blob: ce62e8798cc80da072b452bced0a26fb44b5eb11 [file] [log] [blame]
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020027#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <scsi/scsi_dbg.h>
29#include <scsi/scsi_device.h>
30#include <scsi/scsi_driver.h>
31#include <scsi/scsi_eh.h>
32#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Christoph Hellwig3b5382c2014-05-06 12:25:40 +020034#include <trace/events/scsi.h>
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include "scsi_priv.h"
37#include "scsi_logging.h"
38
39
Tobias Klauser6391a112006-06-08 22:23:48 -070040#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020041#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43struct scsi_host_sg_pool {
44 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020045 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080046 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 mempool_t *pool;
48};
49
James Bottomleyd3f46f32008-01-15 11:11:46 -060050#define SP(x) { x, "sgpool-" __stringify(x) }
51#if (SCSI_MAX_SG_SEGMENTS < 32)
52#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
53#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070054static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 SP(8),
56 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020057#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060058 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020059#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060060 SP(64),
61#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060063#if (SCSI_MAX_SG_SEGMENTS > 256)
64#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020065#endif
66#endif
67#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060068#endif
69 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020070};
Linus Torvalds1da177e2005-04-16 15:20:36 -070071#undef SP
72
Martin K. Petersen7027ad72008-07-17 17:08:48 -040073struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020074
Jens Axboea488e742010-04-16 21:13:15 +020075/*
76 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
77 * not change behaviour from the previous unplug mechanism, experimentation
78 * may prove this needs changing.
79 */
80#define SCSI_QUEUE_DELAY 3
81
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +010082static void
83scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084{
85 struct Scsi_Host *host = cmd->device->host;
86 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -050087 struct scsi_target *starget = scsi_target(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +090090 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 *
92 * If the host/device isn't busy, assume that something actually
93 * completed, and that we should be able to queue a command now.
94 *
95 * Note that the prior mid-layer assumption that any host could
96 * always queue at least one command is now broken. The mid-layer
97 * will implement a user specifiable stall (see
98 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
99 * if a command is requeued with no other commands outstanding
100 * either for the device or for the host.
101 */
Mike Christief0c0a372008-08-17 15:24:38 -0500102 switch (reason) {
103 case SCSI_MLQUEUE_HOST_BUSY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100104 atomic_set(&host->host_blocked, host->max_host_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500105 break;
106 case SCSI_MLQUEUE_DEVICE_BUSY:
James Smart573e5912011-07-06 12:45:17 -0400107 case SCSI_MLQUEUE_EH_RETRY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100108 atomic_set(&device->device_blocked,
109 device->max_device_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500110 break;
111 case SCSI_MLQUEUE_TARGET_BUSY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100112 atomic_set(&starget->target_blocked,
113 starget->max_target_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500114 break;
115 }
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +0100116}
117
Christoph Hellwigd2852032014-01-17 12:06:53 +0100118static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
119{
120 struct scsi_device *sdev = cmd->device;
121 struct request_queue *q = cmd->request->q;
122
123 blk_mq_requeue_request(cmd->request);
124 blk_mq_kick_requeue_list(q);
125 put_device(&sdev->sdev_gendev);
126}
127
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +0100128/**
129 * __scsi_queue_insert - private queue insertion
130 * @cmd: The SCSI command being requeued
131 * @reason: The reason for the requeue
132 * @unbusy: Whether the queue should be unbusied
133 *
134 * This is a private queue insertion. The public interface
135 * scsi_queue_insert() always assumes the queue should be unbusied
136 * because it's always called before the completion. This function is
137 * for a requeue after completion, which should only occur in this
138 * file.
139 */
140static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
141{
142 struct scsi_device *device = cmd->device;
143 struct request_queue *q = device->request_queue;
144 unsigned long flags;
145
146 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
147 "Inserting command %p into mlqueue\n", cmd));
148
149 scsi_set_blocked(cmd, reason);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 * Decrement the counters, since these commands are no longer
153 * active on the host/device.
154 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600155 if (unbusy)
156 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
158 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500159 * Requeue this command. It will go before all other commands
Bart Van Asscheb4854622012-06-29 15:36:07 +0000160 * that are already in the queue. Schedule requeue work under
161 * lock such that the kblockd_schedule_work() call happens
162 * before blk_cleanup_queue() finishes.
Jens Axboea488e742010-04-16 21:13:15 +0200163 */
Alan Stern644373a2014-03-28 10:51:15 -0700164 cmd->result = 0;
Christoph Hellwigd2852032014-01-17 12:06:53 +0100165 if (q->mq_ops) {
166 scsi_mq_requeue_cmd(cmd);
167 return;
168 }
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500169 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400170 blk_requeue_request(q, cmd->request);
Jens Axboe59c3d452014-04-08 09:15:35 -0600171 kblockd_schedule_work(&device->requeue_work);
Bart Van Asscheb4854622012-06-29 15:36:07 +0000172 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173}
174
James Bottomley4f5299a2009-01-02 10:42:21 -0600175/*
176 * Function: scsi_queue_insert()
177 *
178 * Purpose: Insert a command in the midlevel queue.
179 *
180 * Arguments: cmd - command that we are adding to queue.
181 * reason - why we are inserting command to queue.
182 *
183 * Lock status: Assumed that lock is not held upon entry.
184 *
185 * Returns: Nothing.
186 *
187 * Notes: We do this for one of two cases. Either the host is busy
188 * and it cannot accept any more commands for the time being,
189 * or the device returned QUEUE_FULL and can accept no more
190 * commands.
191 * Notes: This could be called either from an interrupt context or a
192 * normal process context.
193 */
Bart Van Assche84feb162012-06-29 15:35:05 +0000194void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
James Bottomley4f5299a2009-01-02 10:42:21 -0600195{
Bart Van Assche84feb162012-06-29 15:35:05 +0000196 __scsi_queue_insert(cmd, reason, 1);
James Bottomley4f5299a2009-01-02 10:42:21 -0600197}
James Bottomley39216032005-06-15 18:48:29 -0500198/**
James Bottomley33aa6872005-08-28 11:31:14 -0500199 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500200 * @sdev: scsi device
201 * @cmd: scsi command
202 * @data_direction: data direction
203 * @buffer: data buffer
204 * @bufflen: len of buffer
205 * @sense: optional sense buffer
206 * @timeout: request timeout in seconds
207 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500208 * @flags: or into request flags;
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900209 * @resid: optional residual length
James Bottomley39216032005-06-15 18:48:29 -0500210 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200211 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500212 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500213 */
James Bottomley33aa6872005-08-28 11:31:14 -0500214int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
215 int data_direction, void *buffer, unsigned bufflen,
Martin K. Petersen2bfad212014-04-09 22:20:48 -0400216 unsigned char *sense, int timeout, int retries, u64 flags,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900217 int *resid)
James Bottomley39216032005-06-15 18:48:29 -0500218{
219 struct request *req;
220 int write = (data_direction == DMA_TO_DEVICE);
221 int ret = DRIVER_ERROR << 24;
222
223 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
James Bottomleybfe159a2011-07-07 15:45:40 -0500224 if (!req)
225 return ret;
Jens Axboef27b0872014-06-06 07:57:37 -0600226 blk_rq_set_block_pc(req);
James Bottomley39216032005-06-15 18:48:29 -0500227
228 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
229 buffer, bufflen, __GFP_WAIT))
230 goto out;
231
232 req->cmd_len = COMMAND_SIZE(cmd[0]);
233 memcpy(req->cmd, cmd, req->cmd_len);
234 req->sense = sense;
235 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600236 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500237 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200238 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500239
240 /*
241 * head injection *required* here otherwise quiesce won't work
242 */
243 blk_execute_rq(req->q, NULL, req, 1);
244
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400245 /*
246 * Some devices (USB mass-storage in particular) may transfer
247 * garbage data together with a residue indicating that the data
248 * is invalid. Prevent the garbage from being misinterpreted
249 * and prevent security leaks by zeroing out the excess data.
250 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900251 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
252 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400253
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900254 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900255 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500256 ret = req->errors;
257 out:
258 blk_put_request(req);
259
260 return ret;
261}
James Bottomley33aa6872005-08-28 11:31:14 -0500262EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500263
Lin Ming9b214932013-03-23 11:42:25 +0800264int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
James Bottomleyea73a9f2005-08-28 11:33:52 -0500265 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900266 struct scsi_sense_hdr *sshdr, int timeout, int retries,
Martin K. Petersen2bfad212014-04-09 22:20:48 -0400267 int *resid, u64 flags)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500268{
269 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700270 int result;
271
James Bottomleyea73a9f2005-08-28 11:33:52 -0500272 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500273 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500274 if (!sense)
275 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500276 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700277 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Lin Ming9b214932013-03-23 11:42:25 +0800278 sense, timeout, retries, flags, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500279 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500280 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500281
282 kfree(sense);
283 return result;
284}
Lin Ming9b214932013-03-23 11:42:25 +0800285EXPORT_SYMBOL(scsi_execute_req_flags);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287/*
288 * Function: scsi_init_cmd_errh()
289 *
290 * Purpose: Initialize cmd fields related to error handling.
291 *
292 * Arguments: cmd - command that is ready to be queued.
293 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 * Notes: This function has the job of initializing a number of
295 * fields related to error handling. Typically this will
296 * be called once for each command, as required.
297 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200298static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200301 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900302 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300304 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305}
306
307void scsi_device_unbusy(struct scsi_device *sdev)
308{
309 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500310 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 unsigned long flags;
312
Christoph Hellwig74665012014-01-22 15:29:29 +0100313 atomic_dec(&shost->host_busy);
Christoph Hellwig2ccbb002014-03-26 10:35:00 +0100314 if (starget->can_queue > 0)
315 atomic_dec(&starget->target_busy);
Christoph Hellwig74665012014-01-22 15:29:29 +0100316
James Bottomley939647e2005-09-18 15:05:20 -0500317 if (unlikely(scsi_host_in_recovery(shost) &&
Christoph Hellwig74665012014-01-22 15:29:29 +0100318 (shost->host_failed || shost->host_eh_scheduled))) {
319 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 scsi_eh_wakeup(shost);
Christoph Hellwig74665012014-01-22 15:29:29 +0100321 spin_unlock_irqrestore(shost->host_lock, flags);
322 }
323
Christoph Hellwig71e75c92014-04-11 19:07:01 +0200324 atomic_dec(&sdev->device_busy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325}
326
Christoph Hellwigd2852032014-01-17 12:06:53 +0100327static void scsi_kick_queue(struct request_queue *q)
328{
329 if (q->mq_ops)
330 blk_mq_start_hw_queues(q);
331 else
332 blk_run_queue(q);
333}
334
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335/*
336 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
337 * and call blk_run_queue for all the scsi_devices on the target -
338 * including current_sdev first.
339 *
340 * Called with *no* scsi locks held.
341 */
342static void scsi_single_lun_run(struct scsi_device *current_sdev)
343{
344 struct Scsi_Host *shost = current_sdev->host;
345 struct scsi_device *sdev, *tmp;
346 struct scsi_target *starget = scsi_target(current_sdev);
347 unsigned long flags;
348
349 spin_lock_irqsave(shost->host_lock, flags);
350 starget->starget_sdev_user = NULL;
351 spin_unlock_irqrestore(shost->host_lock, flags);
352
353 /*
354 * Call blk_run_queue for all LUNs on the target, starting with
355 * current_sdev. We race with others (to set starget_sdev_user),
356 * but in most cases, we will be first. Ideally, each LU on the
357 * target would get some limited time or requests on the target.
