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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
3 *
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
8 */
9
10#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060011#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/blkdev.h>
13#include <linux/completion.h>
14#include <linux/kernel.h>
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 Heo5b936292009-05-07 22:24:38 +0900549 int leftover = blk_rq_sectors(req) << 9;
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;
685 unsigned int dlen = req->data_len;
686 unsigned int next_dlen = req->next_rq->data_len;
687
Tejun Heoc3a4d782009-05-07 22:24:37 +0900688 req->resid_len = scsi_out(cmd)->resid;
689 req->next_rq->resid_len = scsi_in(cmd)->resid;
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500690
691 /* The req and req->next_rq have not been completed */
692 BUG_ON(blk_end_bidi_request(req, 0, dlen, next_dlen));
693
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200694 scsi_release_buffers(cmd);
695
696 /*
697 * This will goose the queue request function at the end, so we don't
698 * need to worry about launching another command.
699 */
700 scsi_next_command(cmd);
701}
702
703/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 * Function: scsi_io_completion()
705 *
706 * Purpose: Completion processing for block device I/O requests.
707 *
708 * Arguments: cmd - command that is finished.
709 *
710 * Lock status: Assumed that no lock is held upon entry.
711 *
712 * Returns: Nothing
713 *
714 * Notes: This function is matched in terms of capabilities to
715 * the function that created the scatter-gather list.
716 * In other words, if there are no bounce buffers
717 * (the normal case for most drivers), we don't need
718 * the logic to deal with cleaning up afterwards.
719 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500720 * We must call scsi_end_request(). This will finish off
721 * the specified number of sectors. If we are done, the
722 * command block will be released and the queue function
723 * will be goosed. If we are not done then we have to
724 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500726 * a) We can call scsi_requeue_command(). The request
727 * will be unprepared and put back on the queue. Then
728 * a new command will be created for it. This should
729 * be used if we made forward progress, or if we want
730 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500732 * b) We can call scsi_queue_insert(). The request will
733 * be put back on the queue and retried using the same
734 * command as before, possibly after a delay.
735 *
736 * c) We can call blk_end_request() with -EIO to fail
737 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700739void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740{
741 int result = cmd->result;
James Bottomley44ea91c2008-09-20 00:31:50 +0000742 int this_count;
Jens Axboe165125e2007-07-24 09:28:11 +0200743 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500745 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 struct scsi_sense_hdr sshdr;
747 int sense_valid = 0;
748 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500749 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
750 ACTION_DELAYED_RETRY} action;
751 char *description = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 if (result) {
754 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
755 if (sense_valid)
756 sense_deferred = scsi_sense_is_deferred(&sshdr);
757 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
760 req->errors = result;
761 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 if (sense_valid && req->sense) {
763 /*
764 * SG_IO wants current and deferred errors
765 */
766 int len = 8 + cmd->sense_buffer[7];
767
768 if (len > SCSI_SENSE_BUFFERSIZE)
769 len = SCSI_SENSE_BUFFERSIZE;
770 memcpy(req->sense, cmd->sense_buffer, len);
771 req->sense_len = len;
772 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500773 if (!sense_deferred)
774 error = -EIO;
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400775 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200776 if (scsi_bidi_cmnd(cmd)) {
777 /* will also release_buffers */
778 scsi_end_bidi_request(cmd);
779 return;
780 }
Tejun Heoc3a4d782009-05-07 22:24:37 +0900781 req->resid_len = scsi_get_resid(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 }
783
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200784 BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200785
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 * Next deal with any sectors which we were able to correctly
788 * handle.
789 */
Tejun Heo83096eb2009-05-07 22:24:39 +0900790 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
James Bottomleyd6b0c532006-07-02 10:06:28 -0500791 "%d bytes done.\n",
Tejun Heo83096eb2009-05-07 22:24:39 +0900792 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793
James Bottomleya9bddd72009-03-30 16:55:51 +0000794 /*
795 * Recovered errors need reporting, but they're always treated
796 * as success, so fiddle the result code here. For BLOCK_PC
797 * we already took a copy of the original into rq->errors which
798 * is what gets returned to the user
799 */
800 if (sense_valid && sshdr.sense_key == RECOVERED_ERROR) {
801 if (!(req->cmd_flags & REQ_QUIET))
802 scsi_print_sense("", cmd);
803 result = 0;
804 /* BLOCK_PC may have set error */
805 error = 0;
806 }
807
808 /*
809 * A number of bytes were successfully read. If there
James Bottomleyd6b0c532006-07-02 10:06:28 -0500810 * are leftovers and there is some kind of error
811 * (result != 0), retry the rest.
812 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500813 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500814 return;
James Bottomley44ea91c2008-09-20 00:31:50 +0000815 this_count = blk_rq_bytes(req);
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700816
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500817 error = -EIO;
818
Alan Sternb60af5b2008-11-03 15:56:47 -0500819 if (host_byte(result) == DID_RESET) {
820 /* Third party bus reset or reset for error recovery
821 * reasons. Just retry the command and see what
822 * happens.
823 */
824 action = ACTION_RETRY;
825 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 switch (sshdr.sense_key) {
827 case UNIT_ATTENTION:
828 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700829 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 * and quietly refuse further access.
831 */
832 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500833 description = "Media Changed";
834 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700836 /* Must have been a power glitch, or a
837 * bus reset. Could not have been a
838 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500839 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700840 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500841 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 }
843 break;
844 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700845 /* If we had an ILLEGAL REQUEST returned, then
846 * we may have performed an unsupported
847 * command. The only thing this should be
848 * would be a ten byte read where only a six
849 * byte read was supported. Also, on a system
850 * where READ CAPACITY failed, we may have
851 * read past the end of the disk.
852 */
Jens Axboe26a68012005-11-29 21:03:34 +0100853 if ((cmd->device->use_10_for_rw &&
854 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 (cmd->cmnd[0] == READ_10 ||
856 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500857 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500859 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500860 } else if (sshdr.asc == 0x10) /* DIX */ {
861 description = "Host Data Integrity Failure";
862 action = ACTION_FAIL;
863 error = -EILSEQ;
Alan Sternb60af5b2008-11-03 15:56:47 -0500864 } else
865 action = ACTION_FAIL;
866 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400867 case ABORTED_COMMAND:
James Bottomley126c0982009-02-19 21:48:54 +0000868 action = ACTION_FAIL;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400869 if (sshdr.asc == 0x10) { /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500870 description = "Target Data Integrity Failure";
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500871 error = -EILSEQ;
James Bottomley126c0982009-02-19 21:48:54 +0000872 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 break;
874 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700875 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500876 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500878 if (sshdr.asc == 0x04) {
879 switch (sshdr.ascq) {
880 case 0x01: /* becoming ready */
881 case 0x04: /* format in progress */
882 case 0x05: /* rebuild in progress */
883 case 0x06: /* recalculation in progress */
884 case 0x07: /* operation in progress */
885 case 0x08: /* Long write in progress */
886 case 0x09: /* self test in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -0500887 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500888 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -0500889 default:
890 description = "Device not ready";
891 action = ACTION_FAIL;
892 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500893 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500894 } else {
895 description = "Device not ready";
896 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500898 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700900 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -0500901 action = ACTION_FAIL;
902 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 default:
Alan Sternb60af5b2008-11-03 15:56:47 -0500904 description = "Unhandled sense code";
905 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 break;
907 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500908 } else {
909 description = "Unhandled error code";
910 action = ACTION_FAIL;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700911 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500912
913 switch (action) {
914 case ACTION_FAIL:
915 /* Give up and fail the remainder of the request */
James Bottomley79ed2422009-01-06 13:15:20 -0600916 scsi_release_buffers(cmd);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200917 if (!(req->cmd_flags & REQ_QUIET)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500918 if (description)
Alan Stern3dbf6a52008-12-15 10:31:28 -0500919 scmd_printk(KERN_INFO, cmd, "%s\n",
Alan Sternb60af5b2008-11-03 15:56:47 -0500920 description);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500921 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500922 if (driver_byte(result) & DRIVER_SENSE)
923 scsi_print_sense("", cmd);
924 }
Tejun Heo40cbbb72009-04-23 11:05:19 +0900925 blk_end_request_all(req, -EIO);
Alan Sternb60af5b2008-11-03 15:56:47 -0500926 scsi_next_command(cmd);
927 break;
928 case ACTION_REPREP:
929 /* Unprep the request and put it back at the head of the queue.
