blob: b8de389636f834f3b2e4faff7bb636de88e27a7a [file] [log] [blame]
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>
15#include <linux/mempool.h>
16#include <linux/slab.h>
17#include <linux/init.h>
18#include <linux/pci.h>
19#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060020#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020021#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020024#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <scsi/scsi_dbg.h>
26#include <scsi/scsi_device.h>
27#include <scsi/scsi_driver.h>
28#include <scsi/scsi_eh.h>
29#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include "scsi_priv.h"
32#include "scsi_logging.h"
33
34
Tobias Klauser6391a112006-06-08 22:23:48 -070035#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020036#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38struct scsi_host_sg_pool {
39 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020040 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080041 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 mempool_t *pool;
43};
44
James Bottomleyd3f46f32008-01-15 11:11:46 -060045#define SP(x) { x, "sgpool-" __stringify(x) }
46#if (SCSI_MAX_SG_SEGMENTS < 32)
47#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
48#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070049static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 SP(8),
51 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020052#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060053 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020054#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060055 SP(64),
56#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060058#if (SCSI_MAX_SG_SEGMENTS > 256)
59#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020060#endif
61#endif
62#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060063#endif
64 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020065};
Linus Torvalds1da177e2005-04-16 15:20:36 -070066#undef SP
67
Martin K. Petersen7027ad72008-07-17 17:08:48 -040068struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020069
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -050070static void scsi_run_queue(struct request_queue *q);
James Bottomleye91442b2005-09-09 10:44:16 -050071
72/*
73 * Function: scsi_unprep_request()
74 *
75 * Purpose: Remove all preparation done for a request, including its
76 * associated scsi_cmnd, so that it can be requeued.
77 *
78 * Arguments: req - request to unprepare
79 *
80 * Lock status: Assumed that no locks are held upon entry.
81 *
82 * Returns: Nothing.
83 */
84static void scsi_unprep_request(struct request *req)
85{
86 struct scsi_cmnd *cmd = req->special;
87
James Bottomley28018c22010-07-01 19:49:17 +090088 blk_unprep_request(req);
Christoph Hellwigbeb40482006-06-10 18:01:03 +020089 req->special = NULL;
James Bottomleye91442b2005-09-09 10:44:16 -050090
James Bottomleye91442b2005-09-09 10:44:16 -050091 scsi_put_command(cmd);
92}
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -050093
James Bottomley4f5299a2009-01-02 10:42:21 -060094/**
95 * __scsi_queue_insert - private queue insertion
96 * @cmd: The SCSI command being requeued
97 * @reason: The reason for the requeue
98 * @unbusy: Whether the queue should be unbusied
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 *
James Bottomley4f5299a2009-01-02 10:42:21 -0600100 * This is a private queue insertion. The public interface
101 * scsi_queue_insert() always assumes the queue should be unbusied
102 * because it's always called before the completion. This function is
103 * for a requeue after completion, which should only occur in this
104 * file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600106static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
108 struct Scsi_Host *host = cmd->device->host;
109 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500110 struct scsi_target *starget = scsi_target(device);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500111 struct request_queue *q = device->request_queue;
112 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 SCSI_LOG_MLQUEUE(1,
115 printk("Inserting command %p into mlqueue\n", cmd));
116
117 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +0900118 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 *
120 * If the host/device isn't busy, assume that something actually
121 * completed, and that we should be able to queue a command now.
122 *
123 * Note that the prior mid-layer assumption that any host could
124 * always queue at least one command is now broken. The mid-layer
125 * will implement a user specifiable stall (see
126 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
127 * if a command is requeued with no other commands outstanding
128 * either for the device or for the host.
129 */
Mike Christief0c0a372008-08-17 15:24:38 -0500130 switch (reason) {
131 case SCSI_MLQUEUE_HOST_BUSY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 host->host_blocked = host->max_host_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500133 break;
134 case SCSI_MLQUEUE_DEVICE_BUSY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 device->device_blocked = device->max_device_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500136 break;
137 case SCSI_MLQUEUE_TARGET_BUSY:
138 starget->target_blocked = starget->max_target_blocked;
139 break;
140 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
142 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 * Decrement the counters, since these commands are no longer
144 * active on the host/device.
145 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600146 if (unbusy)
147 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500150 * Requeue this command. It will go before all other commands
151 * that are already in the queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 *
153 * NOTE: there is magic here about the way the queue is plugged if
154 * we have no outstanding commands.
155 *
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500156 * Although we *don't* plug the queue, we call the request
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 * function. The SCSI request function detects the blocked condition
158 * and plugs the queue appropriately.
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500159 */
160 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
164 scsi_run_queue(q);
165
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);
218
219 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
220 buffer, bufflen, __GFP_WAIT))
221 goto out;
222
223 req->cmd_len = COMMAND_SIZE(cmd[0]);
224 memcpy(req->cmd, cmd, req->cmd_len);
225 req->sense = sense;
226 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600227 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500228 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200229 req->cmd_type = REQ_TYPE_BLOCK_PC;
230 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500231
232 /*
233 * head injection *required* here otherwise quiesce won't work
234 */
235 blk_execute_rq(req->q, NULL, req, 1);
236
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400237 /*
238 * Some devices (USB mass-storage in particular) may transfer
239 * garbage data together with a residue indicating that the data
240 * is invalid. Prevent the garbage from being misinterpreted
241 * and prevent security leaks by zeroing out the excess data.
242 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900243 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
244 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400245
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900246 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900247 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500248 ret = req->errors;
249 out:
250 blk_put_request(req);
251
252 return ret;
253}
James Bottomley33aa6872005-08-28 11:31:14 -0500254EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500255
James Bottomleyea73a9f2005-08-28 11:33:52 -0500256
257int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
258 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900259 struct scsi_sense_hdr *sshdr, int timeout, int retries,
260 int *resid)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500261{
262 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700263 int result;
264
James Bottomleyea73a9f2005-08-28 11:33:52 -0500265 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500266 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500267 if (!sense)
268 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500269 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700270 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900271 sense, timeout, retries, 0, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500272 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500273 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500274
275 kfree(sense);
276 return result;
277}
278EXPORT_SYMBOL(scsi_execute_req);
279
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280/*
281 * Function: scsi_init_cmd_errh()
282 *
283 * Purpose: Initialize cmd fields related to error handling.
284 *
285 * Arguments: cmd - command that is ready to be queued.
286 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 * Notes: This function has the job of initializing a number of
288 * fields related to error handling. Typically this will
289 * be called once for each command, as required.
290 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200291static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200294 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900295 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300297 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298}
299
300void scsi_device_unbusy(struct scsi_device *sdev)
301{
302 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500303 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 unsigned long flags;
305
306 spin_lock_irqsave(shost->host_lock, flags);
307 shost->host_busy--;
Mike Christief0c0a372008-08-17 15:24:38 -0500308 starget->target_busy--;
James Bottomley939647e2005-09-18 15:05:20 -0500309 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900310 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 scsi_eh_wakeup(shost);
312 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500313 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500315 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316}
317
318/*
319 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
320 * and call blk_run_queue for all the scsi_devices on the target -
321 * including current_sdev first.
322 *
323 * Called with *no* scsi locks held.
324 */
325static void scsi_single_lun_run(struct scsi_device *current_sdev)
326{
327 struct Scsi_Host *shost = current_sdev->host;
328 struct scsi_device *sdev, *tmp;
329 struct scsi_target *starget = scsi_target(current_sdev);
330 unsigned long flags;
331
332 spin_lock_irqsave(shost->host_lock, flags);
333 starget->starget_sdev_user = NULL;
334 spin_unlock_irqrestore(shost->host_lock, flags);
335
336 /*
337 * Call blk_run_queue for all LUNs on the target, starting with
338 * current_sdev. We race with others (to set starget_sdev_user),
339 * but in most cases, we will be first. Ideally, each LU on the
340 * target would get some limited time or requests on the target.
341 */
342 blk_run_queue(current_sdev->request_queue);
343
344 spin_lock_irqsave(shost->host_lock, flags);
345 if (starget->starget_sdev_user)
346 goto out;
347 list_for_each_entry_safe(sdev, tmp, &starget->devices,
348 same_target_siblings) {
349 if (sdev == current_sdev)
350 continue;
351 if (scsi_device_get(sdev))
352 continue;
353
354 spin_unlock_irqrestore(shost->host_lock, flags);
355 blk_run_queue(sdev->request_queue);
356 spin_lock_irqsave(shost->host_lock, flags);
357
358 scsi_device_put(sdev);
359 }
360 out:
361 spin_unlock_irqrestore(shost->host_lock, flags);
362}
363
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400364static inline int scsi_device_is_busy(struct scsi_device *sdev)
365{
366 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
367 return 1;
368
369 return 0;
370}
371
Mike Christief0c0a372008-08-17 15:24:38 -0500372static inline int scsi_target_is_busy(struct scsi_target *starget)
373{
374 return ((starget->can_queue > 0 &&
375 starget->target_busy >= starget->can_queue) ||
376 starget->target_blocked);
377}
378
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400379static inline int scsi_host_is_busy(struct Scsi_Host *shost)
380{
381 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
382 shost->host_blocked || shost->host_self_blocked)
383 return 1;
384
385 return 0;
386}
387
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388/*
389 * Function: scsi_run_queue()
390 *
391 * Purpose: Select a proper request queue to serve next
392 *
393 * Arguments: q - last request's queue
394 *
395 * Returns: Nothing
396 *
397 * Notes: The previous command was completely finished, start
398 * a new one if possible.