358 */
Christoph Hellwigd2852032014-01-17 12:06:53 +0100359 scsi_kick_queue(current_sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360
361 spin_lock_irqsave(shost->host_lock, flags);
362 if (starget->starget_sdev_user)
363 goto out;
364 list_for_each_entry_safe(sdev, tmp, &starget->devices,
365 same_target_siblings) {
366 if (sdev == current_sdev)
367 continue;
368 if (scsi_device_get(sdev))
369 continue;
370
371 spin_unlock_irqrestore(shost->host_lock, flags);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100372 scsi_kick_queue(sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 spin_lock_irqsave(shost->host_lock, flags);
374
375 scsi_device_put(sdev);
376 }
377 out:
378 spin_unlock_irqrestore(shost->host_lock, flags);
379}
380
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100381static inline bool scsi_device_is_busy(struct scsi_device *sdev)
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400382{
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100383 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
384 return true;
385 if (atomic_read(&sdev->device_blocked) > 0)
386 return true;
387 return false;
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400388}
389
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100390static inline bool scsi_target_is_busy(struct scsi_target *starget)
Mike Christief0c0a372008-08-17 15:24:38 -0500391{
Christoph Hellwig2ccbb002014-03-26 10:35:00 +0100392 if (starget->can_queue > 0) {
393 if (atomic_read(&starget->target_busy) >= starget->can_queue)
394 return true;
395 if (atomic_read(&starget->target_blocked) > 0)
396 return true;
397 }
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100398 return false;
Mike Christief0c0a372008-08-17 15:24:38 -0500399}
400
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100401static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400402{
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100403 if (shost->can_queue > 0 &&
404 atomic_read(&shost->host_busy) >= shost->can_queue)
405 return true;
406 if (atomic_read(&shost->host_blocked) > 0)
407 return true;
408 if (shost->host_self_blocked)
409 return true;
410 return false;
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400411}
412
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800413static void scsi_starved_list_run(struct Scsi_Host *shost)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600415 LIST_HEAD(starved_list);
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800416 struct scsi_device *sdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 unsigned long flags;
418
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600420 list_splice_init(&shost->starved_list, &starved_list);
421
422 while (!list_empty(&starved_list)) {
James Bottomleye2eb7242013-07-02 15:05:26 +0200423 struct request_queue *slq;
424
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 /*
426 * As long as shost is accepting commands and we have
427 * starved queues, call blk_run_queue. scsi_request_fn
428 * drops the queue_lock and can add us back to the
429 * starved_list.
430 *
431 * host_lock protects the starved_list and starved_entry.
432 * scsi_request_fn must get the host_lock before checking
433 * or modifying starved_list or starved_entry.
434 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600435 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500436 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500437
Mike Christie2a3a59e2008-11-11 13:42:35 -0600438 sdev = list_entry(starved_list.next,
439 struct scsi_device, starved_entry);
440 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500441 if (scsi_target_is_busy(scsi_target(sdev))) {
442 list_move_tail(&sdev->starved_entry,
443 &shost->starved_list);
444 continue;
445 }
446
James Bottomleye2eb7242013-07-02 15:05:26 +0200447 /*
448 * Once we drop the host lock, a racing scsi_remove_device()
449 * call may remove the sdev from the starved list and destroy
450 * it and the queue. Mitigate by taking a reference to the
451 * queue and never touching the sdev again after we drop the
452 * host lock. Note: if __scsi_remove_device() invokes
453 * blk_cleanup_queue() before the queue is run from this
454 * function then blk_run_queue() will return immediately since
455 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
456 */
457 slq = sdev->request_queue;
458 if (!blk_get_queue(slq))
459 continue;
460 spin_unlock_irqrestore(shost->host_lock, flags);
461
Christoph Hellwigd2852032014-01-17 12:06:53 +0100462 scsi_kick_queue(slq);
James Bottomleye2eb7242013-07-02 15:05:26 +0200463 blk_put_queue(slq);
464
465 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600467 /* put any unprocessed entries back */
468 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 spin_unlock_irqrestore(shost->host_lock, flags);
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800470}
471
472/*
473 * Function: scsi_run_queue()
474 *
475 * Purpose: Select a proper request queue to serve next
476 *
477 * Arguments: q - last request's queue
478 *
479 * Returns: Nothing
480 *
481 * Notes: The previous command was completely finished, start
482 * a new one if possible.
483 */
484static void scsi_run_queue(struct request_queue *q)
485{
486 struct scsi_device *sdev = q->queuedata;
487
488 if (scsi_target(sdev)->single_lun)
489 scsi_single_lun_run(sdev);
490 if (!list_empty(&sdev->host->starved_list))
491 scsi_starved_list_run(sdev->host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492
Christoph Hellwigd2852032014-01-17 12:06:53 +0100493 if (q->mq_ops)
494 blk_mq_start_stopped_hw_queues(q, false);
495 else
496 blk_run_queue(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497}
498
Jens Axboe9937a5e2011-05-17 11:04:44 +0200499void scsi_requeue_run_queue(struct work_struct *work)
500{
501 struct scsi_device *sdev;
502 struct request_queue *q;
503
504 sdev = container_of(work, struct scsi_device, requeue_work);
505 q = sdev->request_queue;
506 scsi_run_queue(q);
507}
508
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509/*
510 * Function: scsi_requeue_command()
511 *
512 * Purpose: Handle post-processing of completed commands.
513 *
514 * Arguments: q - queue to operate on
515 * cmd - command that may need to be requeued.
516 *
517 * Returns: Nothing
518 *
519 * Notes: After command completion, there may be blocks left
520 * over which weren't finished by the previous command
521 * this can be for a number of reasons - the main one is
522 * I/O errors in the middle of the request, in which case
523 * we need to request the blocks that come after the bad
524 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500525 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 */
527static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
528{
Bart Van Assche940f5d42012-06-29 15:34:26 +0000529 struct scsi_device *sdev = cmd->device;
James Bottomleye91442b2005-09-09 10:44:16 -0500530 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500531 unsigned long flags;
532
Tejun Heo 283369c2005-04-24 02:06:36 -0500533 spin_lock_irqsave(q->queue_lock, flags);
Christoph Hellwig134997a2014-02-20 14:20:58 -0800534 blk_unprep_request(req);
535 req->special = NULL;
536 scsi_put_command(cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500537 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500538 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540 scsi_run_queue(q);
Bart Van Assche940f5d42012-06-29 15:34:26 +0000541
542 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543}
544
545void scsi_next_command(struct scsi_cmnd *cmd)
546{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800547 struct scsi_device *sdev = cmd->device;
548 struct request_queue *q = sdev->request_queue;
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 scsi_put_command(cmd);
551 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800552
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800553 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554}
555
556void scsi_run_host_queues(struct Scsi_Host *shost)
557{
558 struct scsi_device *sdev;
559
560 shost_for_each_device(sdev, shost)
561 scsi_run_queue(sdev->request_queue);
562}
563
Jens Axboea8474ce2007-08-07 09:02:51 +0200564static inline unsigned int scsi_sgtable_index(unsigned short nents)
565{
566 unsigned int index;
567
James Bottomleyd3f46f32008-01-15 11:11:46 -0600568 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
569
570 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200571 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600572 else
573 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200574
575 return index;
576}
577
Jens Axboe5ed79592007-11-15 09:13:11 +0100578static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579{
580 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100581
582 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
583 mempool_free(sgl, sgp->pool);
584}
585
586static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
587{
588 struct scsi_host_sg_pool *sgp;
589
590 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
591 return mempool_alloc(sgp->pool, gfp_mask);
592}
593
Christoph Hellwigd2852032014-01-17 12:06:53 +0100594static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
Christoph Hellwigc53c6d62014-04-15 14:38:31 +0200595{
Christoph Hellwigd2852032014-01-17 12:06:53 +0100596 if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS)
597 return;
598 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
Christoph Hellwigc53c6d62014-04-15 14:38:31 +0200599}
600
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200601static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
Christoph Hellwigd2852032014-01-17 12:06:53 +0100602 gfp_t gfp_mask, bool mq)
Jens Axboe5ed79592007-11-15 09:13:11 +0100603{
Christoph Hellwigd2852032014-01-17 12:06:53 +0100604 struct scatterlist *first_chunk = NULL;
Jens Axboe5ed79592007-11-15 09:13:11 +0100605 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200607 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
Christoph Hellwigd2852032014-01-17 12:06:53 +0100609 if (mq) {
610 if (nents <= SCSI_MAX_SG_SEGMENTS) {
611 sdb->table.nents = nents;
612 sg_init_table(sdb->table.sgl, sdb->table.nents);
613 return 0;
614 }
615 first_chunk = sdb->table.sgl;
616 }
617
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200618 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
Christoph Hellwigd2852032014-01-17 12:06:53 +0100619 first_chunk, gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100620 if (unlikely(ret))
Christoph Hellwigd2852032014-01-17 12:06:53 +0100621 scsi_free_sgtable(sdb, mq);
Jens Axboea8474ce2007-08-07 09:02:51 +0200622 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623}
624
Christoph Hellwigd2852032014-01-17 12:06:53 +0100625static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
626{
627 if (cmd->request->cmd_type == REQ_TYPE_FS) {
628 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
629
630 if (drv->uninit_command)
631 drv->uninit_command(cmd);
632 }
633}
634
635static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
636{
637 if (cmd->sdb.table.nents)
638 scsi_free_sgtable(&cmd->sdb, true);
639 if (cmd->request->next_rq && cmd->request->next_rq->special)
640 scsi_free_sgtable(cmd->request->next_rq->special, true);
641 if (scsi_prot_sg_count(cmd))
642 scsi_free_sgtable(cmd->prot_sdb, true);
643}
644
645static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
646{
647 struct scsi_device *sdev = cmd->device;
648 unsigned long flags;
649
650 BUG_ON(list_empty(&cmd->list));
651
652 scsi_mq_free_sgtables(cmd);
653 scsi_uninit_cmd(cmd);
654
655 spin_lock_irqsave(&sdev->list_lock, flags);
656 list_del_init(&cmd->list);
657 spin_unlock_irqrestore(&sdev->list_lock, flags);
658}
659
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660/*
661 * Function: scsi_release_buffers()
662 *
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200663 * Purpose: Free resources allocate for a scsi_command.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 *
665 * Arguments: cmd - command that we are bailing.
666 *
667 * Lock status: Assumed that no lock is held upon entry.
668 *
669 * Returns: Nothing
670 *
671 * Notes: In the event that an upper level driver rejects a
672 * command, we must release resources allocated during
673 * the __init_io() function. Primarily this would involve
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200674 * the scatter-gather table.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 */
Christoph Hellwigf1bea552014-04-15 12:26:54 +0200676static void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677{
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200678 if (cmd->sdb.table.nents)
Christoph Hellwigd2852032014-01-17 12:06:53 +0100679 scsi_free_sgtable(&cmd->sdb, false);
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200680
681 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
682
683 if (scsi_prot_sg_count(cmd))
Christoph Hellwigd2852032014-01-17 12:06:53 +0100684 scsi_free_sgtable(cmd->prot_sdb, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685}
686
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200687static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
688{
689 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
690
Christoph Hellwigd2852032014-01-17 12:06:53 +0100691 scsi_free_sgtable(bidi_sdb, false);
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200692 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
693 cmd->request->next_rq->special = NULL;
694}
695
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800696static bool scsi_end_request(struct request *req, int error,
697 unsigned int bytes, unsigned int bidi_bytes)
698{
699 struct scsi_cmnd *cmd = req->special;
700 struct scsi_device *sdev = cmd->device;
701 struct request_queue *q = sdev->request_queue;
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800702
703 if (blk_update_request(req, error, bytes))
704 return true;
705
706 /* Bidi request must be completed as a whole */
707 if (unlikely(bidi_bytes) &&
708 blk_update_request(req->next_rq, error, bidi_bytes))
709 return true;
710
711 if (blk_queue_add_random(q))
712 add_disk_randomness(req->rq_disk);
713
Christoph Hellwigd2852032014-01-17 12:06:53 +0100714 if (req->mq_ctx) {
715 /*
716 * In the MQ case the command gets freed by __blk_mq_end_io,
717 * so we have to do all cleanup that depends on it earlier.
718 *
719 * We also can't kick the queues from irq context, so we
720 * will have to defer it to a workqueue.
721 */
722 scsi_mq_uninit_cmd(cmd);
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800723
Christoph Hellwigd2852032014-01-17 12:06:53 +0100724 __blk_mq_end_io(req, error);
725
726 if (scsi_target(sdev)->single_lun ||
727 !list_empty(&sdev->host->starved_list))
728 kblockd_schedule_work(&sdev->requeue_work);
729 else
730 blk_mq_start_stopped_hw_queues(q, true);
731
732 put_device(&sdev->sdev_gendev);
733 } else {
734 unsigned long flags;
735
736 spin_lock_irqsave(q->queue_lock, flags);
737 blk_finish_request(req, error);
738 spin_unlock_irqrestore(q->queue_lock, flags);
739
740 if (bidi_bytes)
741 scsi_release_bidi_buffers(cmd);
742 scsi_release_buffers(cmd);
743 scsi_next_command(cmd);
744 }
745
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800746 return false;
747}
748
Hannes Reinecke0f7f6232013-07-01 15:16:23 +0200749/**
750 * __scsi_error_from_host_byte - translate SCSI error code into errno
751 * @cmd: SCSI command (unused)
752 * @result: scsi error code
753 *
754 * Translate SCSI error code into standard UNIX errno.
