blob: b12750f82169f37ad3ed6968752dbb0e91e87839 [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 a1bf9d12005-04-24 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
Jens Axboe4aff5e22006-08-10 08:44:47 +020088 req->cmd_flags &= ~REQ_DONTPREP;
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 a1bf9d12005-04-24 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 a1bf9d12005-04-24 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 a1bf9d12005-04-24 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 a1bf9d12005-04-24 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 a1bf9d12005-04-24 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 a1bf9d12005-04-24 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)) {
Tejun Heo1011c1b2009-05-07 22:24:45 +0900549 int leftover = blk_rq_bytes(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550
551 if (blk_pc_request(req))
Tejun Heoc3a4d782009-05-07 22:24:37 +0900552 leftover = req->resid_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
554 /* kill remainder if no retrys */
Mike Christie4a274462008-08-19 18:45:31 -0500555 if (error && scsi_noretry_cmd(cmd))
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500556 blk_end_request(req, error, leftover);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500558 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 /*
560 * Bleah. Leftovers again. Stick the
561 * leftovers in the front of the
562 * queue, and goose the queue again.
563 */
James Bottomley79ed2422009-01-06 13:15:20 -0600564 scsi_release_buffers(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500566 cmd = NULL;
567 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 return cmd;
569 }
570 }
571
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 /*
573 * This will goose the queue request function at the end, so we don't
574 * need to worry about launching another command.
575 */
James Bottomley79ed2422009-01-06 13:15:20 -0600576 __scsi_release_buffers(cmd, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 scsi_next_command(cmd);
578 return NULL;
579}
580
Jens Axboea8474ce2007-08-07 09:02:51 +0200581static inline unsigned int scsi_sgtable_index(unsigned short nents)
582{
583 unsigned int index;
584
James Bottomleyd3f46f32008-01-15 11:11:46 -0600585 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
586
587 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200588 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600589 else
590 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200591
592 return index;
593}
594
Jens Axboe5ed79592007-11-15 09:13:11 +0100595static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596{
597 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100598
599 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
600 mempool_free(sgl, sgp->pool);
601}
602
603static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
604{
605 struct scsi_host_sg_pool *sgp;
606
607 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
608 return mempool_alloc(sgp->pool, gfp_mask);
609}
610
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200611static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
612 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100613{
614 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200616 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200618 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
619 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100620 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200621 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600622 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623
Jens Axboea8474ce2007-08-07 09:02:51 +0200624 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625}
626
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200627static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200629 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630}
631
James Bottomley79ed2422009-01-06 13:15:20 -0600632static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
633{
634
635 if (cmd->sdb.table.nents)
636 scsi_free_sgtable(&cmd->sdb);
637
638 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
639
640 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
641 struct scsi_data_buffer *bidi_sdb =
642 cmd->request->next_rq->special;
643 scsi_free_sgtable(bidi_sdb);
644 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
645 cmd->request->next_rq->special = NULL;
646 }
647
648 if (scsi_prot_sg_count(cmd))
649 scsi_free_sgtable(cmd->prot_sdb);
650}
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652/*
653 * Function: scsi_release_buffers()
654 *
655 * Purpose: Completion processing for block device I/O requests.
656 *
657 * Arguments: cmd - command that we are bailing.
658 *
659 * Lock status: Assumed that no lock is held upon entry.
660 *
661 * Returns: Nothing
662 *
663 * Notes: In the event that an upper level driver rejects a
664 * command, we must release resources allocated during
665 * the __init_io() function. Primarily this would involve
666 * the scatter-gather table, and potentially any bounce
667 * buffers.
668 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800669void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670{
James Bottomley79ed2422009-01-06 13:15:20 -0600671 __scsi_release_buffers(cmd, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800673EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674
675/*
Tejun Heoc3a4d782009-05-07 22:24:37 +0900676 * Bidi commands Must be complete as a whole, both sides at once. If
677 * part of the bytes were written and lld returned scsi_in()->resid
678 * and/or scsi_out()->resid this information will be left in
679 * req->resid_len and req->next_rq->resid_len. The upper-layer driver
680 * can decide what to do with this information.
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200681 */
Adrian Bunk8c5e03d2008-03-31 01:53:55 +0300682static void scsi_end_bidi_request(struct scsi_cmnd *cmd)
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200683{
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500684 struct request *req = cmd->request;
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500685
Tejun Heoc3a4d782009-05-07 22:24:37 +0900686 req->resid_len = scsi_out(cmd)->resid;
687 req->next_rq->resid_len = scsi_in(cmd)->resid;
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500688
689 /* The req and req->next_rq have not been completed */
Tejun Heob0790412009-05-07 22:24:42 +0900690 BUG_ON(blk_end_bidi_request(req, 0, blk_rq_bytes(req),
691 blk_rq_bytes(req->next_rq)));
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500692
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200693 scsi_release_buffers(cmd);
694
695 /*
696 * This will goose the queue request function at the end, so we don't
697 * need to worry about launching another command.
698 */
699 scsi_next_command(cmd);
700}
701
702/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 * Function: scsi_io_completion()
704 *
705 * Purpose: Completion processing for block device I/O requests.
706 *
707 * Arguments: cmd - command that is finished.
708 *
709 * Lock status: Assumed that no lock is held upon entry.
710 *
711 * Returns: Nothing
712 *
713 * Notes: This function is matched in terms of capabilities to
714 * the function that created the scatter-gather list.
715 * In other words, if there are no bounce buffers
716 * (the normal case for most drivers), we don't need
717 * the logic to deal with cleaning up afterwards.
718 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500719 * We must call scsi_end_request(). This will finish off
720 * the specified number of sectors. If we are done, the
721 * command block will be released and the queue function
722 * will be goosed. If we are not done then we have to
723 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500725 * a) We can call scsi_requeue_command(). The request
726 * will be unprepared and put back on the queue. Then
727 * a new command will be created for it. This should
728 * be used if we made forward progress, or if we want
729 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500731 * b) We can call scsi_queue_insert(). The request will
732 * be put back on the queue and retried using the same
733 * command as before, possibly after a delay.
734 *
735 * c) We can call blk_end_request() with -EIO to fail
736 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700738void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739{
740 int result = cmd->result;
James Bottomley44ea91c2008-09-20 00:31:50 +0000741 int this_count;
Jens Axboe165125e2007-07-24 09:28:11 +0200742 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500744 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 struct scsi_sense_hdr sshdr;
746 int sense_valid = 0;
747 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500748 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
749 ACTION_DELAYED_RETRY} action;
750 char *description = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 if (result) {
753 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
754 if (sense_valid)
755 sense_deferred = scsi_sense_is_deferred(&sshdr);
756 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
759 req->errors = result;
760 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 if (sense_valid && req->sense) {
762 /*
763 * SG_IO wants current and deferred errors
764 */
765 int len = 8 + cmd->sense_buffer[7];
766
767 if (len > SCSI_SENSE_BUFFERSIZE)
768 len = SCSI_SENSE_BUFFERSIZE;
769 memcpy(req->sense, cmd->sense_buffer, len);
770 req->sense_len = len;
771 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500772 if (!sense_deferred)
773 error = -EIO;
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400774 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200775 if (scsi_bidi_cmnd(cmd)) {
776 /* will also release_buffers */
777 scsi_end_bidi_request(cmd);
778 return;
779 }
Tejun Heoc3a4d782009-05-07 22:24:37 +0900780 req->resid_len = scsi_get_resid(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 }
782
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200783 BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200784
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 * Next deal with any sectors which we were able to correctly
787 * handle.