930 * A new command will be prepared and issued.
931 */
James Bottomley79ed2422009-01-06 13:15:20 -0600932 scsi_release_buffers(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500933 scsi_requeue_command(q, cmd);
934 break;
935 case ACTION_RETRY:
936 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -0600937 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500938 break;
939 case ACTION_DELAYED_RETRY:
940 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -0600941 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500942 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 }
944}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200946static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
947 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200949 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950
951 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +0100952 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200954 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
955 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -0400957 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958
Christoph Hellwig3b003152006-11-04 20:10:55 +0100959 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960
961 /*
962 * Next, walk the list, and fill in the addresses and sizes of
963 * each segment.
964 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200965 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
966 BUG_ON(count > sdb->table.nents);
967 sdb->table.nents = count;
Tejun Heo6b007692008-02-19 11:36:35 +0100968 if (blk_pc_request(req))
969 sdb->length = req->data_len;
970 else
Tejun Heo83096eb2009-05-07 22:24:39 +0900971 sdb->length = blk_rq_sectors(req) << 9;
Rusty Russell4a03d902007-11-19 11:28:48 +1100972 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200974
975/*
976 * Function: scsi_init_io()
977 *
978 * Purpose: SCSI I/O initialize function.
979 *
980 * Arguments: cmd - Command descriptor we wish to initialize
981 *
982 * Returns: 0 on success
983 * BLKPREP_DEFER if the failure is retryable
984 * BLKPREP_KILL if the failure is fatal
985 */
986int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
987{
988 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
989 if (error)
990 goto err_exit;
991
992 if (blk_bidi_rq(cmd->request)) {
993 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -0400994 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200995 if (!bidi_sdb) {
996 error = BLKPREP_DEFER;
997 goto err_exit;
998 }
999
1000 cmd->request->next_rq->special = bidi_sdb;
1001 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
1002 GFP_ATOMIC);
1003 if (error)
1004 goto err_exit;
1005 }
1006
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001007 if (blk_integrity_rq(cmd->request)) {
1008 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1009 int ivecs, count;
1010
1011 BUG_ON(prot_sdb == NULL);
1012 ivecs = blk_rq_count_integrity_sg(cmd->request);
1013
1014 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1015 error = BLKPREP_DEFER;
1016 goto err_exit;
1017 }
1018
1019 count = blk_rq_map_integrity_sg(cmd->request,
1020 prot_sdb->table.sgl);
1021 BUG_ON(unlikely(count > ivecs));
1022
1023 cmd->prot_sdb = prot_sdb;
1024 cmd->prot_sdb->table.nents = count;
1025 }
1026
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001027 return BLKPREP_OK ;
1028
1029err_exit:
1030 scsi_release_buffers(cmd);
1031 if (error == BLKPREP_KILL)
1032 scsi_put_command(cmd);
1033 else /* BLKPREP_DEFER */
1034 scsi_unprep_request(cmd->request);
1035
1036 return error;
1037}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001038EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039
Christoph Hellwig3b003152006-11-04 20:10:55 +01001040static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1041 struct request *req)
1042{
1043 struct scsi_cmnd *cmd;
1044
1045 if (!req->special) {
1046 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1047 if (unlikely(!cmd))
1048 return NULL;
1049 req->special = cmd;
1050 } else {
1051 cmd = req->special;
1052 }
1053
1054 /* pull a tag out of the request if we have one */
1055 cmd->tag = req->tag;
1056 cmd->request = req;
1057
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001058 cmd->cmnd = req->cmd;
1059
Christoph Hellwig3b003152006-11-04 20:10:55 +01001060 return cmd;
1061}
1062
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001063int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001064{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001065 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001066 int ret = scsi_prep_state_check(sdev, req);
1067
1068 if (ret != BLKPREP_OK)
1069 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001070
1071 cmd = scsi_get_cmd_from_req(sdev, req);
1072 if (unlikely(!cmd))
1073 return BLKPREP_DEFER;
1074
1075 /*
1076 * BLOCK_PC requests may transfer data, in which case they must
1077 * a bio attached to them. Or they might contain a SCSI command
1078 * that does not transfer data, in which case they may optionally
1079 * submit a request without an attached bio.
1080 */
1081 if (req->bio) {
1082 int ret;
1083
1084 BUG_ON(!req->nr_phys_segments);
1085
Boaz Harroshbb52d822007-12-13 16:14:27 -08001086 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001087 if (unlikely(ret))
1088 return ret;
1089 } else {
1090 BUG_ON(req->data_len);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001091
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001092 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001093 req->buffer = NULL;
1094 }
James Bottomley7b163182005-12-15 20:17:02 -06001095
James Bottomley7b163182005-12-15 20:17:02 -06001096 cmd->cmd_len = req->cmd_len;
1097 if (!req->data_len)
1098 cmd->sc_data_direction = DMA_NONE;
1099 else if (rq_data_dir(req) == WRITE)
1100 cmd->sc_data_direction = DMA_TO_DEVICE;
1101 else
1102 cmd->sc_data_direction = DMA_FROM_DEVICE;
1103
1104 cmd->transfersize = req->data_len;
1105 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001106 return BLKPREP_OK;
1107}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001108EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001109
1110/*
1111 * Setup a REQ_TYPE_FS command. These are simple read/write request
1112 * from filesystems that still need to be translated to SCSI CDBs from
1113 * the ULD.
1114 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001115int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001116{
1117 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001118 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001119
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001120 if (ret != BLKPREP_OK)
1121 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001122
1123 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1124 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1125 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1126 if (ret != BLKPREP_OK)
1127 return ret;
1128 }
1129
Christoph Hellwig3b003152006-11-04 20:10:55 +01001130 /*
1131 * Filesystem requests must transfer data.