399 */
400static void scsi_run_queue(struct request_queue *q)
401{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600402 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 struct Scsi_Host *shost = sdev->host;
Mike Christie2a3a59e2008-11-11 13:42:35 -0600404 LIST_HEAD(starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 unsigned long flags;
406
Tony Battersby25d7c362007-11-12 10:00:44 -0500407 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 scsi_single_lun_run(sdev);
409
410 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600411 list_splice_init(&shost->starved_list, &starved_list);
412
413 while (!list_empty(&starved_list)) {
Nick Piggin75ad23b2008-04-29 14:48:33 +0200414 int flagset;
415
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 /*
417 * As long as shost is accepting commands and we have
418 * starved queues, call blk_run_queue. scsi_request_fn
419 * drops the queue_lock and can add us back to the
420 * starved_list.
421 *
422 * host_lock protects the starved_list and starved_entry.
423 * scsi_request_fn must get the host_lock before checking
424 * or modifying starved_list or starved_entry.
425 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600426 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500427 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500428
Mike Christie2a3a59e2008-11-11 13:42:35 -0600429 sdev = list_entry(starved_list.next,
430 struct scsi_device, starved_entry);
431 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500432 if (scsi_target_is_busy(scsi_target(sdev))) {
433 list_move_tail(&sdev->starved_entry,
434 &shost->starved_list);
435 continue;
436 }
437
Nick Piggin75ad23b2008-04-29 14:48:33 +0200438 spin_unlock(shost->host_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
Nick Piggin75ad23b2008-04-29 14:48:33 +0200440 spin_lock(sdev->request_queue->queue_lock);
441 flagset = test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) &&
442 !test_bit(QUEUE_FLAG_REENTER,
443 &sdev->request_queue->queue_flags);
444 if (flagset)
445 queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue);
446 __blk_run_queue(sdev->request_queue);
447 if (flagset)
448 queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue);
449 spin_unlock(sdev->request_queue->queue_lock);
Andreas Herrmann04846f22006-08-09 17:31:16 +0200450
Nick Piggin75ad23b2008-04-29 14:48:33 +0200451 spin_lock(shost->host_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600453 /* put any unprocessed entries back */
454 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 spin_unlock_irqrestore(shost->host_lock, flags);
456
457 blk_run_queue(q);
458}
459
460/*
461 * Function: scsi_requeue_command()
462 *
463 * Purpose: Handle post-processing of completed commands.
464 *
465 * Arguments: q - queue to operate on
466 * cmd - command that may need to be requeued.
467 *
468 * Returns: Nothing
469 *
470 * Notes: After command completion, there may be blocks left
471 * over which weren't finished by the previous command
472 * this can be for a number of reasons - the main one is
473 * I/O errors in the middle of the request, in which case
474 * we need to request the blocks that come after the bad
475 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500476 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 */
478static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
479{
James Bottomleye91442b2005-09-09 10:44:16 -0500480 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500481 unsigned long flags;
482
Tejun Heo 283369c2005-04-24 02:06:36 -0500483 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley02bd3492008-12-12 13:28:29 -0600484 scsi_unprep_request(req);
James Bottomleye91442b2005-09-09 10:44:16 -0500485 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500486 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487
488 scsi_run_queue(q);
489}
490
491void scsi_next_command(struct scsi_cmnd *cmd)
492{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800493 struct scsi_device *sdev = cmd->device;
494 struct request_queue *q = sdev->request_queue;
495
496 /* need to hold a reference on the device before we let go of the cmd */
497 get_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
499 scsi_put_command(cmd);
500 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800501
502 /* ok to remove device now */
503 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504}
505
506void scsi_run_host_queues(struct Scsi_Host *shost)
507{
508 struct scsi_device *sdev;
509
510 shost_for_each_device(sdev, shost)
511 scsi_run_queue(sdev->request_queue);
512}
513
James Bottomley79ed2422009-01-06 13:15:20 -0600514static void __scsi_release_buffers(struct scsi_cmnd *, int);
515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516/*
517 * Function: scsi_end_request()
518 *
519 * Purpose: Post-processing of completed commands (usually invoked at end
520 * of upper level post-processing and scsi_io_completion).
521 *
522 * Arguments: cmd - command that is complete.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500523 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 * bytes - number of bytes of completed I/O
525 * requeue - indicates whether we should requeue leftovers.
526 *
527 * Lock status: Assumed that lock is not held upon entry.
528 *
James Bottomleye91442b2005-09-09 10:44:16 -0500529 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 *
531 * Notes: This is called for block device requests in order to
532 * mark some number of sectors as complete.
533 *
534 * We are guaranteeing that the request queue will be goosed
535 * at some point during this call.
James Bottomleye91442b2005-09-09 10:44:16 -0500536 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500538static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 int bytes, int requeue)
540{
Jens Axboe165125e2007-07-24 09:28:11 +0200541 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
544 /*
545 * If there are blocks left over at the end, set up the command
546 * to queue the remainder of them.
547 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500548 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 /* kill remainder if no retrys */
Mike Christie4a274462008-08-19 18:45:31 -0500550 if (error && scsi_noretry_cmd(cmd))
Tejun Heoe4588242009-05-12 08:49:32 +0200551 blk_end_request_all(req, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500553 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 /*
555 * Bleah. Leftovers again. Stick the
556 * leftovers in the front of the
557 * queue, and goose the queue again.
558 */
James Bottomley79ed2422009-01-06 13:15:20 -0600559 scsi_release_buffers(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500561 cmd = NULL;
562 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 return cmd;
564 }
565 }
566
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 /*
568 * This will goose the queue request function at the end, so we don't
569 * need to worry about launching another command.
570 */
James Bottomley79ed2422009-01-06 13:15:20 -0600571 __scsi_release_buffers(cmd, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 scsi_next_command(cmd);
573 return NULL;
574}
575
Jens Axboea8474ce2007-08-07 09:02:51 +0200576static inline unsigned int scsi_sgtable_index(unsigned short nents)
577{
578 unsigned int index;
579
James Bottomleyd3f46f32008-01-15 11:11:46 -0600580 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
581
582 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200583 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600584 else
585 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200586
587 return index;
588}
589
Jens Axboe5ed79592007-11-15 09:13:11 +0100590static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591{
592 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100593
594 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
595 mempool_free(sgl, sgp->pool);
596}
597
598static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
599{
600 struct scsi_host_sg_pool *sgp;
601
602 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
603 return mempool_alloc(sgp->pool, gfp_mask);
604}
605
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200606static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
607 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100608{
609 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200611 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200613 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
614 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100615 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200616 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600617 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Jens Axboea8474ce2007-08-07 09:02:51 +0200619 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620}
621
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200622static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200624 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625}
626
James Bottomley79ed2422009-01-06 13:15:20 -0600627static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
628{
629
630 if (cmd->sdb.table.nents)
631 scsi_free_sgtable(&cmd->sdb);
632
633 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
634
635 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
636 struct scsi_data_buffer *bidi_sdb =
637 cmd->request->next_rq->special;
638 scsi_free_sgtable(bidi_sdb);
639 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
640 cmd->request->next_rq->special = NULL;
641 }
642
643 if (scsi_prot_sg_count(cmd))
644 scsi_free_sgtable(cmd->prot_sdb);
645}
646
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647/*
648 * Function: scsi_release_buffers()
649 *
650 * Purpose: Completion processing for block device I/O requests.
651 *
652 * Arguments: cmd - command that we are bailing.
653 *
654 * Lock status: Assumed that no lock is held upon entry.
655 *
656 * Returns: Nothing
657 *
658 * Notes: In the event that an upper level driver rejects a
659 * command, we must release resources allocated during
660 * the __init_io() function. Primarily this would involve
661 * the scatter-gather table, and potentially any bounce
662 * buffers.
663 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800664void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665{
James Bottomley79ed2422009-01-06 13:15:20 -0600666 __scsi_release_buffers(cmd, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800668EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669
670/*
671 * Function: scsi_io_completion()
672 *
673 * Purpose: Completion processing for block device I/O requests.
674 *
675 * Arguments: cmd - command that is finished.
676 *
677 * Lock status: Assumed that no lock is held upon entry.
678 *
679 * Returns: Nothing
680 *
681 * Notes: This function is matched in terms of capabilities to
682 * the function that created the scatter-gather list.
683 * In other words, if there are no bounce buffers
684 * (the normal case for most drivers), we don't need
685 * the logic to deal with cleaning up afterwards.
686 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500687 * We must call scsi_end_request(). This will finish off
688 * the specified number of sectors. If we are done, the
689 * command block will be released and the queue function
690 * will be goosed. If we are not done then we have to
691 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500693 * a) We can call scsi_requeue_command(). The request
694 * will be unprepared and put back on the queue. Then
695 * a new command will be created for it. This should
696 * be used if we made forward progress, or if we want
697 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500699 * b) We can call scsi_queue_insert(). The request will
700 * be put back on the queue and retried using the same
701 * command as before, possibly after a delay.