788 */
Tejun Heo83096eb2009-05-07 22:24:39 +0900789 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
James Bottomleyd6b0c532006-07-02 10:06:28 -0500790 "%d bytes done.\n",
Tejun Heo83096eb2009-05-07 22:24:39 +0900791 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
James Bottomleya9bddd72009-03-30 16:55:51 +0000793 /*
794 * Recovered errors need reporting, but they're always treated
795 * as success, so fiddle the result code here. For BLOCK_PC
796 * we already took a copy of the original into rq->errors which
797 * is what gets returned to the user
798 */
799 if (sense_valid && sshdr.sense_key == RECOVERED_ERROR) {
800 if (!(req->cmd_flags & REQ_QUIET))
801 scsi_print_sense("", cmd);
802 result = 0;
803 /* BLOCK_PC may have set error */
804 error = 0;
805 }
806
807 /*
808 * A number of bytes were successfully read. If there
James Bottomleyd6b0c532006-07-02 10:06:28 -0500809 * are leftovers and there is some kind of error
810 * (result != 0), retry the rest.
811 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500812 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500813 return;
James Bottomley44ea91c2008-09-20 00:31:50 +0000814 this_count = blk_rq_bytes(req);
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700815
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500816 error = -EIO;
817
Alan Sternb60af5b2008-11-03 15:56:47 -0500818 if (host_byte(result) == DID_RESET) {
819 /* Third party bus reset or reset for error recovery
820 * reasons. Just retry the command and see what
821 * happens.
822 */
823 action = ACTION_RETRY;
824 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 switch (sshdr.sense_key) {
826 case UNIT_ATTENTION:
827 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700828 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 * and quietly refuse further access.
830 */
831 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500832 description = "Media Changed";
833 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700835 /* Must have been a power glitch, or a
836 * bus reset. Could not have been a
837 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500838 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700839 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500840 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 }
842 break;
843 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700844 /* If we had an ILLEGAL REQUEST returned, then
845 * we may have performed an unsupported
846 * command. The only thing this should be
847 * would be a ten byte read where only a six
848 * byte read was supported. Also, on a system
849 * where READ CAPACITY failed, we may have
850 * read past the end of the disk.
851 */
Jens Axboe26a68012005-11-29 21:03:34 +0100852 if ((cmd->device->use_10_for_rw &&
853 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 (cmd->cmnd[0] == READ_10 ||
855 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500856 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500858 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500859 } else if (sshdr.asc == 0x10) /* DIX */ {
860 description = "Host Data Integrity Failure";
861 action = ACTION_FAIL;
862 error = -EILSEQ;
Alan Sternb60af5b2008-11-03 15:56:47 -0500863 } else
864 action = ACTION_FAIL;
865 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400866 case ABORTED_COMMAND:
James Bottomley126c0982009-02-19 21:48:54 +0000867 action = ACTION_FAIL;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400868 if (sshdr.asc == 0x10) { /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500869 description = "Target Data Integrity Failure";
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500870 error = -EILSEQ;
James Bottomley126c0982009-02-19 21:48:54 +0000871 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 break;
873 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700874 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500875 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500877 if (sshdr.asc == 0x04) {
878 switch (sshdr.ascq) {
879 case 0x01: /* becoming ready */
880 case 0x04: /* format in progress */
881 case 0x05: /* rebuild in progress */
882 case 0x06: /* recalculation in progress */
883 case 0x07: /* operation in progress */
884 case 0x08: /* Long write in progress */
885 case 0x09: /* self test in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -0500886 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500887 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -0500888 default:
889 description = "Device not ready";
890 action = ACTION_FAIL;
891 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500892 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500893 } else {
894 description = "Device not ready";
895 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500897 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700899 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -0500900 action = ACTION_FAIL;
901 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 default:
Alan Sternb60af5b2008-11-03 15:56:47 -0500903 description = "Unhandled sense code";
904 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 break;
906 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500907 } else {
908 description = "Unhandled error code";
909 action = ACTION_FAIL;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700910 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500911
912 switch (action) {
913 case ACTION_FAIL:
914 /* Give up and fail the remainder of the request */
James Bottomley79ed2422009-01-06 13:15:20 -0600915 scsi_release_buffers(cmd);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200916 if (!(req->cmd_flags & REQ_QUIET)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500917 if (description)
Alan Stern3dbf6a52008-12-15 10:31:28 -0500918 scmd_printk(KERN_INFO, cmd, "%s\n",
Alan Sternb60af5b2008-11-03 15:56:47 -0500919 description);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500920 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500921 if (driver_byte(result) & DRIVER_SENSE)
922 scsi_print_sense("", cmd);
923 }
Tejun Heo40cbbb72009-04-23 11:05:19 +0900924 blk_end_request_all(req, -EIO);
Alan Sternb60af5b2008-11-03 15:56:47 -0500925 scsi_next_command(cmd);
926 break;
927 case ACTION_REPREP:
928 /* Unprep the request and put it back at the head of the queue.
929 * A new command will be prepared and issued.
930 */
James Bottomley79ed2422009-01-06 13:15:20 -0600931 scsi_release_buffers(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500932 scsi_requeue_command(q, cmd);
933 break;
934 case ACTION_RETRY:
935 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -0600936 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500937 break;
938 case ACTION_DELAYED_RETRY:
939 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -0600940 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500941 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 }
943}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200945static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
946 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200948 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949
950 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +0100951 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200953 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
954 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -0400956 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957
Christoph Hellwig3b003152006-11-04 20:10:55 +0100958 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
960 /*
961 * Next, walk the list, and fill in the addresses and sizes of
962 * each segment.
963 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200964 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
965 BUG_ON(count > sdb->table.nents);
966 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +0900967 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +1100968 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200970
971/*
972 * Function: scsi_init_io()
973 *
974 * Purpose: SCSI I/O initialize function.
975 *
976 * Arguments: cmd - Command descriptor we wish to initialize
977 *
978 * Returns: 0 on success
979 * BLKPREP_DEFER if the failure is retryable
980 * BLKPREP_KILL if the failure is fatal
981 */
982int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
983{
984 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
985 if (error)
986 goto err_exit;
987
988 if (blk_bidi_rq(cmd->request)) {
989 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -0400990 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200991 if (!bidi_sdb) {
992 error = BLKPREP_DEFER;
993 goto err_exit;
994 }
995
996 cmd->request->next_rq->special = bidi_sdb;
997 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
998 GFP_ATOMIC);
999 if (error)
1000 goto err_exit;
1001 }
1002
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001003 if (blk_integrity_rq(cmd->request)) {
1004 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1005 int ivecs, count;
1006
1007 BUG_ON(prot_sdb == NULL);
1008 ivecs = blk_rq_count_integrity_sg(cmd->request);
1009
1010 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1011 error = BLKPREP_DEFER;
1012 goto err_exit;
1013 }
1014
1015 count = blk_rq_map_integrity_sg(cmd->request,
1016 prot_sdb->table.sgl);
1017 BUG_ON(unlikely(count > ivecs));
1018
1019 cmd->prot_sdb = prot_sdb;
1020 cmd->prot_sdb->table.nents = count;
1021 }
1022
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001023 return BLKPREP_OK ;
1024
1025err_exit:
1026 scsi_release_buffers(cmd);
1027 if (error == BLKPREP_KILL)
1028 scsi_put_command(cmd);
1029 else /* BLKPREP_DEFER */
1030 scsi_unprep_request(cmd->request);
1031
1032 return error;
1033}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001034EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035
Christoph Hellwig3b003152006-11-04 20:10:55 +01001036static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1037 struct request *req)
1038{
1039 struct scsi_cmnd *cmd;
1040
1041 if (!req->special) {
1042 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1043 if (unlikely(!cmd))
1044 return NULL;
1045 req->special = cmd;
1046 } else {
1047 cmd = req->special;
1048 }
1049
1050 /* pull a tag out of the request if we have one */
1051 cmd->tag = req->tag;
1052 cmd->request = req;
1053
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001054 cmd->cmnd = req->cmd;
1055
Christoph Hellwig3b003152006-11-04 20:10:55 +01001056 return cmd;
1057}
1058
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001059int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001060{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001061 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001062 int ret = scsi_prep_state_check(sdev, req);
1063
1064 if (ret != BLKPREP_OK)
1065 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001066
1067 cmd = scsi_get_cmd_from_req(sdev, req);
1068 if (unlikely(!cmd))
1069 return BLKPREP_DEFER;
1070
1071 /*
1072 * BLOCK_PC requests may transfer data, in which case they must
1073 * a bio attached to them. Or they might contain a SCSI command
1074 * that does not transfer data, in which case they may optionally
1075 * submit a request without an attached bio.
