target(dev), NULL,
3044 device_block);
3045 return 0;
3046}
3047
3048void
3049scsi_target_block(struct device *dev)
3050{
3051 if (scsi_is_target_device(dev))
3052 starget_for_each_device(to_scsi_target(dev), NULL,
3053 device_block);
3054 else
3055 device_for_each_child(dev, NULL, target_block);
3056}
3057EXPORT_SYMBOL_GPL(scsi_target_block);
3058
3059static void
3060device_unblock(struct scsi_device *sdev, void *data)
3061{
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003062 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003063}
3064
3065static int
3066target_unblock(struct device *dev, void *data)
3067{
3068 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003069 starget_for_each_device(to_scsi_target(dev), data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07003070 device_unblock);
3071 return 0;
3072}
3073
3074void
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003075scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003076{
3077 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003078 starget_for_each_device(to_scsi_target(dev), &new_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -07003079 device_unblock);
3080 else
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003081 device_for_each_child(dev, &new_state, target_unblock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003082}
3083EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003084
3085/**
3086 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05003087 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003088 * @sg_count: number of segments in sg
3089 * @offset: offset in bytes into sg, on return offset into the mapped area
3090 * @len: bytes to map, on return number of bytes mapped
3091 *
3092 * Returns virtual address of the start of the mapped page
3093 */
Jens Axboec6132da2007-10-16 11:08:49 +02003094void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003095 size_t *offset, size_t *len)
3096{
3097 int i;
3098 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02003099 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003100 struct page *page;
3101
Andrew Morton22cfefb2007-02-05 16:39:03 -08003102 WARN_ON(!irqs_disabled());
3103
Jens Axboec6132da2007-10-16 11:08:49 +02003104 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003105 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02003106 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003107 if (sg_len > *offset)
3108 break;
3109 }
3110
3111 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07003112 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3113 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07003114 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003115 WARN_ON(1);
3116 return NULL;
3117 }
3118
3119 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02003120 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003121
3122 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02003123 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003124 *offset &= ~PAGE_MASK;
3125
3126 /* Bytes in this sg-entry from *offset to the end of the page */
3127 sg_len = PAGE_SIZE - *offset;
3128 if (*len > sg_len)
3129 *len = sg_len;
3130
Cong Wang77dfce02011-11-25 23:14:23 +08003131 return kmap_atomic(page);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003132}
3133EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3134
3135/**
Rob Landleyeb448202007-11-03 13:30:39 -05003136 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003137 * @virt: virtual address to be unmapped
3138 */
3139void scsi_kunmap_atomic_sg(void *virt)
3140{
Cong Wang77dfce02011-11-25 23:14:23 +08003141 kunmap_atomic(virt);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003142}
3143EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
Aaron Lu6f4c8272013-01-23 15:09:32 +08003144
3145void sdev_disable_disk_events(struct scsi_device *sdev)
3146{
3147 atomic_inc(&sdev->disk_events_disable_depth);
3148}
3149EXPORT_SYMBOL(sdev_disable_disk_events);
3150
3151void sdev_enable_disk_events(struct scsi_device *sdev)
3152{
3153 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3154 return;
3155 atomic_dec(&sdev->disk_events_disable_depth);
3156}
3157EXPORT_SYMBOL(sdev_enable_disk_events);
Hannes Reinecke9983bed2015-12-01 10:16:55 +01003158
3159/**
3160 * scsi_vpd_lun_id - return a unique device identification
3161 * @sdev: SCSI device
3162 * @id: buffer for the identification
3163 * @id_len: length of the buffer
3164 *
3165 * Copies a unique device identification into @id based
3166 * on the information in the VPD page 0x83 of the device.
3167 * The string will be formatted as a SCSI name string.
3168 *
3169 * Returns the length of the identification or error on failure.
3170 * If the identifier is longer than the supplied buffer the actual
3171 * identifier length is returned and the buffer is not zero-padded.
3172 */
3173int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3174{
3175 u8 cur_id_type = 0xff;
3176 u8 cur_id_size = 0;
3177 unsigned char *d, *cur_id_str;
3178 unsigned char __rcu *vpd_pg83;
3179 int id_size = -EINVAL;
3180
3181 rcu_read_lock();
3182 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3183 if (!vpd_pg83) {
3184 rcu_read_unlock();
3185 return -ENXIO;
3186 }
3187
3188 /*
3189 * Look for the correct descriptor.
3190 * Order of preference for lun descriptor:
3191 * - SCSI name string
3192 * - NAA IEEE Registered Extended
3193 * - EUI-64 based 16-byte
3194 * - EUI-64 based 12-byte
3195 * - NAA IEEE Registered
3196 * - NAA IEEE Extended
3197 * as longer descriptors reduce the likelyhood
3198 * of identification clashes.
