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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
3 *
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
8 */
9
10#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060011#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/blkdev.h>
13#include <linux/completion.h>
14#include <linux/kernel.h>
Paul Gortmaker09703662011-05-27 09:37:25 -040015#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/mempool.h>
17#include <linux/slab.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060021#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020022#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
24#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020025#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <scsi/scsi_dbg.h>
27#include <scsi/scsi_device.h>
28#include <scsi/scsi_driver.h>
29#include <scsi/scsi_eh.h>
30#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32#include "scsi_priv.h"
33#include "scsi_logging.h"
34
35
Tobias Klauser6391a112006-06-08 22:23:48 -070036#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020037#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39struct scsi_host_sg_pool {
40 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020041 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080042 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 mempool_t *pool;
44};
45
James Bottomleyd3f46f32008-01-15 11:11:46 -060046#define SP(x) { x, "sgpool-" __stringify(x) }
47#if (SCSI_MAX_SG_SEGMENTS < 32)
48#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
49#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070050static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 SP(8),
52 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020053#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060054 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020055#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060056 SP(64),
57#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060059#if (SCSI_MAX_SG_SEGMENTS > 256)
60#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020061#endif
62#endif
63#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060064#endif
65 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020066};
Linus Torvalds1da177e2005-04-16 15:20:36 -070067#undef SP
68
Martin K. Petersen7027ad72008-07-17 17:08:48 -040069struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020070
Jens Axboea488e742010-04-16 21:13:15 +020071/*
72 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
73 * not change behaviour from the previous unplug mechanism, experimentation
74 * may prove this needs changing.
75 */
76#define SCSI_QUEUE_DELAY 3
77
James Bottomleye91442b2005-09-09 10:44:16 -050078/*
79 * Function: scsi_unprep_request()
80 *
81 * Purpose: Remove all preparation done for a request, including its
82 * associated scsi_cmnd, so that it can be requeued.
83 *
84 * Arguments: req - request to unprepare
85 *
86 * Lock status: Assumed that no locks are held upon entry.
87 *
88 * Returns: Nothing.
89 */
90static void scsi_unprep_request(struct request *req)
91{
92 struct scsi_cmnd *cmd = req->special;
93
James Bottomley28018c22010-07-01 19:49:17 +090094 blk_unprep_request(req);
Christoph Hellwigbeb40482006-06-10 18:01:03 +020095 req->special = NULL;
James Bottomleye91442b2005-09-09 10:44:16 -050096
James Bottomleye91442b2005-09-09 10:44:16 -050097 scsi_put_command(cmd);
98}
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -050099
James Bottomley4f5299a2009-01-02 10:42:21 -0600100/**
101 * __scsi_queue_insert - private queue insertion
102 * @cmd: The SCSI command being requeued
103 * @reason: The reason for the requeue
104 * @unbusy: Whether the queue should be unbusied
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 *
James Bottomley4f5299a2009-01-02 10:42:21 -0600106 * This is a private queue insertion. The public interface
107 * scsi_queue_insert() always assumes the queue should be unbusied
108 * because it's always called before the completion. This function is
109 * for a requeue after completion, which should only occur in this
110 * file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600112static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 struct Scsi_Host *host = cmd->device->host;
115 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500116 struct scsi_target *starget = scsi_target(device);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500117 struct request_queue *q = device->request_queue;
118 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120 SCSI_LOG_MLQUEUE(1,
121 printk("Inserting command %p into mlqueue\n", cmd));
122
123 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +0900124 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 *
126 * If the host/device isn't busy, assume that something actually
127 * completed, and that we should be able to queue a command now.
128 *
129 * Note that the prior mid-layer assumption that any host could
130 * always queue at least one command is now broken. The mid-layer
131 * will implement a user specifiable stall (see
132 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
133 * if a command is requeued with no other commands outstanding
134 * either for the device or for the host.
135 */
Mike Christief0c0a372008-08-17 15:24:38 -0500136 switch (reason) {
137 case SCSI_MLQUEUE_HOST_BUSY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 host->host_blocked = host->max_host_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500139 break;
140 case SCSI_MLQUEUE_DEVICE_BUSY:
James Smart573e5912011-07-06 12:45:17 -0400141 case SCSI_MLQUEUE_EH_RETRY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 device->device_blocked = device->max_device_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500143 break;
144 case SCSI_MLQUEUE_TARGET_BUSY:
145 starget->target_blocked = starget->max_target_blocked;
146 break;
147 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 * Decrement the counters, since these commands are no longer
151 * active on the host/device.
152 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600153 if (unbusy)
154 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
156 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500157 * Requeue this command. It will go before all other commands
158 * that are already in the queue.
Jens Axboea488e742010-04-16 21:13:15 +0200159 */
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500160 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400161 blk_requeue_request(q, cmd->request);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500162 spin_unlock_irqrestore(q->queue_lock, flags);
163
Jens Axboe9937a5e2011-05-17 11:04:44 +0200164 kblockd_schedule_work(q, &device->requeue_work);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500165
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 return 0;
167}
168
James Bottomley4f5299a2009-01-02 10:42:21 -0600169/*
170 * Function: scsi_queue_insert()
171 *
172 * Purpose: Insert a command in the midlevel queue.
173 *
174 * Arguments: cmd - command that we are adding to queue.
175 * reason - why we are inserting command to queue.
176 *
177 * Lock status: Assumed that lock is not held upon entry.
178 *
179 * Returns: Nothing.
180 *
181 * Notes: We do this for one of two cases. Either the host is busy
182 * and it cannot accept any more commands for the time being,
183 * or the device returned QUEUE_FULL and can accept no more
184 * commands.
185 * Notes: This could be called either from an interrupt context or a
186 * normal process context.
187 */
188int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
189{
190 return __scsi_queue_insert(cmd, reason, 1);
191}
James Bottomley39216032005-06-15 18:48:29 -0500192/**
James Bottomley33aa6872005-08-28 11:31:14 -0500193 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500194 * @sdev: scsi device
195 * @cmd: scsi command
196 * @data_direction: data direction
197 * @buffer: data buffer
198 * @bufflen: len of buffer
199 * @sense: optional sense buffer
200 * @timeout: request timeout in seconds
201 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500202 * @flags: or into request flags;
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900203 * @resid: optional residual length
James Bottomley39216032005-06-15 18:48:29 -0500204 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200205 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500206 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500207 */
James Bottomley33aa6872005-08-28 11:31:14 -0500208int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
209 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900210 unsigned char *sense, int timeout, int retries, int flags,
211 int *resid)
James Bottomley39216032005-06-15 18:48:29 -0500212{
213 struct request *req;
214 int write = (data_direction == DMA_TO_DEVICE);
215 int ret = DRIVER_ERROR << 24;
216
217 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
James Bottomleybfe159a2011-07-07 15:45:40 -0500218 if (!req)
219 return ret;
James Bottomley39216032005-06-15 18:48:29 -0500220
221 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
222 buffer, bufflen, __GFP_WAIT))
223 goto out;
224
225 req->cmd_len = COMMAND_SIZE(cmd[0]);
226 memcpy(req->cmd, cmd, req->cmd_len);
227 req->sense = sense;
228 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600229 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500230 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200231 req->cmd_type = REQ_TYPE_BLOCK_PC;
232 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500233
234 /*
235 * head injection *required* here otherwise quiesce won't work
236 */
237 blk_execute_rq(req->q, NULL, req, 1);
238
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400239 /*
240 * Some devices (USB mass-storage in particular) may transfer
241 * garbage data together with a residue indicating that the data
242 * is invalid. Prevent the garbage from being misinterpreted
243 * and prevent security leaks by zeroing out the excess data.