702 *
703 * c) We can call blk_end_request() with -EIO to fail
704 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700706void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707{
708 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200709 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500711 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 struct scsi_sense_hdr sshdr;
713 int sense_valid = 0;
714 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500715 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
716 ACTION_DELAYED_RETRY} action;
717 char *description = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 if (result) {
720 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
721 if (sense_valid)
722 sense_deferred = scsi_sense_is_deferred(&sshdr);
723 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200724
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200725 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 req->errors = result;
727 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 if (sense_valid && req->sense) {
729 /*
730 * SG_IO wants current and deferred errors
731 */
732 int len = 8 + cmd->sense_buffer[7];
733
734 if (len > SCSI_SENSE_BUFFERSIZE)
735 len = SCSI_SENSE_BUFFERSIZE;
736 memcpy(req->sense, cmd->sense_buffer, len);
737 req->sense_len = len;
738 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500739 if (!sense_deferred)
740 error = -EIO;
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400741 }
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900742
743 req->resid_len = scsi_get_resid(cmd);
744
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200745 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900746 /*
747 * Bidi commands Must be complete as a whole,
748 * both sides at once.
749 */
750 req->next_rq->resid_len = scsi_in(cmd)->resid;
751
Boaz Harrosh63c43b02009-12-15 17:25:43 +0200752 scsi_release_buffers(cmd);
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900753 blk_end_request_all(req, 0);
754
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900755 scsi_next_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200756 return;
757 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 }
759
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200760 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
761 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200762
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 * Next deal with any sectors which we were able to correctly
765 * handle.
766 */
Tejun Heo83096eb2009-05-07 22:24:39 +0900767 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
James Bottomleyd6b0c532006-07-02 10:06:28 -0500768 "%d bytes done.\n",
Tejun Heo83096eb2009-05-07 22:24:39 +0900769 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
James Bottomleya9bddd72009-03-30 16:55:51 +0000771 /*
772 * Recovered errors need reporting, but they're always treated
773 * as success, so fiddle the result code here. For BLOCK_PC
774 * we already took a copy of the original into rq->errors which
775 * is what gets returned to the user
776 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500777 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
778 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
779 * print since caller wants ATA registers. Only occurs on
780 * SCSI ATA PASS_THROUGH commands when CK_COND=1
781 */
782 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
783 ;
784 else if (!(req->cmd_flags & REQ_QUIET))
James Bottomleya9bddd72009-03-30 16:55:51 +0000785 scsi_print_sense("", cmd);
786 result = 0;
787 /* BLOCK_PC may have set error */
788 error = 0;
789 }
790
791 /*
792 * A number of bytes were successfully read. If there
James Bottomleyd6b0c532006-07-02 10:06:28 -0500793 * are leftovers and there is some kind of error
794 * (result != 0), retry the rest.
795 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500796 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500797 return;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700798
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500799 error = -EIO;
800
Alan Sternb60af5b2008-11-03 15:56:47 -0500801 if (host_byte(result) == DID_RESET) {
802 /* Third party bus reset or reset for error recovery
803 * reasons. Just retry the command and see what
804 * happens.
805 */
806 action = ACTION_RETRY;
807 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 switch (sshdr.sense_key) {
809 case UNIT_ATTENTION:
810 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700811 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 * and quietly refuse further access.
813 */
814 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500815 description = "Media Changed";
816 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700818 /* Must have been a power glitch, or a
819 * bus reset. Could not have been a
820 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500821 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700822 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500823 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 }
825 break;
826 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700827 /* If we had an ILLEGAL REQUEST returned, then
828 * we may have performed an unsupported
829 * command. The only thing this should be
830 * would be a ten byte read where only a six
831 * byte read was supported. Also, on a system
832 * where READ CAPACITY failed, we may have
833 * read past the end of the disk.
834 */
Jens Axboe26a68012005-11-29 21:03:34 +0100835 if ((cmd->device->use_10_for_rw &&
836 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 (cmd->cmnd[0] == READ_10 ||
838 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500839 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500841 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500842 } else if (sshdr.asc == 0x10) /* DIX */ {
843 description = "Host Data Integrity Failure";
844 action = ACTION_FAIL;
845 error = -EILSEQ;
Alan Sternb60af5b2008-11-03 15:56:47 -0500846 } else
847 action = ACTION_FAIL;
848 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400849 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000850 action = ACTION_FAIL;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400851 if (sshdr.asc == 0x10) { /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500852 description = "Target Data Integrity Failure";
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500853 error = -EILSEQ;
James Bottomley126c09822009-02-19 21:48:54 +0000854 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 break;
856 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700857 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500858 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500860 if (sshdr.asc == 0x04) {
861 switch (sshdr.ascq) {
862 case 0x01: /* becoming ready */
863 case 0x04: /* format in progress */
864 case 0x05: /* rebuild in progress */
865 case 0x06: /* recalculation in progress */
866 case 0x07: /* operation in progress */
867 case 0x08: /* Long write in progress */
868 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -0500869 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -0500870 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500871 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -0500872 default:
873 description = "Device not ready";
874 action = ACTION_FAIL;
875 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500876 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500877 } else {
878 description = "Device not ready";
879 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500881 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700883 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -0500884 action = ACTION_FAIL;
885 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 default:
Alan Sternb60af5b2008-11-03 15:56:47 -0500887 description = "Unhandled sense code";
888 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 break;
890 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500891 } else {
892 description = "Unhandled error code";
893 action = ACTION_FAIL;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700894 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500895
896 switch (action) {
897 case ACTION_FAIL:
898 /* Give up and fail the remainder of the request */
James Bottomley79ed2422009-01-06 13:15:20 -0600899 scsi_release_buffers(cmd);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200900 if (!(req->cmd_flags & REQ_QUIET)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500901 if (description)
Alan Stern3dbf6a52008-12-15 10:31:28 -0500902 scmd_printk(KERN_INFO, cmd, "%s\n",
Alan Sternb60af5b2008-11-03 15:56:47 -0500903 description);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500904 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500905 if (driver_byte(result) & DRIVER_SENSE)
906 scsi_print_sense("", cmd);
Martin K. Petersen002b1eb2009-05-23 11:45:07 -0400907 scsi_print_command(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500908 }
Mike Christiead630822009-09-28 15:50:52 -0500909 if (blk_end_request_err(req, error))
Tejun Heoda6c5c72009-09-11 14:26:40 +0200910 scsi_requeue_command(q, cmd);
911 else
912 scsi_next_command(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500913 break;
914 case ACTION_REPREP:
915 /* Unprep the request and put it back at the head of the queue.
916 * A new command will be prepared and issued.
917 */
James Bottomley79ed2422009-01-06 13:15:20 -0600918 scsi_release_buffers(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500919 scsi_requeue_command(q, cmd);
920 break;
921 case ACTION_RETRY:
922 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -0600923 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500924 break;
925 case ACTION_DELAYED_RETRY:
926 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -0600927 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500928 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 }
930}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200932static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
933 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200935 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936
937 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +0100938 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200940 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
941 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -0400943 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944
Christoph Hellwig3b003152006-11-04 20:10:55 +0100945 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946
947 /*
948 * Next, walk the list, and fill in the addresses and sizes of
949 * each segment.
950 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200951 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
952 BUG_ON(count > sdb->table.nents);
953 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +0900954 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +1100955 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200957
958/*
959 * Function: scsi_init_io()
960 *
961 * Purpose: SCSI I/O initialize function.
962 *
963 * Arguments: cmd - Command descriptor we wish to initialize
964 *
965 * Returns: 0 on success
966 * BLKPREP_DEFER if the failure is retryable
967 * BLKPREP_KILL if the failure is fatal
968 */
969int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
970{
971 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
972 if (error)
973 goto err_exit;
974
975 if (blk_bidi_rq(cmd->request)) {
976 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -0400977 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200978 if (!bidi_sdb) {
979 error = BLKPREP_DEFER;
980 goto err_exit;
981 }
982
983 cmd->request->next_rq->special = bidi_sdb;
984 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
985 GFP_ATOMIC);
986 if (error)
987 goto err_exit;
988 }
989
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400990 if (blk_integrity_rq(cmd->request)) {
991 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
992 int ivecs, count;
993
994 BUG_ON(prot_sdb == NULL);
995 ivecs = blk_rq_count_integrity_sg(cmd->request);
996
997 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
998 error = BLKPREP_DEFER;
999 goto err_exit;
1000 }
1001
1002 count = blk_rq_map_integrity_sg(cmd->request,
1003 prot_sdb->table.sgl);
1004 BUG_ON(unlikely(count > ivecs));
1005
1006 cmd->prot_sdb = prot_sdb;
1007 cmd->prot_sdb->table.nents = count;
1008 }
1009
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001010 return BLKPREP_OK ;
1011
1012err_exit:
1013 scsi_release_buffers(cmd);
FUJITA Tomonori610a6342010-07-08 10:16:17 +02001014 scsi_put_command(cmd);
1015 cmd->request->special = NULL;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001016 return error;
1017}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001018EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019
Christoph Hellwig3b003152006-11-04 20:10:55 +01001020static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1021 struct request *req)
1022{
1023 struct scsi_cmnd *cmd;
1024
1025 if (!req->special) {
1026 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1027 if (unlikely(!cmd))
1028 return NULL;
1029 req->special = cmd;
1030 } else {
1031 cmd = req->special;
1032 }
1033
1034 /* pull a tag out of the request if we have one */
1035 cmd->tag = req->tag;
1036 cmd->request = req;
1037
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001038 cmd->cmnd = req->cmd;
1039
Christoph Hellwig3b003152006-11-04 20:10:55 +01001040 return cmd;
1041}
1042
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001043int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001044{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001045 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001046 int ret = scsi_prep_state_check(sdev, req);
1047
1048 if (ret != BLKPREP_OK)
1049 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001050
1051 cmd = scsi_get_cmd_from_req(sdev, req);
1052 if (unlikely(!cmd))
1053 return BLKPREP_DEFER;
1054
1055 /*
1056 * BLOCK_PC requests may transfer data, in which case they must
1057 * a bio attached to them. Or they might contain a SCSI command
1058 * that does not transfer data, in which case they may optionally
1059 * submit a request without an attached bio.