1132 */
1133 BUG_ON(!req->nr_phys_segments);
1134
1135 cmd = scsi_get_cmd_from_req(sdev, req);
1136 if (unlikely(!cmd))
1137 return BLKPREP_DEFER;
1138
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001139 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001140 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001141}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001142EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001143
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001144int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001146 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147
1148 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001149 * If the device is not in running state we will reject some
1150 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001153 switch (sdev->sdev_state) {
1154 case SDEV_OFFLINE:
1155 /*
1156 * If the device is offline we refuse to process any
1157 * commands. The device must be brought online
1158 * before trying any recovery commands.
1159 */
1160 sdev_printk(KERN_ERR, sdev,
1161 "rejecting I/O to offline device\n");
1162 ret = BLKPREP_KILL;
1163 break;
1164 case SDEV_DEL:
1165 /*
1166 * If the device is fully deleted, we refuse to
1167 * process any commands as well.
1168 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001169 sdev_printk(KERN_ERR, sdev,
1170 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001171 ret = BLKPREP_KILL;
1172 break;
1173 case SDEV_QUIESCE:
1174 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001175 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001176 /*
1177 * If the devices is blocked we defer normal commands.
1178 */
1179 if (!(req->cmd_flags & REQ_PREEMPT))
1180 ret = BLKPREP_DEFER;
1181 break;
1182 default:
1183 /*
1184 * For any other not fully online state we only allow
1185 * special commands. In particular any user initiated
1186 * command is not allowed.
1187 */
1188 if (!(req->cmd_flags & REQ_PREEMPT))
1189 ret = BLKPREP_KILL;
1190 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001193 return ret;
1194}
1195EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001197int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1198{
1199 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200
Christoph Hellwig3b003152006-11-04 20:10:55 +01001201 switch (ret) {
1202 case BLKPREP_KILL:
1203 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001204 /* release the command and kill it */
1205 if (req->special) {
1206 struct scsi_cmnd *cmd = req->special;
1207 scsi_release_buffers(cmd);
1208 scsi_put_command(cmd);
1209 req->special = NULL;
1210 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001211 break;
1212 case BLKPREP_DEFER:
1213 /*
1214 * If we defer, the elv_next_request() returns NULL, but the
1215 * queue must be restarted, so we plug here if no returning
1216 * command will automatically do that.
1217 */
1218 if (sdev->device_busy == 0)
1219 blk_plug_device(q);
1220 break;
1221 default:
1222 req->cmd_flags |= REQ_DONTPREP;
1223 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224
Christoph Hellwig3b003152006-11-04 20:10:55 +01001225 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001227EXPORT_SYMBOL(scsi_prep_return);
1228
James Bottomley751bf4d2008-01-02 11:14:30 -06001229int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001230{
1231 struct scsi_device *sdev = q->queuedata;
1232 int ret = BLKPREP_KILL;
1233
1234 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1235 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1236 return scsi_prep_return(q, req, ret);
1237}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238
1239/*
1240 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1241 * return 0.
1242 *
1243 * Called with the queue_lock held.
1244 */
1245static inline int scsi_dev_queue_ready(struct request_queue *q,
1246 struct scsi_device *sdev)
1247{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 if (sdev->device_busy == 0 && sdev->device_blocked) {
1249 /*
1250 * unblock after device_blocked iterates to zero
1251 */
1252 if (--sdev->device_blocked == 0) {
1253 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001254 sdev_printk(KERN_INFO, sdev,
1255 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 } else {
1257 blk_plug_device(q);
1258 return 0;
1259 }
1260 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001261 if (scsi_device_is_busy(sdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 return 0;
1263
1264 return 1;
1265}
1266
Mike Christief0c0a372008-08-17 15:24:38 -05001267
1268/*
1269 * scsi_target_queue_ready: checks if there we can send commands to target
1270 * @sdev: scsi device on starget to check.
1271 *
1272 * Called with the host lock held.
1273 */
1274static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1275 struct scsi_device *sdev)
1276{
1277 struct scsi_target *starget = scsi_target(sdev);
1278
1279 if (starget->single_lun) {
1280 if (starget->starget_sdev_user &&
1281 starget->starget_sdev_user != sdev)
1282 return 0;
1283 starget->starget_sdev_user = sdev;
1284 }
1285
1286 if (starget->target_busy == 0 && starget->target_blocked) {
1287 /*
1288 * unblock after target_blocked iterates to zero
1289 */
1290 if (--starget->target_blocked == 0) {
1291 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1292 "unblocking target at zero depth\n"));
1293 } else {
1294 blk_plug_device(sdev->request_queue);
1295 return 0;
1296 }
1297 }
1298
1299 if (scsi_target_is_busy(starget)) {
1300 if (list_empty(&sdev->starved_entry)) {
1301 list_add_tail(&sdev->starved_entry,
1302 &shost->starved_list);
1303 return 0;
1304 }
1305 }
1306
1307 /* We're OK to process the command, so we can't be starved */
1308 if (!list_empty(&sdev->starved_entry))
1309 list_del_init(&sdev->starved_entry);
1310 return 1;
1311}
1312
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313/*
1314 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1315 * return 0. We must end up running the queue again whenever 0 is
1316 * returned, else IO can hang.
1317 *
1318 * Called with host_lock held.
1319 */
1320static inline int scsi_host_queue_ready(struct request_queue *q,
1321 struct Scsi_Host *shost,
1322 struct scsi_device *sdev)
1323{
James Bottomley939647e2005-09-18 15:05:20 -05001324 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 return 0;
1326 if (shost->host_busy == 0 && shost->host_blocked) {
1327 /*
1328 * unblock after host_blocked iterates to zero
1329 */
1330 if (--shost->host_blocked == 0) {
1331 SCSI_LOG_MLQUEUE(3,
1332 printk("scsi%d unblocking host at zero depth\n",
1333 shost->host_no));
1334 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 return 0;
1336 }
1337 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001338 if (scsi_host_is_busy(shost)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 if (list_empty(&sdev->starved_entry))
1340 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1341 return 0;
1342 }
1343
1344 /* We're OK to process the command, so we can't be starved */
1345 if (!list_empty(&sdev->starved_entry))
1346 list_del_init(&sdev->starved_entry);
1347
1348 return 1;
1349}
1350
1351/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001352 * Busy state exporting function for request stacking drivers.
1353 *
1354 * For efficiency, no lock is taken to check the busy state of
1355 * shost/starget/sdev, since the returned value is not guaranteed and
1356 * may be changed after request stacking drivers call the function,
1357 * regardless of taking lock or not.
1358 *
1359 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1360 * (e.g. !sdev), scsi needs to return 'not busy'.
1361 * Otherwise, request stacking drivers may hold requests forever.