3199 */
3200
3201 /* The id string must be at least 20 bytes + terminating NULL byte */
3202 if (id_len < 21) {
3203 rcu_read_unlock();
3204 return -EINVAL;
3205 }
3206
3207 memset(id, 0, id_len);
3208 d = vpd_pg83 + 4;
3209 while (d < vpd_pg83 + sdev->vpd_pg83_len) {
3210 /* Skip designators not referring to the LUN */
3211 if ((d[1] & 0x30) != 0x00)
3212 goto next_desig;
3213
3214 switch (d[1] & 0xf) {
3215 case 0x2:
3216 /* EUI-64 */
3217 if (cur_id_size > d[3])
3218 break;
3219 /* Prefer NAA IEEE Registered Extended */
3220 if (cur_id_type == 0x3 &&
3221 cur_id_size == d[3])
3222 break;
3223 cur_id_size = d[3];
3224 cur_id_str = d + 4;
3225 cur_id_type = d[1] & 0xf;
3226 switch (cur_id_size) {
3227 case 8:
3228 id_size = snprintf(id, id_len,
3229 "eui.%8phN",
3230 cur_id_str);
3231 break;
3232 case 12:
3233 id_size = snprintf(id, id_len,
3234 "eui.%12phN",
3235 cur_id_str);
3236 break;
3237 case 16:
3238 id_size = snprintf(id, id_len,
3239 "eui.%16phN",
3240 cur_id_str);
3241 break;
3242 default:
3243 cur_id_size = 0;
3244 break;
3245 }
3246 break;
3247 case 0x3:
3248 /* NAA */
3249 if (cur_id_size > d[3])
3250 break;
3251 cur_id_size = d[3];
3252 cur_id_str = d + 4;
3253 cur_id_type = d[1] & 0xf;
3254 switch (cur_id_size) {
3255 case 8:
3256 id_size = snprintf(id, id_len,
3257 "naa.%8phN",
3258 cur_id_str);
3259 break;
3260 case 16:
3261 id_size = snprintf(id, id_len,
3262 "naa.%16phN",
3263 cur_id_str);
3264 break;
3265 default:
3266 cur_id_size = 0;
3267 break;
3268 }
3269 break;
3270 case 0x8:
3271 /* SCSI name string */
3272 if (cur_id_size + 4 > d[3])
3273 break;
3274 /* Prefer others for truncated descriptor */
3275 if (cur_id_size && d[3] > id_len)
3276 break;
3277 cur_id_size = id_size = d[3];
3278 cur_id_str = d + 4;
3279 cur_id_type = d[1] & 0xf;
3280 if (cur_id_size >= id_len)
3281 cur_id_size = id_len - 1;
3282 memcpy(id, cur_id_str, cur_id_size);
3283 /* Decrease priority for truncated descriptor */
3284 if (cur_id_size != id_size)
3285 cur_id_size = 6;
3286 break;
3287 default:
3288 break;
3289 }
3290next_desig:
3291 d += d[3] + 4;
3292 }
3293 rcu_read_unlock();
3294
3295 return id_size;
3296}
3297EXPORT_SYMBOL(scsi_vpd_lun_id);
Hannes Reineckea8aa3972015-12-01 10:16:57 +01003298
3299/*
3300 * scsi_vpd_tpg_id - return a target port group identifier
3301 * @sdev: SCSI device
3302 *
3303 * Returns the Target Port Group identifier from the information
3304 * froom VPD page 0x83 of the device.
3305 *
3306 * Returns the identifier or error on failure.
3307 */
3308int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3309{
3310 unsigned char *d;
3311 unsigned char __rcu *vpd_pg83;
3312 int group_id = -EAGAIN, rel_port = -1;
3313
3314 rcu_read_lock();
3315 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3316 if (!vpd_pg83) {
3317 rcu_read_unlock();
3318 return -ENXIO;
3319 }
3320
3321 d = sdev->vpd_pg83 + 4;
3322 while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
3323 switch (d[1] & 0xf) {
3324 case 0x4:
3325 /* Relative target port */
3326 rel_port = get_unaligned_be16(&d[6]);
3327 break;
3328 case 0x5:
3329 /* Target port group */
3330 group_id = get_unaligned_be16(&d[6]);
3331 break;
3332 default:
3333 break;
3334 }
3335 d += d[3] + 4;
3336 }
3337 rcu_read_unlock();
3338
3339 if (group_id >= 0 && rel_id && rel_port != -1)
3340 *rel_id = rel_port;
3341
3342 return group_id;
3343}
3344EXPORT_SYMBOL(scsi_vpd_tpg_id);