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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
3 *
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
8 */
9
10#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060011#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/blkdev.h>
13#include <linux/completion.h>
14#include <linux/kernel.h>
Paul Gortmaker09703662011-05-27 09:37:25 -040015#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/mempool.h>
17#include <linux/slab.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060021#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020022#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
24#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020025#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <scsi/scsi_dbg.h>
27#include <scsi/scsi_device.h>
28#include <scsi/scsi_driver.h>
29#include <scsi/scsi_eh.h>
30#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32#include "scsi_priv.h"
33#include "scsi_logging.h"
34
35
Tobias Klauser6391a112006-06-08 22:23:48 -070036#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020037#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39struct scsi_host_sg_pool {
40 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020041 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080042 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 mempool_t *pool;
44};
45
James Bottomleyd3f46f32008-01-15 11:11:46 -060046#define SP(x) { x, "sgpool-" __stringify(x) }
47#if (SCSI_MAX_SG_SEGMENTS < 32)
48#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
49#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070050static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 SP(8),
52 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020053#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060054 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020055#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060056 SP(64),
57#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060059#if (SCSI_MAX_SG_SEGMENTS > 256)
60#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020061#endif
62#endif
63#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060064#endif
65 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020066};
Linus Torvalds1da177e2005-04-16 15:20:36 -070067#undef SP
68
Martin K. Petersen7027ad72008-07-17 17:08:48 -040069struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020070
Jens Axboea488e742010-04-16 21:13:15 +020071/*
72 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
73 * not change behaviour from the previous unplug mechanism, experimentation
74 * may prove this needs changing.
75 */
76#define SCSI_QUEUE_DELAY 3
77
James Bottomleye91442b2005-09-09 10:44:16 -050078/*
79 * Function: scsi_unprep_request()
80 *
81 * Purpose: Remove all preparation done for a request, including its
82 * associated scsi_cmnd, so that it can be requeued.
83 *
84 * Arguments: req - request to unprepare
85 *
86 * Lock status: Assumed that no locks are held upon entry.
87 *
88 * Returns: Nothing.
89 */
90static void scsi_unprep_request(struct request *req)
91{
92 struct scsi_cmnd *cmd = req->special;
93
James Bottomley28018c22010-07-01 19:49:17 +090094 blk_unprep_request(req);
Christoph Hellwigbeb40482006-06-10 18:01:03 +020095 req->special = NULL;
James Bottomleye91442b2005-09-09 10:44:16 -050096
James Bottomleye91442b2005-09-09 10:44:16 -050097 scsi_put_command(cmd);
98}
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -050099
James Bottomley4f5299a2009-01-02 10:42:21 -0600100/**
101 * __scsi_queue_insert - private queue insertion
102 * @cmd: The SCSI command being requeued
103 * @reason: The reason for the requeue
104 * @unbusy: Whether the queue should be unbusied
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 *
James Bottomley4f5299a2009-01-02 10:42:21 -0600106 * This is a private queue insertion. The public interface
107 * scsi_queue_insert() always assumes the queue should be unbusied
108 * because it's always called before the completion. This function is
109 * for a requeue after completion, which should only occur in this
110 * file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600112static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 struct Scsi_Host *host = cmd->device->host;
115 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500116 struct scsi_target *starget = scsi_target(device);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500117 struct request_queue *q = device->request_queue;
118 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120 SCSI_LOG_MLQUEUE(1,
121 printk("Inserting command %p into mlqueue\n", cmd));
122
123 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +0900124 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 *
126 * If the host/device isn't busy, assume that something actually
127 * completed, and that we should be able to queue a command now.
128 *
129 * Note that the prior mid-layer assumption that any host could
130 * always queue at least one command is now broken. The mid-layer
131 * will implement a user specifiable stall (see
132 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
133 * if a command is requeued with no other commands outstanding
134 * either for the device or for the host.
135 */
Mike Christief0c0a372008-08-17 15:24:38 -0500136 switch (reason) {
137 case SCSI_MLQUEUE_HOST_BUSY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 host->host_blocked = host->max_host_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500139 break;
140 case SCSI_MLQUEUE_DEVICE_BUSY:
James Smart573e5912011-07-06 12:45:17 -0400141 case SCSI_MLQUEUE_EH_RETRY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 device->device_blocked = device->max_device_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500143 break;
144 case SCSI_MLQUEUE_TARGET_BUSY:
145 starget->target_blocked = starget->max_target_blocked;
146 break;
147 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 * Decrement the counters, since these commands are no longer
151 * active on the host/device.
152 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600153 if (unbusy)
154 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
156 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500157 * Requeue this command. It will go before all other commands
158 * that are already in the queue.
Jens Axboea488e742010-04-16 21:13:15 +0200159 */
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500160 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400161 blk_requeue_request(q, cmd->request);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500162 spin_unlock_irqrestore(q->queue_lock, flags);
163
Jens Axboe9937a5e2011-05-17 11:04:44 +0200164 kblockd_schedule_work(q, &device->requeue_work);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500165
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 return 0;
167}
168
James Bottomley4f5299a2009-01-02 10:42:21 -0600169/*
170 * Function: scsi_queue_insert()
171 *
172 * Purpose: Insert a command in the midlevel queue.
173 *
174 * Arguments: cmd - command that we are adding to queue.
175 * reason - why we are inserting command to queue.
176 *
177 * Lock status: Assumed that lock is not held upon entry.
178 *
179 * Returns: Nothing.
180 *
181 * Notes: We do this for one of two cases. Either the host is busy
182 * and it cannot accept any more commands for the time being,
183 * or the device returned QUEUE_FULL and can accept no more
184 * commands.
185 * Notes: This could be called either from an interrupt context or a
186 * normal process context.
187 */
188int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
189{
190 return __scsi_queue_insert(cmd, reason, 1);
191}
James Bottomley39216032005-06-15 18:48:29 -0500192/**
James Bottomley33aa6872005-08-28 11:31:14 -0500193 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500194 * @sdev: scsi device
195 * @cmd: scsi command
196 * @data_direction: data direction
197 * @buffer: data buffer
198 * @bufflen: len of buffer
199 * @sense: optional sense buffer
200 * @timeout: request timeout in seconds
201 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500202 * @flags: or into request flags;
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900203 * @resid: optional residual length
James Bottomley39216032005-06-15 18:48:29 -0500204 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200205 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500206 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500207 */
James Bottomley33aa6872005-08-28 11:31:14 -0500208int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
209 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900210 unsigned char *sense, int timeout, int retries, int flags,
211 int *resid)
James Bottomley39216032005-06-15 18:48:29 -0500212{
213 struct request *req;
214 int write = (data_direction == DMA_TO_DEVICE);
215 int ret = DRIVER_ERROR << 24;
216
217 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
James Bottomleybfe159a2011-07-07 15:45:40 -0500218 if (!req)
219 return ret;
James Bottomley39216032005-06-15 18:48:29 -0500220
221 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
222 buffer, bufflen, __GFP_WAIT))
223 goto out;
224
225 req->cmd_len = COMMAND_SIZE(cmd[0]);
226 memcpy(req->cmd, cmd, req->cmd_len);
227 req->sense = sense;
228 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600229 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500230 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200231 req->cmd_type = REQ_TYPE_BLOCK_PC;
232 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500233
234 /*
235 * head injection *required* here otherwise quiesce won't work
236 */
237 blk_execute_rq(req->q, NULL, req, 1);
238
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400239 /*
240 * Some devices (USB mass-storage in particular) may transfer
241 * garbage data together with a residue indicating that the data
242 * is invalid. Prevent the garbage from being misinterpreted
243 * and prevent security leaks by zeroing out the excess data.
244 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900245 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
246 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400247
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900248 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900249 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500250 ret = req->errors;
251 out:
252 blk_put_request(req);
253
254 return ret;
255}
James Bottomley33aa6872005-08-28 11:31:14 -0500256EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500257
James Bottomleyea73a9f2005-08-28 11:33:52 -0500258
259int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
260 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900261 struct scsi_sense_hdr *sshdr, int timeout, int retries,
262 int *resid)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500263{
264 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700265 int result;
266
James Bottomleyea73a9f2005-08-28 11:33:52 -0500267 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500268 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500269 if (!sense)
270 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500271 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700272 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900273 sense, timeout, retries, 0, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500274 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500275 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500276
277 kfree(sense);
278 return result;
279}
280EXPORT_SYMBOL(scsi_execute_req);
281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282/*
283 * Function: scsi_init_cmd_errh()
284 *
285 * Purpose: Initialize cmd fields related to error handling.
286 *
287 * Arguments: cmd - command that is ready to be queued.
288 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 * Notes: This function has the job of initializing a number of
290 * fields related to error handling. Typically this will
291 * be called once for each command, as required.
292 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200293static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200296 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900297 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300299 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300}
301
302void scsi_device_unbusy(struct scsi_device *sdev)
303{
304 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500305 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 unsigned long flags;
307
308 spin_lock_irqsave(shost->host_lock, flags);
309 shost->host_busy--;
Mike Christief0c0a372008-08-17 15:24:38 -0500310 starget->target_busy--;
James Bottomley939647e2005-09-18 15:05:20 -0500311 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900312 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 scsi_eh_wakeup(shost);
314 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500315 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500317 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318}
319
320/*
321 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
322 * and call blk_run_queue for all the scsi_devices on the target -
323 * including current_sdev first.
324 *
325 * Called with *no* scsi locks held.