1362 */
1363static int scsi_lld_busy(struct request_queue *q)
1364{
1365 struct scsi_device *sdev = q->queuedata;
1366 struct Scsi_Host *shost;
1367 struct scsi_target *starget;
1368
1369 if (!sdev)
1370 return 0;
1371
1372 shost = sdev->host;
1373 starget = scsi_target(sdev);
1374
1375 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) ||
1376 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev))
1377 return 1;
1378
1379 return 0;
1380}
1381
1382/*
James Bottomleye91442b2005-09-09 10:44:16 -05001383 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 */
Jens Axboe165125e2007-07-24 09:28:11 +02001385static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386{
James Bottomleye91442b2005-09-09 10:44:16 -05001387 struct scsi_cmnd *cmd = req->special;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001388 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -05001389 struct scsi_target *starget = scsi_target(sdev);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001390 struct Scsi_Host *shost = sdev->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391
James Bottomley788ce432005-09-09 13:40:23 -05001392 blkdev_dequeue_request(req);
1393
James Bottomleye91442b2005-09-09 10:44:16 -05001394 if (unlikely(cmd == NULL)) {
1395 printk(KERN_CRIT "impossible request in %s.\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001396 __func__);
James Bottomleye91442b2005-09-09 10:44:16 -05001397 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 }
James Bottomleye91442b2005-09-09 10:44:16 -05001399
1400 scsi_init_cmd_errh(cmd);
1401 cmd->result = DID_NO_CONNECT << 16;
1402 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001403
1404 /*
1405 * SCSI request completion path will do scsi_device_unbusy(),
1406 * bump busy counts. To bump the counters, we need to dance
1407 * with the locks as normal issue path does.
1408 */
1409 sdev->device_busy++;
1410 spin_unlock(sdev->request_queue->queue_lock);
1411 spin_lock(shost->host_lock);
1412 shost->host_busy++;
Mike Christief0c0a372008-08-17 15:24:38 -05001413 starget->target_busy++;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001414 spin_unlock(shost->host_lock);
1415 spin_lock(sdev->request_queue->queue_lock);
1416
Jens Axboe242f9dc2008-09-14 05:55:09 -07001417 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418}
1419
Jens Axboe1aea6432006-01-09 16:03:03 +01001420static void scsi_softirq_done(struct request *rq)
1421{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001422 struct scsi_cmnd *cmd = rq->special;
1423 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001424 int disposition;
1425
1426 INIT_LIST_HEAD(&cmd->eh_entry);
1427
Jens Axboe242f9dc2008-09-14 05:55:09 -07001428 /*
1429 * Set the serial numbers back to zero
1430 */
1431 cmd->serial_number = 0;
1432
1433 atomic_inc(&cmd->device->iodone_cnt);
1434 if (cmd->result)
1435 atomic_inc(&cmd->device->ioerr_cnt);
1436
Jens Axboe1aea6432006-01-09 16:03:03 +01001437 disposition = scsi_decide_disposition(cmd);
1438 if (disposition != SUCCESS &&
1439 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1440 sdev_printk(KERN_ERR, cmd->device,
1441 "timing out command, waited %lus\n",
1442 wait_for/HZ);
1443 disposition = SUCCESS;
1444 }
1445
1446 scsi_log_completion(cmd, disposition);
1447
1448 switch (disposition) {
1449 case SUCCESS:
1450 scsi_finish_command(cmd);
1451 break;
1452 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001453 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001454 break;
1455 case ADD_TO_MLQUEUE:
1456 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1457 break;
1458 default:
1459 if (!scsi_eh_scmd_add(cmd, 0))
1460 scsi_finish_command(cmd);
1461 }
1462}
1463
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464/*
1465 * Function: scsi_request_fn()
1466 *
1467 * Purpose: Main strategy routine for SCSI.
1468 *
1469 * Arguments: q - Pointer to actual queue.
1470 *
1471 * Returns: Nothing
1472 *
1473 * Lock status: IO request lock assumed to be held when called.
1474 */
1475static void scsi_request_fn(struct request_queue *q)
1476{
1477 struct scsi_device *sdev = q->queuedata;
1478 struct Scsi_Host *shost;
1479 struct scsi_cmnd *cmd;
1480 struct request *req;
1481
1482 if (!sdev) {
1483 printk("scsi: killing requests for dead queue\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001484 while ((req = elv_next_request(q)) != NULL)
1485 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486 return;
1487 }
1488
1489 if(!get_device(&sdev->sdev_gendev))
1490 /* We must be tearing the block queue down already */
1491 return;
1492
1493 /*
1494 * To start with, we keep looping until the queue is empty, or until
1495 * the host is no longer able to accept any more requests.
1496 */
1497 shost = sdev->host;
1498 while (!blk_queue_plugged(q)) {
1499 int rtn;
1500 /*
1501 * get next queueable request. We do this early to make sure
1502 * that the request is fully prepared even if we cannot
1503 * accept it.
1504 */
1505 req = elv_next_request(q);
1506 if (!req || !scsi_dev_queue_ready(q, sdev))
1507 break;
1508
1509 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001510 sdev_printk(KERN_ERR, sdev,
1511 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001512 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001513 continue;
1514 }
1515
1516
1517 /*
1518 * Remove the request from the request list.
1519 */
1520 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1521 blkdev_dequeue_request(req);
1522 sdev->device_busy++;
1523
1524 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001525 cmd = req->special;
1526 if (unlikely(cmd == NULL)) {
1527 printk(KERN_CRIT "impossible request in %s.\n"
1528 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001529 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001530 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001531 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001532 BUG();
1533 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534 spin_lock(shost->host_lock);
1535
Mike Christieecefe8a2008-07-11 19:50:35 -05001536 /*
1537 * We hit this when the driver is using a host wide
1538 * tag map. For device level tag maps the queue_depth check
1539 * in the device ready fn would prevent us from trying
1540 * to allocate a tag. Since the map is a shared host resource
1541 * we add the dev to the starved list so it eventually gets
1542 * a run when a tag is freed.
1543 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001544 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001545 if (list_empty(&sdev->starved_entry))
1546 list_add_tail(&sdev->starved_entry,
1547 &shost->starved_list);
1548 goto not_ready;
1549 }
1550
Mike Christief0c0a372008-08-17 15:24:38 -05001551 if (!scsi_target_queue_ready(shost, sdev))
1552 goto not_ready;
1553
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 if (!scsi_host_queue_ready(q, shost, sdev))
1555 goto not_ready;
Mike Christief0c0a372008-08-17 15:24:38 -05001556
1557 scsi_target(sdev)->target_busy++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558 shost->host_busy++;
1559
1560 /*
1561 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1562 * take the lock again.
1563 */
1564 spin_unlock_irq(shost->host_lock);
1565
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 /*
1567 * Finally, initialize any error handling parameters, and set up
1568 * the timers for timeouts.
1569 */
1570 scsi_init_cmd_errh(cmd);
1571
1572 /*
1573 * Dispatch the command to the low-level driver.
1574 */
1575 rtn = scsi_dispatch_cmd(cmd);
1576 spin_lock_irq(q->queue_lock);
1577 if(rtn) {
1578 /* we're refusing the command; because of
1579 * the way locks get dropped, we need to
1580 * check here if plugging is required */
1581 if(sdev->device_busy == 0)
1582 blk_plug_device(q);
1583
1584 break;
1585 }
1586 }
1587
1588 goto out;
1589
1590 not_ready:
1591 spin_unlock_irq(shost->host_lock);
1592
1593 /*
1594 * lock q, handle tag, requeue req, and decrement device_busy. We
1595 * must return with queue_lock held.