1076 */
1077 if (req->bio) {
1078 int ret;
1079
1080 BUG_ON(!req->nr_phys_segments);
1081
Boaz Harroshbb52d822007-12-13 16:14:27 -08001082 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001083 if (unlikely(ret))
1084 return ret;
1085 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001086 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001087
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001088 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001089 req->buffer = NULL;
1090 }
James Bottomley7b163182005-12-15 20:17:02 -06001091
James Bottomley7b163182005-12-15 20:17:02 -06001092 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001093 if (!blk_rq_bytes(req))
James Bottomley7b163182005-12-15 20:17:02 -06001094 cmd->sc_data_direction = DMA_NONE;
1095 else if (rq_data_dir(req) == WRITE)
1096 cmd->sc_data_direction = DMA_TO_DEVICE;
1097 else
1098 cmd->sc_data_direction = DMA_FROM_DEVICE;
1099
Tejun Heob0790412009-05-07 22:24:42 +09001100 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001101 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001102 return BLKPREP_OK;
1103}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001104EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001105
1106/*
1107 * Setup a REQ_TYPE_FS command. These are simple read/write request
1108 * from filesystems that still need to be translated to SCSI CDBs from
1109 * the ULD.
1110 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001111int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001112{
1113 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001114 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001115
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001116 if (ret != BLKPREP_OK)
1117 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001118
1119 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1120 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1121 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1122 if (ret != BLKPREP_OK)
1123 return ret;
1124 }
1125
Christoph Hellwig3b003152006-11-04 20:10:55 +01001126 /*
1127 * Filesystem requests must transfer data.
1128 */
1129 BUG_ON(!req->nr_phys_segments);
1130
1131 cmd = scsi_get_cmd_from_req(sdev, req);
1132 if (unlikely(!cmd))
1133 return BLKPREP_DEFER;
1134
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001135 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001136 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001137}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001138EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001139
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001140int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001142 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143
1144 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001145 * If the device is not in running state we will reject some
1146 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001149 switch (sdev->sdev_state) {
1150 case SDEV_OFFLINE:
1151 /*
1152 * If the device is offline we refuse to process any
1153 * commands. The device must be brought online
1154 * before trying any recovery commands.
1155 */
1156 sdev_printk(KERN_ERR, sdev,
1157 "rejecting I/O to offline device\n");
1158 ret = BLKPREP_KILL;
1159 break;
1160 case SDEV_DEL:
1161 /*
1162 * If the device is fully deleted, we refuse to
1163 * process any commands as well.
1164 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001165 sdev_printk(KERN_ERR, sdev,
1166 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001167 ret = BLKPREP_KILL;
1168 break;
1169 case SDEV_QUIESCE:
1170 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001171 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001172 /*
1173 * If the devices is blocked we defer normal commands.
1174 */
1175 if (!(req->cmd_flags & REQ_PREEMPT))
1176 ret = BLKPREP_DEFER;
1177 break;
1178 default:
1179 /*
1180 * For any other not fully online state we only allow
1181 * special commands. In particular any user initiated
1182 * command is not allowed.
1183 */
1184 if (!(req->cmd_flags & REQ_PREEMPT))
1185 ret = BLKPREP_KILL;
1186 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001189 return ret;
1190}
1191EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001193int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1194{
1195 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196
Christoph Hellwig3b003152006-11-04 20:10:55 +01001197 switch (ret) {
1198 case BLKPREP_KILL:
1199 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001200 /* release the command and kill it */
1201 if (req->special) {
1202 struct scsi_cmnd *cmd = req->special;
1203 scsi_release_buffers(cmd);
1204 scsi_put_command(cmd);
1205 req->special = NULL;
1206 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001207 break;
1208 case BLKPREP_DEFER:
1209 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001210 * If we defer, the blk_peek_request() returns NULL, but the
Christoph Hellwig3b003152006-11-04 20:10:55 +01001211 * queue must be restarted, so we plug here if no returning
1212 * command will automatically do that.
1213 */
1214 if (sdev->device_busy == 0)
1215 blk_plug_device(q);
1216 break;
1217 default:
1218 req->cmd_flags |= REQ_DONTPREP;
1219 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220
Christoph Hellwig3b003152006-11-04 20:10:55 +01001221 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001223EXPORT_SYMBOL(scsi_prep_return);
1224
James Bottomley751bf4d2008-01-02 11:14:30 -06001225int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001226{
1227 struct scsi_device *sdev = q->queuedata;
1228 int ret = BLKPREP_KILL;
1229
1230 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1231 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1232 return scsi_prep_return(q, req, ret);
1233}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234
1235/*
1236 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1237 * return 0.
1238 *
1239 * Called with the queue_lock held.
1240 */
1241static inline int scsi_dev_queue_ready(struct request_queue *q,
1242 struct scsi_device *sdev)
1243{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 if (sdev->device_busy == 0 && sdev->device_blocked) {
1245 /*
1246 * unblock after device_blocked iterates to zero
1247 */
1248 if (--sdev->device_blocked == 0) {
1249 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001250 sdev_printk(KERN_INFO, sdev,
1251 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252 } else {
1253 blk_plug_device(q);
1254 return 0;
1255 }
1256 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001257 if (scsi_device_is_busy(sdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 return 0;
1259
1260 return 1;
1261}
1262
Mike Christief0c0a372008-08-17 15:24:38 -05001263
1264/*
1265 * scsi_target_queue_ready: checks if there we can send commands to target
1266 * @sdev: scsi device on starget to check.
1267 *
1268 * Called with the host lock held.
1269 */
1270static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1271 struct scsi_device *sdev)
1272{
1273 struct scsi_target *starget = scsi_target(sdev);
1274
1275 if (starget->single_lun) {
1276 if (starget->starget_sdev_user &&
1277 starget->starget_sdev_user != sdev)
1278 return 0;
1279 starget->starget_sdev_user = sdev;
1280 }
1281
1282 if (starget->target_busy == 0 && starget->target_blocked) {
1283 /*
1284 * unblock after target_blocked iterates to zero
1285 */
1286 if (--starget->target_blocked == 0) {
1287 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1288 "unblocking target at zero depth\n"));
1289 } else {
1290 blk_plug_device(sdev->request_queue);
1291 return 0;
1292 }
1293 }
1294
1295 if (scsi_target_is_busy(starget)) {
1296 if (list_empty(&sdev->starved_entry)) {
1297 list_add_tail(&sdev->starved_entry,
1298 &shost->starved_list);
1299 return 0;
1300 }
1301 }
1302
1303 /* We're OK to process the command, so we can't be starved */
1304 if (!list_empty(&sdev->starved_entry))
1305 list_del_init(&sdev->starved_entry);
1306 return 1;
1307}
1308
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309/*
1310 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1311 * return 0. We must end up running the queue again whenever 0 is
1312 * returned, else IO can hang.