326 */
327static void scsi_single_lun_run(struct scsi_device *current_sdev)
328{
329 struct Scsi_Host *shost = current_sdev->host;
330 struct scsi_device *sdev, *tmp;
331 struct scsi_target *starget = scsi_target(current_sdev);
332 unsigned long flags;
333
334 spin_lock_irqsave(shost->host_lock, flags);
335 starget->starget_sdev_user = NULL;
336 spin_unlock_irqrestore(shost->host_lock, flags);
337
338 /*
339 * Call blk_run_queue for all LUNs on the target, starting with
340 * current_sdev. We race with others (to set starget_sdev_user),
341 * but in most cases, we will be first. Ideally, each LU on the
342 * target would get some limited time or requests on the target.
343 */
344 blk_run_queue(current_sdev->request_queue);
345
346 spin_lock_irqsave(shost->host_lock, flags);
347 if (starget->starget_sdev_user)
348 goto out;
349 list_for_each_entry_safe(sdev, tmp, &starget->devices,
350 same_target_siblings) {
351 if (sdev == current_sdev)
352 continue;
353 if (scsi_device_get(sdev))
354 continue;
355
356 spin_unlock_irqrestore(shost->host_lock, flags);
357 blk_run_queue(sdev->request_queue);
358 spin_lock_irqsave(shost->host_lock, flags);
359
360 scsi_device_put(sdev);
361 }
362 out:
363 spin_unlock_irqrestore(shost->host_lock, flags);
364}
365
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400366static inline int scsi_device_is_busy(struct scsi_device *sdev)
367{
368 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
369 return 1;
370
371 return 0;
372}
373
Mike Christief0c0a372008-08-17 15:24:38 -0500374static inline int scsi_target_is_busy(struct scsi_target *starget)
375{
376 return ((starget->can_queue > 0 &&
377 starget->target_busy >= starget->can_queue) ||
378 starget->target_blocked);
379}
380
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400381static inline int scsi_host_is_busy(struct Scsi_Host *shost)
382{
383 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
384 shost->host_blocked || shost->host_self_blocked)
385 return 1;
386
387 return 0;
388}
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390/*
391 * Function: scsi_run_queue()
392 *
393 * Purpose: Select a proper request queue to serve next
394 *
395 * Arguments: q - last request's queue
396 *
397 * Returns: Nothing
398 *
399 * Notes: The previous command was completely finished, start
400 * a new one if possible.
401 */
402static void scsi_run_queue(struct request_queue *q)
403{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600404 struct scsi_device *sdev = q->queuedata;
James Bottomleyc055f5b2011-05-01 09:42:07 -0500405 struct Scsi_Host *shost;
Mike Christie2a3a59e2008-11-11 13:42:35 -0600406 LIST_HEAD(starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 unsigned long flags;
408
James Bottomleyc055f5b2011-05-01 09:42:07 -0500409 /* if the device is dead, sdev will be NULL, so no queue to run */
410 if (!sdev)
411 return;
412
413 shost = sdev->host;
Tony Battersby25d7c362007-11-12 10:00:44 -0500414 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 scsi_single_lun_run(sdev);
416
417 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600418 list_splice_init(&shost->starved_list, &starved_list);
419
420 while (!list_empty(&starved_list)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 /*
422 * As long as shost is accepting commands and we have
423 * starved queues, call blk_run_queue. scsi_request_fn
424 * drops the queue_lock and can add us back to the
425 * starved_list.
426 *
427 * host_lock protects the starved_list and starved_entry.
428 * scsi_request_fn must get the host_lock before checking
429 * or modifying starved_list or starved_entry.
430 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600431 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500432 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500433
Mike Christie2a3a59e2008-11-11 13:42:35 -0600434 sdev = list_entry(starved_list.next,
435 struct scsi_device, starved_entry);
436 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500437 if (scsi_target_is_busy(scsi_target(sdev))) {
438 list_move_tail(&sdev->starved_entry,
439 &shost->starved_list);
440 continue;
441 }
442
Jens Axboe9937a5e2011-05-17 11:04:44 +0200443 spin_unlock(shost->host_lock);
444 spin_lock(sdev->request_queue->queue_lock);
445 __blk_run_queue(sdev->request_queue);
446 spin_unlock(sdev->request_queue->queue_lock);
447 spin_lock(shost->host_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600449 /* put any unprocessed entries back */
450 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 spin_unlock_irqrestore(shost->host_lock, flags);
452
453 blk_run_queue(q);
454}
455
Jens Axboe9937a5e2011-05-17 11:04:44 +0200456void scsi_requeue_run_queue(struct work_struct *work)
457{
458 struct scsi_device *sdev;
459 struct request_queue *q;
460
461 sdev = container_of(work, struct scsi_device, requeue_work);
462 q = sdev->request_queue;
463 scsi_run_queue(q);
464}
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466/*
467 * Function: scsi_requeue_command()
468 *
469 * Purpose: Handle post-processing of completed commands.
470 *
471 * Arguments: q - queue to operate on
472 * cmd - command that may need to be requeued.
473 *
474 * Returns: Nothing
475 *
476 * Notes: After command completion, there may be blocks left
477 * over which weren't finished by the previous command
478 * this can be for a number of reasons - the main one is
479 * I/O errors in the middle of the request, in which case
480 * we need to request the blocks that come after the bad
481 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500482 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 */
484static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
485{
James Bottomleye91442b2005-09-09 10:44:16 -0500486 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500487 unsigned long flags;
488
Tejun Heo 283369c2005-04-24 02:06:36 -0500489 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley02bd3492008-12-12 13:28:29 -0600490 scsi_unprep_request(req);
James Bottomleye91442b2005-09-09 10:44:16 -0500491 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500492 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 scsi_run_queue(q);
495}
496
497void scsi_next_command(struct scsi_cmnd *cmd)
498{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800499 struct scsi_device *sdev = cmd->device;
500 struct request_queue *q = sdev->request_queue;
501
502 /* need to hold a reference on the device before we let go of the cmd */
503 get_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
505 scsi_put_command(cmd);
506 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800507
508 /* ok to remove device now */
509 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510}
511
512void scsi_run_host_queues(struct Scsi_Host *shost)
513{
514 struct scsi_device *sdev;
515
516 shost_for_each_device(sdev, shost)
517 scsi_run_queue(sdev->request_queue);
518}
519
James Bottomley79ed2422009-01-06 13:15:20 -0600520static void __scsi_release_buffers(struct scsi_cmnd *, int);
521
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522/*
523 * Function: scsi_end_request()
524 *
525 * Purpose: Post-processing of completed commands (usually invoked at end
526 * of upper level post-processing and scsi_io_completion).
527 *
528 * Arguments: cmd - command that is complete.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500529 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 * bytes - number of bytes of completed I/O
531 * requeue - indicates whether we should requeue leftovers.
532 *
533 * Lock status: Assumed that lock is not held upon entry.
534 *
James Bottomleye91442b2005-09-09 10:44:16 -0500535 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 *
537 * Notes: This is called for block device requests in order to
538 * mark some number of sectors as complete.
539 *
540 * We are guaranteeing that the request queue will be goosed
541 * at some point during this call.
James Bottomleye91442b2005-09-09 10:44:16 -0500542 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500544static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 int bytes, int requeue)
546{
Jens Axboe165125e2007-07-24 09:28:11 +0200547 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
550 /*
551 * If there are blocks left over at the end, set up the command
552 * to queue the remainder of them.
553 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500554 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 /* kill remainder if no retrys */
Mike Christie4a274462008-08-19 18:45:31 -0500556 if (error && scsi_noretry_cmd(cmd))
Tejun Heoe4588242009-05-12 08:49:32 +0200557 blk_end_request_all(req, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500559 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 /*
561 * Bleah. Leftovers again. Stick the
562 * leftovers in the front of the
563 * queue, and goose the queue again.
564 */
James Bottomley79ed2422009-01-06 13:15:20 -0600565 scsi_release_buffers(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500567 cmd = NULL;
568 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 return cmd;
570 }
571 }
572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 /*
574 * This will goose the queue request function at the end, so we don't
575 * need to worry about launching another command.
576 */
James Bottomley79ed2422009-01-06 13:15:20 -0600577 __scsi_release_buffers(cmd, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 scsi_next_command(cmd);
579 return NULL;
580}
581
Jens Axboea8474ce2007-08-07 09:02:51 +0200582static inline unsigned int scsi_sgtable_index(unsigned short nents)
583{
584 unsigned int index;
585
James Bottomleyd3f46f32008-01-15 11:11:46 -0600586 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
587
588 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200589 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600590 else
591 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200592
593 return index;
594}
595
Jens Axboe5ed79592007-11-15 09:13:11 +0100596static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597{
598 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100599
600 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
601 mempool_free(sgl, sgp->pool);
602}
603
604static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
605{
606 struct scsi_host_sg_pool *sgp;
607
608 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
609 return mempool_alloc(sgp->pool, gfp_mask);
610}
611
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200612static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
613 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100614{
615 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200617 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200619 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
620 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100621 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200622 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600623 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
Jens Axboea8474ce2007-08-07 09:02:51 +0200625 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626}
627
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200628static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200630 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631}
632
James Bottomley79ed2422009-01-06 13:15:20 -0600633static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
634{
635
636 if (cmd->sdb.table.nents)
637 scsi_free_sgtable(&cmd->sdb);
638
639 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
640
641 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
642 struct scsi_data_buffer *bidi_sdb =
643 cmd->request->next_rq->special;
644 scsi_free_sgtable(bidi_sdb);
645 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
646 cmd->request->next_rq->special = NULL;
647 }
648
649 if (scsi_prot_sg_count(cmd))
650 scsi_free_sgtable(cmd->prot_sdb);
651}
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653/*
654 * Function: scsi_release_buffers()
655 *
656 * Purpose: Completion processing for block device I/O requests.