1596 *
1597 * Decrementing device_busy without checking it is OK, as all such
1598 * cases (host limits or settings) should run the queue at some
1599 * later time.
1600 */
1601 spin_lock_irq(q->queue_lock);
1602 blk_requeue_request(q, req);
1603 sdev->device_busy--;
1604 if(sdev->device_busy == 0)
1605 blk_plug_device(q);
1606 out:
1607 /* must be careful here...if we trigger the ->remove() function
1608 * we cannot be holding the q lock */
1609 spin_unlock_irq(q->queue_lock);
1610 put_device(&sdev->sdev_gendev);
1611 spin_lock_irq(q->queue_lock);
1612}
1613
1614u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1615{
1616 struct device *host_dev;
1617 u64 bounce_limit = 0xffffffff;
1618
1619 if (shost->unchecked_isa_dma)
1620 return BLK_BOUNCE_ISA;
1621 /*
1622 * Platforms with virtual-DMA translation
1623 * hardware have no practical limit.
1624 */
1625 if (!PCI_DMA_BUS_IS_PHYS)
1626 return BLK_BOUNCE_ANY;
1627
1628 host_dev = scsi_get_device(shost);
1629 if (host_dev && host_dev->dma_mask)
1630 bounce_limit = *host_dev->dma_mask;
1631
1632 return bounce_limit;
1633}
1634EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1635
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001636struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1637 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001640 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001641
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001642 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643 if (!q)
1644 return NULL;
1645
Jens Axboea8474ce2007-08-07 09:02:51 +02001646 /*
1647 * this limit is imposed by hardware restrictions
1648 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649 blk_queue_max_hw_segments(q, shost->sg_tablesize);
James Bottomleyd3f46f32008-01-15 11:11:46 -06001650 blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
Jens Axboea8474ce2007-08-07 09:02:51 +02001651
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652 blk_queue_max_sectors(q, shost->max_sectors);
1653 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1654 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001655 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001657 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1658
Nick Piggin75ad23b2008-04-29 14:48:33 +02001659 /* New queue, no concurrency on queue_flags */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660 if (!shost->use_clustering)
Nick Piggin75ad23b2008-04-29 14:48:33 +02001661 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
James Bottomley465ff312008-01-01 10:00:10 -06001662
1663 /*
1664 * set a reasonable default alignment on word boundaries: the
1665 * host and device may alter it using
1666 * blk_queue_update_dma_alignment() later.
1667 */
1668 blk_queue_dma_alignment(q, 0x03);
1669
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 return q;
1671}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001672EXPORT_SYMBOL(__scsi_alloc_queue);
1673
1674struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1675{
1676 struct request_queue *q;
1677
1678 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1679 if (!q)
1680 return NULL;
1681
1682 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001683 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001684 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001685 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001686 return q;
1687}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688
1689void scsi_free_queue(struct request_queue *q)
1690{
1691 blk_cleanup_queue(q);
1692}
1693
1694/*
1695 * Function: scsi_block_requests()
1696 *
1697 * Purpose: Utility function used by low-level drivers to prevent further
1698 * commands from being queued to the device.
1699 *
1700 * Arguments: shost - Host in question
1701 *
1702 * Returns: Nothing
1703 *
1704 * Lock status: No locks are assumed held.
1705 *
1706 * Notes: There is no timer nor any other means by which the requests
1707 * get unblocked other than the low-level driver calling
1708 * scsi_unblock_requests().
1709 */
1710void scsi_block_requests(struct Scsi_Host *shost)
1711{
1712 shost->host_self_blocked = 1;
1713}
1714EXPORT_SYMBOL(scsi_block_requests);
1715
1716/*
1717 * Function: scsi_unblock_requests()
1718 *
1719 * Purpose: Utility function used by low-level drivers to allow further
1720 * commands from being queued to the device.
1721 *
1722 * Arguments: shost - Host in question
1723 *
1724 * Returns: Nothing
1725 *
1726 * Lock status: No locks are assumed held.
1727 *
1728 * Notes: There is no timer nor any other means by which the requests
1729 * get unblocked other than the low-level driver calling
1730 * scsi_unblock_requests().
1731 *
1732 * This is done as an API function so that changes to the
1733 * internals of the scsi mid-layer won't require wholesale
1734 * changes to drivers that use this feature.
1735 */
1736void scsi_unblock_requests(struct Scsi_Host *shost)
1737{
1738 shost->host_self_blocked = 0;
1739 scsi_run_host_queues(shost);
1740}
1741EXPORT_SYMBOL(scsi_unblock_requests);
1742
1743int __init scsi_init_queue(void)
1744{
1745 int i;
1746
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001747 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1748 sizeof(struct scsi_data_buffer),
1749 0, 0, NULL);
1750 if (!scsi_sdb_cache) {
1751 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09001752 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001753 }
1754
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1756 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1757 int size = sgp->size * sizeof(struct scatterlist);
1758
1759 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001760 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 if (!sgp->slab) {
1762 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1763 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001764 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765 }
1766
Matthew Dobson93d23412006-03-26 01:37:50 -08001767 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1768 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 if (!sgp->pool) {
1770 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1771 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001772 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 }
1774 }
1775
1776 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001777
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001778cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001779 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1780 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1781 if (sgp->pool)
1782 mempool_destroy(sgp->pool);
1783 if (sgp->slab)
1784 kmem_cache_destroy(sgp->slab);
1785 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001786 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001787
1788 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789}
1790
1791void scsi_exit_queue(void)
1792{
1793 int i;
1794
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001795 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001796
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1798 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1799 mempool_destroy(sgp->pool);
1800 kmem_cache_destroy(sgp->slab);
1801 }
1802}
James Bottomley5baba832006-03-18 14:10:35 -06001803
1804/**
1805 * scsi_mode_select - issue a mode select
1806 * @sdev: SCSI device to be queried
1807 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1808 * @sp: Save page bit (0 == don't save, 1 == save)
1809 * @modepage: mode page being requested
1810 * @buffer: request buffer (may not be smaller than eight bytes)
1811 * @len: length of request buffer.
1812 * @timeout: command timeout
1813 * @retries: number of retries before failing
1814 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001815 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001816 * must be SCSI_SENSE_BUFFERSIZE big.