1060 */
1061 if (req->bio) {
1062 int ret;
1063
1064 BUG_ON(!req->nr_phys_segments);
1065
Boaz Harroshbb52d822007-12-13 16:14:27 -08001066 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001067 if (unlikely(ret))
1068 return ret;
1069 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001070 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001071
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001072 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001073 req->buffer = NULL;
1074 }
James Bottomley7b163182005-12-15 20:17:02 -06001075
James Bottomley7b163182005-12-15 20:17:02 -06001076 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001077 if (!blk_rq_bytes(req))
James Bottomley7b163182005-12-15 20:17:02 -06001078 cmd->sc_data_direction = DMA_NONE;
1079 else if (rq_data_dir(req) == WRITE)
1080 cmd->sc_data_direction = DMA_TO_DEVICE;
1081 else
1082 cmd->sc_data_direction = DMA_FROM_DEVICE;
1083
Tejun Heob0790412009-05-07 22:24:42 +09001084 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001085 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001086 return BLKPREP_OK;
1087}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001088EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001089
1090/*
1091 * Setup a REQ_TYPE_FS command. These are simple read/write request
1092 * from filesystems that still need to be translated to SCSI CDBs from
1093 * the ULD.
1094 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001095int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001096{
1097 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001098 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001099
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001100 if (ret != BLKPREP_OK)
1101 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001102
1103 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1104 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1105 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1106 if (ret != BLKPREP_OK)
1107 return ret;
1108 }
1109
Christoph Hellwig3b003152006-11-04 20:10:55 +01001110 /*
1111 * Filesystem requests must transfer data.
1112 */
1113 BUG_ON(!req->nr_phys_segments);
1114
1115 cmd = scsi_get_cmd_from_req(sdev, req);
1116 if (unlikely(!cmd))
1117 return BLKPREP_DEFER;
1118
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001119 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001120 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001121}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001122EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001123
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001124int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001126 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127
1128 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001129 * If the device is not in running state we will reject some
1130 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001133 switch (sdev->sdev_state) {
1134 case SDEV_OFFLINE:
1135 /*
1136 * If the device is offline we refuse to process any
1137 * commands. The device must be brought online
1138 * before trying any recovery commands.
1139 */
1140 sdev_printk(KERN_ERR, sdev,
1141 "rejecting I/O to offline device\n");
1142 ret = BLKPREP_KILL;
1143 break;
1144 case SDEV_DEL:
1145 /*
1146 * If the device is fully deleted, we refuse to
1147 * process any commands as well.
1148 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001149 sdev_printk(KERN_ERR, sdev,
1150 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001151 ret = BLKPREP_KILL;
1152 break;
1153 case SDEV_QUIESCE:
1154 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001155 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001156 /*
1157 * If the devices is blocked we defer normal commands.
1158 */
1159 if (!(req->cmd_flags & REQ_PREEMPT))
1160 ret = BLKPREP_DEFER;
1161 break;
1162 default:
1163 /*
1164 * For any other not fully online state we only allow
1165 * special commands. In particular any user initiated
1166 * command is not allowed.
1167 */
1168 if (!(req->cmd_flags & REQ_PREEMPT))
1169 ret = BLKPREP_KILL;
1170 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001173 return ret;
1174}
1175EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001177int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1178{
1179 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180
Christoph Hellwig3b003152006-11-04 20:10:55 +01001181 switch (ret) {
1182 case BLKPREP_KILL:
1183 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001184 /* release the command and kill it */
1185 if (req->special) {
1186 struct scsi_cmnd *cmd = req->special;
1187 scsi_release_buffers(cmd);
1188 scsi_put_command(cmd);
1189 req->special = NULL;
1190 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001191 break;
1192 case BLKPREP_DEFER:
1193 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001194 * If we defer, the blk_peek_request() returns NULL, but the
Christoph Hellwig3b003152006-11-04 20:10:55 +01001195 * queue must be restarted, so we plug here if no returning
1196 * command will automatically do that.
1197 */
1198 if (sdev->device_busy == 0)
1199 blk_plug_device(q);
1200 break;
1201 default:
1202 req->cmd_flags |= REQ_DONTPREP;
1203 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204
Christoph Hellwig3b003152006-11-04 20:10:55 +01001205 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001207EXPORT_SYMBOL(scsi_prep_return);
1208
James Bottomley751bf4d2008-01-02 11:14:30 -06001209int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001210{
1211 struct scsi_device *sdev = q->queuedata;
1212 int ret = BLKPREP_KILL;
1213
1214 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1215 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1216 return scsi_prep_return(q, req, ret);
1217}
Hannes Reineckeb3912772009-06-18 09:57:18 +02001218EXPORT_SYMBOL(scsi_prep_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219
1220/*
1221 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1222 * return 0.
1223 *
1224 * Called with the queue_lock held.
1225 */
1226static inline int scsi_dev_queue_ready(struct request_queue *q,
1227 struct scsi_device *sdev)
1228{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 if (sdev->device_busy == 0 && sdev->device_blocked) {
1230 /*
1231 * unblock after device_blocked iterates to zero
1232 */
1233 if (--sdev->device_blocked == 0) {
1234 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001235 sdev_printk(KERN_INFO, sdev,
1236 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 } else {
1238 blk_plug_device(q);
1239 return 0;
1240 }
1241 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001242 if (scsi_device_is_busy(sdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 return 0;
1244
1245 return 1;
1246}
1247
Mike Christief0c0a372008-08-17 15:24:38 -05001248
1249/*
1250 * scsi_target_queue_ready: checks if there we can send commands to target
1251 * @sdev: scsi device on starget to check.
1252 *
1253 * Called with the host lock held.
1254 */
1255static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1256 struct scsi_device *sdev)
1257{
1258 struct scsi_target *starget = scsi_target(sdev);
1259
1260 if (starget->single_lun) {
1261 if (starget->starget_sdev_user &&
1262 starget->starget_sdev_user != sdev)
1263 return 0;
1264 starget->starget_sdev_user = sdev;
1265 }
1266
1267 if (starget->target_busy == 0 && starget->target_blocked) {
1268 /*
1269 * unblock after target_blocked iterates to zero
1270 */
1271 if (--starget->target_blocked == 0) {
1272 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1273 "unblocking target at zero depth\n"));
Mike Christieb4efdd52009-04-09 15:57:10 -05001274 } else
Mike Christief0c0a372008-08-17 15:24:38 -05001275 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001276 }
1277
1278 if (scsi_target_is_busy(starget)) {
1279 if (list_empty(&sdev->starved_entry)) {
1280 list_add_tail(&sdev->starved_entry,
1281 &shost->starved_list);
1282 return 0;
1283 }
1284 }
1285
1286 /* We're OK to process the command, so we can't be starved */
1287 if (!list_empty(&sdev->starved_entry))
1288 list_del_init(&sdev->starved_entry);
1289 return 1;
1290}
1291
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292/*
1293 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1294 * return 0. We must end up running the queue again whenever 0 is
1295 * returned, else IO can hang.
1296 *
1297 * Called with host_lock held.
1298 */
1299static inline int scsi_host_queue_ready(struct request_queue *q,
1300 struct Scsi_Host *shost,
1301 struct scsi_device *sdev)
1302{
James Bottomley939647e2005-09-18 15:05:20 -05001303 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 return 0;
1305 if (shost->host_busy == 0 && shost->host_blocked) {
1306 /*
1307 * unblock after host_blocked iterates to zero
1308 */
1309 if (--shost->host_blocked == 0) {
1310 SCSI_LOG_MLQUEUE(3,
1311 printk("scsi%d unblocking host at zero depth\n",
1312 shost->host_no));
1313 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 return 0;
1315 }
1316 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001317 if (scsi_host_is_busy(shost)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 if (list_empty(&sdev->starved_entry))
1319 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1320 return 0;
1321 }
1322
1323 /* We're OK to process the command, so we can't be starved */
1324 if (!list_empty(&sdev->starved_entry))
1325 list_del_init(&sdev->starved_entry);
1326
1327 return 1;
1328}
1329
1330/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001331 * Busy state exporting function for request stacking drivers.