244 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900245 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
246 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400247
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900248 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900249 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500250 ret = req->errors;
251 out:
252 blk_put_request(req);
253
254 return ret;
255}
James Bottomley33aa6872005-08-28 11:31:14 -0500256EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500257
James Bottomleyea73a9f2005-08-28 11:33:52 -0500258
259int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
260 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900261 struct scsi_sense_hdr *sshdr, int timeout, int retries,
262 int *resid)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500263{
264 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700265 int result;
266
James Bottomleyea73a9f2005-08-28 11:33:52 -0500267 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500268 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500269 if (!sense)
270 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500271 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700272 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900273 sense, timeout, retries, 0, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500274 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500275 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500276
277 kfree(sense);
278 return result;
279}
280EXPORT_SYMBOL(scsi_execute_req);
281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282/*
283 * Function: scsi_init_cmd_errh()
284 *
285 * Purpose: Initialize cmd fields related to error handling.
286 *
287 * Arguments: cmd - command that is ready to be queued.
288 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 * Notes: This function has the job of initializing a number of
290 * fields related to error handling. Typically this will
291 * be called once for each command, as required.
292 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200293static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200296 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900297 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300299 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300}
301
302void scsi_device_unbusy(struct scsi_device *sdev)
303{
304 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500305 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 unsigned long flags;
307
308 spin_lock_irqsave(shost->host_lock, flags);
309 shost->host_busy--;
Mike Christief0c0a372008-08-17 15:24:38 -0500310 starget->target_busy--;
James Bottomley939647e2005-09-18 15:05:20 -0500311 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900312 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 scsi_eh_wakeup(shost);
314 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500315 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500317 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318}
319
320/*
321 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
322 * and call blk_run_queue for all the scsi_devices on the target -
323 * including current_sdev first.
324 *
325 * Called with *no* scsi locks held.
326 */
327static void scsi_single_lun_run(struct scsi_device *current_sdev)
328{
329 struct Scsi_Host *shost = current_sdev->host;
330 struct scsi_device *sdev, *tmp;
331 struct scsi_target *starget = scsi_target(current_sdev);
332 unsigned long flags;
333
334 spin_lock_irqsave(shost->host_lock, flags);
335 starget->starget_sdev_user = NULL;
336 spin_unlock_irqrestore(shost->host_lock, flags);
337
338 /*
339 * Call blk_run_queue for all LUNs on the target, starting with
340 * current_sdev. We race with others (to set starget_sdev_user),
341 * but in most cases, we will be first. Ideally, each LU on the
342 * target would get some limited time or requests on the target.
343 */
344 blk_run_queue(current_sdev->request_queue);
345
346 spin_lock_irqsave(shost->host_lock, flags);
347 if (starget->starget_sdev_user)
348 goto out;
349 list_for_each_entry_safe(sdev, tmp, &starget->devices,
350 same_target_siblings) {
351 if (sdev == current_sdev)
352 continue;
353 if (scsi_device_get(sdev))
354 continue;
355
356 spin_unlock_irqrestore(shost->host_lock, flags);
357 blk_run_queue(sdev->request_queue);
358 spin_lock_irqsave(shost->host_lock, flags);
359
360 scsi_device_put(sdev);
361 }
362 out:
363 spin_unlock_irqrestore(shost->host_lock, flags);
364}
365
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400366static inline int scsi_device_is_busy(struct scsi_device *sdev)
367{
368 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
369 return 1;
370
371 return 0;
372}
373
Mike Christief0c0a372008-08-17 15:24:38 -0500374static inline int scsi_target_is_busy(struct scsi_target *starget)
375{
376 return ((starget->can_queue > 0 &&
377 starget->target_busy >= starget->can_queue) ||
378 starget->target_blocked);
379}
380
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400381static inline int scsi_host_is_busy(struct Scsi_Host *shost)
382{
383 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
384 shost->host_blocked || shost->host_self_blocked)
385 return 1;
386
387 return 0;
388}
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390/*
391 * Function: scsi_run_queue()
392 *
393 * Purpose: Select a proper request queue to serve next
394 *
395 * Arguments: q - last request's queue
396 *
397 * Returns: Nothing
398 *
399 * Notes: The previous command was completely finished, start
400 * a new one if possible.
401 */
402static void scsi_run_queue(struct request_queue *q)
403{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600404 struct scsi_device *sdev = q->queuedata;
James Bottomleyc055f5b2011-05-01 09:42:07 -0500405 struct Scsi_Host *shost;
Mike Christie2a3a59e2008-11-11 13:42:35 -0600406 LIST_HEAD(starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 unsigned long flags;
408
James Bottomleyc055f5b2011-05-01 09:42:07 -0500409 /* if the device is dead, sdev will be NULL, so no queue to run */
410 if (!sdev)
411 return;
412
413 shost = sdev->host;
Tony Battersby25d7c362007-11-12 10:00:44 -0500414 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 scsi_single_lun_run(sdev);
416
417 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600418 list_splice_init(&shost->starved_list, &starved_list);
419
420 while (!list_empty(&starved_list)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 /*
422 * As long as shost is accepting commands and we have
423 * starved queues, call blk_run_queue. scsi_request_fn
424 * drops the queue_lock and can add us back to the
425 * starved_list.
426 *
427 * host_lock protects the starved_list and starved_entry.
428 * scsi_request_fn must get the host_lock before checking
429 * or modifying starved_list or starved_entry.
430 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600431 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500432 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500433
Mike Christie2a3a59e2008-11-11 13:42:35 -0600434 sdev = list_entry(starved_list.next,
435 struct scsi_device, starved_entry);
436 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500437 if (scsi_target_is_busy(scsi_target(sdev))) {
438 list_move_tail(&sdev->starved_entry,
439 &shost->starved_list);
440 continue;
441 }
442
Jens Axboe9937a5e2011-05-17 11:04:44 +0200443 spin_unlock(shost->host_lock);
444 spin_lock(sdev->request_queue->queue_lock);
445 __blk_run_queue(sdev->request_queue);
446 spin_unlock(sdev->request_queue->queue_lock);
447 spin_lock(shost->host_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600449 /* put any unprocessed entries back */
450 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 spin_unlock_irqrestore(shost->host_lock, flags);
452
453 blk_run_queue(q);
454}
455
Jens Axboe9937a5e2011-05-17 11:04:44 +0200456void scsi_requeue_run_queue(struct work_struct *work)
457{
458 struct scsi_device *sdev;
459 struct request_queue *q;
460
461 sdev = container_of(work, struct scsi_device, requeue_work);
462 q = sdev->request_queue;
463 scsi_run_queue(q);
464}
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466/*
467 * Function: scsi_requeue_command()
468 *
469 * Purpose: Handle post-processing of completed commands.
470 *
471 * Arguments: q - queue to operate on
472 * cmd - command that may need to be requeued.
473 *
474 * Returns: Nothing
475 *
476 * Notes: After command completion, there may be blocks left
477 * over which weren't finished by the previous command
478 * this can be for a number of reasons - the main one is
479 * I/O errors in the middle of the request, in which case
480 * we need to request the blocks that come after the bad
481 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500482 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 */
484static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
485{
James Bottomleye91442b2005-09-09 10:44:16 -0500486 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500487 unsigned long flags;
488
Tejun Heo 283369c2005-04-24 02:06:36 -0500489 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley02bd3492008-12-12 13:28:29 -0600490 scsi_unprep_request(req);
James Bottomleye91442b2005-09-09 10:44:16 -0500491 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500492 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 scsi_run_queue(q);
495}
496
497void scsi_next_command(struct scsi_cmnd *cmd)
498{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800499 struct scsi_device *sdev = cmd->device;
500 struct request_queue *q = sdev->request_queue;
501
502 /* need to hold a reference on the device before we let go of the cmd */
503 get_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
505 scsi_put_command(cmd);
506 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800507
508 /* ok to remove device now */
509 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510}
511
512void scsi_run_host_queues(struct Scsi_Host *shost)
513{
514 struct scsi_device *sdev;
515
516 shost_for_each_device(sdev, shost)
517 scsi_run_queue(sdev->request_queue);
518}
519
James Bottomley79ed2422009-01-06 13:15:20 -0600520static void __scsi_release_buffers(struct scsi_cmnd *, int);
521
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522/*
523 * Function: scsi_end_request()
524 *
525 * Purpose: Post-processing of completed commands (usually invoked at end
526 * of upper level post-processing and scsi_io_completion).