1817 *
1818 * Returns zero if successful; negative error number or scsi
1819 * status on error
1820 *
1821 */
1822int
1823scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1824 unsigned char *buffer, int len, int timeout, int retries,
1825 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1826{
1827 unsigned char cmd[10];
1828 unsigned char *real_buffer;
1829 int ret;
1830
1831 memset(cmd, 0, sizeof(cmd));
1832 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1833
1834 if (sdev->use_10_for_ms) {
1835 if (len > 65535)
1836 return -EINVAL;
1837 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1838 if (!real_buffer)
1839 return -ENOMEM;
1840 memcpy(real_buffer + 8, buffer, len);
1841 len += 8;
1842 real_buffer[0] = 0;
1843 real_buffer[1] = 0;
1844 real_buffer[2] = data->medium_type;
1845 real_buffer[3] = data->device_specific;
1846 real_buffer[4] = data->longlba ? 0x01 : 0;
1847 real_buffer[5] = 0;
1848 real_buffer[6] = data->block_descriptor_length >> 8;
1849 real_buffer[7] = data->block_descriptor_length;
1850
1851 cmd[0] = MODE_SELECT_10;
1852 cmd[7] = len >> 8;
1853 cmd[8] = len;
1854 } else {
1855 if (len > 255 || data->block_descriptor_length > 255 ||
1856 data->longlba)
1857 return -EINVAL;
1858
1859 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1860 if (!real_buffer)
1861 return -ENOMEM;
1862 memcpy(real_buffer + 4, buffer, len);
1863 len += 4;
1864 real_buffer[0] = 0;
1865 real_buffer[1] = data->medium_type;
1866 real_buffer[2] = data->device_specific;
1867 real_buffer[3] = data->block_descriptor_length;
1868
1869
1870 cmd[0] = MODE_SELECT;
1871 cmd[4] = len;
1872 }
1873
1874 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001875 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06001876 kfree(real_buffer);
1877 return ret;
1878}
1879EXPORT_SYMBOL_GPL(scsi_mode_select);
1880
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881/**
Rob Landleyeb448202007-11-03 13:30:39 -05001882 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001883 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884 * @dbd: set if mode sense will allow block descriptors to be returned
1885 * @modepage: mode page being requested
1886 * @buffer: request buffer (may not be smaller than eight bytes)
1887 * @len: length of request buffer.
1888 * @timeout: command timeout
1889 * @retries: number of retries before failing
1890 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001891 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001892 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 *
1894 * Returns zero if unsuccessful, or the header offset (either 4
1895 * or 8 depending on whether a six or ten byte command was
1896 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001897 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898int
James Bottomley1cf72692005-08-28 11:27:01 -05001899scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001901 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1902{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903 unsigned char cmd[12];
1904 int use_10_for_ms;
1905 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001906 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001907 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908
1909 memset(data, 0, sizeof(*data));
1910 memset(&cmd[0], 0, 12);
1911 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1912 cmd[2] = modepage;
1913
James Bottomleyea73a9f2005-08-28 11:33:52 -05001914 /* caller might not be interested in sense, but we need it */
1915 if (!sshdr)
1916 sshdr = &my_sshdr;
1917
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001919 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920
1921 if (use_10_for_ms) {
1922 if (len < 8)
1923 len = 8;
1924
1925 cmd[0] = MODE_SENSE_10;
1926 cmd[8] = len;
1927 header_length = 8;
1928 } else {
1929 if (len < 4)
1930 len = 4;
1931
1932 cmd[0] = MODE_SENSE;
1933 cmd[4] = len;
1934 header_length = 4;
1935 }
1936
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 memset(buffer, 0, len);
1938
James Bottomley1cf72692005-08-28 11:27:01 -05001939 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001940 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941
1942 /* This code looks awful: what it's doing is making sure an
1943 * ILLEGAL REQUEST sense return identifies the actual command
1944 * byte as the problem. MODE_SENSE commands can return
1945 * ILLEGAL REQUEST if the code page isn't supported */
1946
James Bottomley1cf72692005-08-28 11:27:01 -05001947 if (use_10_for_ms && !scsi_status_is_good(result) &&
1948 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001949 if (scsi_sense_valid(sshdr)) {
1950 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1951 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001952 /*
1953 * Invalid command operation code
1954 */
James Bottomley1cf72692005-08-28 11:27:01 -05001955 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 goto retry;
1957 }
1958 }
1959 }
1960
James Bottomley1cf72692005-08-28 11:27:01 -05001961 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001962 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1963 (modepage == 6 || modepage == 8))) {
1964 /* Initio breakage? */
1965 header_length = 0;
1966 data->length = 13;
1967 data->medium_type = 0;
1968 data->device_specific = 0;
1969 data->longlba = 0;
1970 data->block_descriptor_length = 0;
1971 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 data->length = buffer[0]*256 + buffer[1] + 2;
1973 data->medium_type = buffer[2];
1974 data->device_specific = buffer[3];
1975 data->longlba = buffer[4] & 0x01;
1976 data->block_descriptor_length = buffer[6]*256
1977 + buffer[7];
1978 } else {
1979 data->length = buffer[0] + 1;
1980 data->medium_type = buffer[1];
1981 data->device_specific = buffer[2];
1982 data->block_descriptor_length = buffer[3];
1983 }
Al Viro6d73c852006-02-23 02:03:16 +01001984 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 }
1986
James Bottomley1cf72692005-08-28 11:27:01 -05001987 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988}
1989EXPORT_SYMBOL(scsi_mode_sense);
1990
James Bottomley001aac22007-12-02 19:10:40 +02001991/**
1992 * scsi_test_unit_ready - test if unit is ready
1993 * @sdev: scsi device to change the state of.
1994 * @timeout: command timeout
1995 * @retries: number of retries before failing
1996 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1997 * returning sense. Make sure that this is cleared before passing
1998 * in.
1999 *
2000 * Returns zero if unsuccessful or an error if TUR failed. For
2001 * removable media, a return of NOT_READY or UNIT_ATTENTION is
2002 * translated to success, with the ->changed flag updated.
2003 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004int
James Bottomley001aac22007-12-02 19:10:40 +02002005scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2006 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 char cmd[] = {
2009 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2010 };
James Bottomley001aac22007-12-02 19:10:40 +02002011 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002012 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002013
2014 if (!sshdr_external)
2015 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2016 else
2017 sshdr = sshdr_external;
2018
2019 /* try to eat the UNIT_ATTENTION if there are enough retries */
2020 do {
2021 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002022 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002023 if (sdev->removable && scsi_sense_valid(sshdr) &&
2024 sshdr->sense_key == UNIT_ATTENTION)
2025 sdev->changed = 1;
2026 } while (scsi_sense_valid(sshdr) &&
2027 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002028
2029 if (!sshdr)
2030 /* could not allocate sense buffer, so can't process it */
2031 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032
James Bottomley32c356d2008-08-20 00:58:13 +02002033 if (sdev->removable && scsi_sense_valid(sshdr) &&
2034 (sshdr->sense_key == UNIT_ATTENTION ||
2035 sshdr->sense_key == NOT_READY)) {
2036 sdev->changed = 1;
2037 result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002038 }
James Bottomley001aac22007-12-02 19:10:40 +02002039 if (!sshdr_external)
2040 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041 return result;
2042}
2043EXPORT_SYMBOL(scsi_test_unit_ready);
2044
2045/**
Rob Landleyeb448202007-11-03 13:30:39 -05002046 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047 * @sdev: scsi device to change the state of.
2048 * @state: state to change to.