755 * Return values:
756 * -ENOLINK temporary transport failure
757 * -EREMOTEIO permanent target failure, do not retry
758 * -EBADE permanent nexus failure, retry on other path
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +0200759 * -ENOSPC No write space available
Hannes Reinecke7e782af2013-07-01 15:16:26 +0200760 * -ENODATA Medium error
Hannes Reinecke0f7f6232013-07-01 15:16:23 +0200761 * -EIO unspecified I/O error
762 */
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100763static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
764{
765 int error = 0;
766
767 switch(host_byte(result)) {
768 case DID_TRANSPORT_FAILFAST:
769 error = -ENOLINK;
770 break;
771 case DID_TARGET_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000772 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100773 error = -EREMOTEIO;
774 break;
775 case DID_NEXUS_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000776 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100777 error = -EBADE;
778 break;
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +0200779 case DID_ALLOC_FAILURE:
780 set_host_byte(cmd, DID_OK);
781 error = -ENOSPC;
782 break;
Hannes Reinecke7e782af2013-07-01 15:16:26 +0200783 case DID_MEDIUM_ERROR:
784 set_host_byte(cmd, DID_OK);
785 error = -ENODATA;
786 break;
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100787 default:
788 error = -EIO;
789 break;
790 }
791
792 return error;
793}
794
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795/*
796 * Function: scsi_io_completion()
797 *
798 * Purpose: Completion processing for block device I/O requests.
799 *
800 * Arguments: cmd - command that is finished.
801 *
802 * Lock status: Assumed that no lock is held upon entry.
803 *
804 * Returns: Nothing
805 *
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200806 * Notes: We will finish off the specified number of sectors. If we
807 * are done, the command block will be released and the queue
808 * function will be goosed. If we are not done then we have to
Alan Sternb60af5b2008-11-03 15:56:47 -0500809 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500811 * a) We can call scsi_requeue_command(). The request
812 * will be unprepared and put back on the queue. Then
813 * a new command will be created for it. This should
814 * be used if we made forward progress, or if we want
815 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 *
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200817 * b) We can call __scsi_queue_insert(). The request will
Alan Sternb60af5b2008-11-03 15:56:47 -0500818 * be put back on the queue and retried using the same
819 * command as before, possibly after a delay.
820 *
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800821 * c) We can call scsi_end_request() with -EIO to fail
Alan Sternb60af5b2008-11-03 15:56:47 -0500822 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700824void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825{
826 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200827 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500829 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 struct scsi_sense_hdr sshdr;
831 int sense_valid = 0;
832 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500833 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
834 ACTION_DELAYED_RETRY} action;
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +0900835 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 if (result) {
838 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
839 if (sense_valid)
840 sense_deferred = scsi_sense_is_deferred(&sshdr);
841 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200842
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200843 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 if (sense_valid && req->sense) {
846 /*
847 * SG_IO wants current and deferred errors
848 */
849 int len = 8 + cmd->sense_buffer[7];
850
851 if (len > SCSI_SENSE_BUFFERSIZE)
852 len = SCSI_SENSE_BUFFERSIZE;
853 memcpy(req->sense, cmd->sense_buffer, len);
854 req->sense_len = len;
855 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500856 if (!sense_deferred)
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100857 error = __scsi_error_from_host_byte(cmd, result);
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400858 }
Mike Snitzer27c41972012-05-31 15:05:33 -0400859 /*
860 * __scsi_error_from_host_byte may have reset the host_byte
861 */
862 req->errors = cmd->result;
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900863
864 req->resid_len = scsi_get_resid(cmd);
865
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200866 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900867 /*
868 * Bidi commands Must be complete as a whole,
869 * both sides at once.
870 */
871 req->next_rq->resid_len = scsi_in(cmd)->resid;
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800872 if (scsi_end_request(req, 0, blk_rq_bytes(req),
873 blk_rq_bytes(req->next_rq)))
874 BUG();
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200875 return;
876 }
James Bottomley89fb4cd2014-07-03 19:17:34 +0200877 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
878 /*
879 * Certain non BLOCK_PC requests are commands that don't
880 * actually transfer anything (FLUSH), so cannot use
881 * good_bytes != blk_rq_bytes(req) as the signal for an error.
882 * This sets the error explicitly for the problem case.
883 */
884 error = __scsi_error_from_host_byte(cmd, result);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 }
886
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200887 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
888 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200889
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 * Next deal with any sectors which we were able to correctly
892 * handle.
893 */
Hannes Reinecke91921e02014-06-25 16:39:59 +0200894 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
895 "%u sectors total, %d bytes done.\n",
896 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
James Bottomleya9bddd72009-03-30 16:55:51 +0000898 /*
899 * Recovered errors need reporting, but they're always treated
900 * as success, so fiddle the result code here. For BLOCK_PC
901 * we already took a copy of the original into rq->errors which
902 * is what gets returned to the user
903 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500904 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
905 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
906 * print since caller wants ATA registers. Only occurs on
907 * SCSI ATA PASS_THROUGH commands when CK_COND=1
908 */
909 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
910 ;
911 else if (!(req->cmd_flags & REQ_QUIET))
James Bottomleya9bddd72009-03-30 16:55:51 +0000912 scsi_print_sense("", cmd);
913 result = 0;
914 /* BLOCK_PC may have set error */
915 error = 0;
916 }
917
918 /*
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200919 * If we finished all bytes in the request we are done now.
James Bottomleyd6b0c532006-07-02 10:06:28 -0500920 */
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800921 if (!scsi_end_request(req, error, good_bytes, 0))
922 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200923
924 /*
925 * Kill remainder if no retrys.
926 */
927 if (error && scsi_noretry_cmd(cmd)) {
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800928 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
929 BUG();
930 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200931 }
932
933 /*
934 * If there had been no error, but we have leftover bytes in the
935 * requeues just queue the command up again.
936 */
937 if (result == 0)
938 goto requeue;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700939
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100940 error = __scsi_error_from_host_byte(cmd, result);
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500941
Alan Sternb60af5b2008-11-03 15:56:47 -0500942 if (host_byte(result) == DID_RESET) {
943 /* Third party bus reset or reset for error recovery
944 * reasons. Just retry the command and see what
945 * happens.
946 */
947 action = ACTION_RETRY;
948 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 switch (sshdr.sense_key) {
950 case UNIT_ATTENTION:
951 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700952 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 * and quietly refuse further access.
954 */
955 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500956 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700958 /* Must have been a power glitch, or a
959 * bus reset. Could not have been a
960 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500961 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700962 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500963 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 }
965 break;
966 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700967 /* If we had an ILLEGAL REQUEST returned, then
968 * we may have performed an unsupported
969 * command. The only thing this should be
970 * would be a ten byte read where only a six
971 * byte read was supported. Also, on a system
972 * where READ CAPACITY failed, we may have
973 * read past the end of the disk.
974 */
Jens Axboe26a68012005-11-29 21:03:34 +0100975 if ((cmd->device->use_10_for_rw &&
976 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 (cmd->cmnd[0] == READ_10 ||
978 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500979 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500981 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500982 } else if (sshdr.asc == 0x10) /* DIX */ {
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500983 action = ACTION_FAIL;
984 error = -EILSEQ;
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500985 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
Martin K. Petersen5db44862012-09-18 12:19:32 -0400986 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500987 action = ACTION_FAIL;
Martin K. Petersen66a651a2012-02-13 15:38:22 -0500988 error = -EREMOTEIO;
Alan Sternb60af5b2008-11-03 15:56:47 -0500989 } else
990 action = ACTION_FAIL;
991 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400992 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000993 action = ACTION_FAIL;
Maurizio Lombardie6c11db2014-07-10 09:41:53 +0200994 if (sshdr.asc == 0x10) /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500995 error = -EILSEQ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 break;
997 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700998 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500999 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 */
James Bottomleyf3e93f72006-04-25 16:48:30 -05001001 if (sshdr.asc == 0x04) {
1002 switch (sshdr.ascq) {
1003 case 0x01: /* becoming ready */
1004 case 0x04: /* format in progress */
1005 case 0x05: /* rebuild in progress */
1006 case 0x06: /* recalculation in progress */
1007 case 0x07: /* operation in progress */
1008 case 0x08: /* Long write in progress */
1009 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -05001010 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -05001011 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -05001012 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -05001013 default:
Alan Stern3dbf6a52008-12-15 10:31:28 -05001014 action = ACTION_FAIL;
1015 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -05001016 }
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001017 } else
Alan Sternb60af5b2008-11-03 15:56:47 -05001018 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -05001019 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -07001021 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -05001022 action = ACTION_FAIL;
1023 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 default:
Alan Sternb60af5b2008-11-03 15:56:47 -05001025 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 break;
1027 }
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001028 } else
Alan Sternb60af5b2008-11-03 15:56:47 -05001029 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -05001030
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001031 if (action != ACTION_FAIL &&
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001032 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001033 action = ACTION_FAIL;
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001034
Alan Sternb60af5b2008-11-03 15:56:47 -05001035 switch (action) {
1036 case ACTION_FAIL:
1037 /* Give up and fail the remainder of the request */
Jens Axboe4aff5e22006-08-10 08:44:47 +02001038 if (!(req->cmd_flags & REQ_QUIET)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -05001039 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -05001040 if (driver_byte(result) & DRIVER_SENSE)
1041 scsi_print_sense("", cmd);
Martin K. Petersen002b1eb2009-05-23 11:45:07 -04001042 scsi_print_command(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -05001043 }
Christoph Hellwigf6d47e72014-02-16 06:16:13 -08001044 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1045 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +02001046 /*FALLTHRU*/
Alan Sternb60af5b2008-11-03 15:56:47 -05001047 case ACTION_REPREP:
Christoph Hellwigbc85dc52014-05-01 16:51:03 +02001048 requeue:
Alan Sternb60af5b2008-11-03 15:56:47 -05001049 /* Unprep the request and put it back at the head of the queue.
1050 * A new command will be prepared and issued.
1051 */
Christoph Hellwigd2852032014-01-17 12:06:53 +01001052 if (q->mq_ops) {
1053 cmd->request->cmd_flags &= ~REQ_DONTPREP;
1054 scsi_mq_uninit_cmd(cmd);
1055 scsi_mq_requeue_cmd(cmd);
1056 } else {
1057 scsi_release_buffers(cmd);
1058 scsi_requeue_command(q, cmd);
1059 }
Alan Sternb60af5b2008-11-03 15:56:47 -05001060 break;
1061 case ACTION_RETRY:
1062 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -06001063 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001064 break;
1065 case ACTION_DELAYED_RETRY:
1066 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -06001067 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001068 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 }
1070}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001072static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1073 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001075 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076
1077 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001078 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001080 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
Christoph Hellwigd2852032014-01-17 12:06:53 +01001081 gfp_mask, req->mq_ctx != NULL)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 return BLKPREP_DEFER;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 /*
1085 * Next, walk the list, and fill in the addresses and sizes of
1086 * each segment.
1087 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001088 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1089 BUG_ON(count > sdb->table.nents);
1090 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +09001091 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +11001092 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001094
1095/*
1096 * Function: scsi_init_io()
1097 *
1098 * Purpose: SCSI I/O initialize function.