527 *
528 * Arguments: cmd - command that is complete.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500529 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 * bytes - number of bytes of completed I/O
531 * requeue - indicates whether we should requeue leftovers.
532 *
533 * Lock status: Assumed that lock is not held upon entry.
534 *
James Bottomleye91442b2005-09-09 10:44:16 -0500535 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 *
537 * Notes: This is called for block device requests in order to
538 * mark some number of sectors as complete.
539 *
540 * We are guaranteeing that the request queue will be goosed
541 * at some point during this call.
James Bottomleye91442b2005-09-09 10:44:16 -0500542 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500544static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 int bytes, int requeue)
546{
Jens Axboe165125e2007-07-24 09:28:11 +0200547 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
550 /*
551 * If there are blocks left over at the end, set up the command
552 * to queue the remainder of them.
553 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500554 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 /* kill remainder if no retrys */
Mike Christie4a274462008-08-19 18:45:31 -0500556 if (error && scsi_noretry_cmd(cmd))
Tejun Heoe4588242009-05-12 08:49:32 +0200557 blk_end_request_all(req, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500559 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 /*
561 * Bleah. Leftovers again. Stick the
562 * leftovers in the front of the
563 * queue, and goose the queue again.
564 */
James Bottomley79ed2422009-01-06 13:15:20 -0600565 scsi_release_buffers(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500567 cmd = NULL;
568 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 return cmd;
570 }
571 }
572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 /*
574 * This will goose the queue request function at the end, so we don't
575 * need to worry about launching another command.
576 */
James Bottomley79ed2422009-01-06 13:15:20 -0600577 __scsi_release_buffers(cmd, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 scsi_next_command(cmd);
579 return NULL;
580}
581
Jens Axboea8474ce2007-08-07 09:02:51 +0200582static inline unsigned int scsi_sgtable_index(unsigned short nents)
583{
584 unsigned int index;
585
James Bottomleyd3f46f32008-01-15 11:11:46 -0600586 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
587
588 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200589 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600590 else
591 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200592
593 return index;
594}
595
Jens Axboe5ed79592007-11-15 09:13:11 +0100596static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597{
598 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100599
600 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
601 mempool_free(sgl, sgp->pool);
602}
603
604static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
605{
606 struct scsi_host_sg_pool *sgp;
607
608 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
609 return mempool_alloc(sgp->pool, gfp_mask);
610}
611
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200612static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
613 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100614{
615 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200617 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200619 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
620 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100621 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200622 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600623 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
Jens Axboea8474ce2007-08-07 09:02:51 +0200625 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626}
627
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200628static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200630 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631}
632
James Bottomley79ed2422009-01-06 13:15:20 -0600633static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
634{
635
636 if (cmd->sdb.table.nents)
637 scsi_free_sgtable(&cmd->sdb);
638
639 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
640
641 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
642 struct scsi_data_buffer *bidi_sdb =
643 cmd->request->next_rq->special;
644 scsi_free_sgtable(bidi_sdb);
645 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
646 cmd->request->next_rq->special = NULL;
647 }
648
649 if (scsi_prot_sg_count(cmd))
650 scsi_free_sgtable(cmd->prot_sdb);
651}
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653/*
654 * Function: scsi_release_buffers()
655 *
656 * Purpose: Completion processing for block device I/O requests.
657 *
658 * Arguments: cmd - command that we are bailing.
659 *
660 * Lock status: Assumed that no lock is held upon entry.
661 *
662 * Returns: Nothing
663 *
664 * Notes: In the event that an upper level driver rejects a
665 * command, we must release resources allocated during
666 * the __init_io() function. Primarily this would involve
667 * the scatter-gather table, and potentially any bounce
668 * buffers.
669 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800670void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671{
James Bottomley79ed2422009-01-06 13:15:20 -0600672 __scsi_release_buffers(cmd, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800674EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100676static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
677{
678 int error = 0;
679
680 switch(host_byte(result)) {
681 case DID_TRANSPORT_FAILFAST:
682 error = -ENOLINK;
683 break;
684 case DID_TARGET_FAILURE:
685 cmd->result |= (DID_OK << 16);
686 error = -EREMOTEIO;
687 break;
688 case DID_NEXUS_FAILURE:
689 cmd->result |= (DID_OK << 16);
690 error = -EBADE;
691 break;
692 default:
693 error = -EIO;
694 break;
695 }
696
697 return error;
698}
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700/*
701 * Function: scsi_io_completion()
702 *
703 * Purpose: Completion processing for block device I/O requests.
704 *
705 * Arguments: cmd - command that is finished.
706 *
707 * Lock status: Assumed that no lock is held upon entry.
708 *
709 * Returns: Nothing
710 *
711 * Notes: This function is matched in terms of capabilities to
712 * the function that created the scatter-gather list.
713 * In other words, if there are no bounce buffers
714 * (the normal case for most drivers), we don't need
715 * the logic to deal with cleaning up afterwards.
716 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500717 * We must call scsi_end_request(). This will finish off
718 * the specified number of sectors. If we are done, the
719 * command block will be released and the queue function
720 * will be goosed. If we are not done then we have to
721 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500723 * a) We can call scsi_requeue_command(). The request
724 * will be unprepared and put back on the queue. Then
725 * a new command will be created for it. This should
726 * be used if we made forward progress, or if we want
727 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500729 * b) We can call scsi_queue_insert(). The request will
730 * be put back on the queue and retried using the same
731 * command as before, possibly after a delay.
732 *
733 * c) We can call blk_end_request() with -EIO to fail
734 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700736void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737{
738 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200739 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500741 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 struct scsi_sense_hdr sshdr;
743 int sense_valid = 0;
744 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500745 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
746 ACTION_DELAYED_RETRY} action;
747 char *description = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 if (result) {
750 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
751 if (sense_valid)
752 sense_deferred = scsi_sense_is_deferred(&sshdr);
753 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200754
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200755 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 req->errors = result;
757 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if (sense_valid && req->sense) {
759 /*
760 * SG_IO wants current and deferred errors
761 */
762 int len = 8 + cmd->sense_buffer[7];
763
764 if (len > SCSI_SENSE_BUFFERSIZE)
765 len = SCSI_SENSE_BUFFERSIZE;
766 memcpy(req->sense, cmd->sense_buffer, len);
767 req->sense_len = len;
768 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500769 if (!sense_deferred)
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100770 error = __scsi_error_from_host_byte(cmd, result);
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400771 }
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900772
773 req->resid_len = scsi_get_resid(cmd);
774
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200775 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900776 /*
777 * Bidi commands Must be complete as a whole,
778 * both sides at once.
779 */
780 req->next_rq->resid_len = scsi_in(cmd)->resid;
781
Boaz Harrosh63c43b02009-12-15 17:25:43 +0200782 scsi_release_buffers(cmd);
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900783 blk_end_request_all(req, 0);
784
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900785 scsi_next_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200786 return;
787 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 }
789
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200790 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
791 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 * Next deal with any sectors which we were able to correctly
795 * handle.