1332 *
1333 * For efficiency, no lock is taken to check the busy state of
1334 * shost/starget/sdev, since the returned value is not guaranteed and
1335 * may be changed after request stacking drivers call the function,
1336 * regardless of taking lock or not.
1337 *
1338 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1339 * (e.g. !sdev), scsi needs to return 'not busy'.
1340 * Otherwise, request stacking drivers may hold requests forever.
1341 */
1342static int scsi_lld_busy(struct request_queue *q)
1343{
1344 struct scsi_device *sdev = q->queuedata;
1345 struct Scsi_Host *shost;
1346 struct scsi_target *starget;
1347
1348 if (!sdev)
1349 return 0;
1350
1351 shost = sdev->host;
1352 starget = scsi_target(sdev);
1353
1354 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) ||
1355 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev))
1356 return 1;
1357
1358 return 0;
1359}
1360
1361/*
James Bottomleye91442b2005-09-09 10:44:16 -05001362 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363 */
Jens Axboe165125e2007-07-24 09:28:11 +02001364static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365{
James Bottomleye91442b2005-09-09 10:44:16 -05001366 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001367 struct scsi_device *sdev;
1368 struct scsi_target *starget;
1369 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370
Tejun Heo9934c8c2009-05-08 11:54:16 +09001371 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001372
James Bottomleye91442b2005-09-09 10:44:16 -05001373 if (unlikely(cmd == NULL)) {
1374 printk(KERN_CRIT "impossible request in %s.\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001375 __func__);
James Bottomleye91442b2005-09-09 10:44:16 -05001376 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 }
James Bottomleye91442b2005-09-09 10:44:16 -05001378
Jiri Slaby03b14702009-09-23 16:15:35 +02001379 sdev = cmd->device;
1380 starget = scsi_target(sdev);
1381 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001382 scsi_init_cmd_errh(cmd);
1383 cmd->result = DID_NO_CONNECT << 16;
1384 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001385
1386 /*
1387 * SCSI request completion path will do scsi_device_unbusy(),
1388 * bump busy counts. To bump the counters, we need to dance
1389 * with the locks as normal issue path does.
1390 */
1391 sdev->device_busy++;
1392 spin_unlock(sdev->request_queue->queue_lock);
1393 spin_lock(shost->host_lock);
1394 shost->host_busy++;
Mike Christief0c0a372008-08-17 15:24:38 -05001395 starget->target_busy++;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001396 spin_unlock(shost->host_lock);
1397 spin_lock(sdev->request_queue->queue_lock);
1398
Jens Axboe242f9dc2008-09-14 05:55:09 -07001399 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400}
1401
Jens Axboe1aea6432006-01-09 16:03:03 +01001402static void scsi_softirq_done(struct request *rq)
1403{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001404 struct scsi_cmnd *cmd = rq->special;
1405 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001406 int disposition;
1407
1408 INIT_LIST_HEAD(&cmd->eh_entry);
1409
Jens Axboe242f9dc2008-09-14 05:55:09 -07001410 /*
1411 * Set the serial numbers back to zero
1412 */
1413 cmd->serial_number = 0;
1414
1415 atomic_inc(&cmd->device->iodone_cnt);
1416 if (cmd->result)
1417 atomic_inc(&cmd->device->ioerr_cnt);
1418
Jens Axboe1aea6432006-01-09 16:03:03 +01001419 disposition = scsi_decide_disposition(cmd);
1420 if (disposition != SUCCESS &&
1421 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1422 sdev_printk(KERN_ERR, cmd->device,
1423 "timing out command, waited %lus\n",
1424 wait_for/HZ);
1425 disposition = SUCCESS;
1426 }
1427
1428 scsi_log_completion(cmd, disposition);
1429
1430 switch (disposition) {
1431 case SUCCESS:
1432 scsi_finish_command(cmd);
1433 break;
1434 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001435 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001436 break;
1437 case ADD_TO_MLQUEUE:
1438 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1439 break;
1440 default:
1441 if (!scsi_eh_scmd_add(cmd, 0))
1442 scsi_finish_command(cmd);
1443 }
1444}
1445
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446/*
1447 * Function: scsi_request_fn()
1448 *
1449 * Purpose: Main strategy routine for SCSI.
1450 *
1451 * Arguments: q - Pointer to actual queue.
1452 *
1453 * Returns: Nothing
1454 *
1455 * Lock status: IO request lock assumed to be held when called.
1456 */
1457static void scsi_request_fn(struct request_queue *q)
1458{
1459 struct scsi_device *sdev = q->queuedata;
1460 struct Scsi_Host *shost;
1461 struct scsi_cmnd *cmd;
1462 struct request *req;
1463
1464 if (!sdev) {
1465 printk("scsi: killing requests for dead queue\n");
Tejun Heo9934c8c2009-05-08 11:54:16 +09001466 while ((req = blk_peek_request(q)) != NULL)
James Bottomleye91442b2005-09-09 10:44:16 -05001467 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 return;
1469 }
1470
1471 if(!get_device(&sdev->sdev_gendev))
1472 /* We must be tearing the block queue down already */
1473 return;
1474
1475 /*
1476 * To start with, we keep looping until the queue is empty, or until
1477 * the host is no longer able to accept any more requests.
1478 */
1479 shost = sdev->host;
1480 while (!blk_queue_plugged(q)) {
1481 int rtn;
1482 /*
1483 * get next queueable request. We do this early to make sure
1484 * that the request is fully prepared even if we cannot
1485 * accept it.
1486 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001487 req = blk_peek_request(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 if (!req || !scsi_dev_queue_ready(q, sdev))
1489 break;
1490
1491 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001492 sdev_printk(KERN_ERR, sdev,
1493 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001494 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 continue;
1496 }
1497
1498
1499 /*
1500 * Remove the request from the request list.
1501 */
1502 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001503 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 sdev->device_busy++;
1505
1506 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001507 cmd = req->special;
1508 if (unlikely(cmd == NULL)) {
1509 printk(KERN_CRIT "impossible request in %s.\n"
1510 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001511 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001512 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001513 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001514 BUG();
1515 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516 spin_lock(shost->host_lock);
1517
Mike Christieecefe8a2008-07-11 19:50:35 -05001518 /*
1519 * We hit this when the driver is using a host wide
1520 * tag map. For device level tag maps the queue_depth check
1521 * in the device ready fn would prevent us from trying
1522 * to allocate a tag. Since the map is a shared host resource
1523 * we add the dev to the starved list so it eventually gets
1524 * a run when a tag is freed.
1525 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001526 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001527 if (list_empty(&sdev->starved_entry))
1528 list_add_tail(&sdev->starved_entry,
1529 &shost->starved_list);
1530 goto not_ready;
1531 }
1532
Mike Christief0c0a372008-08-17 15:24:38 -05001533 if (!scsi_target_queue_ready(shost, sdev))
1534 goto not_ready;
1535
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 if (!scsi_host_queue_ready(q, shost, sdev))
1537 goto not_ready;
Mike Christief0c0a372008-08-17 15:24:38 -05001538
1539 scsi_target(sdev)->target_busy++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540 shost->host_busy++;
1541
1542 /*
1543 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1544 * take the lock again.
1545 */
1546 spin_unlock_irq(shost->host_lock);
1547
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548 /*
1549 * Finally, initialize any error handling parameters, and set up
1550 * the timers for timeouts.
1551 */
1552 scsi_init_cmd_errh(cmd);
1553
1554 /*
1555 * Dispatch the command to the low-level driver.
1556 */
1557 rtn = scsi_dispatch_cmd(cmd);
1558 spin_lock_irq(q->queue_lock);
1559 if(rtn) {
1560 /* we're refusing the command; because of
1561 * the way locks get dropped, we need to
1562 * check here if plugging is required */
1563 if(sdev->device_busy == 0)
1564 blk_plug_device(q);
1565
1566 break;
1567 }
1568 }
1569
1570 goto out;
1571
1572 not_ready:
1573 spin_unlock_irq(shost->host_lock);
1574
1575 /*
1576 * lock q, handle tag, requeue req, and decrement device_busy. We
1577 * must return with queue_lock held.
1578 *
1579 * Decrementing device_busy without checking it is OK, as all such
1580 * cases (host limits or settings) should run the queue at some
1581 * later time.
1582 */
1583 spin_lock_irq(q->queue_lock);
1584 blk_requeue_request(q, req);
1585 sdev->device_busy--;
1586 if(sdev->device_busy == 0)
1587 blk_plug_device(q);
1588 out:
1589 /* must be careful here...if we trigger the ->remove() function
1590 * we cannot be holding the q lock */
1591 spin_unlock_irq(q->queue_lock);
1592 put_device(&sdev->sdev_gendev);
1593 spin_lock_irq(q->queue_lock);
1594}
1595
1596u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1597{
1598 struct device *host_dev;
1599 u64 bounce_limit = 0xffffffff;
1600
1601 if (shost->unchecked_isa_dma)
1602 return BLK_BOUNCE_ISA;
1603 /*
1604 * Platforms with virtual-DMA translation
1605 * hardware have no practical limit.