1099 *
1100 * Arguments: cmd - Command descriptor we wish to initialize
1101 *
1102 * Returns: 0 on success
1103 * BLKPREP_DEFER if the failure is retryable
1104 * BLKPREP_KILL if the failure is fatal
1105 */
1106int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1107{
Christoph Hellwig5e012aa2014-04-15 12:24:55 +02001108 struct scsi_device *sdev = cmd->device;
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001109 struct request *rq = cmd->request;
Christoph Hellwigd2852032014-01-17 12:06:53 +01001110 bool is_mq = (rq->mq_ctx != NULL);
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001111 int error;
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001112
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001113 BUG_ON(!rq->nr_phys_segments);
1114
1115 error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001116 if (error)
1117 goto err_exit;
1118
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001119 if (blk_bidi_rq(rq)) {
Christoph Hellwigd2852032014-01-17 12:06:53 +01001120 if (!rq->q->mq_ops) {
1121 struct scsi_data_buffer *bidi_sdb =
1122 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1123 if (!bidi_sdb) {
1124 error = BLKPREP_DEFER;
1125 goto err_exit;
1126 }
1127
1128 rq->next_rq->special = bidi_sdb;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001129 }
1130
Christoph Hellwigd2852032014-01-17 12:06:53 +01001131 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special,
1132 GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001133 if (error)
1134 goto err_exit;
1135 }
1136
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001137 if (blk_integrity_rq(rq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001138 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1139 int ivecs, count;
1140
1141 BUG_ON(prot_sdb == NULL);
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001142 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001143
Christoph Hellwigd2852032014-01-17 12:06:53 +01001144 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask, is_mq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001145 error = BLKPREP_DEFER;
1146 goto err_exit;
1147 }
1148
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001149 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001150 prot_sdb->table.sgl);
1151 BUG_ON(unlikely(count > ivecs));
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001152 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001153
1154 cmd->prot_sdb = prot_sdb;
1155 cmd->prot_sdb->table.nents = count;
1156 }
1157
Christoph Hellwigd2852032014-01-17 12:06:53 +01001158 return BLKPREP_OK;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001159err_exit:
Christoph Hellwigd2852032014-01-17 12:06:53 +01001160 if (is_mq) {
1161 scsi_mq_free_sgtables(cmd);
1162 } else {
1163 scsi_release_buffers(cmd);
1164 cmd->request->special = NULL;
1165 scsi_put_command(cmd);
1166 put_device(&sdev->sdev_gendev);
1167 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001168 return error;
1169}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001170EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171
Christoph Hellwig3b003152006-11-04 20:10:55 +01001172static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1173 struct request *req)
1174{
1175 struct scsi_cmnd *cmd;
1176
1177 if (!req->special) {
Christoph Hellwig04796332014-02-20 14:20:55 -08001178 /* Bail if we can't get a reference to the device */
1179 if (!get_device(&sdev->sdev_gendev))
Christoph Hellwig3b003152006-11-04 20:10:55 +01001180 return NULL;
Christoph Hellwig04796332014-02-20 14:20:55 -08001181
1182 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1183 if (unlikely(!cmd)) {
1184 put_device(&sdev->sdev_gendev);
1185 return NULL;
1186 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001187 req->special = cmd;
1188 } else {
1189 cmd = req->special;
1190 }
1191
1192 /* pull a tag out of the request if we have one */
1193 cmd->tag = req->tag;
1194 cmd->request = req;
1195
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001196 cmd->cmnd = req->cmd;
Martin K. Petersen72f7d322011-03-08 02:03:59 -05001197 cmd->prot_op = SCSI_PROT_NORMAL;
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001198
Christoph Hellwig3b003152006-11-04 20:10:55 +01001199 return cmd;
1200}
1201
Christoph Hellwig4f1e5762014-06-28 12:36:28 +02001202static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001203{
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001204 struct scsi_cmnd *cmd = req->special;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001205
1206 /*
1207 * BLOCK_PC requests may transfer data, in which case they must
1208 * a bio attached to them. Or they might contain a SCSI command
1209 * that does not transfer data, in which case they may optionally
1210 * submit a request without an attached bio.
1211 */
1212 if (req->bio) {
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001213 int ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001214 if (unlikely(ret))
1215 return ret;
1216 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001217 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001218
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001219 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001220 }
James Bottomley7b163182005-12-15 20:17:02 -06001221
James Bottomley7b163182005-12-15 20:17:02 -06001222 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001223 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001224 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001225 return BLKPREP_OK;
1226}
1227
1228/*
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001229 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1230 * that still need to be translated to SCSI CDBs from the ULD.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001231 */
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001232static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001233{
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001234 struct scsi_cmnd *cmd = req->special;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001235
1236 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1237 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001238 int ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001239 if (ret != BLKPREP_OK)
1240 return ret;
1241 }
1242
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001243 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001244 return scsi_cmd_to_driver(cmd)->init_command(cmd);
James Bottomley7b163182005-12-15 20:17:02 -06001245}
James Bottomley7b163182005-12-15 20:17:02 -06001246
Christoph Hellwig6af7a4f2014-07-08 13:16:17 +02001247static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1248{
1249 struct scsi_cmnd *cmd = req->special;
1250
1251 if (!blk_rq_bytes(req))
1252 cmd->sc_data_direction = DMA_NONE;
1253 else if (rq_data_dir(req) == WRITE)
1254 cmd->sc_data_direction = DMA_TO_DEVICE;
1255 else
1256 cmd->sc_data_direction = DMA_FROM_DEVICE;
1257
1258 switch (req->cmd_type) {
1259 case REQ_TYPE_FS:
1260 return scsi_setup_fs_cmnd(sdev, req);
1261 case REQ_TYPE_BLOCK_PC:
1262 return scsi_setup_blk_pc_cmnd(sdev, req);
1263 default:
1264 return BLKPREP_KILL;
1265 }
1266}
1267
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001268static int
1269scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001271 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272
1273 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001274 * If the device is not in running state we will reject some
1275 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001278 switch (sdev->sdev_state) {
1279 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05001280 case SDEV_TRANSPORT_OFFLINE:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001281 /*
1282 * If the device is offline we refuse to process any
1283 * commands. The device must be brought online
1284 * before trying any recovery commands.
1285 */
1286 sdev_printk(KERN_ERR, sdev,
1287 "rejecting I/O to offline device\n");
1288 ret = BLKPREP_KILL;
1289 break;
1290 case SDEV_DEL:
1291 /*
1292 * If the device is fully deleted, we refuse to
1293 * process any commands as well.
1294 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001295 sdev_printk(KERN_ERR, sdev,
1296 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001297 ret = BLKPREP_KILL;
1298 break;
1299 case SDEV_QUIESCE:
1300 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001301 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001302 /*
1303 * If the devices is blocked we defer normal commands.
1304 */
1305 if (!(req->cmd_flags & REQ_PREEMPT))
1306 ret = BLKPREP_DEFER;
1307 break;
1308 default:
1309 /*
1310 * For any other not fully online state we only allow
1311 * special commands. In particular any user initiated
1312 * command is not allowed.
1313 */
1314 if (!(req->cmd_flags & REQ_PREEMPT))
1315 ret = BLKPREP_KILL;
1316 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001319 return ret;
1320}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001322static int
1323scsi_prep_return(struct request_queue *q, struct request *req, int ret)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001324{
1325 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326
Christoph Hellwig3b003152006-11-04 20:10:55 +01001327 switch (ret) {
1328 case BLKPREP_KILL:
1329 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001330 /* release the command and kill it */
1331 if (req->special) {
1332 struct scsi_cmnd *cmd = req->special;
1333 scsi_release_buffers(cmd);
1334 scsi_put_command(cmd);
Christoph Hellwig68c03d92014-04-15 12:24:56 +02001335 put_device(&sdev->sdev_gendev);
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001336 req->special = NULL;
1337 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001338 break;
1339 case BLKPREP_DEFER:
1340 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001341 * If we defer, the blk_peek_request() returns NULL, but the
Jens Axboea488e742010-04-16 21:13:15 +02001342 * queue must be restarted, so we schedule a callback to happen
1343 * shortly.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001344 */
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001345 if (atomic_read(&sdev->device_busy) == 0)
Jens Axboea488e742010-04-16 21:13:15 +02001346 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001347 break;
1348 default:
1349 req->cmd_flags |= REQ_DONTPREP;
1350 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351
Christoph Hellwig3b003152006-11-04 20:10:55 +01001352 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001354
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001355static int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001356{
1357 struct scsi_device *sdev = q->queuedata;
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001358 struct scsi_cmnd *cmd;
1359 int ret;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001360
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001361 ret = scsi_prep_state_check(sdev, req);
1362 if (ret != BLKPREP_OK)
1363 goto out;
1364
1365 cmd = scsi_get_cmd_from_req(sdev, req);
1366 if (unlikely(!cmd)) {
1367 ret = BLKPREP_DEFER;
1368 goto out;
1369 }
1370
Christoph Hellwig6af7a4f2014-07-08 13:16:17 +02001371 ret = scsi_setup_cmnd(sdev, req);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001372out:
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001373 return scsi_prep_return(q, req, ret);
1374}
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001375
1376static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1377{
Christoph Hellwigd2852032014-01-17 12:06:53 +01001378 scsi_uninit_cmd(req->special);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001379}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380
1381/*
1382 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1383 * return 0.
1384 *
1385 * Called with the queue_lock held.
1386 */
1387static inline int scsi_dev_queue_ready(struct request_queue *q,
1388 struct scsi_device *sdev)
1389{
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001390 unsigned int busy;
1391
1392 busy = atomic_inc_return(&sdev->device_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001393 if (atomic_read(&sdev->device_blocked)) {
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001394 if (busy)
1395 goto out_dec;
1396
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 /*
1398 * unblock after device_blocked iterates to zero
1399 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001400 if (atomic_dec_return(&sdev->device_blocked) > 0) {
Christoph Hellwigd2852032014-01-17 12:06:53 +01001401 /*
1402 * For the MQ case we take care of this in the caller.
1403 */
1404 if (!q->mq_ops)
1405 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001406 goto out_dec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407 }
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001408 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1409 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 }
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001411
1412 if (busy >= sdev->queue_depth)
1413 goto out_dec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
1415 return 1;
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001416out_dec:
1417 atomic_dec(&sdev->device_busy);
1418 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419}
1420
Mike Christief0c0a372008-08-17 15:24:38 -05001421/*
1422 * scsi_target_queue_ready: checks if there we can send commands to target
1423 * @sdev: scsi device on starget to check.
Mike Christief0c0a372008-08-17 15:24:38 -05001424 */
1425static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1426 struct scsi_device *sdev)
1427{
1428 struct scsi_target *starget = scsi_target(sdev);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001429 unsigned int busy;
Mike Christief0c0a372008-08-17 15:24:38 -05001430
1431 if (starget->single_lun) {
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001432 spin_lock_irq(shost->host_lock);
Mike Christief0c0a372008-08-17 15:24:38 -05001433 if (starget->starget_sdev_user &&
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001434 starget->starget_sdev_user != sdev) {
1435 spin_unlock_irq(shost->host_lock);
1436 return 0;
1437 }
Mike Christief0c0a372008-08-17 15:24:38 -05001438 starget->starget_sdev_user = sdev;
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001439 spin_unlock_irq(shost->host_lock);
Mike Christief0c0a372008-08-17 15:24:38 -05001440 }
1441
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001442 if (starget->can_queue <= 0)
1443 return 1;
1444
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001445 busy = atomic_inc_return(&starget->target_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001446 if (atomic_read(&starget->target_blocked) > 0) {
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001447 if (busy)
1448 goto starved;
1449
Mike Christief0c0a372008-08-17 15:24:38 -05001450 /*
1451 * unblock after target_blocked iterates to zero
1452 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001453 if (atomic_dec_return(&starget->target_blocked) > 0)
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001454 goto out_dec;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001455
1456 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1457 "unblocking target at zero depth\n"));
Mike Christief0c0a372008-08-17 15:24:38 -05001458 }
1459
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001460 if (busy >= starget->can_queue)
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001461 goto starved;
Mike Christief0c0a372008-08-17 15:24:38 -05001462
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001463 return 1;
1464
1465starved:
1466 spin_lock_irq(shost->host_lock);
1467 list_move_tail(&sdev->starved_entry, &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001468 spin_unlock_irq(shost->host_lock);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001469out_dec:
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001470 if (starget->can_queue > 0)
1471 atomic_dec(&starget->target_busy);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001472 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001473}
1474
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475/*
1476 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1477 * return 0. We must end up running the queue again whenever 0 is
1478 * returned, else IO can hang.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 */
1480static inline int scsi_host_queue_ready(struct request_queue *q,
1481 struct Scsi_Host *shost,
1482 struct scsi_device *sdev)
1483{
Christoph Hellwig74665012014-01-22 15:29:29 +01001484 unsigned int busy;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001485
James Bottomley939647e2005-09-18 15:05:20 -05001486 if (scsi_host_in_recovery(shost))
Christoph Hellwig74665012014-01-22 15:29:29 +01001487 return 0;
1488
1489 busy = atomic_inc_return(&shost->host_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001490 if (atomic_read(&shost->host_blocked) > 0) {
Christoph Hellwig74665012014-01-22 15:29:29 +01001491 if (busy)
1492 goto starved;
1493
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494 /*
1495 * unblock after host_blocked iterates to zero
1496 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001497 if (atomic_dec_return(&shost->host_blocked) > 0)
Christoph Hellwig74665012014-01-22 15:29:29 +01001498 goto out_dec;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001499
1500 SCSI_LOG_MLQUEUE(3,
1501 shost_printk(KERN_INFO, shost,
1502 "unblocking host at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001503 }
Christoph Hellwig74665012014-01-22 15:29:29 +01001504
1505 if (shost->can_queue > 0 && busy >= shost->can_queue)
1506 goto starved;
1507 if (shost->host_self_blocked)
1508 goto starved;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509
1510 /* We're OK to process the command, so we can't be starved */
Christoph Hellwig74665012014-01-22 15:29:29 +01001511 if (!list_empty(&sdev->starved_entry)) {
1512 spin_lock_irq(shost->host_lock);
1513 if (!list_empty(&sdev->starved_entry))
1514 list_del_init(&sdev->starved_entry);
1515 spin_unlock_irq(shost->host_lock);
1516 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517
Christoph Hellwig74665012014-01-22 15:29:29 +01001518 return 1;
1519
1520starved:
1521 spin_lock_irq(shost->host_lock);
1522 if (list_empty(&sdev->starved_entry))
1523 list_add_tail(&sdev->starved_entry, &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001524 spin_unlock_irq(shost->host_lock);
Christoph Hellwig74665012014-01-22 15:29:29 +01001525out_dec:
1526 atomic_dec(&shost->host_busy);
1527 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528}
1529
1530/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001531 * Busy state exporting function for request stacking drivers.