796 */
Tejun Heo83096eb2009-05-07 22:24:39 +0900797 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
James Bottomleyd6b0c532006-07-02 10:06:28 -0500798 "%d bytes done.\n",
Tejun Heo83096eb2009-05-07 22:24:39 +0900799 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
James Bottomleya9bddd72009-03-30 16:55:51 +0000801 /*
802 * Recovered errors need reporting, but they're always treated
803 * as success, so fiddle the result code here. For BLOCK_PC
804 * we already took a copy of the original into rq->errors which
805 * is what gets returned to the user
806 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500807 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
808 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
809 * print since caller wants ATA registers. Only occurs on
810 * SCSI ATA PASS_THROUGH commands when CK_COND=1
811 */
812 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
813 ;
814 else if (!(req->cmd_flags & REQ_QUIET))
James Bottomleya9bddd72009-03-30 16:55:51 +0000815 scsi_print_sense("", cmd);
816 result = 0;
817 /* BLOCK_PC may have set error */
818 error = 0;
819 }
820
821 /*
822 * A number of bytes were successfully read. If there
James Bottomleyd6b0c532006-07-02 10:06:28 -0500823 * are leftovers and there is some kind of error
824 * (result != 0), retry the rest.
825 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500826 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500827 return;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700828
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100829 error = __scsi_error_from_host_byte(cmd, result);
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500830
Alan Sternb60af5b2008-11-03 15:56:47 -0500831 if (host_byte(result) == DID_RESET) {
832 /* Third party bus reset or reset for error recovery
833 * reasons. Just retry the command and see what
834 * happens.
835 */
836 action = ACTION_RETRY;
837 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 switch (sshdr.sense_key) {
839 case UNIT_ATTENTION:
840 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700841 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 * and quietly refuse further access.
843 */
844 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500845 description = "Media Changed";
846 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700848 /* Must have been a power glitch, or a
849 * bus reset. Could not have been a
850 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500851 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700852 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500853 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 }
855 break;
856 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700857 /* If we had an ILLEGAL REQUEST returned, then
858 * we may have performed an unsupported
859 * command. The only thing this should be
860 * would be a ten byte read where only a six
861 * byte read was supported. Also, on a system
862 * where READ CAPACITY failed, we may have
863 * read past the end of the disk.
864 */
Jens Axboe26a68012005-11-29 21:03:34 +0100865 if ((cmd->device->use_10_for_rw &&
866 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 (cmd->cmnd[0] == READ_10 ||
868 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500869 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500871 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500872 } else if (sshdr.asc == 0x10) /* DIX */ {
873 description = "Host Data Integrity Failure";
874 action = ACTION_FAIL;
875 error = -EILSEQ;
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500876 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
877 } else if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
878 (cmd->cmnd[0] == UNMAP ||
879 cmd->cmnd[0] == WRITE_SAME_16 ||
880 cmd->cmnd[0] == WRITE_SAME)) {
881 description = "Discard failure";
882 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -0500883 } else
884 action = ACTION_FAIL;
885 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400886 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000887 action = ACTION_FAIL;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400888 if (sshdr.asc == 0x10) { /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500889 description = "Target Data Integrity Failure";
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500890 error = -EILSEQ;
James Bottomley126c09822009-02-19 21:48:54 +0000891 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 break;
893 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700894 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500895 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500897 if (sshdr.asc == 0x04) {
898 switch (sshdr.ascq) {
899 case 0x01: /* becoming ready */
900 case 0x04: /* format in progress */
901 case 0x05: /* rebuild in progress */
902 case 0x06: /* recalculation in progress */
903 case 0x07: /* operation in progress */
904 case 0x08: /* Long write in progress */
905 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -0500906 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -0500907 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500908 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -0500909 default:
910 description = "Device not ready";
911 action = ACTION_FAIL;
912 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500913 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500914 } else {
915 description = "Device not ready";
916 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500918 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700920 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -0500921 action = ACTION_FAIL;
922 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 default:
Alan Sternb60af5b2008-11-03 15:56:47 -0500924 description = "Unhandled sense code";
925 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 break;
927 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500928 } else {
929 description = "Unhandled error code";
930 action = ACTION_FAIL;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700931 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500932
933 switch (action) {
934 case ACTION_FAIL:
935 /* Give up and fail the remainder of the request */
James Bottomley79ed2422009-01-06 13:15:20 -0600936 scsi_release_buffers(cmd);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200937 if (!(req->cmd_flags & REQ_QUIET)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500938 if (description)
Alan Stern3dbf6a52008-12-15 10:31:28 -0500939 scmd_printk(KERN_INFO, cmd, "%s\n",
Alan Sternb60af5b2008-11-03 15:56:47 -0500940 description);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500941 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500942 if (driver_byte(result) & DRIVER_SENSE)
943 scsi_print_sense("", cmd);
Martin K. Petersen002b1eb2009-05-23 11:45:07 -0400944 scsi_print_command(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500945 }
Mike Christiead630822009-09-28 15:50:52 -0500946 if (blk_end_request_err(req, error))
Tejun Heoda6c5c72009-09-11 14:26:40 +0200947 scsi_requeue_command(q, cmd);
948 else
949 scsi_next_command(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500950 break;
951 case ACTION_REPREP:
952 /* Unprep the request and put it back at the head of the queue.
953 * A new command will be prepared and issued.
954 */
James Bottomley79ed2422009-01-06 13:15:20 -0600955 scsi_release_buffers(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -0500956 scsi_requeue_command(q, cmd);
957 break;
958 case ACTION_RETRY:
959 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -0600960 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500961 break;
962 case ACTION_DELAYED_RETRY:
963 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -0600964 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -0500965 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 }
967}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200969static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
970 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200972 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
974 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +0100975 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200977 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
978 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -0400980 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981
Christoph Hellwig3b003152006-11-04 20:10:55 +0100982 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983
984 /*
985 * Next, walk the list, and fill in the addresses and sizes of
986 * each segment.
987 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200988 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
989 BUG_ON(count > sdb->table.nents);
990 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +0900991 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +1100992 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200994
995/*
996 * Function: scsi_init_io()
997 *
998 * Purpose: SCSI I/O initialize function.
999 *
1000 * Arguments: cmd - Command descriptor we wish to initialize
1001 *
1002 * Returns: 0 on success
1003 * BLKPREP_DEFER if the failure is retryable
1004 * BLKPREP_KILL if the failure is fatal
1005 */
1006int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1007{
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001008 struct request *rq = cmd->request;
1009
1010 int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001011 if (error)
1012 goto err_exit;
1013
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001014 if (blk_bidi_rq(rq)) {
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001015 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001016 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001017 if (!bidi_sdb) {
1018 error = BLKPREP_DEFER;
1019 goto err_exit;
1020 }
1021
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001022 rq->next_rq->special = bidi_sdb;
1023 error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001024 if (error)
1025 goto err_exit;
1026 }
1027
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001028 if (blk_integrity_rq(rq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001029 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1030 int ivecs, count;
1031
1032 BUG_ON(prot_sdb == NULL);
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001033 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001034
1035 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1036 error = BLKPREP_DEFER;
1037 goto err_exit;
1038 }
1039
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001040 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001041 prot_sdb->table.sgl);
1042 BUG_ON(unlikely(count > ivecs));
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001043 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001044
1045 cmd->prot_sdb = prot_sdb;
1046 cmd->prot_sdb->table.nents = count;
1047 }
1048
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001049 return BLKPREP_OK ;
1050
1051err_exit:
1052 scsi_release_buffers(cmd);
FUJITA Tomonori610a6342010-07-08 10:16:17 +02001053 cmd->request->special = NULL;
James Bottomley3a5c19c2010-08-16 10:06:26 -05001054 scsi_put_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001055 return error;
1056}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001057EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058
Christoph Hellwig3b003152006-11-04 20:10:55 +01001059static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1060 struct request *req)
1061{
1062 struct scsi_cmnd *cmd;
1063
1064 if (!req->special) {
1065 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1066 if (unlikely(!cmd))
1067 return NULL;
1068 req->special = cmd;
1069 } else {
1070 cmd = req->special;
1071 }
1072
1073 /* pull a tag out of the request if we have one */
1074 cmd->tag = req->tag;
1075 cmd->request = req;
1076
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001077 cmd->cmnd = req->cmd;
Martin K. Petersen72f7d322011-03-08 02:03:59 -05001078 cmd->prot_op = SCSI_PROT_NORMAL;
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001079
Christoph Hellwig3b003152006-11-04 20:10:55 +01001080 return cmd;
1081}
1082
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001083int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001084{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001085 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001086 int ret = scsi_prep_state_check(sdev, req);
1087
1088 if (ret != BLKPREP_OK)
1089 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001090
1091 cmd = scsi_get_cmd_from_req(sdev, req);
1092 if (unlikely(!cmd))
1093 return BLKPREP_DEFER;
1094
1095 /*
1096 * BLOCK_PC requests may transfer data, in which case they must
1097 * a bio attached to them. Or they might contain a SCSI command
1098 * that does not transfer data, in which case they may optionally
1099 * submit a request without an attached bio.