657 *
658 * Arguments: cmd - command that we are bailing.
659 *
660 * Lock status: Assumed that no lock is held upon entry.
661 *
662 * Returns: Nothing
663 *
664 * Notes: In the event that an upper level driver rejects a
665 * command, we must release resources allocated during
666 * the __init_io() function. Primarily this would involve
667 * the scatter-gather table, and potentially any bounce
668 * buffers.
669 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800670void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671{
James Bottomley79ed2422009-01-06 13:15:20 -0600672 __scsi_release_buffers(cmd, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800674EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100676static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
677{
678 int error = 0;
679
680 switch(host_byte(result)) {
681 case DID_TRANSPORT_FAILFAST:
682 error = -ENOLINK;
683 break;
684 case DID_TARGET_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000685 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100686 error = -EREMOTEIO;
687 break;
688 case DID_NEXUS_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000689 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100690 error = -EBADE;
691 break;
692 default:
693 error = -EIO;
694 break;
695 }
696
697 return error;
698}
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700/*
701 * Function: scsi_io_completion()
702 *
703 * Purpose: Completion processing for block device I/O requests.
704 *
705 * Arguments: cmd - command that is finished.
706 *
707 * Lock status: Assumed that no lock is held upon entry.
708 *
709 * Returns: Nothing
710 *
711 * Notes: This function is matched in terms of capabilities to
712 * the function that created the scatter-gather list.
713 * In other words, if there are no bounce buffers
714 * (the normal case for most drivers), we don't need
715 * the logic to deal with cleaning up afterwards.
716 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500717 * We must call scsi_end_request(). This will finish off
718 * the specified number of sectors. If we are done, the
719 * command block will be released and the queue function
720 * will be goosed. If we are not done then we have to
721 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500723 * a) We can call scsi_requeue_command(). The request
724 * will be unprepared and put back on the queue. Then
725 * a new command will be created for it. This should
726 * be used if we made forward progress, or if we want
727 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500729 * b) We can call scsi_queue_insert(). The request will
730 * be put back on the queue and retried using the same
731 * command as before, possibly after a delay.
732 *
733 * c) We can call blk_end_request() with -EIO to fail
734 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700736void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737{
738 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200739 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500741 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 struct scsi_sense_hdr sshdr;
743 int sense_valid = 0;
744 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500745 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
746 ACTION_DELAYED_RETRY} action;
747 char *description = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 if (result) {
750 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
751 if (sense_valid)
752 sense_deferred = scsi_sense_is_deferred(&sshdr);
753 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200754
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200755 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 req->errors = result;
757 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if (sense_valid && req->sense) {
759 /*
760 * SG_IO wants current and deferred errors
761 */
762 int len = 8 + cmd->sense_buffer[7];
763
764 if (len > SCSI_SENSE_BUFFERSIZE)
765 len = SCSI_SENSE_BUFFERSIZE;
766 memcpy(req->sense, cmd->sense_buffer, len);
767 req->sense_len = len;
768 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500769 if (!sense_deferred)
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100770 error = __scsi_error_from_host_byte(cmd, result);
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400771 }
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900772
773 req->resid_len = scsi_get_resid(cmd);
774
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200775 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900776 /*
777 * Bidi commands Must be complete as a whole,
778 * both sides at once.
779 */
780 req->next_rq->resid_len = scsi_in(cmd)->resid;
781
Boaz Harrosh63c43b02009-12-15 17:25:43 +0200782 scsi_release_buffers(cmd);
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900783 blk_end_request_all(req, 0);
784
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900785 scsi_next_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200786 return;
787 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 }
789
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200790 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
791 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 * Next deal with any sectors which we were able to correctly
795 * handle.
796 */
Tejun Heo83096eb2009-05-07 22:24:39 +0900797 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
James Bottomleyd6b0c532006-07-02 10:06:28 -0500798 "%d bytes done.\n",
Tejun Heo83096eb2009-05-07 22:24:39 +0900799 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
James Bottomleya9bddd72009-03-30 16:55:51 +0000801 /*
802 * Recovered errors need reporting, but they're always treated
803 * as success, so fiddle the result code here. For BLOCK_PC
804 * we already took a copy of the original into rq->errors which
805 * is what gets returned to the user
806 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500807 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
808 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
809 * print since caller wants ATA registers. Only occurs on
810 * SCSI ATA PASS_THROUGH commands when CK_COND=1
811 */
812 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
813 ;
814 else if (!(req->cmd_flags & REQ_QUIET))
James Bottomleya9bddd72009-03-30 16:55:51 +0000815 scsi_print_sense("", cmd);
816 result = 0;
817 /* BLOCK_PC may have set error */
818 error = 0;
819 }
820
821 /*
822 * A number of bytes were successfully read. If there
James Bottomleyd6b0c532006-07-02 10:06:28 -0500823 * are leftovers and there is some kind of error
824 * (result != 0), retry the rest.
825 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500826 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500827 return;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700828
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100829 error = __scsi_error_from_host_byte(cmd, result);
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500830
Alan Sternb60af5b2008-11-03 15:56:47 -0500831 if (host_byte(result) == DID_RESET) {
832 /* Third party bus reset or reset for error recovery
833 * reasons. Just retry the command and see what
834 * happens.
835 */
836 action = ACTION_RETRY;
837 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 switch (sshdr.sense_key) {
839 case UNIT_ATTENTION:
840 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700841 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 * and quietly refuse further access.
843 */
844 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500845 description = "Media Changed";
846 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700848 /* Must have been a power glitch, or a
849 * bus reset. Could not have been a
850 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500851 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700852 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500853 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 }
855 break;
856 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700857 /* If we had an ILLEGAL REQUEST returned, then
858 * we may have performed an unsupported
859 * command. The only thing this should be
860 * would be a ten byte read where only a six
861 * byte read was supported. Also, on a system
862 * where READ CAPACITY failed, we may have
863 * read past the end of the disk.
864 */
Jens Axboe26a68012005-11-29 21:03:34 +0100865 if ((cmd->device->use_10_for_rw &&
866 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 (cmd->cmnd[0] == READ_10 ||
868 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500869 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500871 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500872 } else if (sshdr.asc == 0x10) /* DIX */ {
873 description = "Host Data Integrity Failure";
874 action = ACTION_FAIL;
875 error = -EILSEQ;
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500876 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
877 } else if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
878 (cmd->cmnd[0] == UNMAP ||
879 cmd->cmnd[0] == WRITE_SAME_16 ||
880 cmd->cmnd[0] == WRITE_SAME)) {
881 description = "Discard failure";
882 action = ACTION_FAIL;
Martin K. Petersen66a651a2012-02-13 15:38:22 -0500883 error = -EREMOTEIO;
Alan Sternb60af5b2008-11-03 15:56:47 -0500884 } else
885 action = ACTION_FAIL;
886 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400887 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000888 action = ACTION_FAIL;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400889 if (sshdr.asc == 0x10) { /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500890 description = "Target Data Integrity Failure";
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500891 error = -EILSEQ;
James Bottomley126c09822009-02-19 21:48:54 +0000892 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 break;
894 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700895 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500896 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500898 if (sshdr.asc == 0x04) {
899 switch (sshdr.ascq) {
900 case 0x01: /* becoming ready */
901 case 0x04: /* format in progress */
902 case 0x05: /* rebuild in progress */
903 case 0x06: /* recalculation in progress */
904 case 0x07: /* operation in progress */
905 case 0x08: /* Long write in progress */
906 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -0500907 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -0500908 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500909 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -0500910 default:
911 description = "Device not ready";
912 action = ACTION_FAIL;
913 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500914 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500915 } else {
916 description = "Device not ready";
917 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500919 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700921 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -0500922 action = ACTION_FAIL;
923 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 default:
Alan Sternb60af5b2008-11-03 15:56:47 -0500925 description = "Unhandled sense code";
926 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 break;
928 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500929 } else {
930 description = "Unhandled error code";
931 action = ACTION_FAIL;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700932 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500933
934 switch (action) {
935 case ACTION_FAIL:
936 /* Give up and fail the remainder of the request */
James Bottomley79ed2422009-01-06 13:15:20 -0600937 scsi_release_buffers(cmd);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200938 if (!(req->cmd_flags & REQ_QUIET)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500939 if (description)
Alan Stern3dbf6a52008-12-15 10:31:28 -0500940 scmd_printk(KERN_INFO, cmd, "%s\n",
Alan Sternb60af5b2008-11-03 15:56:47 -0500941 description);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500942 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500943 if (driver_byte(result) & DRIVER_SENSE)
944 scsi_print_sense("", cmd);
Martin K. Petersen002b1eb2009-05-23 11:45:07 -0400945 scsi_print_command(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500946 }
Mike Christiead630822009-09-28 15:50:52 -0500947 if (blk_end_request_err(req, error))
Tejun Heoda6c5c72009-09-11 14:26:40 +0200948 scsi_requeue_command(q, cmd);
949 else
950 scsi_next_command(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500951 break;
952 case ACTION_REPREP:
953 /* Unprep the request and put it back at the head of the queue.
954 * A new command will be prepared and issued.
955 */
James Bottomley79ed2422009-01-06 13:15:20 -0600956 scsi_release_buffers(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500957 scsi_requeue_command(q, cmd);
958 break;
959 case ACTION_RETRY:
960 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -0600961 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500962 break;
963 case ACTION_DELAYED_RETRY:
964 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -0600965 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500966 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 }
968}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200970static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
971 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200973 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974
975 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +0100976 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200978 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
979 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -0400981 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
Christoph Hellwig3b003152006-11-04 20:10:55 +0100983 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984
985 /*
986 * Next, walk the list, and fill in the addresses and sizes of
987 * each segment.