1313 *
1314 * Called with host_lock held.
1315 */
1316static inline int scsi_host_queue_ready(struct request_queue *q,
1317 struct Scsi_Host *shost,
1318 struct scsi_device *sdev)
1319{
James Bottomley939647e2005-09-18 15:05:20 -05001320 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 return 0;
1322 if (shost->host_busy == 0 && shost->host_blocked) {
1323 /*
1324 * unblock after host_blocked iterates to zero
1325 */
1326 if (--shost->host_blocked == 0) {
1327 SCSI_LOG_MLQUEUE(3,
1328 printk("scsi%d unblocking host at zero depth\n",
1329 shost->host_no));
1330 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 return 0;
1332 }
1333 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001334 if (scsi_host_is_busy(shost)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 if (list_empty(&sdev->starved_entry))
1336 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1337 return 0;
1338 }
1339
1340 /* We're OK to process the command, so we can't be starved */
1341 if (!list_empty(&sdev->starved_entry))
1342 list_del_init(&sdev->starved_entry);
1343
1344 return 1;
1345}
1346
1347/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001348 * Busy state exporting function for request stacking drivers.
1349 *
1350 * For efficiency, no lock is taken to check the busy state of
1351 * shost/starget/sdev, since the returned value is not guaranteed and
1352 * may be changed after request stacking drivers call the function,
1353 * regardless of taking lock or not.
1354 *
1355 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1356 * (e.g. !sdev), scsi needs to return 'not busy'.
1357 * Otherwise, request stacking drivers may hold requests forever.
1358 */
1359static int scsi_lld_busy(struct request_queue *q)
1360{
1361 struct scsi_device *sdev = q->queuedata;
1362 struct Scsi_Host *shost;
1363 struct scsi_target *starget;
1364
1365 if (!sdev)
1366 return 0;
1367
1368 shost = sdev->host;
1369 starget = scsi_target(sdev);
1370
1371 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) ||
1372 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev))
1373 return 1;
1374
1375 return 0;
1376}
1377
1378/*
James Bottomleye91442b2005-09-09 10:44:16 -05001379 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380 */
Jens Axboe165125e2007-07-24 09:28:11 +02001381static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382{
James Bottomleye91442b2005-09-09 10:44:16 -05001383 struct scsi_cmnd *cmd = req->special;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001384 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -05001385 struct scsi_target *starget = scsi_target(sdev);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001386 struct Scsi_Host *shost = sdev->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387
Tejun Heo9934c8c2009-05-08 11:54:16 +09001388 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001389
James Bottomleye91442b2005-09-09 10:44:16 -05001390 if (unlikely(cmd == NULL)) {
1391 printk(KERN_CRIT "impossible request in %s.\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001392 __func__);
James Bottomleye91442b2005-09-09 10:44:16 -05001393 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 }
James Bottomleye91442b2005-09-09 10:44:16 -05001395
1396 scsi_init_cmd_errh(cmd);
1397 cmd->result = DID_NO_CONNECT << 16;
1398 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001399
1400 /*
1401 * SCSI request completion path will do scsi_device_unbusy(),
1402 * bump busy counts. To bump the counters, we need to dance
1403 * with the locks as normal issue path does.
1404 */
1405 sdev->device_busy++;
1406 spin_unlock(sdev->request_queue->queue_lock);
1407 spin_lock(shost->host_lock);
1408 shost->host_busy++;
Mike Christief0c0a372008-08-17 15:24:38 -05001409 starget->target_busy++;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001410 spin_unlock(shost->host_lock);
1411 spin_lock(sdev->request_queue->queue_lock);
1412
Jens Axboe242f9dc2008-09-14 05:55:09 -07001413 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414}
1415
Jens Axboe1aea6432006-01-09 16:03:03 +01001416static void scsi_softirq_done(struct request *rq)
1417{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001418 struct scsi_cmnd *cmd = rq->special;
1419 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001420 int disposition;
1421
1422 INIT_LIST_HEAD(&cmd->eh_entry);
1423
Jens Axboe242f9dc2008-09-14 05:55:09 -07001424 /*
1425 * Set the serial numbers back to zero
1426 */
1427 cmd->serial_number = 0;
1428
1429 atomic_inc(&cmd->device->iodone_cnt);
1430 if (cmd->result)
1431 atomic_inc(&cmd->device->ioerr_cnt);
1432
Jens Axboe1aea6432006-01-09 16:03:03 +01001433 disposition = scsi_decide_disposition(cmd);
1434 if (disposition != SUCCESS &&
1435 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1436 sdev_printk(KERN_ERR, cmd->device,
1437 "timing out command, waited %lus\n",
1438 wait_for/HZ);
1439 disposition = SUCCESS;
1440 }
1441
1442 scsi_log_completion(cmd, disposition);
1443
1444 switch (disposition) {
1445 case SUCCESS:
1446 scsi_finish_command(cmd);
1447 break;
1448 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001449 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001450 break;
1451 case ADD_TO_MLQUEUE:
1452 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1453 break;
1454 default:
1455 if (!scsi_eh_scmd_add(cmd, 0))
1456 scsi_finish_command(cmd);
1457 }
1458}
1459
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460/*
1461 * Function: scsi_request_fn()
1462 *
1463 * Purpose: Main strategy routine for SCSI.
1464 *
1465 * Arguments: q - Pointer to actual queue.
1466 *
1467 * Returns: Nothing
1468 *
1469 * Lock status: IO request lock assumed to be held when called.
1470 */
1471static void scsi_request_fn(struct request_queue *q)
1472{
1473 struct scsi_device *sdev = q->queuedata;
1474 struct Scsi_Host *shost;
1475 struct scsi_cmnd *cmd;
1476 struct request *req;
1477
1478 if (!sdev) {
1479 printk("scsi: killing requests for dead queue\n");
Tejun Heo9934c8c2009-05-08 11:54:16 +09001480 while ((req = blk_peek_request(q)) != NULL)
James Bottomleye91442b2005-09-09 10:44:16 -05001481 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 return;
1483 }
1484
1485 if(!get_device(&sdev->sdev_gendev))
1486 /* We must be tearing the block queue down already */
1487 return;
1488
1489 /*
1490 * To start with, we keep looping until the queue is empty, or until
1491 * the host is no longer able to accept any more requests.
1492 */
1493 shost = sdev->host;
1494 while (!blk_queue_plugged(q)) {
1495 int rtn;
1496 /*
1497 * get next queueable request. We do this early to make sure
1498 * that the request is fully prepared even if we cannot
1499 * accept it.
1500 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001501 req = blk_peek_request(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502 if (!req || !scsi_dev_queue_ready(q, sdev))
1503 break;
1504
1505 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001506 sdev_printk(KERN_ERR, sdev,
1507 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001508 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509 continue;
1510 }
1511
1512
1513 /*
1514 * Remove the request from the request list.
1515 */
1516 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001517 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 sdev->device_busy++;
1519
1520 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001521 cmd = req->special;
1522 if (unlikely(cmd == NULL)) {
1523 printk(KERN_CRIT "impossible request in %s.\n"
1524 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001525 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001526 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001527 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001528 BUG();
1529 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 spin_lock(shost->host_lock);
1531
Mike Christieecefe8a2008-07-11 19:50:35 -05001532 /*
1533 * We hit this when the driver is using a host wide
1534 * tag map. For device level tag maps the queue_depth check
1535 * in the device ready fn would prevent us from trying
1536 * to allocate a tag. Since the map is a shared host resource
1537 * we add the dev to the starved list so it eventually gets
1538 * a run when a tag is freed.