1100 */
1101 if (req->bio) {
1102 int ret;
1103
1104 BUG_ON(!req->nr_phys_segments);
1105
Boaz Harroshbb52d822007-12-13 16:14:27 -08001106 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001107 if (unlikely(ret))
1108 return ret;
1109 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001110 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001111
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001112 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001113 req->buffer = NULL;
1114 }
James Bottomley7b163182005-12-15 20:17:02 -06001115
James Bottomley7b163182005-12-15 20:17:02 -06001116 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001117 if (!blk_rq_bytes(req))
James Bottomley7b163182005-12-15 20:17:02 -06001118 cmd->sc_data_direction = DMA_NONE;
1119 else if (rq_data_dir(req) == WRITE)
1120 cmd->sc_data_direction = DMA_TO_DEVICE;
1121 else
1122 cmd->sc_data_direction = DMA_FROM_DEVICE;
1123
Tejun Heob0790412009-05-07 22:24:42 +09001124 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001125 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001126 return BLKPREP_OK;
1127}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001128EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001129
1130/*
1131 * Setup a REQ_TYPE_FS command. These are simple read/write request
1132 * from filesystems that still need to be translated to SCSI CDBs from
1133 * the ULD.
1134 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001135int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001136{
1137 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001138 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001139
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001140 if (ret != BLKPREP_OK)
1141 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001142
1143 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1144 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1145 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1146 if (ret != BLKPREP_OK)
1147 return ret;
1148 }
1149
Christoph Hellwig3b003152006-11-04 20:10:55 +01001150 /*
1151 * Filesystem requests must transfer data.
1152 */
1153 BUG_ON(!req->nr_phys_segments);
1154
1155 cmd = scsi_get_cmd_from_req(sdev, req);
1156 if (unlikely(!cmd))
1157 return BLKPREP_DEFER;
1158
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001159 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001160 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001161}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001162EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001163
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001164int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001166 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167
1168 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001169 * If the device is not in running state we will reject some
1170 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001173 switch (sdev->sdev_state) {
1174 case SDEV_OFFLINE:
1175 /*
1176 * If the device is offline we refuse to process any
1177 * commands. The device must be brought online
1178 * before trying any recovery commands.
1179 */
1180 sdev_printk(KERN_ERR, sdev,
1181 "rejecting I/O to offline device\n");
1182 ret = BLKPREP_KILL;
1183 break;
1184 case SDEV_DEL:
1185 /*
1186 * If the device is fully deleted, we refuse to
1187 * process any commands as well.
1188 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001189 sdev_printk(KERN_ERR, sdev,
1190 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001191 ret = BLKPREP_KILL;
1192 break;
1193 case SDEV_QUIESCE:
1194 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001195 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001196 /*
1197 * If the devices is blocked we defer normal commands.
1198 */
1199 if (!(req->cmd_flags & REQ_PREEMPT))
1200 ret = BLKPREP_DEFER;
1201 break;
1202 default:
1203 /*
1204 * For any other not fully online state we only allow
1205 * special commands. In particular any user initiated
1206 * command is not allowed.
1207 */
1208 if (!(req->cmd_flags & REQ_PREEMPT))
1209 ret = BLKPREP_KILL;
1210 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001213 return ret;
1214}
1215EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001217int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1218{
1219 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220
Christoph Hellwig3b003152006-11-04 20:10:55 +01001221 switch (ret) {
1222 case BLKPREP_KILL:
1223 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001224 /* release the command and kill it */
1225 if (req->special) {
1226 struct scsi_cmnd *cmd = req->special;
1227 scsi_release_buffers(cmd);
1228 scsi_put_command(cmd);
1229 req->special = NULL;
1230 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001231 break;
1232 case BLKPREP_DEFER:
1233 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001234 * If we defer, the blk_peek_request() returns NULL, but the
Jens Axboea488e742010-04-16 21:13:15 +02001235 * queue must be restarted, so we schedule a callback to happen
1236 * shortly.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001237 */
1238 if (sdev->device_busy == 0)
Jens Axboea488e742010-04-16 21:13:15 +02001239 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001240 break;
1241 default:
1242 req->cmd_flags |= REQ_DONTPREP;
1243 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244
Christoph Hellwig3b003152006-11-04 20:10:55 +01001245 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001247EXPORT_SYMBOL(scsi_prep_return);
1248
James Bottomley751bf4d2008-01-02 11:14:30 -06001249int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001250{
1251 struct scsi_device *sdev = q->queuedata;
1252 int ret = BLKPREP_KILL;
1253
1254 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1255 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1256 return scsi_prep_return(q, req, ret);
1257}
Hannes Reineckeb3912772009-06-18 09:57:18 +02001258EXPORT_SYMBOL(scsi_prep_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259
1260/*
1261 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1262 * return 0.
1263 *
1264 * Called with the queue_lock held.
1265 */
1266static inline int scsi_dev_queue_ready(struct request_queue *q,
1267 struct scsi_device *sdev)
1268{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 if (sdev->device_busy == 0 && sdev->device_blocked) {
1270 /*
1271 * unblock after device_blocked iterates to zero
1272 */
1273 if (--sdev->device_blocked == 0) {
1274 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001275 sdev_printk(KERN_INFO, sdev,
1276 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 } else {
Jens Axboea488e742010-04-16 21:13:15 +02001278 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 return 0;
1280 }
1281 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001282 if (scsi_device_is_busy(sdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 return 0;
1284
1285 return 1;
1286}
1287
Mike Christief0c0a372008-08-17 15:24:38 -05001288
1289/*
1290 * scsi_target_queue_ready: checks if there we can send commands to target
1291 * @sdev: scsi device on starget to check.
1292 *
1293 * Called with the host lock held.