988 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200989 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
990 BUG_ON(count > sdb->table.nents);
991 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +0900992 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +1100993 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200995
996/*
997 * Function: scsi_init_io()
998 *
999 * Purpose: SCSI I/O initialize function.
1000 *
1001 * Arguments: cmd - Command descriptor we wish to initialize
1002 *
1003 * Returns: 0 on success
1004 * BLKPREP_DEFER if the failure is retryable
1005 * BLKPREP_KILL if the failure is fatal
1006 */
1007int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1008{
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001009 struct request *rq = cmd->request;
1010
1011 int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001012 if (error)
1013 goto err_exit;
1014
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001015 if (blk_bidi_rq(rq)) {
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001016 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001017 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001018 if (!bidi_sdb) {
1019 error = BLKPREP_DEFER;
1020 goto err_exit;
1021 }
1022
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001023 rq->next_rq->special = bidi_sdb;
1024 error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001025 if (error)
1026 goto err_exit;
1027 }
1028
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001029 if (blk_integrity_rq(rq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001030 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1031 int ivecs, count;
1032
1033 BUG_ON(prot_sdb == NULL);
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001034 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001035
1036 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1037 error = BLKPREP_DEFER;
1038 goto err_exit;
1039 }
1040
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001041 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001042 prot_sdb->table.sgl);
1043 BUG_ON(unlikely(count > ivecs));
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001044 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001045
1046 cmd->prot_sdb = prot_sdb;
1047 cmd->prot_sdb->table.nents = count;
1048 }
1049
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001050 return BLKPREP_OK ;
1051
1052err_exit:
1053 scsi_release_buffers(cmd);
FUJITA Tomonori610a6342010-07-08 10:16:17 +02001054 cmd->request->special = NULL;
James Bottomley3a5c19c2010-08-16 10:06:26 -05001055 scsi_put_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001056 return error;
1057}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001058EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059
Christoph Hellwig3b003152006-11-04 20:10:55 +01001060static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1061 struct request *req)
1062{
1063 struct scsi_cmnd *cmd;
1064
1065 if (!req->special) {
1066 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1067 if (unlikely(!cmd))
1068 return NULL;
1069 req->special = cmd;
1070 } else {
1071 cmd = req->special;
1072 }
1073
1074 /* pull a tag out of the request if we have one */
1075 cmd->tag = req->tag;
1076 cmd->request = req;
1077
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001078 cmd->cmnd = req->cmd;
Martin K. Petersen72f7d322011-03-08 02:03:59 -05001079 cmd->prot_op = SCSI_PROT_NORMAL;
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001080
Christoph Hellwig3b003152006-11-04 20:10:55 +01001081 return cmd;
1082}
1083
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001084int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001085{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001086 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001087 int ret = scsi_prep_state_check(sdev, req);
1088
1089 if (ret != BLKPREP_OK)
1090 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001091
1092 cmd = scsi_get_cmd_from_req(sdev, req);
1093 if (unlikely(!cmd))
1094 return BLKPREP_DEFER;
1095
1096 /*
1097 * BLOCK_PC requests may transfer data, in which case they must
1098 * a bio attached to them. Or they might contain a SCSI command
1099 * that does not transfer data, in which case they may optionally
1100 * submit a request without an attached bio.
1101 */
1102 if (req->bio) {
1103 int ret;
1104
1105 BUG_ON(!req->nr_phys_segments);
1106
Boaz Harroshbb52d822007-12-13 16:14:27 -08001107 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001108 if (unlikely(ret))
1109 return ret;
1110 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001111 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001112
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001113 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001114 req->buffer = NULL;
1115 }
James Bottomley7b163182005-12-15 20:17:02 -06001116
James Bottomley7b163182005-12-15 20:17:02 -06001117 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001118 if (!blk_rq_bytes(req))
James Bottomley7b163182005-12-15 20:17:02 -06001119 cmd->sc_data_direction = DMA_NONE;
1120 else if (rq_data_dir(req) == WRITE)
1121 cmd->sc_data_direction = DMA_TO_DEVICE;
1122 else
1123 cmd->sc_data_direction = DMA_FROM_DEVICE;
1124
Tejun Heob0790412009-05-07 22:24:42 +09001125 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001126 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001127 return BLKPREP_OK;
1128}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001129EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001130
1131/*
1132 * Setup a REQ_TYPE_FS command. These are simple read/write request
1133 * from filesystems that still need to be translated to SCSI CDBs from
1134 * the ULD.
1135 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001136int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001137{
1138 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001139 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001140
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001141 if (ret != BLKPREP_OK)
1142 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001143
1144 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1145 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1146 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1147 if (ret != BLKPREP_OK)
1148 return ret;
1149 }
1150
Christoph Hellwig3b003152006-11-04 20:10:55 +01001151 /*
1152 * Filesystem requests must transfer data.
1153 */
1154 BUG_ON(!req->nr_phys_segments);
1155
1156 cmd = scsi_get_cmd_from_req(sdev, req);
1157 if (unlikely(!cmd))
1158 return BLKPREP_DEFER;
1159
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001160 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001161 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001162}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001163EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001164
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001165int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001167 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168
1169 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001170 * If the device is not in running state we will reject some
1171 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001174 switch (sdev->sdev_state) {
1175 case SDEV_OFFLINE:
1176 /*
1177 * If the device is offline we refuse to process any
1178 * commands. The device must be brought online
1179 * before trying any recovery commands.
1180 */
1181 sdev_printk(KERN_ERR, sdev,
1182 "rejecting I/O to offline device\n");
1183 ret = BLKPREP_KILL;
1184 break;
1185 case SDEV_DEL:
1186 /*
1187 * If the device is fully deleted, we refuse to
1188 * process any commands as well.
1189 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001190 sdev_printk(KERN_ERR, sdev,
1191 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001192 ret = BLKPREP_KILL;
1193 break;
1194 case SDEV_QUIESCE:
1195 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001196 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001197 /*
1198 * If the devices is blocked we defer normal commands.
1199 */
1200 if (!(req->cmd_flags & REQ_PREEMPT))
1201 ret = BLKPREP_DEFER;
1202 break;
1203 default:
1204 /*
1205 * For any other not fully online state we only allow
1206 * special commands. In particular any user initiated
1207 * command is not allowed.
1208 */
1209 if (!(req->cmd_flags & REQ_PREEMPT))
1210 ret = BLKPREP_KILL;
1211 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001214 return ret;
1215}
1216EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001218int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1219{
1220 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221
Christoph Hellwig3b003152006-11-04 20:10:55 +01001222 switch (ret) {
1223 case BLKPREP_KILL:
1224 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001225 /* release the command and kill it */
1226 if (req->special) {
1227 struct scsi_cmnd *cmd = req->special;
1228 scsi_release_buffers(cmd);
1229 scsi_put_command(cmd);
1230 req->special = NULL;
1231 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001232 break;
1233 case BLKPREP_DEFER:
1234 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001235 * If we defer, the blk_peek_request() returns NULL, but the
Jens Axboea488e742010-04-16 21:13:15 +02001236 * queue must be restarted, so we schedule a callback to happen
1237 * shortly.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001238 */
1239 if (sdev->device_busy == 0)
Jens Axboea488e742010-04-16 21:13:15 +02001240 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001241 break;
1242 default:
1243 req->cmd_flags |= REQ_DONTPREP;
1244 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245
Christoph Hellwig3b003152006-11-04 20:10:55 +01001246 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001248EXPORT_SYMBOL(scsi_prep_return);
1249
James Bottomley751bf4d2008-01-02 11:14:30 -06001250int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001251{
1252 struct scsi_device *sdev = q->queuedata;
1253 int ret = BLKPREP_KILL;
1254
1255 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1256 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1257 return scsi_prep_return(q, req, ret);
1258}
Hannes Reineckeb3912772009-06-18 09:57:18 +02001259EXPORT_SYMBOL(scsi_prep_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260
1261/*
1262 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1263 * return 0.
1264 *
1265 * Called with the queue_lock held.
1266 */
1267static inline int scsi_dev_queue_ready(struct request_queue *q,
1268 struct scsi_device *sdev)
1269{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 if (sdev->device_busy == 0 && sdev->device_blocked) {
1271 /*
1272 * unblock after device_blocked iterates to zero
1273 */
1274 if (--sdev->device_blocked == 0) {
1275 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001276 sdev_printk(KERN_INFO, sdev,
1277 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 } else {
Jens Axboea488e742010-04-16 21:13:15 +02001279 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 return 0;
1281 }
1282 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001283 if (scsi_device_is_busy(sdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 return 0;
1285
1286 return 1;
1287}
1288
Mike Christief0c0a372008-08-17 15:24:38 -05001289
1290/*
1291 * scsi_target_queue_ready: checks if there we can send commands to target
1292 * @sdev: scsi device on starget to check.
1293 *
1294 * Called with the host lock held.