1539 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001540 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001541 if (list_empty(&sdev->starved_entry))
1542 list_add_tail(&sdev->starved_entry,
1543 &shost->starved_list);
1544 goto not_ready;
1545 }
1546
Mike Christief0c0a372008-08-17 15:24:38 -05001547 if (!scsi_target_queue_ready(shost, sdev))
1548 goto not_ready;
1549
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550 if (!scsi_host_queue_ready(q, shost, sdev))
1551 goto not_ready;
Mike Christief0c0a372008-08-17 15:24:38 -05001552
1553 scsi_target(sdev)->target_busy++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 shost->host_busy++;
1555
1556 /*
1557 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1558 * take the lock again.
1559 */
1560 spin_unlock_irq(shost->host_lock);
1561
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 /*
1563 * Finally, initialize any error handling parameters, and set up
1564 * the timers for timeouts.
1565 */
1566 scsi_init_cmd_errh(cmd);
1567
1568 /*
1569 * Dispatch the command to the low-level driver.
1570 */
1571 rtn = scsi_dispatch_cmd(cmd);
1572 spin_lock_irq(q->queue_lock);
1573 if(rtn) {
1574 /* we're refusing the command; because of
1575 * the way locks get dropped, we need to
1576 * check here if plugging is required */
1577 if(sdev->device_busy == 0)
1578 blk_plug_device(q);
1579
1580 break;
1581 }
1582 }
1583
1584 goto out;
1585
1586 not_ready:
1587 spin_unlock_irq(shost->host_lock);
1588
1589 /*
1590 * lock q, handle tag, requeue req, and decrement device_busy. We
1591 * must return with queue_lock held.
1592 *
1593 * Decrementing device_busy without checking it is OK, as all such
1594 * cases (host limits or settings) should run the queue at some
1595 * later time.
1596 */
1597 spin_lock_irq(q->queue_lock);
1598 blk_requeue_request(q, req);
1599 sdev->device_busy--;
1600 if(sdev->device_busy == 0)
1601 blk_plug_device(q);
1602 out:
1603 /* must be careful here...if we trigger the ->remove() function
1604 * we cannot be holding the q lock */
1605 spin_unlock_irq(q->queue_lock);
1606 put_device(&sdev->sdev_gendev);
1607 spin_lock_irq(q->queue_lock);
1608}
1609
1610u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1611{
1612 struct device *host_dev;
1613 u64 bounce_limit = 0xffffffff;
1614
1615 if (shost->unchecked_isa_dma)
1616 return BLK_BOUNCE_ISA;
1617 /*
1618 * Platforms with virtual-DMA translation
1619 * hardware have no practical limit.
1620 */
1621 if (!PCI_DMA_BUS_IS_PHYS)
1622 return BLK_BOUNCE_ANY;
1623
1624 host_dev = scsi_get_device(shost);
1625 if (host_dev && host_dev->dma_mask)
1626 bounce_limit = *host_dev->dma_mask;
1627
1628 return bounce_limit;
1629}
1630EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1631
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001632struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1633 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001635 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001636 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001638 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639 if (!q)
1640 return NULL;
1641
Jens Axboea8474ce2007-08-07 09:02:51 +02001642 /*
1643 * this limit is imposed by hardware restrictions
1644 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645 blk_queue_max_hw_segments(q, shost->sg_tablesize);
James Bottomleyd3f46f32008-01-15 11:11:46 -06001646 blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
Jens Axboea8474ce2007-08-07 09:02:51 +02001647
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648 blk_queue_max_sectors(q, shost->max_sectors);
1649 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1650 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001651 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001653 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1654
Nick Piggin75ad23b2008-04-29 14:48:33 +02001655 /* New queue, no concurrency on queue_flags */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656 if (!shost->use_clustering)
Nick Piggin75ad23b2008-04-29 14:48:33 +02001657 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
James Bottomley465ff312008-01-01 10:00:10 -06001658
1659 /*
1660 * set a reasonable default alignment on word boundaries: the
1661 * host and device may alter it using
1662 * blk_queue_update_dma_alignment() later.
1663 */
1664 blk_queue_dma_alignment(q, 0x03);
1665
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 return q;
1667}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001668EXPORT_SYMBOL(__scsi_alloc_queue);
1669
1670struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1671{
1672 struct request_queue *q;
1673
1674 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1675 if (!q)
1676 return NULL;
1677
1678 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001679 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001680 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001681 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001682 return q;
1683}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684
1685void scsi_free_queue(struct request_queue *q)
1686{
1687 blk_cleanup_queue(q);
1688}
1689
1690/*
1691 * Function: scsi_block_requests()
1692 *
1693 * Purpose: Utility function used by low-level drivers to prevent further
1694 * commands from being queued to the device.
1695 *
1696 * Arguments: shost - Host in question
1697 *
1698 * Returns: Nothing
1699 *
1700 * Lock status: No locks are assumed held.
1701 *
1702 * Notes: There is no timer nor any other means by which the requests
1703 * get unblocked other than the low-level driver calling
1704 * scsi_unblock_requests().
1705 */
1706void scsi_block_requests(struct Scsi_Host *shost)
1707{
1708 shost->host_self_blocked = 1;
1709}
1710EXPORT_SYMBOL(scsi_block_requests);
1711
1712/*
1713 * Function: scsi_unblock_requests()
1714 *
1715 * Purpose: Utility function used by low-level drivers to allow further
1716 * commands from being queued to the device.
1717 *
1718 * Arguments: shost - Host in question
1719 *
1720 * Returns: Nothing
1721 *
1722 * Lock status: No locks are assumed held.
1723 *
1724 * Notes: There is no timer nor any other means by which the requests
1725 * get unblocked other than the low-level driver calling
1726 * scsi_unblock_requests().
1727 *
1728 * This is done as an API function so that changes to the
1729 * internals of the scsi mid-layer won't require wholesale
1730 * changes to drivers that use this feature.
1731 */
1732void scsi_unblock_requests(struct Scsi_Host *shost)
1733{
1734 shost->host_self_blocked = 0;
1735 scsi_run_host_queues(shost);
1736}
1737EXPORT_SYMBOL(scsi_unblock_requests);
1738
1739int __init scsi_init_queue(void)
1740{
1741 int i;
1742
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001743 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1744 sizeof(struct scsi_data_buffer),
1745 0, 0, NULL);
1746 if (!scsi_sdb_cache) {
1747 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09001748 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001749 }
1750
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1752 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1753 int size = sgp->size * sizeof(struct scatterlist);
1754
1755 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001756 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 if (!sgp->slab) {
1758 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1759 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001760 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 }
1762
Matthew Dobson93d23412006-03-26 01:37:50 -08001763 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1764 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765 if (!sgp->pool) {
1766 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1767 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001768 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 }
1770 }
1771
1772 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001773
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001774cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001775 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1776 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1777 if (sgp->pool)
1778 mempool_destroy(sgp->pool);
1779 if (sgp->slab)
1780 kmem_cache_destroy(sgp->slab);
1781 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001782 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001783
1784 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785}
1786
1787void scsi_exit_queue(void)
1788{
1789 int i;
1790
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001791 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001792
Linus Torvalds1da177e2005-04-16 15:20:36 -07001793 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1794 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1795 mempool_destroy(sgp->pool);
1796 kmem_cache_destroy(sgp->slab);
1797 }
1798}
James Bottomley5baba832006-03-18 14:10:35 -06001799
1800/**
1801 * scsi_mode_select - issue a mode select
1802 * @sdev: SCSI device to be queried
1803 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1804 * @sp: Save page bit (0 == don't save, 1 == save)
1805 * @modepage: mode page being requested
1806 * @buffer: request buffer (may not be smaller than eight bytes)
1807 * @len: length of request buffer.