1294 */
1295static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1296 struct scsi_device *sdev)
1297{
1298 struct scsi_target *starget = scsi_target(sdev);
1299
1300 if (starget->single_lun) {
1301 if (starget->starget_sdev_user &&
1302 starget->starget_sdev_user != sdev)
1303 return 0;
1304 starget->starget_sdev_user = sdev;
1305 }
1306
1307 if (starget->target_busy == 0 && starget->target_blocked) {
1308 /*
1309 * unblock after target_blocked iterates to zero
1310 */
1311 if (--starget->target_blocked == 0) {
1312 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1313 "unblocking target at zero depth\n"));
Mike Christieb4efdd52009-04-09 15:57:10 -05001314 } else
Mike Christief0c0a372008-08-17 15:24:38 -05001315 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001316 }
1317
1318 if (scsi_target_is_busy(starget)) {
Hillf Dantonfd01a662010-12-16 14:26:37 -06001319 if (list_empty(&sdev->starved_entry))
Mike Christief0c0a372008-08-17 15:24:38 -05001320 list_add_tail(&sdev->starved_entry,
1321 &shost->starved_list);
Hillf Dantonfd01a662010-12-16 14:26:37 -06001322 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001323 }
1324
1325 /* We're OK to process the command, so we can't be starved */
1326 if (!list_empty(&sdev->starved_entry))
1327 list_del_init(&sdev->starved_entry);
1328 return 1;
1329}
1330
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331/*
1332 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1333 * return 0. We must end up running the queue again whenever 0 is
1334 * returned, else IO can hang.
1335 *
1336 * Called with host_lock held.
1337 */
1338static inline int scsi_host_queue_ready(struct request_queue *q,
1339 struct Scsi_Host *shost,
1340 struct scsi_device *sdev)
1341{
James Bottomley939647e2005-09-18 15:05:20 -05001342 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 return 0;
1344 if (shost->host_busy == 0 && shost->host_blocked) {
1345 /*
1346 * unblock after host_blocked iterates to zero
1347 */
1348 if (--shost->host_blocked == 0) {
1349 SCSI_LOG_MLQUEUE(3,
1350 printk("scsi%d unblocking host at zero depth\n",
1351 shost->host_no));
1352 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 return 0;
1354 }
1355 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001356 if (scsi_host_is_busy(shost)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 if (list_empty(&sdev->starved_entry))
1358 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1359 return 0;
1360 }
1361
1362 /* We're OK to process the command, so we can't be starved */
1363 if (!list_empty(&sdev->starved_entry))
1364 list_del_init(&sdev->starved_entry);
1365
1366 return 1;
1367}
1368
1369/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001370 * Busy state exporting function for request stacking drivers.
1371 *
1372 * For efficiency, no lock is taken to check the busy state of
1373 * shost/starget/sdev, since the returned value is not guaranteed and
1374 * may be changed after request stacking drivers call the function,
1375 * regardless of taking lock or not.
1376 *
1377 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1378 * (e.g. !sdev), scsi needs to return 'not busy'.
1379 * Otherwise, request stacking drivers may hold requests forever.
1380 */
1381static int scsi_lld_busy(struct request_queue *q)
1382{
1383 struct scsi_device *sdev = q->queuedata;
1384 struct Scsi_Host *shost;
1385 struct scsi_target *starget;
1386
1387 if (!sdev)
1388 return 0;
1389
1390 shost = sdev->host;
1391 starget = scsi_target(sdev);
1392
1393 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) ||
1394 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev))
1395 return 1;
1396
1397 return 0;
1398}
1399
1400/*
James Bottomleye91442b2005-09-09 10:44:16 -05001401 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 */
Jens Axboe165125e2007-07-24 09:28:11 +02001403static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404{
James Bottomleye91442b2005-09-09 10:44:16 -05001405 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001406 struct scsi_device *sdev;
1407 struct scsi_target *starget;
1408 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409
Tejun Heo9934c8c2009-05-08 11:54:16 +09001410 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001411
Hannes Reinecke74571812011-11-09 08:39:24 +01001412 scmd_printk(KERN_INFO, cmd, "killing request\n");
1413
Jiri Slaby03b14702009-09-23 16:15:35 +02001414 sdev = cmd->device;
1415 starget = scsi_target(sdev);
1416 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001417 scsi_init_cmd_errh(cmd);
1418 cmd->result = DID_NO_CONNECT << 16;
1419 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001420
1421 /*
1422 * SCSI request completion path will do scsi_device_unbusy(),
1423 * bump busy counts. To bump the counters, we need to dance
1424 * with the locks as normal issue path does.
1425 */
1426 sdev->device_busy++;
1427 spin_unlock(sdev->request_queue->queue_lock);
1428 spin_lock(shost->host_lock);
1429 shost->host_busy++;
Mike Christief0c0a372008-08-17 15:24:38 -05001430 starget->target_busy++;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001431 spin_unlock(shost->host_lock);
1432 spin_lock(sdev->request_queue->queue_lock);
1433
Jens Axboe242f9dc2008-09-14 05:55:09 -07001434 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435}
1436
Jens Axboe1aea6432006-01-09 16:03:03 +01001437static void scsi_softirq_done(struct request *rq)
1438{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001439 struct scsi_cmnd *cmd = rq->special;
1440 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001441 int disposition;
1442
1443 INIT_LIST_HEAD(&cmd->eh_entry);
1444
Jens Axboe242f9dc2008-09-14 05:55:09 -07001445 atomic_inc(&cmd->device->iodone_cnt);
1446 if (cmd->result)
1447 atomic_inc(&cmd->device->ioerr_cnt);
1448
Jens Axboe1aea6432006-01-09 16:03:03 +01001449 disposition = scsi_decide_disposition(cmd);
1450 if (disposition != SUCCESS &&
1451 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1452 sdev_printk(KERN_ERR, cmd->device,
1453 "timing out command, waited %lus\n",
1454 wait_for/HZ);
1455 disposition = SUCCESS;
1456 }
1457
1458 scsi_log_completion(cmd, disposition);
1459
1460 switch (disposition) {
1461 case SUCCESS:
1462 scsi_finish_command(cmd);
1463 break;
1464 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001465 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001466 break;
1467 case ADD_TO_MLQUEUE:
1468 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1469 break;
1470 default:
1471 if (!scsi_eh_scmd_add(cmd, 0))
1472 scsi_finish_command(cmd);
1473 }
1474}
1475
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476/*
1477 * Function: scsi_request_fn()
1478 *
1479 * Purpose: Main strategy routine for SCSI.
1480 *
1481 * Arguments: q - Pointer to actual queue.
1482 *
1483 * Returns: Nothing
1484 *
1485 * Lock status: IO request lock assumed to be held when called.
1486 */
1487static void scsi_request_fn(struct request_queue *q)
1488{
1489 struct scsi_device *sdev = q->queuedata;
1490 struct Scsi_Host *shost;
1491 struct scsi_cmnd *cmd;
1492 struct request *req;
1493
1494 if (!sdev) {
Tejun Heo9934c8c2009-05-08 11:54:16 +09001495 while ((req = blk_peek_request(q)) != NULL)
James Bottomleye91442b2005-09-09 10:44:16 -05001496 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 return;
1498 }
1499
1500 if(!get_device(&sdev->sdev_gendev))
1501 /* We must be tearing the block queue down already */
1502 return;
1503
1504 /*
1505 * To start with, we keep looping until the queue is empty, or until
1506 * the host is no longer able to accept any more requests.
1507 */
1508 shost = sdev->host;
Jens Axboea488e742010-04-16 21:13:15 +02001509 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 int rtn;
1511 /*
1512 * get next queueable request. We do this early to make sure
1513 * that the request is fully prepared even if we cannot
1514 * accept it.
1515 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001516 req = blk_peek_request(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517 if (!req || !scsi_dev_queue_ready(q, sdev))
1518 break;
1519
1520 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001521 sdev_printk(KERN_ERR, sdev,
1522 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001523 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524 continue;
1525 }
1526
1527
1528 /*
1529 * Remove the request from the request list.