2049 *
2050 * Returns zero if unsuccessful or an error if the requested
2051 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002052 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002053int
2054scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2055{
2056 enum scsi_device_state oldstate = sdev->sdev_state;
2057
2058 if (state == oldstate)
2059 return 0;
2060
2061 switch (state) {
2062 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002063 switch (oldstate) {
2064 case SDEV_CREATED_BLOCK:
2065 break;
2066 default:
2067 goto illegal;
2068 }
2069 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070
2071 case SDEV_RUNNING:
2072 switch (oldstate) {
2073 case SDEV_CREATED:
2074 case SDEV_OFFLINE:
2075 case SDEV_QUIESCE:
2076 case SDEV_BLOCK:
2077 break;
2078 default:
2079 goto illegal;
2080 }
2081 break;
2082
2083 case SDEV_QUIESCE:
2084 switch (oldstate) {
2085 case SDEV_RUNNING:
2086 case SDEV_OFFLINE:
2087 break;
2088 default:
2089 goto illegal;
2090 }
2091 break;
2092
2093 case SDEV_OFFLINE:
2094 switch (oldstate) {
2095 case SDEV_CREATED:
2096 case SDEV_RUNNING:
2097 case SDEV_QUIESCE:
2098 case SDEV_BLOCK:
2099 break;
2100 default:
2101 goto illegal;
2102 }
2103 break;
2104
2105 case SDEV_BLOCK:
2106 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002108 case SDEV_CREATED_BLOCK:
2109 break;
2110 default:
2111 goto illegal;
2112 }
2113 break;
2114
2115 case SDEV_CREATED_BLOCK:
2116 switch (oldstate) {
2117 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118 break;
2119 default:
2120 goto illegal;
2121 }
2122 break;
2123
2124 case SDEV_CANCEL:
2125 switch (oldstate) {
2126 case SDEV_CREATED:
2127 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002128 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002129 case SDEV_OFFLINE:
2130 case SDEV_BLOCK:
2131 break;
2132 default:
2133 goto illegal;
2134 }
2135 break;
2136
2137 case SDEV_DEL:
2138 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002139 case SDEV_CREATED:
2140 case SDEV_RUNNING:
2141 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002142 case SDEV_CANCEL:
2143 break;
2144 default:
2145 goto illegal;
2146 }
2147 break;
2148
2149 }
2150 sdev->sdev_state = state;
2151 return 0;
2152
2153 illegal:
2154 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002155 sdev_printk(KERN_ERR, sdev,
2156 "Illegal state transition %s->%s\n",
2157 scsi_device_state_name(oldstate),
2158 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002159 );
2160 return -EINVAL;
2161}
2162EXPORT_SYMBOL(scsi_device_set_state);
2163
2164/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002165 * sdev_evt_emit - emit a single SCSI device uevent
2166 * @sdev: associated SCSI device
2167 * @evt: event to emit
2168 *
2169 * Send a single uevent (scsi_event) to the associated scsi_device.
2170 */
2171static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2172{
2173 int idx = 0;
2174 char *envp[3];
2175
2176 switch (evt->evt_type) {
2177 case SDEV_EVT_MEDIA_CHANGE:
2178 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2179 break;
2180
2181 default:
2182 /* do nothing */
2183 break;
2184 }
2185
2186 envp[idx++] = NULL;
2187
2188 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2189}
2190
2191/**
2192 * sdev_evt_thread - send a uevent for each scsi event
2193 * @work: work struct for scsi_device
2194 *
2195 * Dispatch queued events to their associated scsi_device kobjects
2196 * as uevents.
2197 */
2198void scsi_evt_thread(struct work_struct *work)
2199{
2200 struct scsi_device *sdev;
2201 LIST_HEAD(event_list);
2202
2203 sdev = container_of(work, struct scsi_device, event_work);
2204
2205 while (1) {
2206 struct scsi_event *evt;
2207 struct list_head *this, *tmp;
2208 unsigned long flags;
2209
2210 spin_lock_irqsave(&sdev->list_lock, flags);
2211 list_splice_init(&sdev->event_list, &event_list);
2212 spin_unlock_irqrestore(&sdev->list_lock, flags);
2213
2214 if (list_empty(&event_list))
2215 break;
2216
2217 list_for_each_safe(this, tmp, &event_list) {
2218 evt = list_entry(this, struct scsi_event, node);
2219 list_del(&evt->node);
2220 scsi_evt_emit(sdev, evt);
2221 kfree(evt);
2222 }
2223 }
2224}
2225
2226/**
2227 * sdev_evt_send - send asserted event to uevent thread
2228 * @sdev: scsi_device event occurred on
2229 * @evt: event to send
2230 *
2231 * Assert scsi device event asynchronously.
2232 */
2233void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2234{
2235 unsigned long flags;
2236
Kay Sievers4d1566e2008-03-19 13:04:47 +01002237#if 0
2238 /* FIXME: currently this check eliminates all media change events
2239 * for polled devices. Need to update to discriminate between AN
2240 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002241 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2242 kfree(evt);
2243 return;
2244 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002245#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002246
2247 spin_lock_irqsave(&sdev->list_lock, flags);
2248 list_add_tail(&evt->node, &sdev->event_list);
2249 schedule_work(&sdev->event_work);
2250 spin_unlock_irqrestore(&sdev->list_lock, flags);
2251}
2252EXPORT_SYMBOL_GPL(sdev_evt_send);
2253
2254/**
2255 * sdev_evt_alloc - allocate a new scsi event
2256 * @evt_type: type of event to allocate
2257 * @gfpflags: GFP flags for allocation
2258 *
2259 * Allocates and returns a new scsi_event.
2260 */
2261struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2262 gfp_t gfpflags)
2263{
2264 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2265 if (!evt)
2266 return NULL;
2267
2268 evt->evt_type = evt_type;
2269 INIT_LIST_HEAD(&evt->node);
2270
2271 /* evt_type-specific initialization, if any */
2272 switch (evt_type) {
2273 case SDEV_EVT_MEDIA_CHANGE:
2274 default:
2275 /* do nothing */
2276 break;
2277 }
2278
2279 return evt;
2280}
2281EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2282
2283/**
2284 * sdev_evt_send_simple - send asserted event to uevent thread
2285 * @sdev: scsi_device event occurred on
2286 * @evt_type: type of event to send
2287 * @gfpflags: GFP flags for allocation
2288 *
2289 * Assert scsi device event asynchronously, given an event type.
2290 */
2291void sdev_evt_send_simple(struct scsi_device *sdev,
2292 enum scsi_device_event evt_type, gfp_t gfpflags)
2293{
2294 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2295 if (!evt) {
2296 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2297 evt_type);
2298 return;
2299 }
2300
2301 sdev_evt_send(sdev, evt);
2302}
2303EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2304
2305/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002306 * scsi_device_quiesce - Block user issued commands.
2307 * @sdev: scsi device to quiesce.
2308 *
2309 * This works by trying to transition to the SDEV_QUIESCE state
2310 * (which must be a legal transition). When the device is in this
2311 * state, only special requests will be accepted, all others will
2312 * be deferred. Since special requests may also be requeued requests,
2313 * a successful return doesn't guarantee the device will be
2314 * totally quiescent.
2315 *
2316 * Must be called with user context, may sleep.
2317 *
2318 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002319 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320int
2321scsi_device_quiesce(struct scsi_device *sdev)
2322{
2323 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2324 if (err)
2325 return err;
2326
2327 scsi_run_queue(sdev->request_queue);
2328 while (sdev->device_busy) {
2329 msleep_interruptible(200);
2330 scsi_run_queue(sdev->request_queue);
2331 }
2332 return 0;
2333}
2334EXPORT_SYMBOL(scsi_device_quiesce);
2335
2336/**
2337 * scsi_device_resume - Restart user issued commands to a quiesced device.