1606 */
1607 if (!PCI_DMA_BUS_IS_PHYS)
1608 return BLK_BOUNCE_ANY;
1609
1610 host_dev = scsi_get_device(shost);
1611 if (host_dev && host_dev->dma_mask)
1612 bounce_limit = *host_dev->dma_mask;
1613
1614 return bounce_limit;
1615}
1616EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1617
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001618struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1619 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001621 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001622 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001624 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001625 if (!q)
1626 return NULL;
1627
Jens Axboea8474ce2007-08-07 09:02:51 +02001628 /*
1629 * this limit is imposed by hardware restrictions
1630 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05001631 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1632 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02001633
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05001634 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001635 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1636 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001637 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001639 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1640
Nick Piggin75ad23b2008-04-29 14:48:33 +02001641 /* New queue, no concurrency on queue_flags */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 if (!shost->use_clustering)
Nick Piggin75ad23b2008-04-29 14:48:33 +02001643 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
James Bottomley465ff312008-01-01 10:00:10 -06001644
1645 /*
1646 * set a reasonable default alignment on word boundaries: the
1647 * host and device may alter it using
1648 * blk_queue_update_dma_alignment() later.
1649 */
1650 blk_queue_dma_alignment(q, 0x03);
1651
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652 return q;
1653}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001654EXPORT_SYMBOL(__scsi_alloc_queue);
1655
1656struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1657{
1658 struct request_queue *q;
1659
1660 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1661 if (!q)
1662 return NULL;
1663
1664 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001665 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001666 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001667 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001668 return q;
1669}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670
1671void scsi_free_queue(struct request_queue *q)
1672{
1673 blk_cleanup_queue(q);
1674}
1675
1676/*
1677 * Function: scsi_block_requests()
1678 *
1679 * Purpose: Utility function used by low-level drivers to prevent further
1680 * commands from being queued to the device.
1681 *
1682 * Arguments: shost - Host in question
1683 *
1684 * Returns: Nothing
1685 *
1686 * Lock status: No locks are assumed held.
1687 *
1688 * Notes: There is no timer nor any other means by which the requests
1689 * get unblocked other than the low-level driver calling
1690 * scsi_unblock_requests().
1691 */
1692void scsi_block_requests(struct Scsi_Host *shost)
1693{
1694 shost->host_self_blocked = 1;
1695}
1696EXPORT_SYMBOL(scsi_block_requests);
1697
1698/*
1699 * Function: scsi_unblock_requests()
1700 *
1701 * Purpose: Utility function used by low-level drivers to allow further
1702 * commands from being queued to the device.
1703 *
1704 * Arguments: shost - Host in question
1705 *
1706 * Returns: Nothing
1707 *
1708 * Lock status: No locks are assumed held.
1709 *
1710 * Notes: There is no timer nor any other means by which the requests
1711 * get unblocked other than the low-level driver calling
1712 * scsi_unblock_requests().
1713 *
1714 * This is done as an API function so that changes to the
1715 * internals of the scsi mid-layer won't require wholesale
1716 * changes to drivers that use this feature.
1717 */
1718void scsi_unblock_requests(struct Scsi_Host *shost)
1719{
1720 shost->host_self_blocked = 0;
1721 scsi_run_host_queues(shost);
1722}
1723EXPORT_SYMBOL(scsi_unblock_requests);
1724
1725int __init scsi_init_queue(void)
1726{
1727 int i;
1728
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001729 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1730 sizeof(struct scsi_data_buffer),
1731 0, 0, NULL);
1732 if (!scsi_sdb_cache) {
1733 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09001734 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001735 }
1736
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1738 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1739 int size = sgp->size * sizeof(struct scatterlist);
1740
1741 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001742 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 if (!sgp->slab) {
1744 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1745 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001746 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747 }
1748
Matthew Dobson93d23412006-03-26 01:37:50 -08001749 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1750 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 if (!sgp->pool) {
1752 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1753 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001754 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755 }
1756 }
1757
1758 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001759
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001760cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001761 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1762 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1763 if (sgp->pool)
1764 mempool_destroy(sgp->pool);
1765 if (sgp->slab)
1766 kmem_cache_destroy(sgp->slab);
1767 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001768 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001769
1770 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771}
1772
1773void scsi_exit_queue(void)
1774{
1775 int i;
1776
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001777 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001778
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1780 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1781 mempool_destroy(sgp->pool);
1782 kmem_cache_destroy(sgp->slab);
1783 }
1784}
James Bottomley5baba832006-03-18 14:10:35 -06001785
1786/**
1787 * scsi_mode_select - issue a mode select
1788 * @sdev: SCSI device to be queried
1789 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1790 * @sp: Save page bit (0 == don't save, 1 == save)
1791 * @modepage: mode page being requested
1792 * @buffer: request buffer (may not be smaller than eight bytes)
1793 * @len: length of request buffer.
1794 * @timeout: command timeout
1795 * @retries: number of retries before failing
1796 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001797 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001798 * must be SCSI_SENSE_BUFFERSIZE big.
1799 *
1800 * Returns zero if successful; negative error number or scsi
1801 * status on error
1802 *
1803 */
1804int
1805scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1806 unsigned char *buffer, int len, int timeout, int retries,
1807 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1808{
1809 unsigned char cmd[10];
1810 unsigned char *real_buffer;
1811 int ret;
1812
1813 memset(cmd, 0, sizeof(cmd));
1814 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1815
1816 if (sdev->use_10_for_ms) {
1817 if (len > 65535)
1818 return -EINVAL;
1819 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1820 if (!real_buffer)
1821 return -ENOMEM;
1822 memcpy(real_buffer + 8, buffer, len);
1823 len += 8;
1824 real_buffer[0] = 0;
1825 real_buffer[1] = 0;
1826 real_buffer[2] = data->medium_type;
1827 real_buffer[3] = data->device_specific;
1828 real_buffer[4] = data->longlba ? 0x01 : 0;
1829 real_buffer[5] = 0;
1830 real_buffer[6] = data->block_descriptor_length >> 8;
1831 real_buffer[7] = data->block_descriptor_length;
1832
1833 cmd[0] = MODE_SELECT_10;
1834 cmd[7] = len >> 8;
1835 cmd[8] = len;
1836 } else {
1837 if (len > 255 || data->block_descriptor_length > 255 ||
1838 data->longlba)
1839 return -EINVAL;
1840
1841 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1842 if (!real_buffer)
1843 return -ENOMEM;
1844 memcpy(real_buffer + 4, buffer, len);
1845 len += 4;
1846 real_buffer[0] = 0;
1847 real_buffer[1] = data->medium_type;
1848 real_buffer[2] = data->device_specific;
1849 real_buffer[3] = data->block_descriptor_length;
1850
1851
1852 cmd[0] = MODE_SELECT;
1853 cmd[4] = len;
1854 }
1855
1856 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001857 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06001858 kfree(real_buffer);
1859 return ret;
1860}
1861EXPORT_SYMBOL_GPL(scsi_mode_select);
1862
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863/**
Rob Landleyeb448202007-11-03 13:30:39 -05001864 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001865 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 * @dbd: set if mode sense will allow block descriptors to be returned
1867 * @modepage: mode page being requested
1868 * @buffer: request buffer (may not be smaller than eight bytes)
1869 * @len: length of request buffer.
1870 * @timeout: command timeout
1871 * @retries: number of retries before failing
1872 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001873 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001874 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 *
1876 * Returns zero if unsuccessful, or the header offset (either 4
1877 * or 8 depending on whether a six or ten byte command was
1878 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001879 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880int
James Bottomley1cf72692005-08-28 11:27:01 -05001881scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001883 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1884{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 unsigned char cmd[12];
1886 int use_10_for_ms;
1887 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001888 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001889 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890
1891 memset(data, 0, sizeof(*data));
1892 memset(&cmd[0], 0, 12);
1893 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1894 cmd[2] = modepage;
1895
James Bottomleyea73a9f2005-08-28 11:33:52 -05001896 /* caller might not be interested in sense, but we need it */
1897 if (!sshdr)
1898 sshdr = &my_sshdr;
1899
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001901 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902
1903 if (use_10_for_ms) {
1904 if (len < 8)
1905 len = 8;
1906
1907 cmd[0] = MODE_SENSE_10;
1908 cmd[8] = len;
1909 header_length = 8;
1910 } else {
1911 if (len < 4)
1912 len = 4;
1913
1914 cmd[0] = MODE_SENSE;
1915 cmd[4] = len;
1916 header_length = 4;
1917 }
1918
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919 memset(buffer, 0, len);
1920
James Bottomley1cf72692005-08-28 11:27:01 -05001921 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001922 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923
1924 /* This code looks awful: what it's doing is making sure an
1925 * ILLEGAL REQUEST sense return identifies the actual command
1926 * byte as the problem. MODE_SENSE commands can return
1927 * ILLEGAL REQUEST if the code page isn't supported */
1928
James Bottomley1cf72692005-08-28 11:27:01 -05001929 if (use_10_for_ms && !scsi_status_is_good(result) &&
1930 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001931 if (scsi_sense_valid(sshdr)) {
1932 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1933 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934 /*
1935 * Invalid command operation code
1936 */
James Bottomley1cf72692005-08-28 11:27:01 -05001937 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001938 goto retry;
1939 }
1940 }
1941 }
1942
James Bottomley1cf72692005-08-28 11:27:01 -05001943 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001944 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1945 (modepage == 6 || modepage == 8))) {
1946 /* Initio breakage? */
1947 header_length = 0;
1948 data->length = 13;
1949 data->medium_type = 0;
1950 data->device_specific = 0;
1951 data->longlba = 0;
1952 data->block_descriptor_length = 0;
1953 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 data->length = buffer[0]*256 + buffer[1] + 2;
1955 data->medium_type = buffer[2];
1956 data->device_specific = buffer[3];
1957 data->longlba = buffer[4] & 0x01;
1958 data->block_descriptor_length = buffer[6]*256
1959 + buffer[7];
1960 } else {
1961 data->length = buffer[0] + 1;
1962 data->medium_type = buffer[1];
1963 data->device_specific = buffer[2];
1964 data->block_descriptor_length = buffer[3];
1965 }
Al Viro6d73c852006-02-23 02:03:16 +01001966 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 }
1968
James Bottomley1cf72692005-08-28 11:27:01 -05001969 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970}
1971EXPORT_SYMBOL(scsi_mode_sense);
1972
James Bottomley001aac22007-12-02 19:10:40 +02001973/**
1974 * scsi_test_unit_ready - test if unit is ready
1975 * @sdev: scsi device to change the state of.