1530 */
1531 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001532 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 sdev->device_busy++;
1534
1535 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001536 cmd = req->special;
1537 if (unlikely(cmd == NULL)) {
1538 printk(KERN_CRIT "impossible request in %s.\n"
1539 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001540 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001541 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001542 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001543 BUG();
1544 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545 spin_lock(shost->host_lock);
1546
Mike Christieecefe8a2008-07-11 19:50:35 -05001547 /*
1548 * We hit this when the driver is using a host wide
1549 * tag map. For device level tag maps the queue_depth check
1550 * in the device ready fn would prevent us from trying
1551 * to allocate a tag. Since the map is a shared host resource
1552 * we add the dev to the starved list so it eventually gets
1553 * a run when a tag is freed.
1554 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001555 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001556 if (list_empty(&sdev->starved_entry))
1557 list_add_tail(&sdev->starved_entry,
1558 &shost->starved_list);
1559 goto not_ready;
1560 }
1561
Mike Christief0c0a372008-08-17 15:24:38 -05001562 if (!scsi_target_queue_ready(shost, sdev))
1563 goto not_ready;
1564
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 if (!scsi_host_queue_ready(q, shost, sdev))
1566 goto not_ready;
Mike Christief0c0a372008-08-17 15:24:38 -05001567
1568 scsi_target(sdev)->target_busy++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 shost->host_busy++;
1570
1571 /*
1572 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1573 * take the lock again.
1574 */
1575 spin_unlock_irq(shost->host_lock);
1576
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577 /*
1578 * Finally, initialize any error handling parameters, and set up
1579 * the timers for timeouts.
1580 */
1581 scsi_init_cmd_errh(cmd);
1582
1583 /*
1584 * Dispatch the command to the low-level driver.
1585 */
1586 rtn = scsi_dispatch_cmd(cmd);
1587 spin_lock_irq(q->queue_lock);
Jens Axboea488e742010-04-16 21:13:15 +02001588 if (rtn)
1589 goto out_delay;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001590 }
1591
1592 goto out;
1593
1594 not_ready:
1595 spin_unlock_irq(shost->host_lock);
1596
1597 /*
1598 * lock q, handle tag, requeue req, and decrement device_busy. We
1599 * must return with queue_lock held.
1600 *
1601 * Decrementing device_busy without checking it is OK, as all such
1602 * cases (host limits or settings) should run the queue at some
1603 * later time.
1604 */
1605 spin_lock_irq(q->queue_lock);
1606 blk_requeue_request(q, req);
1607 sdev->device_busy--;
Jens Axboea488e742010-04-16 21:13:15 +02001608out_delay:
1609 if (sdev->device_busy == 0)
1610 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1611out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 /* must be careful here...if we trigger the ->remove() function
1613 * we cannot be holding the q lock */
1614 spin_unlock_irq(q->queue_lock);
1615 put_device(&sdev->sdev_gendev);
1616 spin_lock_irq(q->queue_lock);
1617}
1618
1619u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1620{
1621 struct device *host_dev;
1622 u64 bounce_limit = 0xffffffff;
1623
1624 if (shost->unchecked_isa_dma)
1625 return BLK_BOUNCE_ISA;
1626 /*
1627 * Platforms with virtual-DMA translation
1628 * hardware have no practical limit.
1629 */
1630 if (!PCI_DMA_BUS_IS_PHYS)
1631 return BLK_BOUNCE_ANY;
1632
1633 host_dev = scsi_get_device(shost);
1634 if (host_dev && host_dev->dma_mask)
1635 bounce_limit = *host_dev->dma_mask;
1636
1637 return bounce_limit;
1638}
1639EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1640
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001641struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1642 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001645 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001647 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648 if (!q)
1649 return NULL;
1650
Jens Axboea8474ce2007-08-07 09:02:51 +02001651 /*
1652 * this limit is imposed by hardware restrictions
1653 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05001654 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1655 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02001656
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001657 if (scsi_host_prot_dma(shost)) {
1658 shost->sg_prot_tablesize =
1659 min_not_zero(shost->sg_prot_tablesize,
1660 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1661 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1662 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1663 }
1664
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05001665 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1667 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001668 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001670 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1671
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672 if (!shost->use_clustering)
Martin K. Petersene692cb62010-12-01 19:41:49 +01001673 q->limits.cluster = 0;
James Bottomley465ff312008-01-01 10:00:10 -06001674
1675 /*
1676 * set a reasonable default alignment on word boundaries: the
1677 * host and device may alter it using
1678 * blk_queue_update_dma_alignment() later.
1679 */
1680 blk_queue_dma_alignment(q, 0x03);
1681
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682 return q;
1683}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001684EXPORT_SYMBOL(__scsi_alloc_queue);
1685
1686struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1687{
1688 struct request_queue *q;
1689
1690 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1691 if (!q)
1692 return NULL;
1693
1694 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001695 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001696 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001697 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001698 return q;
1699}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700
1701void scsi_free_queue(struct request_queue *q)
1702{
Bart Van Assche33085112011-09-23 19:48:18 +02001703 unsigned long flags;
1704
1705 WARN_ON(q->queuedata);
1706
1707 /* cause scsi_request_fn() to kill all non-finished requests */
1708 spin_lock_irqsave(q->queue_lock, flags);
1709 q->request_fn(q);
1710 spin_unlock_irqrestore(q->queue_lock, flags);
1711
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712 blk_cleanup_queue(q);
1713}
1714
1715/*
1716 * Function: scsi_block_requests()
1717 *
1718 * Purpose: Utility function used by low-level drivers to prevent further
1719 * commands from being queued to the device.
1720 *
1721 * Arguments: shost - Host in question
1722 *
1723 * Returns: Nothing
1724 *
1725 * Lock status: No locks are assumed held.
1726 *
1727 * Notes: There is no timer nor any other means by which the requests
1728 * get unblocked other than the low-level driver calling
1729 * scsi_unblock_requests().
1730 */
1731void scsi_block_requests(struct Scsi_Host *shost)
1732{
1733 shost->host_self_blocked = 1;
1734}
1735EXPORT_SYMBOL(scsi_block_requests);
1736
1737/*
1738 * Function: scsi_unblock_requests()
1739 *
1740 * Purpose: Utility function used by low-level drivers to allow further
1741 * commands from being queued to the device.
1742 *
1743 * Arguments: shost - Host in question
1744 *
1745 * Returns: Nothing
1746 *
1747 * Lock status: No locks are assumed held.
1748 *
1749 * Notes: There is no timer nor any other means by which the requests
1750 * get unblocked other than the low-level driver calling
1751 * scsi_unblock_requests().
1752 *
1753 * This is done as an API function so that changes to the
1754 * internals of the scsi mid-layer won't require wholesale
1755 * changes to drivers that use this feature.
1756 */
1757void scsi_unblock_requests(struct Scsi_Host *shost)
1758{
1759 shost->host_self_blocked = 0;
1760 scsi_run_host_queues(shost);
1761}
1762EXPORT_SYMBOL(scsi_unblock_requests);
1763
1764int __init scsi_init_queue(void)
1765{
1766 int i;
1767
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001768 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1769 sizeof(struct scsi_data_buffer),
1770 0, 0, NULL);
1771 if (!scsi_sdb_cache) {
1772 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09001773 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001774 }
1775
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1777 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1778 int size = sgp->size * sizeof(struct scatterlist);
1779
1780 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001781 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 if (!sgp->slab) {
1783 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1784 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001785 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 }
1787
Matthew Dobson93d23412006-03-26 01:37:50 -08001788 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1789 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 if (!sgp->pool) {
1791 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1792 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001793 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 }
1795 }
1796
1797 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001798
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001799cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001800 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1801 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1802 if (sgp->pool)
1803 mempool_destroy(sgp->pool);
1804 if (sgp->slab)
1805 kmem_cache_destroy(sgp->slab);
1806 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001807 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001808
1809 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810}
1811
1812void scsi_exit_queue(void)
1813{
1814 int i;
1815
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001816 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001817
Linus Torvalds1da177e2005-04-16 15:20:36 -07001818 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1819 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1820 mempool_destroy(sgp->pool);
1821 kmem_cache_destroy(sgp->slab);
1822 }
1823}
James Bottomley5baba832006-03-18 14:10:35 -06001824
1825/**
1826 * scsi_mode_select - issue a mode select
1827 * @sdev: SCSI device to be queried
1828 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1829 * @sp: Save page bit (0 == don't save, 1 == save)
1830 * @modepage: mode page being requested
1831 * @buffer: request buffer (may not be smaller than eight bytes)
1832 * @len: length of request buffer.