1532 *
1533 * For efficiency, no lock is taken to check the busy state of
1534 * shost/starget/sdev, since the returned value is not guaranteed and
1535 * may be changed after request stacking drivers call the function,
1536 * regardless of taking lock or not.
1537 *
Bart Van Assche67bd9412012-06-29 15:33:22 +00001538 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1539 * needs to return 'not busy'. Otherwise, request stacking drivers
1540 * may hold requests forever.
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001541 */
1542static int scsi_lld_busy(struct request_queue *q)
1543{
1544 struct scsi_device *sdev = q->queuedata;
1545 struct Scsi_Host *shost;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001546
Bart Van Assche3f3299d2012-11-28 13:42:38 +01001547 if (blk_queue_dying(q))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001548 return 0;
1549
1550 shost = sdev->host;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001551
Jun'ichi Nomurab7e94a12012-05-22 18:57:17 +09001552 /*
1553 * Ignore host/starget busy state.
1554 * Since block layer does not have a concept of fairness across
1555 * multiple queues, congestion of host/starget needs to be handled
1556 * in SCSI layer.
1557 */
1558 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001559 return 1;
1560
1561 return 0;
1562}
1563
1564/*
James Bottomleye91442b2005-09-09 10:44:16 -05001565 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 */
Jens Axboe165125e2007-07-24 09:28:11 +02001567static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568{
James Bottomleye91442b2005-09-09 10:44:16 -05001569 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001570 struct scsi_device *sdev;
1571 struct scsi_target *starget;
1572 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573
Tejun Heo9934c8c2009-05-08 11:54:16 +09001574 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001575
Hannes Reinecke74571812011-11-09 08:39:24 +01001576 scmd_printk(KERN_INFO, cmd, "killing request\n");
1577
Jiri Slaby03b14702009-09-23 16:15:35 +02001578 sdev = cmd->device;
1579 starget = scsi_target(sdev);
1580 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001581 scsi_init_cmd_errh(cmd);
1582 cmd->result = DID_NO_CONNECT << 16;
1583 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001584
1585 /*
1586 * SCSI request completion path will do scsi_device_unbusy(),
1587 * bump busy counts. To bump the counters, we need to dance
1588 * with the locks as normal issue path does.
1589 */
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001590 atomic_inc(&sdev->device_busy);
Christoph Hellwig74665012014-01-22 15:29:29 +01001591 atomic_inc(&shost->host_busy);
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001592 if (starget->can_queue > 0)
1593 atomic_inc(&starget->target_busy);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001594
Jens Axboe242f9dc2008-09-14 05:55:09 -07001595 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596}
1597
Jens Axboe1aea6432006-01-09 16:03:03 +01001598static void scsi_softirq_done(struct request *rq)
1599{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001600 struct scsi_cmnd *cmd = rq->special;
1601 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001602 int disposition;
1603
1604 INIT_LIST_HEAD(&cmd->eh_entry);
1605
Jens Axboe242f9dc2008-09-14 05:55:09 -07001606 atomic_inc(&cmd->device->iodone_cnt);
1607 if (cmd->result)
1608 atomic_inc(&cmd->device->ioerr_cnt);
1609
Jens Axboe1aea6432006-01-09 16:03:03 +01001610 disposition = scsi_decide_disposition(cmd);
1611 if (disposition != SUCCESS &&
1612 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1613 sdev_printk(KERN_ERR, cmd->device,
1614 "timing out command, waited %lus\n",
1615 wait_for/HZ);
1616 disposition = SUCCESS;
1617 }
Hannes Reinecke91921e02014-06-25 16:39:59 +02001618
Jens Axboe1aea6432006-01-09 16:03:03 +01001619 scsi_log_completion(cmd, disposition);
1620
1621 switch (disposition) {
1622 case SUCCESS:
1623 scsi_finish_command(cmd);
1624 break;
1625 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001626 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001627 break;
1628 case ADD_TO_MLQUEUE:
1629 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1630 break;
1631 default:
1632 if (!scsi_eh_scmd_add(cmd, 0))
1633 scsi_finish_command(cmd);
1634 }
1635}
1636
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001637/**
1638 * scsi_done - Invoke completion on finished SCSI command.
1639 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1640 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1641 *
1642 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1643 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1644 * calls blk_complete_request() for further processing.
1645 *
1646 * This function is interrupt context safe.
1647 */
1648static void scsi_done(struct scsi_cmnd *cmd)
1649{
1650 trace_scsi_dispatch_cmd_done(cmd);
1651 blk_complete_request(cmd->request);
1652}
1653
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654/*
1655 * Function: scsi_request_fn()
1656 *
1657 * Purpose: Main strategy routine for SCSI.
1658 *
1659 * Arguments: q - Pointer to actual queue.
1660 *
1661 * Returns: Nothing
1662 *
1663 * Lock status: IO request lock assumed to be held when called.
1664 */
1665static void scsi_request_fn(struct request_queue *q)
Bart Van Assche613be1f2014-02-20 14:20:56 -08001666 __releases(q->queue_lock)
1667 __acquires(q->queue_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668{
1669 struct scsi_device *sdev = q->queuedata;
1670 struct Scsi_Host *shost;
1671 struct scsi_cmnd *cmd;
1672 struct request *req;
1673
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674 /*
1675 * To start with, we keep looping until the queue is empty, or until
1676 * the host is no longer able to accept any more requests.
1677 */
1678 shost = sdev->host;
Jens Axboea488e742010-04-16 21:13:15 +02001679 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680 int rtn;
1681 /*
1682 * get next queueable request. We do this early to make sure
Hannes Reinecke91921e02014-06-25 16:39:59 +02001683 * that the request is fully prepared even if we cannot
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684 * accept it.
1685 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001686 req = blk_peek_request(q);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001687 if (!req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688 break;
1689
1690 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001691 sdev_printk(KERN_ERR, sdev,
1692 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001693 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 continue;
1695 }
1696
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001697 if (!scsi_dev_queue_ready(q, sdev))
1698 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699
1700 /*
1701 * Remove the request from the request list.
1702 */
1703 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001704 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001706 spin_unlock_irq(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001707 cmd = req->special;
1708 if (unlikely(cmd == NULL)) {
1709 printk(KERN_CRIT "impossible request in %s.\n"
1710 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001711 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001712 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001713 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001714 BUG();
1715 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716
Mike Christieecefe8a2008-07-11 19:50:35 -05001717 /*
1718 * We hit this when the driver is using a host wide
1719 * tag map. For device level tag maps the queue_depth check
1720 * in the device ready fn would prevent us from trying
1721 * to allocate a tag. Since the map is a shared host resource
1722 * we add the dev to the starved list so it eventually gets
1723 * a run when a tag is freed.
1724 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001725 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001726 spin_lock_irq(shost->host_lock);
Mike Christieecefe8a2008-07-11 19:50:35 -05001727 if (list_empty(&sdev->starved_entry))
1728 list_add_tail(&sdev->starved_entry,
1729 &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001730 spin_unlock_irq(shost->host_lock);
Mike Christieecefe8a2008-07-11 19:50:35 -05001731 goto not_ready;
1732 }
1733
Mike Christief0c0a372008-08-17 15:24:38 -05001734 if (!scsi_target_queue_ready(shost, sdev))
1735 goto not_ready;
1736
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 if (!scsi_host_queue_ready(q, shost, sdev))
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001738 goto host_not_ready;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 /*
1741 * Finally, initialize any error handling parameters, and set up
1742 * the timers for timeouts.
1743 */
1744 scsi_init_cmd_errh(cmd);
1745
1746 /*
1747 * Dispatch the command to the low-level driver.
1748 */
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001749 cmd->scsi_done = scsi_done;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 rtn = scsi_dispatch_cmd(cmd);
Christoph Hellwigd0d3bbf2014-01-22 18:39:04 +01001751 if (rtn) {
1752 scsi_queue_insert(cmd, rtn);
1753 spin_lock_irq(q->queue_lock);
Jens Axboea488e742010-04-16 21:13:15 +02001754 goto out_delay;
Christoph Hellwigd0d3bbf2014-01-22 18:39:04 +01001755 }
1756 spin_lock_irq(q->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 }
1758
Bart Van Assche613be1f2014-02-20 14:20:56 -08001759 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001761 host_not_ready:
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001762 if (scsi_target(sdev)->can_queue > 0)
1763 atomic_dec(&scsi_target(sdev)->target_busy);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001764 not_ready:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765 /*
1766 * lock q, handle tag, requeue req, and decrement device_busy. We
1767 * must return with queue_lock held.
1768 *
1769 * Decrementing device_busy without checking it is OK, as all such
1770 * cases (host limits or settings) should run the queue at some
1771 * later time.
1772 */
1773 spin_lock_irq(q->queue_lock);
1774 blk_requeue_request(q, req);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001775 atomic_dec(&sdev->device_busy);
Jens Axboea488e742010-04-16 21:13:15 +02001776out_delay:
Guenter Roeck480cadc2014-08-10 05:54:25 -07001777 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
Jens Axboea488e742010-04-16 21:13:15 +02001778 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779}
1780
Christoph Hellwigd2852032014-01-17 12:06:53 +01001781static inline int prep_to_mq(int ret)
1782{
1783 switch (ret) {
1784 case BLKPREP_OK:
1785 return 0;
1786 case BLKPREP_DEFER:
1787 return BLK_MQ_RQ_QUEUE_BUSY;
1788 default:
1789 return BLK_MQ_RQ_QUEUE_ERROR;
1790 }
1791}
1792
1793static int scsi_mq_prep_fn(struct request *req)
1794{
1795 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1796 struct scsi_device *sdev = req->q->queuedata;
1797 struct Scsi_Host *shost = sdev->host;
1798 unsigned char *sense_buf = cmd->sense_buffer;
1799 struct scatterlist *sg;
1800
1801 memset(cmd, 0, sizeof(struct scsi_cmnd));
1802
1803 req->special = cmd;
1804
1805 cmd->request = req;
1806 cmd->device = sdev;
1807 cmd->sense_buffer = sense_buf;
1808
1809 cmd->tag = req->tag;
1810
1811 req->cmd = req->__cmd;
1812 cmd->cmnd = req->cmd;
1813 cmd->prot_op = SCSI_PROT_NORMAL;
1814
1815 INIT_LIST_HEAD(&cmd->list);
1816 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1817 cmd->jiffies_at_alloc = jiffies;
1818
1819 /*
1820 * XXX: cmd_list lookups are only used by two drivers, try to get
1821 * rid of this list in common code.