1808 * @timeout: command timeout
1809 * @retries: number of retries before failing
1810 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001811 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001812 * must be SCSI_SENSE_BUFFERSIZE big.
1813 *
1814 * Returns zero if successful; negative error number or scsi
1815 * status on error
1816 *
1817 */
1818int
1819scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1820 unsigned char *buffer, int len, int timeout, int retries,
1821 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1822{
1823 unsigned char cmd[10];
1824 unsigned char *real_buffer;
1825 int ret;
1826
1827 memset(cmd, 0, sizeof(cmd));
1828 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1829
1830 if (sdev->use_10_for_ms) {
1831 if (len > 65535)
1832 return -EINVAL;
1833 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1834 if (!real_buffer)
1835 return -ENOMEM;
1836 memcpy(real_buffer + 8, buffer, len);
1837 len += 8;
1838 real_buffer[0] = 0;
1839 real_buffer[1] = 0;
1840 real_buffer[2] = data->medium_type;
1841 real_buffer[3] = data->device_specific;
1842 real_buffer[4] = data->longlba ? 0x01 : 0;
1843 real_buffer[5] = 0;
1844 real_buffer[6] = data->block_descriptor_length >> 8;
1845 real_buffer[7] = data->block_descriptor_length;
1846
1847 cmd[0] = MODE_SELECT_10;
1848 cmd[7] = len >> 8;
1849 cmd[8] = len;
1850 } else {
1851 if (len > 255 || data->block_descriptor_length > 255 ||
1852 data->longlba)
1853 return -EINVAL;
1854
1855 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1856 if (!real_buffer)
1857 return -ENOMEM;
1858 memcpy(real_buffer + 4, buffer, len);
1859 len += 4;
1860 real_buffer[0] = 0;
1861 real_buffer[1] = data->medium_type;
1862 real_buffer[2] = data->device_specific;
1863 real_buffer[3] = data->block_descriptor_length;
1864
1865
1866 cmd[0] = MODE_SELECT;
1867 cmd[4] = len;
1868 }
1869
1870 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001871 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06001872 kfree(real_buffer);
1873 return ret;
1874}
1875EXPORT_SYMBOL_GPL(scsi_mode_select);
1876
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877/**
Rob Landleyeb448202007-11-03 13:30:39 -05001878 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001879 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 * @dbd: set if mode sense will allow block descriptors to be returned
1881 * @modepage: mode page being requested
1882 * @buffer: request buffer (may not be smaller than eight bytes)
1883 * @len: length of request buffer.
1884 * @timeout: command timeout
1885 * @retries: number of retries before failing
1886 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001887 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001888 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889 *
1890 * Returns zero if unsuccessful, or the header offset (either 4
1891 * or 8 depending on whether a six or ten byte command was
1892 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001893 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894int
James Bottomley1cf72692005-08-28 11:27:01 -05001895scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001897 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1898{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899 unsigned char cmd[12];
1900 int use_10_for_ms;
1901 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001902 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001903 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904
1905 memset(data, 0, sizeof(*data));
1906 memset(&cmd[0], 0, 12);
1907 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1908 cmd[2] = modepage;
1909
James Bottomleyea73a9f2005-08-28 11:33:52 -05001910 /* caller might not be interested in sense, but we need it */
1911 if (!sshdr)
1912 sshdr = &my_sshdr;
1913
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001915 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001916
1917 if (use_10_for_ms) {
1918 if (len < 8)
1919 len = 8;
1920
1921 cmd[0] = MODE_SENSE_10;
1922 cmd[8] = len;
1923 header_length = 8;
1924 } else {
1925 if (len < 4)
1926 len = 4;
1927
1928 cmd[0] = MODE_SENSE;
1929 cmd[4] = len;
1930 header_length = 4;
1931 }
1932
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933 memset(buffer, 0, len);
1934
James Bottomley1cf72692005-08-28 11:27:01 -05001935 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001936 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937
1938 /* This code looks awful: what it's doing is making sure an
1939 * ILLEGAL REQUEST sense return identifies the actual command
1940 * byte as the problem. MODE_SENSE commands can return
1941 * ILLEGAL REQUEST if the code page isn't supported */
1942
James Bottomley1cf72692005-08-28 11:27:01 -05001943 if (use_10_for_ms && !scsi_status_is_good(result) &&
1944 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001945 if (scsi_sense_valid(sshdr)) {
1946 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1947 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948 /*
1949 * Invalid command operation code
1950 */
James Bottomley1cf72692005-08-28 11:27:01 -05001951 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001952 goto retry;
1953 }
1954 }
1955 }
1956
James Bottomley1cf72692005-08-28 11:27:01 -05001957 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001958 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1959 (modepage == 6 || modepage == 8))) {
1960 /* Initio breakage? */
1961 header_length = 0;
1962 data->length = 13;
1963 data->medium_type = 0;
1964 data->device_specific = 0;
1965 data->longlba = 0;
1966 data->block_descriptor_length = 0;
1967 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001968 data->length = buffer[0]*256 + buffer[1] + 2;
1969 data->medium_type = buffer[2];
1970 data->device_specific = buffer[3];
1971 data->longlba = buffer[4] & 0x01;
1972 data->block_descriptor_length = buffer[6]*256
1973 + buffer[7];
1974 } else {
1975 data->length = buffer[0] + 1;
1976 data->medium_type = buffer[1];
1977 data->device_specific = buffer[2];
1978 data->block_descriptor_length = buffer[3];
1979 }
Al Viro6d73c852006-02-23 02:03:16 +01001980 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981 }
1982
James Bottomley1cf72692005-08-28 11:27:01 -05001983 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984}
1985EXPORT_SYMBOL(scsi_mode_sense);
1986
James Bottomley001aac22007-12-02 19:10:40 +02001987/**
1988 * scsi_test_unit_ready - test if unit is ready
1989 * @sdev: scsi device to change the state of.
1990 * @timeout: command timeout
1991 * @retries: number of retries before failing
1992 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1993 * returning sense. Make sure that this is cleared before passing
1994 * in.
1995 *
1996 * Returns zero if unsuccessful or an error if TUR failed. For
1997 * removable media, a return of NOT_READY or UNIT_ATTENTION is
1998 * translated to success, with the ->changed flag updated.
1999 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000int
James Bottomley001aac22007-12-02 19:10:40 +02002001scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2002 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004 char cmd[] = {
2005 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2006 };
James Bottomley001aac22007-12-02 19:10:40 +02002007 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002009
2010 if (!sshdr_external)
2011 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2012 else
2013 sshdr = sshdr_external;
2014
2015 /* try to eat the UNIT_ATTENTION if there are enough retries */
2016 do {
2017 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002018 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002019 if (sdev->removable && scsi_sense_valid(sshdr) &&
2020 sshdr->sense_key == UNIT_ATTENTION)
2021 sdev->changed = 1;
2022 } while (scsi_sense_valid(sshdr) &&
2023 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002024
2025 if (!sshdr)
2026 /* could not allocate sense buffer, so can't process it */
2027 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028
James Bottomley32c356d2008-08-20 00:58:13 +02002029 if (sdev->removable && scsi_sense_valid(sshdr) &&
2030 (sshdr->sense_key == UNIT_ATTENTION ||
2031 sshdr->sense_key == NOT_READY)) {
2032 sdev->changed = 1;
2033 result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034 }
James Bottomley001aac22007-12-02 19:10:40 +02002035 if (!sshdr_external)
2036 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 return result;
2038}
2039EXPORT_SYMBOL(scsi_test_unit_ready);
2040
2041/**
Rob Landleyeb448202007-11-03 13:30:39 -05002042 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043 * @sdev: scsi device to change the state of.