2338 * @sdev: scsi device to resume.
2339 *
2340 * Moves the device from quiesced back to running and restarts the
2341 * queues.
2342 *
2343 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002344 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002345void
2346scsi_device_resume(struct scsi_device *sdev)
2347{
2348 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2349 return;
2350 scsi_run_queue(sdev->request_queue);
2351}
2352EXPORT_SYMBOL(scsi_device_resume);
2353
2354static void
2355device_quiesce_fn(struct scsi_device *sdev, void *data)
2356{
2357 scsi_device_quiesce(sdev);
2358}
2359
2360void
2361scsi_target_quiesce(struct scsi_target *starget)
2362{
2363 starget_for_each_device(starget, NULL, device_quiesce_fn);
2364}
2365EXPORT_SYMBOL(scsi_target_quiesce);
2366
2367static void
2368device_resume_fn(struct scsi_device *sdev, void *data)
2369{
2370 scsi_device_resume(sdev);
2371}
2372
2373void
2374scsi_target_resume(struct scsi_target *starget)
2375{
2376 starget_for_each_device(starget, NULL, device_resume_fn);
2377}
2378EXPORT_SYMBOL(scsi_target_resume);
2379
2380/**
Rob Landleyeb448202007-11-03 13:30:39 -05002381 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382 * @sdev: device to block
2383 *
2384 * Block request made by scsi lld's to temporarily stop all
2385 * scsi commands on the specified device. Called from interrupt
2386 * or normal process context.
2387 *
2388 * Returns zero if successful or error if not
2389 *
2390 * Notes:
2391 * This routine transitions the device to the SDEV_BLOCK state
2392 * (which must be a legal transition). When the device is in this
2393 * state, all commands are deferred until the scsi lld reenables
2394 * the device with scsi_device_unblock or device_block_tmo fires.
2395 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002396 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397int
2398scsi_internal_device_block(struct scsi_device *sdev)
2399{
Jens Axboe165125e2007-07-24 09:28:11 +02002400 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002401 unsigned long flags;
2402 int err = 0;
2403
2404 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002405 if (err) {
2406 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2407
2408 if (err)
2409 return err;
2410 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411
2412 /*
2413 * The device has transitioned to SDEV_BLOCK. Stop the
2414 * block layer from calling the midlayer with this device's
2415 * request queue.
2416 */
2417 spin_lock_irqsave(q->queue_lock, flags);
2418 blk_stop_queue(q);
2419 spin_unlock_irqrestore(q->queue_lock, flags);
2420
2421 return 0;
2422}
2423EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2424
2425/**
2426 * scsi_internal_device_unblock - resume a device after a block request
2427 * @sdev: device to resume
2428 *
2429 * Called by scsi lld's or the midlayer to restart the device queue
2430 * for the previously suspended scsi device. Called from interrupt or
2431 * normal process context.
2432 *
2433 * Returns zero if successful or error if not.
2434 *
2435 * Notes:
2436 * This routine transitions the device to the SDEV_RUNNING state
2437 * (which must be a legal transition) allowing the midlayer to
2438 * goose the queue for this device. This routine assumes the
2439 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002440 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002441int
2442scsi_internal_device_unblock(struct scsi_device *sdev)
2443{
Jens Axboe165125e2007-07-24 09:28:11 +02002444 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002445 int err;
2446 unsigned long flags;
2447
2448 /*
2449 * Try to transition the scsi device to SDEV_RUNNING
2450 * and goose the device queue if successful.
2451 */
2452 err = scsi_device_set_state(sdev, SDEV_RUNNING);
James Bottomley6f4267e2008-08-22 16:53:31 -05002453 if (err) {
2454 err = scsi_device_set_state(sdev, SDEV_CREATED);
2455
2456 if (err)
2457 return err;
2458 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002459
2460 spin_lock_irqsave(q->queue_lock, flags);
2461 blk_start_queue(q);
2462 spin_unlock_irqrestore(q->queue_lock, flags);
2463
2464 return 0;
2465}
2466EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2467
2468static void
2469device_block(struct scsi_device *sdev, void *data)
2470{
2471 scsi_internal_device_block(sdev);
2472}
2473
2474static int
2475target_block(struct device *dev, void *data)
2476{
2477 if (scsi_is_target_device(dev))
2478 starget_for_each_device(to_scsi_target(dev), NULL,
2479 device_block);
2480 return 0;
2481}
2482
2483void
2484scsi_target_block(struct device *dev)
2485{
2486 if (scsi_is_target_device(dev))
2487 starget_for_each_device(to_scsi_target(dev), NULL,
2488 device_block);
2489 else
2490 device_for_each_child(dev, NULL, target_block);
2491}
2492EXPORT_SYMBOL_GPL(scsi_target_block);
2493
2494static void
2495device_unblock(struct scsi_device *sdev, void *data)
2496{
2497 scsi_internal_device_unblock(sdev);
2498}
2499
2500static int
2501target_unblock(struct device *dev, void *data)
2502{
2503 if (scsi_is_target_device(dev))
2504 starget_for_each_device(to_scsi_target(dev), NULL,
2505 device_unblock);
2506 return 0;
2507}
2508
2509void
2510scsi_target_unblock(struct device *dev)
2511{
2512 if (scsi_is_target_device(dev))
2513 starget_for_each_device(to_scsi_target(dev), NULL,
2514 device_unblock);
2515 else
2516 device_for_each_child(dev, NULL, target_unblock);
2517}
2518EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002519
2520/**
2521 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002522 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002523 * @sg_count: number of segments in sg
2524 * @offset: offset in bytes into sg, on return offset into the mapped area
2525 * @len: bytes to map, on return number of bytes mapped
2526 *
2527 * Returns virtual address of the start of the mapped page
2528 */
Jens Axboec6132da2007-10-16 11:08:49 +02002529void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002530 size_t *offset, size_t *len)
2531{
2532 int i;
2533 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002534 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002535 struct page *page;
2536
Andrew Morton22cfefb2007-02-05 16:39:03 -08002537 WARN_ON(!irqs_disabled());
2538
Jens Axboec6132da2007-10-16 11:08:49 +02002539 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002540 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002541 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002542 if (sg_len > *offset)
2543 break;
2544 }
2545
2546 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002547 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2548 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002549 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002550 WARN_ON(1);
2551 return NULL;
2552 }
2553
2554 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002555 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002556
2557 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002558 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002559 *offset &= ~PAGE_MASK;
2560
2561 /* Bytes in this sg-entry from *offset to the end of the page */
2562 sg_len = PAGE_SIZE - *offset;
2563 if (*len > sg_len)
2564 *len = sg_len;
2565
2566 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2567}
2568EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2569
2570/**
Rob Landleyeb448202007-11-03 13:30:39 -05002571 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002572 * @virt: virtual address to be unmapped
2573 */
2574void scsi_kunmap_atomic_sg(void *virt)
2575{
2576 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2577}
2578EXPORT_SYMBOL(scsi_kunmap_atomic_sg);