1822 */
1823 spin_lock_irq(&sdev->list_lock);
1824 list_add_tail(&cmd->list, &sdev->cmd_list);
1825 spin_unlock_irq(&sdev->list_lock);
1826
1827 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1828 cmd->sdb.table.sgl = sg;
1829
1830 if (scsi_host_get_prot(shost)) {
1831 cmd->prot_sdb = (void *)sg +
1832 shost->sg_tablesize * sizeof(struct scatterlist);
1833 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1834
1835 cmd->prot_sdb->table.sgl =
1836 (struct scatterlist *)(cmd->prot_sdb + 1);
1837 }
1838
1839 if (blk_bidi_rq(req)) {
1840 struct request *next_rq = req->next_rq;
1841 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1842
1843 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1844 bidi_sdb->table.sgl =
1845 (struct scatterlist *)(bidi_sdb + 1);
1846
1847 next_rq->special = bidi_sdb;
1848 }
1849
1850 return scsi_setup_cmnd(sdev, req);
1851}
1852
1853static void scsi_mq_done(struct scsi_cmnd *cmd)
1854{
1855 trace_scsi_dispatch_cmd_done(cmd);
1856 blk_mq_complete_request(cmd->request);
1857}
1858
1859static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
1860{
1861 struct request_queue *q = req->q;
1862 struct scsi_device *sdev = q->queuedata;
1863 struct Scsi_Host *shost = sdev->host;
1864 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1865 int ret;
1866 int reason;
1867
1868 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1869 if (ret)
1870 goto out;
1871
1872 ret = BLK_MQ_RQ_QUEUE_BUSY;
1873 if (!get_device(&sdev->sdev_gendev))
1874 goto out;
1875
1876 if (!scsi_dev_queue_ready(q, sdev))
1877 goto out_put_device;
1878 if (!scsi_target_queue_ready(shost, sdev))
1879 goto out_dec_device_busy;
1880 if (!scsi_host_queue_ready(q, shost, sdev))
1881 goto out_dec_target_busy;
1882
1883 if (!(req->cmd_flags & REQ_DONTPREP)) {
1884 ret = prep_to_mq(scsi_mq_prep_fn(req));
1885 if (ret)
1886 goto out_dec_host_busy;
1887 req->cmd_flags |= REQ_DONTPREP;
1888 }
1889
1890 scsi_init_cmd_errh(cmd);
1891 cmd->scsi_done = scsi_mq_done;
1892
1893 reason = scsi_dispatch_cmd(cmd);
1894 if (reason) {
1895 scsi_set_blocked(cmd, reason);
1896 ret = BLK_MQ_RQ_QUEUE_BUSY;
1897 goto out_dec_host_busy;
1898 }
1899
1900 return BLK_MQ_RQ_QUEUE_OK;
1901
1902out_dec_host_busy:
1903 atomic_dec(&shost->host_busy);
1904out_dec_target_busy:
1905 if (scsi_target(sdev)->can_queue > 0)
1906 atomic_dec(&scsi_target(sdev)->target_busy);
1907out_dec_device_busy:
1908 atomic_dec(&sdev->device_busy);
1909out_put_device:
1910 put_device(&sdev->sdev_gendev);
1911out:
1912 switch (ret) {
1913 case BLK_MQ_RQ_QUEUE_BUSY:
1914 blk_mq_stop_hw_queue(hctx);
1915 if (atomic_read(&sdev->device_busy) == 0 &&
1916 !scsi_device_blocked(sdev))
1917 blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
1918 break;
1919 case BLK_MQ_RQ_QUEUE_ERROR:
1920 /*
1921 * Make sure to release all allocated ressources when
1922 * we hit an error, as we will never see this command
1923 * again.
1924 */
1925 if (req->cmd_flags & REQ_DONTPREP)
1926 scsi_mq_uninit_cmd(cmd);
1927 break;
1928 default:
1929 break;
1930 }
1931 return ret;
1932}
1933
1934static int scsi_init_request(void *data, struct request *rq,
1935 unsigned int hctx_idx, unsigned int request_idx,
1936 unsigned int numa_node)
1937{
1938 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1939
1940 cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
1941 numa_node);
1942 if (!cmd->sense_buffer)
1943 return -ENOMEM;
1944 return 0;
1945}
1946
1947static void scsi_exit_request(void *data, struct request *rq,
1948 unsigned int hctx_idx, unsigned int request_idx)
1949{
1950 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1951
1952 kfree(cmd->sense_buffer);
1953}
1954
Christoph Hellwigf1bea552014-04-15 12:26:54 +02001955static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956{
1957 struct device *host_dev;
1958 u64 bounce_limit = 0xffffffff;
1959
1960 if (shost->unchecked_isa_dma)
1961 return BLK_BOUNCE_ISA;
1962 /*
1963 * Platforms with virtual-DMA translation
1964 * hardware have no practical limit.
1965 */
1966 if (!PCI_DMA_BUS_IS_PHYS)
1967 return BLK_BOUNCE_ANY;
1968
1969 host_dev = scsi_get_device(shost);
1970 if (host_dev && host_dev->dma_mask)
Russell Kinge83b3662014-02-11 17:11:04 +00001971 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972
1973 return bounce_limit;
1974}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975
Christoph Hellwigd2852032014-01-17 12:06:53 +01001976static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977{
Lin Ming6f381fa2012-04-12 13:50:38 +08001978 struct device *dev = shost->dma_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979
Jens Axboea8474ce2007-08-07 09:02:51 +02001980 /*
1981 * this limit is imposed by hardware restrictions
1982 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05001983 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1984 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02001985
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001986 if (scsi_host_prot_dma(shost)) {
1987 shost->sg_prot_tablesize =
1988 min_not_zero(shost->sg_prot_tablesize,
1989 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1990 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1991 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1992 }
1993
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05001994 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001995 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1996 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001997 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001999 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2000
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001 if (!shost->use_clustering)
Martin K. Petersene692cb62010-12-01 19:41:49 +01002002 q->limits.cluster = 0;
James Bottomley465ff312008-01-01 10:00:10 -06002003
2004 /*
2005 * set a reasonable default alignment on word boundaries: the
2006 * host and device may alter it using
2007 * blk_queue_update_dma_alignment() later.
2008 */
2009 blk_queue_dma_alignment(q, 0x03);
Christoph Hellwigd2852032014-01-17 12:06:53 +01002010}
James Bottomley465ff312008-01-01 10:00:10 -06002011
Christoph Hellwigd2852032014-01-17 12:06:53 +01002012struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2013 request_fn_proc *request_fn)
2014{
2015 struct request_queue *q;
2016
2017 q = blk_init_queue(request_fn, NULL);
2018 if (!q)
2019 return NULL;
2020 __scsi_init_queue(shost, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021 return q;
2022}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002023EXPORT_SYMBOL(__scsi_alloc_queue);
2024
2025struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2026{
2027 struct request_queue *q;
2028
2029 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2030 if (!q)
2031 return NULL;
2032
2033 blk_queue_prep_rq(q, scsi_prep_fn);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02002034 blk_queue_unprep_rq(q, scsi_unprep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002035 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07002036 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04002037 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002038 return q;
2039}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002040
Christoph Hellwigd2852032014-01-17 12:06:53 +01002041static struct blk_mq_ops scsi_mq_ops = {
2042 .map_queue = blk_mq_map_queue,
2043 .queue_rq = scsi_queue_rq,
2044 .complete = scsi_softirq_done,
2045 .timeout = scsi_times_out,
2046 .init_request = scsi_init_request,
2047 .exit_request = scsi_exit_request,
2048};
2049
2050struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2051{
2052 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2053 if (IS_ERR(sdev->request_queue))
2054 return NULL;
2055
2056 sdev->request_queue->queuedata = sdev;
2057 __scsi_init_queue(sdev->host, sdev->request_queue);
2058 return sdev->request_queue;
2059}
2060
2061int scsi_mq_setup_tags(struct Scsi_Host *shost)
2062{
2063 unsigned int cmd_size, sgl_size, tbl_size;
2064
2065 tbl_size = shost->sg_tablesize;
2066 if (tbl_size > SCSI_MAX_SG_SEGMENTS)
2067 tbl_size = SCSI_MAX_SG_SEGMENTS;
2068 sgl_size = tbl_size * sizeof(struct scatterlist);
2069 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2070 if (scsi_host_get_prot(shost))
2071 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2072
2073 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2074 shost->tag_set.ops = &scsi_mq_ops;
2075 shost->tag_set.nr_hw_queues = 1;
2076 shost->tag_set.queue_depth = shost->can_queue;
2077 shost->tag_set.cmd_size = cmd_size;
2078 shost->tag_set.numa_node = NUMA_NO_NODE;
2079 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2080 shost->tag_set.driver_data = shost;
2081
2082 return blk_mq_alloc_tag_set(&shost->tag_set);
2083}
2084
2085void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2086{
2087 blk_mq_free_tag_set(&shost->tag_set);
2088}
2089
Linus Torvalds1da177e2005-04-16 15:20:36 -07002090/*
2091 * Function: scsi_block_requests()
2092 *
2093 * Purpose: Utility function used by low-level drivers to prevent further
2094 * commands from being queued to the device.
2095 *
2096 * Arguments: shost - Host in question
2097 *
2098 * Returns: Nothing
2099 *
2100 * Lock status: No locks are assumed held.
2101 *
2102 * Notes: There is no timer nor any other means by which the requests
2103 * get unblocked other than the low-level driver calling
2104 * scsi_unblock_requests().
2105 */
2106void scsi_block_requests(struct Scsi_Host *shost)
2107{
2108 shost->host_self_blocked = 1;
2109}
2110EXPORT_SYMBOL(scsi_block_requests);
2111
2112/*
2113 * Function: scsi_unblock_requests()
2114 *
2115 * Purpose: Utility function used by low-level drivers to allow further
2116 * commands from being queued to the device.
2117 *
2118 * Arguments: shost - Host in question
2119 *
2120 * Returns: Nothing
2121 *
2122 * Lock status: No locks are assumed held.
2123 *
2124 * Notes: There is no timer nor any other means by which the requests
2125 * get unblocked other than the low-level driver calling
2126 * scsi_unblock_requests().
2127 *
2128 * This is done as an API function so that changes to the
2129 * internals of the scsi mid-layer won't require wholesale
2130 * changes to drivers that use this feature.
2131 */
2132void scsi_unblock_requests(struct Scsi_Host *shost)
2133{
2134 shost->host_self_blocked = 0;
2135 scsi_run_host_queues(shost);
2136}
2137EXPORT_SYMBOL(scsi_unblock_requests);
2138
2139int __init scsi_init_queue(void)
2140{
2141 int i;
2142
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002143 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2144 sizeof(struct scsi_data_buffer),
2145 0, 0, NULL);
2146 if (!scsi_sdb_cache) {
2147 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09002148 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02002149 }
2150
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2152 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2153 int size = sgp->size * sizeof(struct scatterlist);
2154
2155 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09002156 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002157 if (!sgp->slab) {
2158 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
2159 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002160 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002161 }
2162
Matthew Dobson93d23412006-03-26 01:37:50 -08002163 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
2164 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165 if (!sgp->pool) {
2166 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
2167 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002168 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169 }
2170 }
2171
2172 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002173
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002174cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002175 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2176 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2177 if (sgp->pool)
2178 mempool_destroy(sgp->pool);
2179 if (sgp->slab)
2180 kmem_cache_destroy(sgp->slab);
2181 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002182 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002183
2184 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185}
2186
2187void scsi_exit_queue(void)
2188{
2189 int i;
2190
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002191 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06002192
Linus Torvalds1da177e2005-04-16 15:20:36 -07002193 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2194 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2195 mempool_destroy(sgp->pool);
2196 kmem_cache_destroy(sgp->slab);
2197 }
2198}
James Bottomley5baba832006-03-18 14:10:35 -06002199
2200/**
2201 * scsi_mode_select - issue a mode select
2202 * @sdev: SCSI device to be queried
2203 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2204 * @sp: Save page bit (0 == don't save, 1 == save)
2205 * @modepage: mode page being requested
2206 * @buffer: request buffer (may not be smaller than eight bytes)
2207 * @len: length of request buffer.
2208 * @timeout: command timeout
2209 * @retries: number of retries before failing
2210 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05002211 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06002212 * must be SCSI_SENSE_BUFFERSIZE big.