1976 * @timeout: command timeout
1977 * @retries: number of retries before failing
1978 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1979 * returning sense. Make sure that this is cleared before passing
1980 * in.
1981 *
1982 * Returns zero if unsuccessful or an error if TUR failed. For
1983 * removable media, a return of NOT_READY or UNIT_ATTENTION is
1984 * translated to success, with the ->changed flag updated.
1985 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986int
James Bottomley001aac22007-12-02 19:10:40 +02001987scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
1988 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990 char cmd[] = {
1991 TEST_UNIT_READY, 0, 0, 0, 0, 0,
1992 };
James Bottomley001aac22007-12-02 19:10:40 +02001993 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 int result;
James Bottomley001aac22007-12-02 19:10:40 +02001995
1996 if (!sshdr_external)
1997 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
1998 else
1999 sshdr = sshdr_external;
2000
2001 /* try to eat the UNIT_ATTENTION if there are enough retries */
2002 do {
2003 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002004 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002005 if (sdev->removable && scsi_sense_valid(sshdr) &&
2006 sshdr->sense_key == UNIT_ATTENTION)
2007 sdev->changed = 1;
2008 } while (scsi_sense_valid(sshdr) &&
2009 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002010
2011 if (!sshdr)
2012 /* could not allocate sense buffer, so can't process it */
2013 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014
James Bottomley32c356d2008-08-20 00:58:13 +02002015 if (sdev->removable && scsi_sense_valid(sshdr) &&
2016 (sshdr->sense_key == UNIT_ATTENTION ||
2017 sshdr->sense_key == NOT_READY)) {
2018 sdev->changed = 1;
2019 result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 }
James Bottomley001aac22007-12-02 19:10:40 +02002021 if (!sshdr_external)
2022 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 return result;
2024}
2025EXPORT_SYMBOL(scsi_test_unit_ready);
2026
2027/**
Rob Landleyeb448202007-11-03 13:30:39 -05002028 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002029 * @sdev: scsi device to change the state of.
2030 * @state: state to change to.
2031 *
2032 * Returns zero if unsuccessful or an error if the requested
2033 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002034 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035int
2036scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2037{
2038 enum scsi_device_state oldstate = sdev->sdev_state;
2039
2040 if (state == oldstate)
2041 return 0;
2042
2043 switch (state) {
2044 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002045 switch (oldstate) {
2046 case SDEV_CREATED_BLOCK:
2047 break;
2048 default:
2049 goto illegal;
2050 }
2051 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052
2053 case SDEV_RUNNING:
2054 switch (oldstate) {
2055 case SDEV_CREATED:
2056 case SDEV_OFFLINE:
2057 case SDEV_QUIESCE:
2058 case SDEV_BLOCK:
2059 break;
2060 default:
2061 goto illegal;
2062 }
2063 break;
2064
2065 case SDEV_QUIESCE:
2066 switch (oldstate) {
2067 case SDEV_RUNNING:
2068 case SDEV_OFFLINE:
2069 break;
2070 default:
2071 goto illegal;
2072 }
2073 break;
2074
2075 case SDEV_OFFLINE:
2076 switch (oldstate) {
2077 case SDEV_CREATED:
2078 case SDEV_RUNNING:
2079 case SDEV_QUIESCE:
2080 case SDEV_BLOCK:
2081 break;
2082 default:
2083 goto illegal;
2084 }
2085 break;
2086
2087 case SDEV_BLOCK:
2088 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002090 case SDEV_CREATED_BLOCK:
2091 break;
2092 default:
2093 goto illegal;
2094 }
2095 break;
2096
2097 case SDEV_CREATED_BLOCK:
2098 switch (oldstate) {
2099 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100 break;
2101 default:
2102 goto illegal;
2103 }
2104 break;
2105
2106 case SDEV_CANCEL:
2107 switch (oldstate) {
2108 case SDEV_CREATED:
2109 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002110 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 case SDEV_OFFLINE:
2112 case SDEV_BLOCK:
2113 break;
2114 default:
2115 goto illegal;
2116 }
2117 break;
2118
2119 case SDEV_DEL:
2120 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002121 case SDEV_CREATED:
2122 case SDEV_RUNNING:
2123 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 case SDEV_CANCEL:
2125 break;
2126 default:
2127 goto illegal;
2128 }
2129 break;
2130
2131 }
2132 sdev->sdev_state = state;
2133 return 0;
2134
2135 illegal:
2136 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002137 sdev_printk(KERN_ERR, sdev,
2138 "Illegal state transition %s->%s\n",
2139 scsi_device_state_name(oldstate),
2140 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002141 );
2142 return -EINVAL;
2143}
2144EXPORT_SYMBOL(scsi_device_set_state);
2145
2146/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002147 * sdev_evt_emit - emit a single SCSI device uevent
2148 * @sdev: associated SCSI device
2149 * @evt: event to emit
2150 *
2151 * Send a single uevent (scsi_event) to the associated scsi_device.
2152 */
2153static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2154{
2155 int idx = 0;
2156 char *envp[3];
2157
2158 switch (evt->evt_type) {
2159 case SDEV_EVT_MEDIA_CHANGE:
2160 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2161 break;
2162
2163 default:
2164 /* do nothing */
2165 break;
2166 }
2167
2168 envp[idx++] = NULL;
2169
2170 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2171}
2172
2173/**
2174 * sdev_evt_thread - send a uevent for each scsi event
2175 * @work: work struct for scsi_device
2176 *
2177 * Dispatch queued events to their associated scsi_device kobjects
2178 * as uevents.
2179 */
2180void scsi_evt_thread(struct work_struct *work)
2181{
2182 struct scsi_device *sdev;
2183 LIST_HEAD(event_list);
2184
2185 sdev = container_of(work, struct scsi_device, event_work);
2186
2187 while (1) {
2188 struct scsi_event *evt;
2189 struct list_head *this, *tmp;
2190 unsigned long flags;
2191
2192 spin_lock_irqsave(&sdev->list_lock, flags);
2193 list_splice_init(&sdev->event_list, &event_list);
2194 spin_unlock_irqrestore(&sdev->list_lock, flags);
2195
2196 if (list_empty(&event_list))
2197 break;
2198
2199 list_for_each_safe(this, tmp, &event_list) {
2200 evt = list_entry(this, struct scsi_event, node);
2201 list_del(&evt->node);
2202 scsi_evt_emit(sdev, evt);
2203 kfree(evt);
2204 }
2205 }
2206}
2207
2208/**
2209 * sdev_evt_send - send asserted event to uevent thread
2210 * @sdev: scsi_device event occurred on
2211 * @evt: event to send
2212 *
2213 * Assert scsi device event asynchronously.
2214 */
2215void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2216{
2217 unsigned long flags;
2218
Kay Sievers4d1566e2008-03-19 13:04:47 +01002219#if 0
2220 /* FIXME: currently this check eliminates all media change events
2221 * for polled devices. Need to update to discriminate between AN
2222 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002223 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2224 kfree(evt);
2225 return;
2226 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002227#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002228
2229 spin_lock_irqsave(&sdev->list_lock, flags);
2230 list_add_tail(&evt->node, &sdev->event_list);
2231 schedule_work(&sdev->event_work);
2232 spin_unlock_irqrestore(&sdev->list_lock, flags);
2233}
2234EXPORT_SYMBOL_GPL(sdev_evt_send);
2235
2236/**
2237 * sdev_evt_alloc - allocate a new scsi event
2238 * @evt_type: type of event to allocate
2239 * @gfpflags: GFP flags for allocation
2240 *
2241 * Allocates and returns a new scsi_event.