1295 */
1296static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1297 struct scsi_device *sdev)
1298{
1299 struct scsi_target *starget = scsi_target(sdev);
1300
1301 if (starget->single_lun) {
1302 if (starget->starget_sdev_user &&
1303 starget->starget_sdev_user != sdev)
1304 return 0;
1305 starget->starget_sdev_user = sdev;
1306 }
1307
1308 if (starget->target_busy == 0 && starget->target_blocked) {
1309 /*
1310 * unblock after target_blocked iterates to zero
1311 */
1312 if (--starget->target_blocked == 0) {
1313 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1314 "unblocking target at zero depth\n"));
Mike Christieb4efdd52009-04-09 15:57:10 -05001315 } else
Mike Christief0c0a372008-08-17 15:24:38 -05001316 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001317 }
1318
1319 if (scsi_target_is_busy(starget)) {
Shaohua Li466c08c2012-01-10 11:27:01 +08001320 list_move_tail(&sdev->starved_entry, &shost->starved_list);
Hillf Dantonfd01a662010-12-16 14:26:37 -06001321 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001322 }
1323
Mike Christief0c0a372008-08-17 15:24:38 -05001324 return 1;
1325}
1326
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327/*
1328 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1329 * return 0. We must end up running the queue again whenever 0 is
1330 * returned, else IO can hang.
1331 *
1332 * Called with host_lock held.
1333 */
1334static inline int scsi_host_queue_ready(struct request_queue *q,
1335 struct Scsi_Host *shost,
1336 struct scsi_device *sdev)
1337{
James Bottomley939647e2005-09-18 15:05:20 -05001338 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 return 0;
1340 if (shost->host_busy == 0 && shost->host_blocked) {
1341 /*
1342 * unblock after host_blocked iterates to zero
1343 */
1344 if (--shost->host_blocked == 0) {
1345 SCSI_LOG_MLQUEUE(3,
1346 printk("scsi%d unblocking host at zero depth\n",
1347 shost->host_no));
1348 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 return 0;
1350 }
1351 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001352 if (scsi_host_is_busy(shost)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 if (list_empty(&sdev->starved_entry))
1354 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1355 return 0;
1356 }
1357
1358 /* We're OK to process the command, so we can't be starved */
1359 if (!list_empty(&sdev->starved_entry))
1360 list_del_init(&sdev->starved_entry);
1361
1362 return 1;
1363}
1364
1365/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001366 * Busy state exporting function for request stacking drivers.
1367 *
1368 * For efficiency, no lock is taken to check the busy state of
1369 * shost/starget/sdev, since the returned value is not guaranteed and
1370 * may be changed after request stacking drivers call the function,
1371 * regardless of taking lock or not.
1372 *
1373 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1374 * (e.g. !sdev), scsi needs to return 'not busy'.
1375 * Otherwise, request stacking drivers may hold requests forever.
1376 */
1377static int scsi_lld_busy(struct request_queue *q)
1378{
1379 struct scsi_device *sdev = q->queuedata;
1380 struct Scsi_Host *shost;
1381 struct scsi_target *starget;
1382
1383 if (!sdev)
1384 return 0;
1385
1386 shost = sdev->host;
1387 starget = scsi_target(sdev);
1388
1389 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) ||
1390 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev))
1391 return 1;
1392
1393 return 0;
1394}
1395
1396/*
James Bottomleye91442b2005-09-09 10:44:16 -05001397 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 */
Jens Axboe165125e2007-07-24 09:28:11 +02001399static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400{
James Bottomleye91442b2005-09-09 10:44:16 -05001401 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001402 struct scsi_device *sdev;
1403 struct scsi_target *starget;
1404 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405
Tejun Heo9934c8c2009-05-08 11:54:16 +09001406 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001407
Hannes Reinecke74571812011-11-09 08:39:24 +01001408 scmd_printk(KERN_INFO, cmd, "killing request\n");
1409
Jiri Slaby03b14702009-09-23 16:15:35 +02001410 sdev = cmd->device;
1411 starget = scsi_target(sdev);
1412 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001413 scsi_init_cmd_errh(cmd);
1414 cmd->result = DID_NO_CONNECT << 16;
1415 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001416
1417 /*
1418 * SCSI request completion path will do scsi_device_unbusy(),
1419 * bump busy counts. To bump the counters, we need to dance
1420 * with the locks as normal issue path does.
1421 */
1422 sdev->device_busy++;
1423 spin_unlock(sdev->request_queue->queue_lock);
1424 spin_lock(shost->host_lock);
1425 shost->host_busy++;
Mike Christief0c0a372008-08-17 15:24:38 -05001426 starget->target_busy++;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001427 spin_unlock(shost->host_lock);
1428 spin_lock(sdev->request_queue->queue_lock);
1429
Jens Axboe242f9dc2008-09-14 05:55:09 -07001430 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431}
1432
Jens Axboe1aea6432006-01-09 16:03:03 +01001433static void scsi_softirq_done(struct request *rq)
1434{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001435 struct scsi_cmnd *cmd = rq->special;
1436 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001437 int disposition;
1438
1439 INIT_LIST_HEAD(&cmd->eh_entry);
1440
Jens Axboe242f9dc2008-09-14 05:55:09 -07001441 atomic_inc(&cmd->device->iodone_cnt);
1442 if (cmd->result)
1443 atomic_inc(&cmd->device->ioerr_cnt);
1444
Jens Axboe1aea6432006-01-09 16:03:03 +01001445 disposition = scsi_decide_disposition(cmd);
1446 if (disposition != SUCCESS &&
1447 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1448 sdev_printk(KERN_ERR, cmd->device,
1449 "timing out command, waited %lus\n",
1450 wait_for/HZ);
1451 disposition = SUCCESS;
1452 }
1453
1454 scsi_log_completion(cmd, disposition);
1455
1456 switch (disposition) {
1457 case SUCCESS:
1458 scsi_finish_command(cmd);
1459 break;
1460 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001461 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001462 break;
1463 case ADD_TO_MLQUEUE:
1464 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1465 break;
1466 default:
1467 if (!scsi_eh_scmd_add(cmd, 0))
1468 scsi_finish_command(cmd);
1469 }
1470}
1471
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472/*
1473 * Function: scsi_request_fn()
1474 *
1475 * Purpose: Main strategy routine for SCSI.
1476 *
1477 * Arguments: q - Pointer to actual queue.
1478 *
1479 * Returns: Nothing
1480 *
1481 * Lock status: IO request lock assumed to be held when called.
1482 */
1483static void scsi_request_fn(struct request_queue *q)
1484{
1485 struct scsi_device *sdev = q->queuedata;
1486 struct Scsi_Host *shost;
1487 struct scsi_cmnd *cmd;
1488 struct request *req;
1489
1490 if (!sdev) {
Tejun Heo9934c8c2009-05-08 11:54:16 +09001491 while ((req = blk_peek_request(q)) != NULL)
James Bottomleye91442b2005-09-09 10:44:16 -05001492 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 return;
1494 }
1495
1496 if(!get_device(&sdev->sdev_gendev))
1497 /* We must be tearing the block queue down already */
1498 return;
1499
1500 /*
1501 * To start with, we keep looping until the queue is empty, or until
1502 * the host is no longer able to accept any more requests.
1503 */
1504 shost = sdev->host;
Jens Axboea488e742010-04-16 21:13:15 +02001505 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506 int rtn;
1507 /*
1508 * get next queueable request. We do this early to make sure
1509 * that the request is fully prepared even if we cannot
1510 * accept it.
1511 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001512 req = blk_peek_request(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001513 if (!req || !scsi_dev_queue_ready(q, sdev))
1514 break;
1515
1516 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001517 sdev_printk(KERN_ERR, sdev,
1518 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001519 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001520 continue;
1521 }
1522
1523
1524 /*
1525 * Remove the request from the request list.
1526 */
1527 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001528 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529 sdev->device_busy++;
1530
1531 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001532 cmd = req->special;
1533 if (unlikely(cmd == NULL)) {
1534 printk(KERN_CRIT "impossible request in %s.\n"
1535 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001536 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001537 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001538 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001539 BUG();
1540 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 spin_lock(shost->host_lock);
1542
Mike Christieecefe8a2008-07-11 19:50:35 -05001543 /*
1544 * We hit this when the driver is using a host wide
1545 * tag map. For device level tag maps the queue_depth check
1546 * in the device ready fn would prevent us from trying
1547 * to allocate a tag. Since the map is a shared host resource
1548 * we add the dev to the starved list so it eventually gets
1549 * a run when a tag is freed.
1550 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001551 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001552 if (list_empty(&sdev->starved_entry))
1553 list_add_tail(&sdev->starved_entry,
1554 &shost->starved_list);
1555 goto not_ready;
1556 }
1557
Mike Christief0c0a372008-08-17 15:24:38 -05001558 if (!scsi_target_queue_ready(shost, sdev))
1559 goto not_ready;
1560
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 if (!scsi_host_queue_ready(q, shost, sdev))
1562 goto not_ready;
Mike Christief0c0a372008-08-17 15:24:38 -05001563
1564 scsi_target(sdev)->target_busy++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 shost->host_busy++;
1566
1567 /*
1568 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1569 * take the lock again.
1570 */
1571 spin_unlock_irq(shost->host_lock);
1572
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 /*
1574 * Finally, initialize any error handling parameters, and set up
1575 * the timers for timeouts.
1576 */
1577 scsi_init_cmd_errh(cmd);
1578
1579 /*
1580 * Dispatch the command to the low-level driver.
1581 */
1582 rtn = scsi_dispatch_cmd(cmd);
1583 spin_lock_irq(q->queue_lock);
Jens Axboea488e742010-04-16 21:13:15 +02001584 if (rtn)
1585 goto out_delay;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586 }
1587
1588 goto out;
1589
1590 not_ready:
1591 spin_unlock_irq(shost->host_lock);
1592
1593 /*
1594 * lock q, handle tag, requeue req, and decrement device_busy. We
1595 * must return with queue_lock held.