2213 *
2214 * Returns zero if successful; negative error number or scsi
2215 * status on error
2216 *
2217 */
2218int
2219scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2220 unsigned char *buffer, int len, int timeout, int retries,
2221 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2222{
2223 unsigned char cmd[10];
2224 unsigned char *real_buffer;
2225 int ret;
2226
2227 memset(cmd, 0, sizeof(cmd));
2228 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2229
2230 if (sdev->use_10_for_ms) {
2231 if (len > 65535)
2232 return -EINVAL;
2233 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2234 if (!real_buffer)
2235 return -ENOMEM;
2236 memcpy(real_buffer + 8, buffer, len);
2237 len += 8;
2238 real_buffer[0] = 0;
2239 real_buffer[1] = 0;
2240 real_buffer[2] = data->medium_type;
2241 real_buffer[3] = data->device_specific;
2242 real_buffer[4] = data->longlba ? 0x01 : 0;
2243 real_buffer[5] = 0;
2244 real_buffer[6] = data->block_descriptor_length >> 8;
2245 real_buffer[7] = data->block_descriptor_length;
2246
2247 cmd[0] = MODE_SELECT_10;
2248 cmd[7] = len >> 8;
2249 cmd[8] = len;
2250 } else {
2251 if (len > 255 || data->block_descriptor_length > 255 ||
2252 data->longlba)
2253 return -EINVAL;
2254
2255 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2256 if (!real_buffer)
2257 return -ENOMEM;
2258 memcpy(real_buffer + 4, buffer, len);
2259 len += 4;
2260 real_buffer[0] = 0;
2261 real_buffer[1] = data->medium_type;
2262 real_buffer[2] = data->device_specific;
2263 real_buffer[3] = data->block_descriptor_length;
2264
2265
2266 cmd[0] = MODE_SELECT;
2267 cmd[4] = len;
2268 }
2269
2270 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002271 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06002272 kfree(real_buffer);
2273 return ret;
2274}
2275EXPORT_SYMBOL_GPL(scsi_mode_select);
2276
Linus Torvalds1da177e2005-04-16 15:20:36 -07002277/**
Rob Landleyeb448202007-11-03 13:30:39 -05002278 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05002279 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 * @dbd: set if mode sense will allow block descriptors to be returned
2281 * @modepage: mode page being requested
2282 * @buffer: request buffer (may not be smaller than eight bytes)
2283 * @len: length of request buffer.
2284 * @timeout: command timeout
2285 * @retries: number of retries before failing
2286 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05002287 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05002288 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289 *
2290 * Returns zero if unsuccessful, or the header offset (either 4
2291 * or 8 depending on whether a six or ten byte command was
2292 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05002293 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294int
James Bottomley1cf72692005-08-28 11:27:01 -05002295scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002296 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06002297 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2298{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002299 unsigned char cmd[12];
2300 int use_10_for_ms;
2301 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05002302 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05002303 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002304
2305 memset(data, 0, sizeof(*data));
2306 memset(&cmd[0], 0, 12);
2307 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2308 cmd[2] = modepage;
2309
James Bottomleyea73a9f2005-08-28 11:33:52 -05002310 /* caller might not be interested in sense, but we need it */
2311 if (!sshdr)
2312 sshdr = &my_sshdr;
2313
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05002315 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316
2317 if (use_10_for_ms) {
2318 if (len < 8)
2319 len = 8;
2320
2321 cmd[0] = MODE_SENSE_10;
2322 cmd[8] = len;
2323 header_length = 8;
2324 } else {
2325 if (len < 4)
2326 len = 4;
2327
2328 cmd[0] = MODE_SENSE;
2329 cmd[4] = len;
2330 header_length = 4;
2331 }
2332
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333 memset(buffer, 0, len);
2334
James Bottomley1cf72692005-08-28 11:27:01 -05002335 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002336 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002337
2338 /* This code looks awful: what it's doing is making sure an
2339 * ILLEGAL REQUEST sense return identifies the actual command
2340 * byte as the problem. MODE_SENSE commands can return
2341 * ILLEGAL REQUEST if the code page isn't supported */
2342
James Bottomley1cf72692005-08-28 11:27:01 -05002343 if (use_10_for_ms && !scsi_status_is_good(result) &&
2344 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05002345 if (scsi_sense_valid(sshdr)) {
2346 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2347 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348 /*
2349 * Invalid command operation code
2350 */
James Bottomley1cf72692005-08-28 11:27:01 -05002351 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352 goto retry;
2353 }
2354 }
2355 }
2356
James Bottomley1cf72692005-08-28 11:27:01 -05002357 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01002358 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2359 (modepage == 6 || modepage == 8))) {
2360 /* Initio breakage? */
2361 header_length = 0;
2362 data->length = 13;
2363 data->medium_type = 0;
2364 data->device_specific = 0;
2365 data->longlba = 0;
2366 data->block_descriptor_length = 0;
2367 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002368 data->length = buffer[0]*256 + buffer[1] + 2;
2369 data->medium_type = buffer[2];
2370 data->device_specific = buffer[3];
2371 data->longlba = buffer[4] & 0x01;
2372 data->block_descriptor_length = buffer[6]*256
2373 + buffer[7];
2374 } else {
2375 data->length = buffer[0] + 1;
2376 data->medium_type = buffer[1];
2377 data->device_specific = buffer[2];
2378 data->block_descriptor_length = buffer[3];
2379 }
Al Viro6d73c852006-02-23 02:03:16 +01002380 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002381 }
2382
James Bottomley1cf72692005-08-28 11:27:01 -05002383 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002384}
2385EXPORT_SYMBOL(scsi_mode_sense);
2386
James Bottomley001aac22007-12-02 19:10:40 +02002387/**
2388 * scsi_test_unit_ready - test if unit is ready
2389 * @sdev: scsi device to change the state of.
2390 * @timeout: command timeout
2391 * @retries: number of retries before failing
2392 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2393 * returning sense. Make sure that this is cleared before passing
2394 * in.
2395 *
2396 * Returns zero if unsuccessful or an error if TUR failed. For
Tejun Heo9f8a2c22010-12-08 20:57:40 +01002397 * removable media, UNIT_ATTENTION sets ->changed flag.
James Bottomley001aac22007-12-02 19:10:40 +02002398 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002399int
James Bottomley001aac22007-12-02 19:10:40 +02002400scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2401 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002402{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002403 char cmd[] = {
2404 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2405 };
James Bottomley001aac22007-12-02 19:10:40 +02002406 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002408
2409 if (!sshdr_external)
2410 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2411 else
2412 sshdr = sshdr_external;
2413
2414 /* try to eat the UNIT_ATTENTION if there are enough retries */
2415 do {
2416 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002417 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002418 if (sdev->removable && scsi_sense_valid(sshdr) &&
2419 sshdr->sense_key == UNIT_ATTENTION)
2420 sdev->changed = 1;
2421 } while (scsi_sense_valid(sshdr) &&
2422 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002423
James Bottomley001aac22007-12-02 19:10:40 +02002424 if (!sshdr_external)
2425 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002426 return result;
2427}
2428EXPORT_SYMBOL(scsi_test_unit_ready);
2429
2430/**
Rob Landleyeb448202007-11-03 13:30:39 -05002431 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002432 * @sdev: scsi device to change the state of.
2433 * @state: state to change to.
2434 *
2435 * Returns zero if unsuccessful or an error if the requested
2436 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002437 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002438int
2439scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2440{
2441 enum scsi_device_state oldstate = sdev->sdev_state;
2442
2443 if (state == oldstate)
2444 return 0;
2445
2446 switch (state) {
2447 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002448 switch (oldstate) {
2449 case SDEV_CREATED_BLOCK:
2450 break;
2451 default:
2452 goto illegal;
2453 }
2454 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455
2456 case SDEV_RUNNING:
2457 switch (oldstate) {
2458 case SDEV_CREATED:
2459 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002460 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002461 case SDEV_QUIESCE:
2462 case SDEV_BLOCK:
2463 break;
2464 default:
2465 goto illegal;
2466 }
2467 break;
2468
2469 case SDEV_QUIESCE:
2470 switch (oldstate) {
2471 case SDEV_RUNNING:
2472 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002473 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002474 break;
2475 default:
2476 goto illegal;
2477 }
2478 break;
2479
2480 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002481 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002482 switch (oldstate) {
2483 case SDEV_CREATED:
2484 case SDEV_RUNNING:
2485 case SDEV_QUIESCE:
2486 case SDEV_BLOCK:
2487 break;
2488 default:
2489 goto illegal;
2490 }
2491 break;
2492
2493 case SDEV_BLOCK:
2494 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002495 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002496 case SDEV_CREATED_BLOCK:
2497 break;
2498 default:
2499 goto illegal;
2500 }
2501 break;
2502
2503 case SDEV_CREATED_BLOCK:
2504 switch (oldstate) {
2505 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002506 break;
2507 default:
2508 goto illegal;
2509 }
2510 break;
2511
2512 case SDEV_CANCEL:
2513 switch (oldstate) {
2514 case SDEV_CREATED:
2515 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002516 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002517 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002518 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002519 case SDEV_BLOCK:
2520 break;
2521 default:
2522 goto illegal;
2523 }
2524 break;
2525
2526 case SDEV_DEL:
2527 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002528 case SDEV_CREATED:
2529 case SDEV_RUNNING:
2530 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002531 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002532 case SDEV_CANCEL:
Bart Van Assche0516c082013-07-02 15:06:33 +02002533 case SDEV_CREATED_BLOCK:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002534 break;
2535 default:
2536 goto illegal;
2537 }
2538 break;
2539
2540 }
2541 sdev->sdev_state = state;
2542 return 0;
2543
2544 illegal:
Hannes Reinecke91921e02014-06-25 16:39:59 +02002545 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002546 sdev_printk(KERN_ERR, sdev,
Hannes Reinecke91921e02014-06-25 16:39:59 +02002547 "Illegal state transition %s->%s",
James Bottomley9ccfc752005-10-02 11:45:08 -05002548 scsi_device_state_name(oldstate),
2549 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002550 );
2551 return -EINVAL;
2552}
2553EXPORT_SYMBOL(scsi_device_set_state);
2554
2555/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002556 * sdev_evt_emit - emit a single SCSI device uevent
2557 * @sdev: associated SCSI device
2558 * @evt: event to emit
2559 *
2560 * Send a single uevent (scsi_event) to the associated scsi_device.
2561 */
2562static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2563{
2564 int idx = 0;
2565 char *envp[3];
2566
2567 switch (evt->evt_type) {
2568 case SDEV_EVT_MEDIA_CHANGE:
2569 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2570 break;
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002571 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2572 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2573 break;
2574 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2575 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2576 break;
2577 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2578 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2579 break;
2580 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2581 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2582 break;
2583 case SDEV_EVT_LUN_CHANGE_REPORTED:
2584 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2585 break;
Jeff Garzika341cd02007-10-29 17:15:22 -04002586 default:
2587 /* do nothing */
2588 break;
2589 }
2590
2591 envp[idx++] = NULL;
2592
2593 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2594}
2595
2596/**
2597 * sdev_evt_thread - send a uevent for each scsi event
2598 * @work: work struct for scsi_device
2599 *
2600 * Dispatch queued events to their associated scsi_device kobjects
2601 * as uevents.
2602 */
2603void scsi_evt_thread(struct work_struct *work)
2604{
2605 struct scsi_device *sdev;
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002606 enum scsi_device_event evt_type;
Jeff Garzika341cd02007-10-29 17:15:22 -04002607 LIST_HEAD(event_list);
2608
2609 sdev = container_of(work, struct scsi_device, event_work);
2610
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002611 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2612 if (test_and_clear_bit(evt_type, sdev->pending_events))
2613 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2614
Jeff Garzika341cd02007-10-29 17:15:22 -04002615 while (1) {
2616 struct scsi_event *evt;
2617 struct list_head *this, *tmp;
2618 unsigned long flags;
2619
2620 spin_lock_irqsave(&sdev->list_lock, flags);
2621 list_splice_init(&sdev->event_list, &event_list);
2622 spin_unlock_irqrestore(&sdev->list_lock, flags);
2623
2624 if (list_empty(&event_list))
2625 break;
2626
2627 list_for_each_safe(this, tmp, &event_list) {
2628 evt = list_entry(this, struct scsi_event, node);
2629 list_del(&evt->node);
2630 scsi_evt_emit(sdev, evt);
2631 kfree(evt);
2632 }
2633 }
2634}
2635
2636/**
2637 * sdev_evt_send - send asserted event to uevent thread
2638 * @sdev: scsi_device event occurred on
2639 * @evt: event to send
2640 *
2641 * Assert scsi device event asynchronously.