2242 */
2243struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2244 gfp_t gfpflags)
2245{
2246 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2247 if (!evt)
2248 return NULL;
2249
2250 evt->evt_type = evt_type;
2251 INIT_LIST_HEAD(&evt->node);
2252
2253 /* evt_type-specific initialization, if any */
2254 switch (evt_type) {
2255 case SDEV_EVT_MEDIA_CHANGE:
2256 default:
2257 /* do nothing */
2258 break;
2259 }
2260
2261 return evt;
2262}
2263EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2264
2265/**
2266 * sdev_evt_send_simple - send asserted event to uevent thread
2267 * @sdev: scsi_device event occurred on
2268 * @evt_type: type of event to send
2269 * @gfpflags: GFP flags for allocation
2270 *
2271 * Assert scsi device event asynchronously, given an event type.
2272 */
2273void sdev_evt_send_simple(struct scsi_device *sdev,
2274 enum scsi_device_event evt_type, gfp_t gfpflags)
2275{
2276 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2277 if (!evt) {
2278 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2279 evt_type);
2280 return;
2281 }
2282
2283 sdev_evt_send(sdev, evt);
2284}
2285EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2286
2287/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288 * scsi_device_quiesce - Block user issued commands.
2289 * @sdev: scsi device to quiesce.
2290 *
2291 * This works by trying to transition to the SDEV_QUIESCE state
2292 * (which must be a legal transition). When the device is in this
2293 * state, only special requests will be accepted, all others will
2294 * be deferred. Since special requests may also be requeued requests,
2295 * a successful return doesn't guarantee the device will be
2296 * totally quiescent.
2297 *
2298 * Must be called with user context, may sleep.
2299 *
2300 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002301 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302int
2303scsi_device_quiesce(struct scsi_device *sdev)
2304{
2305 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2306 if (err)
2307 return err;
2308
2309 scsi_run_queue(sdev->request_queue);
2310 while (sdev->device_busy) {
2311 msleep_interruptible(200);
2312 scsi_run_queue(sdev->request_queue);
2313 }
2314 return 0;
2315}
2316EXPORT_SYMBOL(scsi_device_quiesce);
2317
2318/**
2319 * scsi_device_resume - Restart user issued commands to a quiesced device.
2320 * @sdev: scsi device to resume.
2321 *
2322 * Moves the device from quiesced back to running and restarts the
2323 * queues.
2324 *
2325 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002326 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002327void
2328scsi_device_resume(struct scsi_device *sdev)
2329{
2330 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2331 return;
2332 scsi_run_queue(sdev->request_queue);
2333}
2334EXPORT_SYMBOL(scsi_device_resume);
2335
2336static void
2337device_quiesce_fn(struct scsi_device *sdev, void *data)
2338{
2339 scsi_device_quiesce(sdev);
2340}
2341
2342void
2343scsi_target_quiesce(struct scsi_target *starget)
2344{
2345 starget_for_each_device(starget, NULL, device_quiesce_fn);
2346}
2347EXPORT_SYMBOL(scsi_target_quiesce);
2348
2349static void
2350device_resume_fn(struct scsi_device *sdev, void *data)
2351{
2352 scsi_device_resume(sdev);
2353}
2354
2355void
2356scsi_target_resume(struct scsi_target *starget)
2357{
2358 starget_for_each_device(starget, NULL, device_resume_fn);
2359}
2360EXPORT_SYMBOL(scsi_target_resume);
2361
2362/**
Rob Landleyeb448202007-11-03 13:30:39 -05002363 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002364 * @sdev: device to block
2365 *
2366 * Block request made by scsi lld's to temporarily stop all
2367 * scsi commands on the specified device. Called from interrupt
2368 * or normal process context.
2369 *
2370 * Returns zero if successful or error if not
2371 *
2372 * Notes:
2373 * This routine transitions the device to the SDEV_BLOCK state
2374 * (which must be a legal transition). When the device is in this
2375 * state, all commands are deferred until the scsi lld reenables
2376 * the device with scsi_device_unblock or device_block_tmo fires.
2377 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002378 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002379int
2380scsi_internal_device_block(struct scsi_device *sdev)
2381{
Jens Axboe165125e2007-07-24 09:28:11 +02002382 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383 unsigned long flags;
2384 int err = 0;
2385
2386 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002387 if (err) {
2388 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2389
2390 if (err)
2391 return err;
2392 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393
2394 /*
2395 * The device has transitioned to SDEV_BLOCK. Stop the
2396 * block layer from calling the midlayer with this device's
2397 * request queue.
2398 */
2399 spin_lock_irqsave(q->queue_lock, flags);
2400 blk_stop_queue(q);
2401 spin_unlock_irqrestore(q->queue_lock, flags);
2402
2403 return 0;
2404}
2405EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2406
2407/**
2408 * scsi_internal_device_unblock - resume a device after a block request
2409 * @sdev: device to resume
2410 *
2411 * Called by scsi lld's or the midlayer to restart the device queue
2412 * for the previously suspended scsi device. Called from interrupt or
2413 * normal process context.
2414 *
2415 * Returns zero if successful or error if not.
2416 *
2417 * Notes:
2418 * This routine transitions the device to the SDEV_RUNNING state
2419 * (which must be a legal transition) allowing the midlayer to
2420 * goose the queue for this device. This routine assumes the
2421 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002422 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002423int
2424scsi_internal_device_unblock(struct scsi_device *sdev)
2425{
Jens Axboe165125e2007-07-24 09:28:11 +02002426 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002427 unsigned long flags;
2428
2429 /*
2430 * Try to transition the scsi device to SDEV_RUNNING
2431 * and goose the device queue if successful.
2432 */
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002433 if (sdev->sdev_state == SDEV_BLOCK)
2434 sdev->sdev_state = SDEV_RUNNING;
2435 else if (sdev->sdev_state == SDEV_CREATED_BLOCK)
2436 sdev->sdev_state = SDEV_CREATED;
2437 else
2438 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002439
2440 spin_lock_irqsave(q->queue_lock, flags);
2441 blk_start_queue(q);
2442 spin_unlock_irqrestore(q->queue_lock, flags);
2443
2444 return 0;
2445}
2446EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2447
2448static void
2449device_block(struct scsi_device *sdev, void *data)
2450{
2451 scsi_internal_device_block(sdev);
2452}
2453
2454static int
2455target_block(struct device *dev, void *data)
2456{
2457 if (scsi_is_target_device(dev))
2458 starget_for_each_device(to_scsi_target(dev), NULL,
2459 device_block);
2460 return 0;
2461}
2462
2463void
2464scsi_target_block(struct device *dev)
2465{
2466 if (scsi_is_target_device(dev))
2467 starget_for_each_device(to_scsi_target(dev), NULL,
2468 device_block);
2469 else
2470 device_for_each_child(dev, NULL, target_block);
2471}
2472EXPORT_SYMBOL_GPL(scsi_target_block);
2473
2474static void
2475device_unblock(struct scsi_device *sdev, void *data)
2476{
2477 scsi_internal_device_unblock(sdev);
2478}
2479
2480static int
2481target_unblock(struct device *dev, void *data)
2482{
2483 if (scsi_is_target_device(dev))
2484 starget_for_each_device(to_scsi_target(dev), NULL,
2485 device_unblock);
2486 return 0;
2487}
2488
2489void
2490scsi_target_unblock(struct device *dev)
2491{
2492 if (scsi_is_target_device(dev))
2493 starget_for_each_device(to_scsi_target(dev), NULL,
2494 device_unblock);
2495 else
2496 device_for_each_child(dev, NULL, target_unblock);
2497}
2498EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002499
2500/**
2501 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002502 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002503 * @sg_count: number of segments in sg
2504 * @offset: offset in bytes into sg, on return offset into the mapped area
2505 * @len: bytes to map, on return number of bytes mapped
2506 *
2507 * Returns virtual address of the start of the mapped page
2508 */
Jens Axboec6132da2007-10-16 11:08:49 +02002509void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002510 size_t *offset, size_t *len)
2511{
2512 int i;
2513 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002514 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002515 struct page *page;
2516
Andrew Morton22cfefb2007-02-05 16:39:03 -08002517 WARN_ON(!irqs_disabled());
2518
Jens Axboec6132da2007-10-16 11:08:49 +02002519 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002520 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002521 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002522 if (sg_len > *offset)
2523 break;
2524 }
2525
2526 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002527 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2528 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002529 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002530 WARN_ON(1);
2531 return NULL;
2532 }
2533
2534 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002535 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002536
2537 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002538 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002539 *offset &= ~PAGE_MASK;
2540
2541 /* Bytes in this sg-entry from *offset to the end of the page */
2542 sg_len = PAGE_SIZE - *offset;
2543 if (*len > sg_len)
2544 *len = sg_len;
2545
2546 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2547}
2548EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2549
2550/**
Rob Landleyeb448202007-11-03 13:30:39 -05002551 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002552 * @virt: virtual address to be unmapped
2553 */
2554void scsi_kunmap_atomic_sg(void *virt)
2555{
2556 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2557}
2558EXPORT_SYMBOL(scsi_kunmap_atomic_sg);