1596 *
1597 * Decrementing device_busy without checking it is OK, as all such
1598 * cases (host limits or settings) should run the queue at some
1599 * later time.
1600 */
1601 spin_lock_irq(q->queue_lock);
1602 blk_requeue_request(q, req);
1603 sdev->device_busy--;
Jens Axboea488e742010-04-16 21:13:15 +02001604out_delay:
1605 if (sdev->device_busy == 0)
1606 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1607out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608 /* must be careful here...if we trigger the ->remove() function
1609 * we cannot be holding the q lock */
1610 spin_unlock_irq(q->queue_lock);
1611 put_device(&sdev->sdev_gendev);
1612 spin_lock_irq(q->queue_lock);
1613}
1614
1615u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1616{
1617 struct device *host_dev;
1618 u64 bounce_limit = 0xffffffff;
1619
1620 if (shost->unchecked_isa_dma)
1621 return BLK_BOUNCE_ISA;
1622 /*
1623 * Platforms with virtual-DMA translation
1624 * hardware have no practical limit.
1625 */
1626 if (!PCI_DMA_BUS_IS_PHYS)
1627 return BLK_BOUNCE_ANY;
1628
1629 host_dev = scsi_get_device(shost);
1630 if (host_dev && host_dev->dma_mask)
1631 bounce_limit = *host_dev->dma_mask;
1632
1633 return bounce_limit;
1634}
1635EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1636
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001637struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1638 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001641 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001643 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644 if (!q)
1645 return NULL;
1646
Jens Axboea8474ce2007-08-07 09:02:51 +02001647 /*
1648 * this limit is imposed by hardware restrictions
1649 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05001650 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1651 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02001652
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001653 if (scsi_host_prot_dma(shost)) {
1654 shost->sg_prot_tablesize =
1655 min_not_zero(shost->sg_prot_tablesize,
1656 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1657 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1658 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1659 }
1660
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05001661 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1663 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001664 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001666 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1667
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668 if (!shost->use_clustering)
Martin K. Petersene692cb62010-12-01 19:41:49 +01001669 q->limits.cluster = 0;
James Bottomley465ff312008-01-01 10:00:10 -06001670
1671 /*
1672 * set a reasonable default alignment on word boundaries: the
1673 * host and device may alter it using
1674 * blk_queue_update_dma_alignment() later.
1675 */
1676 blk_queue_dma_alignment(q, 0x03);
1677
Linus Torvalds1da177e2005-04-16 15:20:36 -07001678 return q;
1679}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001680EXPORT_SYMBOL(__scsi_alloc_queue);
1681
1682struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1683{
1684 struct request_queue *q;
1685
1686 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1687 if (!q)
1688 return NULL;
1689
1690 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001691 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001692 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001693 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001694 return q;
1695}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696
1697void scsi_free_queue(struct request_queue *q)
1698{
Bart Van Assche33085112011-09-23 19:48:18 +02001699 unsigned long flags;
1700
1701 WARN_ON(q->queuedata);
1702
1703 /* cause scsi_request_fn() to kill all non-finished requests */
1704 spin_lock_irqsave(q->queue_lock, flags);
1705 q->request_fn(q);
1706 spin_unlock_irqrestore(q->queue_lock, flags);
1707
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708 blk_cleanup_queue(q);
1709}
1710
1711/*
1712 * Function: scsi_block_requests()
1713 *
1714 * Purpose: Utility function used by low-level drivers to prevent further
1715 * commands from being queued to the device.
1716 *
1717 * Arguments: shost - Host in question
1718 *
1719 * Returns: Nothing
1720 *
1721 * Lock status: No locks are assumed held.
1722 *
1723 * Notes: There is no timer nor any other means by which the requests
1724 * get unblocked other than the low-level driver calling
1725 * scsi_unblock_requests().
1726 */
1727void scsi_block_requests(struct Scsi_Host *shost)
1728{
1729 shost->host_self_blocked = 1;
1730}
1731EXPORT_SYMBOL(scsi_block_requests);
1732
1733/*
1734 * Function: scsi_unblock_requests()
1735 *
1736 * Purpose: Utility function used by low-level drivers to allow further
1737 * commands from being queued to the device.
1738 *
1739 * Arguments: shost - Host in question
1740 *
1741 * Returns: Nothing
1742 *
1743 * Lock status: No locks are assumed held.
1744 *
1745 * Notes: There is no timer nor any other means by which the requests
1746 * get unblocked other than the low-level driver calling
1747 * scsi_unblock_requests().
1748 *
1749 * This is done as an API function so that changes to the
1750 * internals of the scsi mid-layer won't require wholesale
1751 * changes to drivers that use this feature.
1752 */
1753void scsi_unblock_requests(struct Scsi_Host *shost)
1754{
1755 shost->host_self_blocked = 0;
1756 scsi_run_host_queues(shost);
1757}
1758EXPORT_SYMBOL(scsi_unblock_requests);
1759
1760int __init scsi_init_queue(void)
1761{
1762 int i;
1763
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001764 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1765 sizeof(struct scsi_data_buffer),
1766 0, 0, NULL);
1767 if (!scsi_sdb_cache) {
1768 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09001769 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001770 }
1771
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1773 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1774 int size = sgp->size * sizeof(struct scatterlist);
1775
1776 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001777 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 if (!sgp->slab) {
1779 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1780 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001781 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 }
1783
Matthew Dobson93d23412006-03-26 01:37:50 -08001784 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1785 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 if (!sgp->pool) {
1787 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1788 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001789 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 }
1791 }
1792
1793 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001794
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001795cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001796 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1797 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1798 if (sgp->pool)
1799 mempool_destroy(sgp->pool);
1800 if (sgp->slab)
1801 kmem_cache_destroy(sgp->slab);
1802 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001803 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001804
1805 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806}
1807
1808void scsi_exit_queue(void)
1809{
1810 int i;
1811
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001812 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001813
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1815 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1816 mempool_destroy(sgp->pool);
1817 kmem_cache_destroy(sgp->slab);
1818 }
1819}
James Bottomley5baba832006-03-18 14:10:35 -06001820
1821/**
1822 * scsi_mode_select - issue a mode select
1823 * @sdev: SCSI device to be queried
1824 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1825 * @sp: Save page bit (0 == don't save, 1 == save)
1826 * @modepage: mode page being requested
1827 * @buffer: request buffer (may not be smaller than eight bytes)
1828 * @len: length of request buffer.
1829 * @timeout: command timeout
1830 * @retries: number of retries before failing
1831 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001832 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001833 * must be SCSI_SENSE_BUFFERSIZE big.
1834 *
1835 * Returns zero if successful; negative error number or scsi
1836 * status on error
1837 *
1838 */
1839int
1840scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1841 unsigned char *buffer, int len, int timeout, int retries,
1842 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1843{
1844 unsigned char cmd[10];
1845 unsigned char *real_buffer;
1846 int ret;
1847
1848 memset(cmd, 0, sizeof(cmd));
1849 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1850
1851 if (sdev->use_10_for_ms) {
1852 if (len > 65535)
1853 return -EINVAL;
1854 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1855 if (!real_buffer)
1856 return -ENOMEM;
1857 memcpy(real_buffer + 8, buffer, len);
1858 len += 8;
1859 real_buffer[0] = 0;
1860 real_buffer[1] = 0;
1861 real_buffer[2] = data->medium_type;
1862 real_buffer[3] = data->device_specific;
1863 real_buffer[4] = data->longlba ? 0x01 : 0;
1864 real_buffer[5] = 0;
1865 real_buffer[6] = data->block_descriptor_length >> 8;
1866 real_buffer[7] = data->block_descriptor_length;
1867
1868 cmd[0] = MODE_SELECT_10;
1869 cmd[7] = len >> 8;
1870 cmd[8] = len;
1871 } else {
1872 if (len > 255 || data->block_descriptor_length > 255 ||
1873 data->longlba)
1874 return -EINVAL;
1875
1876 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1877 if (!real_buffer)
1878 return -ENOMEM;
1879 memcpy(real_buffer + 4, buffer, len);
1880 len += 4;
1881 real_buffer[0] = 0;
1882 real_buffer[1] = data->medium_type;
1883 real_buffer[2] = data->device_specific;
1884 real_buffer[3] = data->block_descriptor_length;
1885
1886
1887 cmd[0] = MODE_SELECT;
1888 cmd[4] = len;
1889 }
1890
1891 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001892 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06001893 kfree(real_buffer);
1894 return ret;
1895}
1896EXPORT_SYMBOL_GPL(scsi_mode_select);
1897
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898/**
Rob Landleyeb448202007-11-03 13:30:39 -05001899 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001900 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 * @dbd: set if mode sense will allow block descriptors to be returned
1902 * @modepage: mode page being requested
1903 * @buffer: request buffer (may not be smaller than eight bytes)
1904 * @len: length of request buffer.