2044 * @state: state to change to.
2045 *
2046 * Returns zero if unsuccessful or an error if the requested
2047 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002048 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049int
2050scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2051{
2052 enum scsi_device_state oldstate = sdev->sdev_state;
2053
2054 if (state == oldstate)
2055 return 0;
2056
2057 switch (state) {
2058 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002059 switch (oldstate) {
2060 case SDEV_CREATED_BLOCK:
2061 break;
2062 default:
2063 goto illegal;
2064 }
2065 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066
2067 case SDEV_RUNNING:
2068 switch (oldstate) {
2069 case SDEV_CREATED:
2070 case SDEV_OFFLINE:
2071 case SDEV_QUIESCE:
2072 case SDEV_BLOCK:
2073 break;
2074 default:
2075 goto illegal;
2076 }
2077 break;
2078
2079 case SDEV_QUIESCE:
2080 switch (oldstate) {
2081 case SDEV_RUNNING:
2082 case SDEV_OFFLINE:
2083 break;
2084 default:
2085 goto illegal;
2086 }
2087 break;
2088
2089 case SDEV_OFFLINE:
2090 switch (oldstate) {
2091 case SDEV_CREATED:
2092 case SDEV_RUNNING:
2093 case SDEV_QUIESCE:
2094 case SDEV_BLOCK:
2095 break;
2096 default:
2097 goto illegal;
2098 }
2099 break;
2100
2101 case SDEV_BLOCK:
2102 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002103 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002104 case SDEV_CREATED_BLOCK:
2105 break;
2106 default:
2107 goto illegal;
2108 }
2109 break;
2110
2111 case SDEV_CREATED_BLOCK:
2112 switch (oldstate) {
2113 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002114 break;
2115 default:
2116 goto illegal;
2117 }
2118 break;
2119
2120 case SDEV_CANCEL:
2121 switch (oldstate) {
2122 case SDEV_CREATED:
2123 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002124 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 case SDEV_OFFLINE:
2126 case SDEV_BLOCK:
2127 break;
2128 default:
2129 goto illegal;
2130 }
2131 break;
2132
2133 case SDEV_DEL:
2134 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002135 case SDEV_CREATED:
2136 case SDEV_RUNNING:
2137 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002138 case SDEV_CANCEL:
2139 break;
2140 default:
2141 goto illegal;
2142 }
2143 break;
2144
2145 }
2146 sdev->sdev_state = state;
2147 return 0;
2148
2149 illegal:
2150 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002151 sdev_printk(KERN_ERR, sdev,
2152 "Illegal state transition %s->%s\n",
2153 scsi_device_state_name(oldstate),
2154 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 );
2156 return -EINVAL;
2157}
2158EXPORT_SYMBOL(scsi_device_set_state);
2159
2160/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002161 * sdev_evt_emit - emit a single SCSI device uevent
2162 * @sdev: associated SCSI device
2163 * @evt: event to emit
2164 *
2165 * Send a single uevent (scsi_event) to the associated scsi_device.
2166 */
2167static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2168{
2169 int idx = 0;
2170 char *envp[3];
2171
2172 switch (evt->evt_type) {
2173 case SDEV_EVT_MEDIA_CHANGE:
2174 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2175 break;
2176
2177 default:
2178 /* do nothing */
2179 break;
2180 }
2181
2182 envp[idx++] = NULL;
2183
2184 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2185}
2186
2187/**
2188 * sdev_evt_thread - send a uevent for each scsi event
2189 * @work: work struct for scsi_device
2190 *
2191 * Dispatch queued events to their associated scsi_device kobjects
2192 * as uevents.
2193 */
2194void scsi_evt_thread(struct work_struct *work)
2195{
2196 struct scsi_device *sdev;
2197 LIST_HEAD(event_list);
2198
2199 sdev = container_of(work, struct scsi_device, event_work);
2200
2201 while (1) {
2202 struct scsi_event *evt;
2203 struct list_head *this, *tmp;
2204 unsigned long flags;
2205
2206 spin_lock_irqsave(&sdev->list_lock, flags);
2207 list_splice_init(&sdev->event_list, &event_list);
2208 spin_unlock_irqrestore(&sdev->list_lock, flags);
2209
2210 if (list_empty(&event_list))
2211 break;
2212
2213 list_for_each_safe(this, tmp, &event_list) {
2214 evt = list_entry(this, struct scsi_event, node);
2215 list_del(&evt->node);
2216 scsi_evt_emit(sdev, evt);
2217 kfree(evt);
2218 }
2219 }
2220}
2221
2222/**
2223 * sdev_evt_send - send asserted event to uevent thread
2224 * @sdev: scsi_device event occurred on
2225 * @evt: event to send
2226 *
2227 * Assert scsi device event asynchronously.
2228 */
2229void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2230{
2231 unsigned long flags;
2232
Kay Sievers4d1566e2008-03-19 13:04:47 +01002233#if 0
2234 /* FIXME: currently this check eliminates all media change events
2235 * for polled devices. Need to update to discriminate between AN
2236 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002237 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2238 kfree(evt);
2239 return;
2240 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002241#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002242
2243 spin_lock_irqsave(&sdev->list_lock, flags);
2244 list_add_tail(&evt->node, &sdev->event_list);
2245 schedule_work(&sdev->event_work);
2246 spin_unlock_irqrestore(&sdev->list_lock, flags);
2247}
2248EXPORT_SYMBOL_GPL(sdev_evt_send);
2249
2250/**
2251 * sdev_evt_alloc - allocate a new scsi event
2252 * @evt_type: type of event to allocate
2253 * @gfpflags: GFP flags for allocation
2254 *
2255 * Allocates and returns a new scsi_event.
2256 */
2257struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2258 gfp_t gfpflags)
2259{
2260 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2261 if (!evt)
2262 return NULL;
2263
2264 evt->evt_type = evt_type;
2265 INIT_LIST_HEAD(&evt->node);
2266
2267 /* evt_type-specific initialization, if any */
2268 switch (evt_type) {
2269 case SDEV_EVT_MEDIA_CHANGE:
2270 default:
2271 /* do nothing */
2272 break;
2273 }
2274
2275 return evt;
2276}
2277EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2278
2279/**
2280 * sdev_evt_send_simple - send asserted event to uevent thread
2281 * @sdev: scsi_device event occurred on
2282 * @evt_type: type of event to send
2283 * @gfpflags: GFP flags for allocation
2284 *
2285 * Assert scsi device event asynchronously, given an event type.
2286 */
2287void sdev_evt_send_simple(struct scsi_device *sdev,
2288 enum scsi_device_event evt_type, gfp_t gfpflags)
2289{
2290 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2291 if (!evt) {
2292 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2293 evt_type);
2294 return;
2295 }
2296
2297 sdev_evt_send(sdev, evt);
2298}
2299EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2300
2301/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302 * scsi_device_quiesce - Block user issued commands.
2303 * @sdev: scsi device to quiesce.
2304 *
2305 * This works by trying to transition to the SDEV_QUIESCE state
2306 * (which must be a legal transition). When the device is in this
2307 * state, only special requests will be accepted, all others will
2308 * be deferred. Since special requests may also be requeued requests,
2309 * a successful return doesn't guarantee the device will be
2310 * totally quiescent.