2642 */
2643void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2644{
2645 unsigned long flags;
2646
Kay Sievers4d1566e2008-03-19 13:04:47 +01002647#if 0
2648 /* FIXME: currently this check eliminates all media change events
2649 * for polled devices. Need to update to discriminate between AN
2650 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002651 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2652 kfree(evt);
2653 return;
2654 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002655#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002656
2657 spin_lock_irqsave(&sdev->list_lock, flags);
2658 list_add_tail(&evt->node, &sdev->event_list);
2659 schedule_work(&sdev->event_work);
2660 spin_unlock_irqrestore(&sdev->list_lock, flags);
2661}
2662EXPORT_SYMBOL_GPL(sdev_evt_send);
2663
2664/**
2665 * sdev_evt_alloc - allocate a new scsi event
2666 * @evt_type: type of event to allocate
2667 * @gfpflags: GFP flags for allocation
2668 *
2669 * Allocates and returns a new scsi_event.
2670 */
2671struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2672 gfp_t gfpflags)
2673{
2674 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2675 if (!evt)
2676 return NULL;
2677
2678 evt->evt_type = evt_type;
2679 INIT_LIST_HEAD(&evt->node);
2680
2681 /* evt_type-specific initialization, if any */
2682 switch (evt_type) {
2683 case SDEV_EVT_MEDIA_CHANGE:
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002684 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2685 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2686 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2687 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2688 case SDEV_EVT_LUN_CHANGE_REPORTED:
Jeff Garzika341cd02007-10-29 17:15:22 -04002689 default:
2690 /* do nothing */
2691 break;
2692 }
2693
2694 return evt;
2695}
2696EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2697
2698/**
2699 * sdev_evt_send_simple - send asserted event to uevent thread
2700 * @sdev: scsi_device event occurred on
2701 * @evt_type: type of event to send
2702 * @gfpflags: GFP flags for allocation
2703 *
2704 * Assert scsi device event asynchronously, given an event type.
2705 */
2706void sdev_evt_send_simple(struct scsi_device *sdev,
2707 enum scsi_device_event evt_type, gfp_t gfpflags)
2708{
2709 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2710 if (!evt) {
2711 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2712 evt_type);
2713 return;
2714 }
2715
2716 sdev_evt_send(sdev, evt);
2717}
2718EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2719
2720/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002721 * scsi_device_quiesce - Block user issued commands.
2722 * @sdev: scsi device to quiesce.
2723 *
2724 * This works by trying to transition to the SDEV_QUIESCE state
2725 * (which must be a legal transition). When the device is in this
2726 * state, only special requests will be accepted, all others will
2727 * be deferred. Since special requests may also be requeued requests,
2728 * a successful return doesn't guarantee the device will be
2729 * totally quiescent.
2730 *
2731 * Must be called with user context, may sleep.
2732 *
2733 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002734 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002735int
2736scsi_device_quiesce(struct scsi_device *sdev)
2737{
2738 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2739 if (err)
2740 return err;
2741
2742 scsi_run_queue(sdev->request_queue);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02002743 while (atomic_read(&sdev->device_busy)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002744 msleep_interruptible(200);
2745 scsi_run_queue(sdev->request_queue);
2746 }
2747 return 0;
2748}
2749EXPORT_SYMBOL(scsi_device_quiesce);
2750
2751/**
2752 * scsi_device_resume - Restart user issued commands to a quiesced device.
2753 * @sdev: scsi device to resume.
2754 *
2755 * Moves the device from quiesced back to running and restarts the
2756 * queues.
2757 *
2758 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002759 */
Dan Williamsa7a20d12012-03-22 17:05:11 -07002760void scsi_device_resume(struct scsi_device *sdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002761{
Dan Williamsa7a20d12012-03-22 17:05:11 -07002762 /* check if the device state was mutated prior to resume, and if
2763 * so assume the state is being managed elsewhere (for example
2764 * device deleted during suspend)
2765 */
2766 if (sdev->sdev_state != SDEV_QUIESCE ||
2767 scsi_device_set_state(sdev, SDEV_RUNNING))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002768 return;
2769 scsi_run_queue(sdev->request_queue);
2770}
2771EXPORT_SYMBOL(scsi_device_resume);
2772
2773static void
2774device_quiesce_fn(struct scsi_device *sdev, void *data)
2775{
2776 scsi_device_quiesce(sdev);
2777}
2778
2779void
2780scsi_target_quiesce(struct scsi_target *starget)
2781{
2782 starget_for_each_device(starget, NULL, device_quiesce_fn);
2783}
2784EXPORT_SYMBOL(scsi_target_quiesce);
2785
2786static void
2787device_resume_fn(struct scsi_device *sdev, void *data)
2788{
2789 scsi_device_resume(sdev);
2790}
2791
2792void
2793scsi_target_resume(struct scsi_target *starget)
2794{
2795 starget_for_each_device(starget, NULL, device_resume_fn);
2796}
2797EXPORT_SYMBOL(scsi_target_resume);
2798
2799/**
Rob Landleyeb448202007-11-03 13:30:39 -05002800 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002801 * @sdev: device to block
2802 *
2803 * Block request made by scsi lld's to temporarily stop all
2804 * scsi commands on the specified device. Called from interrupt
2805 * or normal process context.
2806 *
2807 * Returns zero if successful or error if not
2808 *
2809 * Notes:
2810 * This routine transitions the device to the SDEV_BLOCK state
2811 * (which must be a legal transition). When the device is in this
2812 * state, all commands are deferred until the scsi lld reenables
2813 * the device with scsi_device_unblock or device_block_tmo fires.
Rob Landleyeb448202007-11-03 13:30:39 -05002814 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002815int
2816scsi_internal_device_block(struct scsi_device *sdev)
2817{
Jens Axboe165125e2007-07-24 09:28:11 +02002818 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002819 unsigned long flags;
2820 int err = 0;
2821
2822 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002823 if (err) {
2824 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2825
2826 if (err)
2827 return err;
2828 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002829
2830 /*
2831 * The device has transitioned to SDEV_BLOCK. Stop the
2832 * block layer from calling the midlayer with this device's
2833 * request queue.
2834 */
Christoph Hellwigd2852032014-01-17 12:06:53 +01002835 if (q->mq_ops) {
2836 blk_mq_stop_hw_queues(q);
2837 } else {
2838 spin_lock_irqsave(q->queue_lock, flags);
2839 blk_stop_queue(q);
2840 spin_unlock_irqrestore(q->queue_lock, flags);
2841 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002842
2843 return 0;
2844}
2845EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2846
2847/**
2848 * scsi_internal_device_unblock - resume a device after a block request
2849 * @sdev: device to resume
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002850 * @new_state: state to set devices to after unblocking
Linus Torvalds1da177e2005-04-16 15:20:36 -07002851 *
2852 * Called by scsi lld's or the midlayer to restart the device queue
2853 * for the previously suspended scsi device. Called from interrupt or
2854 * normal process context.
2855 *
2856 * Returns zero if successful or error if not.
2857 *
2858 * Notes:
2859 * This routine transitions the device to the SDEV_RUNNING state
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002860 * or to one of the offline states (which must be a legal transition)
Mike Christied0754982012-05-17 23:56:58 -05002861 * allowing the midlayer to goose the queue for this device.
Rob Landleyeb448202007-11-03 13:30:39 -05002862 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002863int
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002864scsi_internal_device_unblock(struct scsi_device *sdev,
2865 enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002866{
Jens Axboe165125e2007-07-24 09:28:11 +02002867 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002868 unsigned long flags;
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002869
2870 /*
2871 * Try to transition the scsi device to SDEV_RUNNING or one of the
2872 * offlined states and goose the device queue if successful.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002873 */
Vikas Chaudhary0e580762012-08-09 04:51:30 -04002874 if ((sdev->sdev_state == SDEV_BLOCK) ||
2875 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002876 sdev->sdev_state = new_state;
2877 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
2878 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2879 new_state == SDEV_OFFLINE)
2880 sdev->sdev_state = new_state;
2881 else
2882 sdev->sdev_state = SDEV_CREATED;
2883 } else if (sdev->sdev_state != SDEV_CANCEL &&
Mike Christie986fe6c2010-10-06 03:10:59 -05002884 sdev->sdev_state != SDEV_OFFLINE)
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002885 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002886
Christoph Hellwigd2852032014-01-17 12:06:53 +01002887 if (q->mq_ops) {
2888 blk_mq_start_stopped_hw_queues(q, false);
2889 } else {
2890 spin_lock_irqsave(q->queue_lock, flags);
2891 blk_start_queue(q);
2892 spin_unlock_irqrestore(q->queue_lock, flags);
2893 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002894
2895 return 0;
2896}
2897EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2898
2899static void
2900device_block(struct scsi_device *sdev, void *data)
2901{
2902 scsi_internal_device_block(sdev);
2903}
2904
2905static int
2906target_block(struct device *dev, void *data)
2907{
2908 if (scsi_is_target_device(dev))
2909 starget_for_each_device(to_scsi_target(dev), NULL,
2910 device_block);
2911 return 0;
2912}
2913
2914void
2915scsi_target_block(struct device *dev)
2916{
2917 if (scsi_is_target_device(dev))
2918 starget_for_each_device(to_scsi_target(dev), NULL,
2919 device_block);
2920 else
2921 device_for_each_child(dev, NULL, target_block);
2922}
2923EXPORT_SYMBOL_GPL(scsi_target_block);
2924
2925static void
2926device_unblock(struct scsi_device *sdev, void *data)
2927{
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002928 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002929}
2930
2931static int
2932target_unblock(struct device *dev, void *data)
2933{
2934 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002935 starget_for_each_device(to_scsi_target(dev), data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002936 device_unblock);
2937 return 0;
2938}
2939
2940void
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002941scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002942{
2943 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002944 starget_for_each_device(to_scsi_target(dev), &new_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002945 device_unblock);
2946 else
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002947 device_for_each_child(dev, &new_state, target_unblock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002948}
2949EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002950
2951/**
2952 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002953 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002954 * @sg_count: number of segments in sg
2955 * @offset: offset in bytes into sg, on return offset into the mapped area
2956 * @len: bytes to map, on return number of bytes mapped
2957 *
2958 * Returns virtual address of the start of the mapped page
2959 */
Jens Axboec6132da2007-10-16 11:08:49 +02002960void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002961 size_t *offset, size_t *len)
2962{
2963 int i;
2964 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002965 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002966 struct page *page;
2967
Andrew Morton22cfefb2007-02-05 16:39:03 -08002968 WARN_ON(!irqs_disabled());
2969
Jens Axboec6132da2007-10-16 11:08:49 +02002970 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002971 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002972 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002973 if (sg_len > *offset)
2974 break;
2975 }
2976
2977 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002978 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2979 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002980 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002981 WARN_ON(1);
2982 return NULL;
2983 }
2984
2985 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002986 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002987
2988 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002989 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002990 *offset &= ~PAGE_MASK;
2991
2992 /* Bytes in this sg-entry from *offset to the end of the page */
2993 sg_len = PAGE_SIZE - *offset;
2994 if (*len > sg_len)
2995 *len = sg_len;
2996
Cong Wang77dfce02011-11-25 23:14:23 +08002997 return kmap_atomic(page);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002998}
2999EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3000
3001/**
Rob Landleyeb448202007-11-03 13:30:39 -05003002 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003003 * @virt: virtual address to be unmapped
3004 */
3005void scsi_kunmap_atomic_sg(void *virt)
3006{
Cong Wang77dfce02011-11-25 23:14:23 +08003007 kunmap_atomic(virt);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003008}
3009EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
Aaron Lu6f4c8272013-01-23 15:09:32 +08003010
3011void sdev_disable_disk_events(struct scsi_device *sdev)
3012{
3013 atomic_inc(&sdev->disk_events_disable_depth);
3014}
3015EXPORT_SYMBOL(sdev_disable_disk_events);
3016
3017void sdev_enable_disk_events(struct scsi_device *sdev)
3018{
3019 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3020 return;
3021 atomic_dec(&sdev->disk_events_disable_depth);
3022}
3023EXPORT_SYMBOL(sdev_enable_disk_events);