1905 * @timeout: command timeout
1906 * @retries: number of retries before failing
1907 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001908 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001909 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 *
1911 * Returns zero if unsuccessful, or the header offset (either 4
1912 * or 8 depending on whether a six or ten byte command was
1913 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001914 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915int
James Bottomley1cf72692005-08-28 11:27:01 -05001916scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001918 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1919{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 unsigned char cmd[12];
1921 int use_10_for_ms;
1922 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001923 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001924 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925
1926 memset(data, 0, sizeof(*data));
1927 memset(&cmd[0], 0, 12);
1928 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1929 cmd[2] = modepage;
1930
James Bottomleyea73a9f2005-08-28 11:33:52 -05001931 /* caller might not be interested in sense, but we need it */
1932 if (!sshdr)
1933 sshdr = &my_sshdr;
1934
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001936 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937
1938 if (use_10_for_ms) {
1939 if (len < 8)
1940 len = 8;
1941
1942 cmd[0] = MODE_SENSE_10;
1943 cmd[8] = len;
1944 header_length = 8;
1945 } else {
1946 if (len < 4)
1947 len = 4;
1948
1949 cmd[0] = MODE_SENSE;
1950 cmd[4] = len;
1951 header_length = 4;
1952 }
1953
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 memset(buffer, 0, len);
1955
James Bottomley1cf72692005-08-28 11:27:01 -05001956 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001957 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958
1959 /* This code looks awful: what it's doing is making sure an
1960 * ILLEGAL REQUEST sense return identifies the actual command
1961 * byte as the problem. MODE_SENSE commands can return
1962 * ILLEGAL REQUEST if the code page isn't supported */
1963
James Bottomley1cf72692005-08-28 11:27:01 -05001964 if (use_10_for_ms && !scsi_status_is_good(result) &&
1965 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001966 if (scsi_sense_valid(sshdr)) {
1967 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1968 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001969 /*
1970 * Invalid command operation code
1971 */
James Bottomley1cf72692005-08-28 11:27:01 -05001972 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 goto retry;
1974 }
1975 }
1976 }
1977
James Bottomley1cf72692005-08-28 11:27:01 -05001978 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001979 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1980 (modepage == 6 || modepage == 8))) {
1981 /* Initio breakage? */
1982 header_length = 0;
1983 data->length = 13;
1984 data->medium_type = 0;
1985 data->device_specific = 0;
1986 data->longlba = 0;
1987 data->block_descriptor_length = 0;
1988 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989 data->length = buffer[0]*256 + buffer[1] + 2;
1990 data->medium_type = buffer[2];
1991 data->device_specific = buffer[3];
1992 data->longlba = buffer[4] & 0x01;
1993 data->block_descriptor_length = buffer[6]*256
1994 + buffer[7];
1995 } else {
1996 data->length = buffer[0] + 1;
1997 data->medium_type = buffer[1];
1998 data->device_specific = buffer[2];
1999 data->block_descriptor_length = buffer[3];
2000 }
Al Viro6d73c852006-02-23 02:03:16 +01002001 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002002 }
2003
James Bottomley1cf72692005-08-28 11:27:01 -05002004 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005}
2006EXPORT_SYMBOL(scsi_mode_sense);
2007
James Bottomley001aac22007-12-02 19:10:40 +02002008/**
2009 * scsi_test_unit_ready - test if unit is ready
2010 * @sdev: scsi device to change the state of.
2011 * @timeout: command timeout
2012 * @retries: number of retries before failing
2013 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2014 * returning sense. Make sure that this is cleared before passing
2015 * in.
2016 *
2017 * Returns zero if unsuccessful or an error if TUR failed. For
Tejun Heo9f8a2c22010-12-08 20:57:40 +01002018 * removable media, UNIT_ATTENTION sets ->changed flag.
James Bottomley001aac22007-12-02 19:10:40 +02002019 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020int
James Bottomley001aac22007-12-02 19:10:40 +02002021scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2022 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024 char cmd[] = {
2025 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2026 };
James Bottomley001aac22007-12-02 19:10:40 +02002027 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002029
2030 if (!sshdr_external)
2031 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2032 else
2033 sshdr = sshdr_external;
2034
2035 /* try to eat the UNIT_ATTENTION if there are enough retries */
2036 do {
2037 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002038 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002039 if (sdev->removable && scsi_sense_valid(sshdr) &&
2040 sshdr->sense_key == UNIT_ATTENTION)
2041 sdev->changed = 1;
2042 } while (scsi_sense_valid(sshdr) &&
2043 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002044
James Bottomley001aac22007-12-02 19:10:40 +02002045 if (!sshdr_external)
2046 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047 return result;
2048}
2049EXPORT_SYMBOL(scsi_test_unit_ready);
2050
2051/**
Rob Landleyeb448202007-11-03 13:30:39 -05002052 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002053 * @sdev: scsi device to change the state of.
2054 * @state: state to change to.
2055 *
2056 * Returns zero if unsuccessful or an error if the requested
2057 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002058 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002059int
2060scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2061{
2062 enum scsi_device_state oldstate = sdev->sdev_state;
2063
2064 if (state == oldstate)
2065 return 0;
2066
2067 switch (state) {
2068 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002069 switch (oldstate) {
2070 case SDEV_CREATED_BLOCK:
2071 break;
2072 default:
2073 goto illegal;
2074 }
2075 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002076
2077 case SDEV_RUNNING:
2078 switch (oldstate) {
2079 case SDEV_CREATED:
2080 case SDEV_OFFLINE:
2081 case SDEV_QUIESCE:
2082 case SDEV_BLOCK:
2083 break;
2084 default:
2085 goto illegal;
2086 }
2087 break;
2088
2089 case SDEV_QUIESCE:
2090 switch (oldstate) {
2091 case SDEV_RUNNING:
2092 case SDEV_OFFLINE:
2093 break;
2094 default:
2095 goto illegal;
2096 }
2097 break;
2098
2099 case SDEV_OFFLINE:
2100 switch (oldstate) {
2101 case SDEV_CREATED:
2102 case SDEV_RUNNING:
2103 case SDEV_QUIESCE:
2104 case SDEV_BLOCK:
2105 break;
2106 default:
2107 goto illegal;
2108 }
2109 break;
2110
2111 case SDEV_BLOCK:
2112 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002113 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002114 case SDEV_CREATED_BLOCK:
2115 break;
2116 default:
2117 goto illegal;
2118 }
2119 break;
2120
2121 case SDEV_CREATED_BLOCK:
2122 switch (oldstate) {
2123 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 break;
2125 default:
2126 goto illegal;
2127 }
2128 break;
2129
2130 case SDEV_CANCEL:
2131 switch (oldstate) {
2132 case SDEV_CREATED:
2133 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002134 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 case SDEV_OFFLINE:
2136 case SDEV_BLOCK:
2137 break;
2138 default:
2139 goto illegal;
2140 }
2141 break;
2142
2143 case SDEV_DEL:
2144 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002145 case SDEV_CREATED:
2146 case SDEV_RUNNING:
2147 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148 case SDEV_CANCEL:
2149 break;
2150 default:
2151 goto illegal;
2152 }
2153 break;
2154
2155 }
2156 sdev->sdev_state = state;
2157 return 0;
2158
2159 illegal:
2160 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002161 sdev_printk(KERN_ERR, sdev,
2162 "Illegal state transition %s->%s\n",
2163 scsi_device_state_name(oldstate),
2164 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165 );
2166 return -EINVAL;
2167}
2168EXPORT_SYMBOL(scsi_device_set_state);
2169
2170/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002171 * sdev_evt_emit - emit a single SCSI device uevent
2172 * @sdev: associated SCSI device
2173 * @evt: event to emit
2174 *
2175 * Send a single uevent (scsi_event) to the associated scsi_device.
2176 */
2177static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2178{
2179 int idx = 0;
2180 char *envp[3];
2181
2182 switch (evt->evt_type) {
2183 case SDEV_EVT_MEDIA_CHANGE:
2184 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2185 break;
2186
2187 default:
2188 /* do nothing */
2189 break;
2190 }
2191
2192 envp[idx++] = NULL;
2193
2194 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2195}
2196
2197/**
2198 * sdev_evt_thread - send a uevent for each scsi event
2199 * @work: work struct for scsi_device
2200 *
2201 * Dispatch queued events to their associated scsi_device kobjects
2202 * as uevents.
2203 */
2204void scsi_evt_thread(struct work_struct *work)
2205{
2206 struct scsi_device *sdev;
2207 LIST_HEAD(event_list);
2208
2209 sdev = container_of(work, struct scsi_device, event_work);
2210
2211 while (1) {
2212 struct scsi_event *evt;
2213 struct list_head *this, *tmp;
2214 unsigned long flags;
2215
2216 spin_lock_irqsave(&sdev->list_lock, flags);
2217 list_splice_init(&sdev->event_list, &event_list);
2218 spin_unlock_irqrestore(&sdev->list_lock, flags);
2219
2220 if (list_empty(&event_list))
2221 break;
2222
2223 list_for_each_safe(this, tmp, &event_list) {
2224 evt = list_entry(this, struct scsi_event, node);
2225 list_del(&evt->node);
2226 scsi_evt_emit(sdev, evt);
2227 kfree(evt);
2228 }
2229 }
2230}
2231
2232/**
2233 * sdev_evt_send - send asserted event to uevent thread
2234 * @sdev: scsi_device event occurred on
2235 * @evt: event to send
2236 *
2237 * Assert scsi device event asynchronously.
2238 */
2239void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2240{
2241 unsigned long flags;
2242
Kay Sievers4d1566e2008-03-19 13:04:47 +01002243#if 0
2244 /* FIXME: currently this check eliminates all media change events
2245 * for polled devices. Need to update to discriminate between AN
2246 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002247 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2248 kfree(evt);
2249 return;
2250 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002251#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002252
2253 spin_lock_irqsave(&sdev->list_lock, flags);
2254 list_add_tail(&evt->node, &sdev->event_list);
2255 schedule_work(&sdev->event_work);
2256 spin_unlock_irqrestore(&sdev->list_lock, flags);
2257}
2258EXPORT_SYMBOL_GPL(sdev_evt_send);
2259
2260/**
2261 * sdev_evt_alloc - allocate a new scsi event
2262 * @evt_type: type of event to allocate
2263 * @gfpflags: GFP flags for allocation
2264 *
2265 * Allocates and returns a new scsi_event.