2311 *
2312 * Must be called with user context, may sleep.
2313 *
2314 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002315 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316int
2317scsi_device_quiesce(struct scsi_device *sdev)
2318{
2319 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2320 if (err)
2321 return err;
2322
2323 scsi_run_queue(sdev->request_queue);
2324 while (sdev->device_busy) {
2325 msleep_interruptible(200);
2326 scsi_run_queue(sdev->request_queue);
2327 }
2328 return 0;
2329}
2330EXPORT_SYMBOL(scsi_device_quiesce);
2331
2332/**
2333 * scsi_device_resume - Restart user issued commands to a quiesced device.
2334 * @sdev: scsi device to resume.
2335 *
2336 * Moves the device from quiesced back to running and restarts the
2337 * queues.
2338 *
2339 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002340 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341void
2342scsi_device_resume(struct scsi_device *sdev)
2343{
2344 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2345 return;
2346 scsi_run_queue(sdev->request_queue);
2347}
2348EXPORT_SYMBOL(scsi_device_resume);
2349
2350static void
2351device_quiesce_fn(struct scsi_device *sdev, void *data)
2352{
2353 scsi_device_quiesce(sdev);
2354}
2355
2356void
2357scsi_target_quiesce(struct scsi_target *starget)
2358{
2359 starget_for_each_device(starget, NULL, device_quiesce_fn);
2360}
2361EXPORT_SYMBOL(scsi_target_quiesce);
2362
2363static void
2364device_resume_fn(struct scsi_device *sdev, void *data)
2365{
2366 scsi_device_resume(sdev);
2367}
2368
2369void
2370scsi_target_resume(struct scsi_target *starget)
2371{
2372 starget_for_each_device(starget, NULL, device_resume_fn);
2373}
2374EXPORT_SYMBOL(scsi_target_resume);
2375
2376/**
Rob Landleyeb448202007-11-03 13:30:39 -05002377 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378 * @sdev: device to block
2379 *
2380 * Block request made by scsi lld's to temporarily stop all
2381 * scsi commands on the specified device. Called from interrupt
2382 * or normal process context.
2383 *
2384 * Returns zero if successful or error if not
2385 *
2386 * Notes:
2387 * This routine transitions the device to the SDEV_BLOCK state
2388 * (which must be a legal transition). When the device is in this
2389 * state, all commands are deferred until the scsi lld reenables
2390 * the device with scsi_device_unblock or device_block_tmo fires.
2391 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002392 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393int
2394scsi_internal_device_block(struct scsi_device *sdev)
2395{
Jens Axboe165125e2007-07-24 09:28:11 +02002396 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397 unsigned long flags;
2398 int err = 0;
2399
2400 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002401 if (err) {
2402 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2403
2404 if (err)
2405 return err;
2406 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407
2408 /*
2409 * The device has transitioned to SDEV_BLOCK. Stop the
2410 * block layer from calling the midlayer with this device's
2411 * request queue.
2412 */
2413 spin_lock_irqsave(q->queue_lock, flags);
2414 blk_stop_queue(q);
2415 spin_unlock_irqrestore(q->queue_lock, flags);
2416
2417 return 0;
2418}
2419EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2420
2421/**
2422 * scsi_internal_device_unblock - resume a device after a block request
2423 * @sdev: device to resume
2424 *
2425 * Called by scsi lld's or the midlayer to restart the device queue
2426 * for the previously suspended scsi device. Called from interrupt or
2427 * normal process context.
2428 *
2429 * Returns zero if successful or error if not.
2430 *
2431 * Notes:
2432 * This routine transitions the device to the SDEV_RUNNING state
2433 * (which must be a legal transition) allowing the midlayer to
2434 * goose the queue for this device. This routine assumes the
2435 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002436 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002437int
2438scsi_internal_device_unblock(struct scsi_device *sdev)
2439{
Jens Axboe165125e2007-07-24 09:28:11 +02002440 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002441 int err;
2442 unsigned long flags;
2443
2444 /*
2445 * Try to transition the scsi device to SDEV_RUNNING
2446 * and goose the device queue if successful.
2447 */
2448 err = scsi_device_set_state(sdev, SDEV_RUNNING);
James Bottomley6f4267e2008-08-22 16:53:31 -05002449 if (err) {
2450 err = scsi_device_set_state(sdev, SDEV_CREATED);
2451
2452 if (err)
2453 return err;
2454 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455
2456 spin_lock_irqsave(q->queue_lock, flags);
2457 blk_start_queue(q);
2458 spin_unlock_irqrestore(q->queue_lock, flags);
2459
2460 return 0;
2461}
2462EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2463
2464static void
2465device_block(struct scsi_device *sdev, void *data)
2466{
2467 scsi_internal_device_block(sdev);
2468}
2469
2470static int
2471target_block(struct device *dev, void *data)
2472{
2473 if (scsi_is_target_device(dev))
2474 starget_for_each_device(to_scsi_target(dev), NULL,
2475 device_block);
2476 return 0;
2477}
2478
2479void
2480scsi_target_block(struct device *dev)
2481{
2482 if (scsi_is_target_device(dev))
2483 starget_for_each_device(to_scsi_target(dev), NULL,
2484 device_block);
2485 else
2486 device_for_each_child(dev, NULL, target_block);
2487}
2488EXPORT_SYMBOL_GPL(scsi_target_block);
2489
2490static void
2491device_unblock(struct scsi_device *sdev, void *data)
2492{
2493 scsi_internal_device_unblock(sdev);
2494}
2495
2496static int
2497target_unblock(struct device *dev, void *data)
2498{
2499 if (scsi_is_target_device(dev))
2500 starget_for_each_device(to_scsi_target(dev), NULL,
2501 device_unblock);
2502 return 0;
2503}
2504
2505void
2506scsi_target_unblock(struct device *dev)
2507{
2508 if (scsi_is_target_device(dev))
2509 starget_for_each_device(to_scsi_target(dev), NULL,
2510 device_unblock);
2511 else
2512 device_for_each_child(dev, NULL, target_unblock);
2513}
2514EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002515
2516/**
2517 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002518 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002519 * @sg_count: number of segments in sg
2520 * @offset: offset in bytes into sg, on return offset into the mapped area
2521 * @len: bytes to map, on return number of bytes mapped
2522 *
2523 * Returns virtual address of the start of the mapped page
2524 */
Jens Axboec6132da2007-10-16 11:08:49 +02002525void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002526 size_t *offset, size_t *len)
2527{
2528 int i;
2529 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002530 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002531 struct page *page;
2532
Andrew Morton22cfefb2007-02-05 16:39:03 -08002533 WARN_ON(!irqs_disabled());
2534
Jens Axboec6132da2007-10-16 11:08:49 +02002535 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002536 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002537 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002538 if (sg_len > *offset)
2539 break;
2540 }
2541
2542 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002543 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2544 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002545 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002546 WARN_ON(1);
2547 return NULL;
2548 }
2549
2550 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002551 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002552
2553 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002554 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002555 *offset &= ~PAGE_MASK;
2556
2557 /* Bytes in this sg-entry from *offset to the end of the page */
2558 sg_len = PAGE_SIZE - *offset;
2559 if (*len > sg_len)
2560 *len = sg_len;
2561
2562 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2563}
2564EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2565
2566/**
Rob Landleyeb448202007-11-03 13:30:39 -05002567 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002568 * @virt: virtual address to be unmapped
2569 */
2570void scsi_kunmap_atomic_sg(void *virt)
2571{
2572 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2573}
2574EXPORT_SYMBOL(scsi_kunmap_atomic_sg);