2266 */
2267struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2268 gfp_t gfpflags)
2269{
2270 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2271 if (!evt)
2272 return NULL;
2273
2274 evt->evt_type = evt_type;
2275 INIT_LIST_HEAD(&evt->node);
2276
2277 /* evt_type-specific initialization, if any */
2278 switch (evt_type) {
2279 case SDEV_EVT_MEDIA_CHANGE:
2280 default:
2281 /* do nothing */
2282 break;
2283 }
2284
2285 return evt;
2286}
2287EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2288
2289/**
2290 * sdev_evt_send_simple - send asserted event to uevent thread
2291 * @sdev: scsi_device event occurred on
2292 * @evt_type: type of event to send
2293 * @gfpflags: GFP flags for allocation
2294 *
2295 * Assert scsi device event asynchronously, given an event type.
2296 */
2297void sdev_evt_send_simple(struct scsi_device *sdev,
2298 enum scsi_device_event evt_type, gfp_t gfpflags)
2299{
2300 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2301 if (!evt) {
2302 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2303 evt_type);
2304 return;
2305 }
2306
2307 sdev_evt_send(sdev, evt);
2308}
2309EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2310
2311/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312 * scsi_device_quiesce - Block user issued commands.
2313 * @sdev: scsi device to quiesce.
2314 *
2315 * This works by trying to transition to the SDEV_QUIESCE state
2316 * (which must be a legal transition). When the device is in this
2317 * state, only special requests will be accepted, all others will
2318 * be deferred. Since special requests may also be requeued requests,
2319 * a successful return doesn't guarantee the device will be
2320 * totally quiescent.
2321 *
2322 * Must be called with user context, may sleep.
2323 *
2324 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002325 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326int
2327scsi_device_quiesce(struct scsi_device *sdev)
2328{
2329 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2330 if (err)
2331 return err;
2332
2333 scsi_run_queue(sdev->request_queue);
2334 while (sdev->device_busy) {
2335 msleep_interruptible(200);
2336 scsi_run_queue(sdev->request_queue);
2337 }
2338 return 0;
2339}
2340EXPORT_SYMBOL(scsi_device_quiesce);
2341
2342/**
2343 * scsi_device_resume - Restart user issued commands to a quiesced device.
2344 * @sdev: scsi device to resume.
2345 *
2346 * Moves the device from quiesced back to running and restarts the
2347 * queues.
2348 *
2349 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002350 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002351void
2352scsi_device_resume(struct scsi_device *sdev)
2353{
2354 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2355 return;
2356 scsi_run_queue(sdev->request_queue);
2357}
2358EXPORT_SYMBOL(scsi_device_resume);
2359
2360static void
2361device_quiesce_fn(struct scsi_device *sdev, void *data)
2362{
2363 scsi_device_quiesce(sdev);
2364}
2365
2366void
2367scsi_target_quiesce(struct scsi_target *starget)
2368{
2369 starget_for_each_device(starget, NULL, device_quiesce_fn);
2370}
2371EXPORT_SYMBOL(scsi_target_quiesce);
2372
2373static void
2374device_resume_fn(struct scsi_device *sdev, void *data)
2375{
2376 scsi_device_resume(sdev);
2377}
2378
2379void
2380scsi_target_resume(struct scsi_target *starget)
2381{
2382 starget_for_each_device(starget, NULL, device_resume_fn);
2383}
2384EXPORT_SYMBOL(scsi_target_resume);
2385
2386/**
Rob Landleyeb448202007-11-03 13:30:39 -05002387 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388 * @sdev: device to block
2389 *
2390 * Block request made by scsi lld's to temporarily stop all
2391 * scsi commands on the specified device. Called from interrupt
2392 * or normal process context.
2393 *
2394 * Returns zero if successful or error if not
2395 *
2396 * Notes:
2397 * This routine transitions the device to the SDEV_BLOCK state
2398 * (which must be a legal transition). When the device is in this
2399 * state, all commands are deferred until the scsi lld reenables
2400 * the device with scsi_device_unblock or device_block_tmo fires.
2401 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002402 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002403int
2404scsi_internal_device_block(struct scsi_device *sdev)
2405{
Jens Axboe165125e2007-07-24 09:28:11 +02002406 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 unsigned long flags;
2408 int err = 0;
2409
2410 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002411 if (err) {
2412 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2413
2414 if (err)
2415 return err;
2416 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002417
2418 /*
2419 * The device has transitioned to SDEV_BLOCK. Stop the
2420 * block layer from calling the midlayer with this device's
2421 * request queue.
2422 */
2423 spin_lock_irqsave(q->queue_lock, flags);
2424 blk_stop_queue(q);
2425 spin_unlock_irqrestore(q->queue_lock, flags);
2426
2427 return 0;
2428}
2429EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2430
2431/**
2432 * scsi_internal_device_unblock - resume a device after a block request
2433 * @sdev: device to resume
2434 *
2435 * Called by scsi lld's or the midlayer to restart the device queue
2436 * for the previously suspended scsi device. Called from interrupt or
2437 * normal process context.
2438 *
2439 * Returns zero if successful or error if not.
2440 *
2441 * Notes:
2442 * This routine transitions the device to the SDEV_RUNNING state
2443 * (which must be a legal transition) allowing the midlayer to
2444 * goose the queue for this device. This routine assumes the
2445 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002446 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002447int
2448scsi_internal_device_unblock(struct scsi_device *sdev)
2449{
Jens Axboe165125e2007-07-24 09:28:11 +02002450 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451 unsigned long flags;
2452
2453 /*
2454 * Try to transition the scsi device to SDEV_RUNNING
2455 * and goose the device queue if successful.
2456 */
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002457 if (sdev->sdev_state == SDEV_BLOCK)
2458 sdev->sdev_state = SDEV_RUNNING;
2459 else if (sdev->sdev_state == SDEV_CREATED_BLOCK)
2460 sdev->sdev_state = SDEV_CREATED;
Mike Christie986fe6c2010-10-06 03:10:59 -05002461 else if (sdev->sdev_state != SDEV_CANCEL &&
2462 sdev->sdev_state != SDEV_OFFLINE)
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002463 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002464
2465 spin_lock_irqsave(q->queue_lock, flags);
2466 blk_start_queue(q);
2467 spin_unlock_irqrestore(q->queue_lock, flags);
2468
2469 return 0;
2470}
2471EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2472
2473static void
2474device_block(struct scsi_device *sdev, void *data)
2475{
2476 scsi_internal_device_block(sdev);
2477}
2478
2479static int
2480target_block(struct device *dev, void *data)
2481{
2482 if (scsi_is_target_device(dev))
2483 starget_for_each_device(to_scsi_target(dev), NULL,
2484 device_block);
2485 return 0;
2486}
2487
2488void
2489scsi_target_block(struct device *dev)
2490{
2491 if (scsi_is_target_device(dev))
2492 starget_for_each_device(to_scsi_target(dev), NULL,
2493 device_block);
2494 else
2495 device_for_each_child(dev, NULL, target_block);
2496}
2497EXPORT_SYMBOL_GPL(scsi_target_block);
2498
2499static void
2500device_unblock(struct scsi_device *sdev, void *data)
2501{
2502 scsi_internal_device_unblock(sdev);
2503}
2504
2505static int
2506target_unblock(struct device *dev, void *data)
2507{
2508 if (scsi_is_target_device(dev))
2509 starget_for_each_device(to_scsi_target(dev), NULL,
2510 device_unblock);
2511 return 0;
2512}
2513
2514void
2515scsi_target_unblock(struct device *dev)
2516{
2517 if (scsi_is_target_device(dev))
2518 starget_for_each_device(to_scsi_target(dev), NULL,
2519 device_unblock);
2520 else
2521 device_for_each_child(dev, NULL, target_unblock);
2522}
2523EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002524
2525/**
2526 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002527 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002528 * @sg_count: number of segments in sg
2529 * @offset: offset in bytes into sg, on return offset into the mapped area
2530 * @len: bytes to map, on return number of bytes mapped
2531 *
2532 * Returns virtual address of the start of the mapped page
2533 */
Jens Axboec6132da2007-10-16 11:08:49 +02002534void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002535 size_t *offset, size_t *len)
2536{
2537 int i;
2538 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002539 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002540 struct page *page;
2541
Andrew Morton22cfefb2007-02-05 16:39:03 -08002542 WARN_ON(!irqs_disabled());
2543
Jens Axboec6132da2007-10-16 11:08:49 +02002544 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002545 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002546 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002547 if (sg_len > *offset)
2548 break;
2549 }
2550
2551 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002552 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2553 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002554 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002555 WARN_ON(1);
2556 return NULL;
2557 }
2558
2559 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002560 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002561
2562 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002563 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002564 *offset &= ~PAGE_MASK;
2565
2566 /* Bytes in this sg-entry from *offset to the end of the page */
2567 sg_len = PAGE_SIZE - *offset;
2568 if (*len > sg_len)
2569 *len = sg_len;
2570
Cong Wang77dfce02011-11-25 23:14:23 +08002571 return kmap_atomic(page);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002572}
2573EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2574
2575/**
Rob Landleyeb448202007-11-03 13:30:39 -05002576 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002577 * @virt: virtual address to be unmapped
2578 */
2579void scsi_kunmap_atomic_sg(void *virt)
2580{
Cong Wang77dfce02011-11-25 23:14:23 +08002581 kunmap_atomic(virt);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002582}
2583EXPORT_SYMBOL(scsi_kunmap_atomic_sg);