1833 * @timeout: command timeout
1834 * @retries: number of retries before failing
1835 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001836 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001837 * must be SCSI_SENSE_BUFFERSIZE big.
1838 *
1839 * Returns zero if successful; negative error number or scsi
1840 * status on error
1841 *
1842 */
1843int
1844scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1845 unsigned char *buffer, int len, int timeout, int retries,
1846 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1847{
1848 unsigned char cmd[10];
1849 unsigned char *real_buffer;
1850 int ret;
1851
1852 memset(cmd, 0, sizeof(cmd));
1853 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1854
1855 if (sdev->use_10_for_ms) {
1856 if (len > 65535)
1857 return -EINVAL;
1858 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1859 if (!real_buffer)
1860 return -ENOMEM;
1861 memcpy(real_buffer + 8, buffer, len);
1862 len += 8;
1863 real_buffer[0] = 0;
1864 real_buffer[1] = 0;
1865 real_buffer[2] = data->medium_type;
1866 real_buffer[3] = data->device_specific;
1867 real_buffer[4] = data->longlba ? 0x01 : 0;
1868 real_buffer[5] = 0;
1869 real_buffer[6] = data->block_descriptor_length >> 8;
1870 real_buffer[7] = data->block_descriptor_length;
1871
1872 cmd[0] = MODE_SELECT_10;
1873 cmd[7] = len >> 8;
1874 cmd[8] = len;
1875 } else {
1876 if (len > 255 || data->block_descriptor_length > 255 ||
1877 data->longlba)
1878 return -EINVAL;
1879
1880 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1881 if (!real_buffer)
1882 return -ENOMEM;
1883 memcpy(real_buffer + 4, buffer, len);
1884 len += 4;
1885 real_buffer[0] = 0;
1886 real_buffer[1] = data->medium_type;
1887 real_buffer[2] = data->device_specific;
1888 real_buffer[3] = data->block_descriptor_length;
1889
1890
1891 cmd[0] = MODE_SELECT;
1892 cmd[4] = len;
1893 }
1894
1895 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001896 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06001897 kfree(real_buffer);
1898 return ret;
1899}
1900EXPORT_SYMBOL_GPL(scsi_mode_select);
1901
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902/**
Rob Landleyeb448202007-11-03 13:30:39 -05001903 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001904 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001905 * @dbd: set if mode sense will allow block descriptors to be returned
1906 * @modepage: mode page being requested
1907 * @buffer: request buffer (may not be smaller than eight bytes)
1908 * @len: length of request buffer.
1909 * @timeout: command timeout
1910 * @retries: number of retries before failing
1911 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001912 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001913 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914 *
1915 * Returns zero if unsuccessful, or the header offset (either 4
1916 * or 8 depending on whether a six or ten byte command was
1917 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001918 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919int
James Bottomley1cf72692005-08-28 11:27:01 -05001920scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001922 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1923{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 unsigned char cmd[12];
1925 int use_10_for_ms;
1926 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001927 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001928 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001929
1930 memset(data, 0, sizeof(*data));
1931 memset(&cmd[0], 0, 12);
1932 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1933 cmd[2] = modepage;
1934
James Bottomleyea73a9f2005-08-28 11:33:52 -05001935 /* caller might not be interested in sense, but we need it */
1936 if (!sshdr)
1937 sshdr = &my_sshdr;
1938
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001940 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941
1942 if (use_10_for_ms) {
1943 if (len < 8)
1944 len = 8;
1945
1946 cmd[0] = MODE_SENSE_10;
1947 cmd[8] = len;
1948 header_length = 8;
1949 } else {
1950 if (len < 4)
1951 len = 4;
1952
1953 cmd[0] = MODE_SENSE;
1954 cmd[4] = len;
1955 header_length = 4;
1956 }
1957
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 memset(buffer, 0, len);
1959
James Bottomley1cf72692005-08-28 11:27:01 -05001960 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001961 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962
1963 /* This code looks awful: what it's doing is making sure an
1964 * ILLEGAL REQUEST sense return identifies the actual command
1965 * byte as the problem. MODE_SENSE commands can return
1966 * ILLEGAL REQUEST if the code page isn't supported */
1967
James Bottomley1cf72692005-08-28 11:27:01 -05001968 if (use_10_for_ms && !scsi_status_is_good(result) &&
1969 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001970 if (scsi_sense_valid(sshdr)) {
1971 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1972 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 /*
1974 * Invalid command operation code
1975 */
James Bottomley1cf72692005-08-28 11:27:01 -05001976 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 goto retry;
1978 }
1979 }
1980 }
1981
James Bottomley1cf72692005-08-28 11:27:01 -05001982 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001983 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1984 (modepage == 6 || modepage == 8))) {
1985 /* Initio breakage? */
1986 header_length = 0;
1987 data->length = 13;
1988 data->medium_type = 0;
1989 data->device_specific = 0;
1990 data->longlba = 0;
1991 data->block_descriptor_length = 0;
1992 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001993 data->length = buffer[0]*256 + buffer[1] + 2;
1994 data->medium_type = buffer[2];
1995 data->device_specific = buffer[3];
1996 data->longlba = buffer[4] & 0x01;
1997 data->block_descriptor_length = buffer[6]*256
1998 + buffer[7];
1999 } else {
2000 data->length = buffer[0] + 1;
2001 data->medium_type = buffer[1];
2002 data->device_specific = buffer[2];
2003 data->block_descriptor_length = buffer[3];
2004 }
Al Viro6d73c852006-02-23 02:03:16 +01002005 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006 }
2007
James Bottomley1cf72692005-08-28 11:27:01 -05002008 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009}
2010EXPORT_SYMBOL(scsi_mode_sense);
2011
James Bottomley001aac22007-12-02 19:10:40 +02002012/**
2013 * scsi_test_unit_ready - test if unit is ready
2014 * @sdev: scsi device to change the state of.
2015 * @timeout: command timeout
2016 * @retries: number of retries before failing
2017 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2018 * returning sense. Make sure that this is cleared before passing
2019 * in.
2020 *
2021 * Returns zero if unsuccessful or an error if TUR failed. For
Tejun Heo9f8a2c22010-12-08 20:57:40 +01002022 * removable media, UNIT_ATTENTION sets ->changed flag.
James Bottomley001aac22007-12-02 19:10:40 +02002023 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024int
James Bottomley001aac22007-12-02 19:10:40 +02002025scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2026 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028 char cmd[] = {
2029 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2030 };
James Bottomley001aac22007-12-02 19:10:40 +02002031 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002033
2034 if (!sshdr_external)
2035 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2036 else
2037 sshdr = sshdr_external;
2038
2039 /* try to eat the UNIT_ATTENTION if there are enough retries */
2040 do {
2041 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002042 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002043 if (sdev->removable && scsi_sense_valid(sshdr) &&
2044 sshdr->sense_key == UNIT_ATTENTION)
2045 sdev->changed = 1;
2046 } while (scsi_sense_valid(sshdr) &&
2047 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002048
James Bottomley001aac22007-12-02 19:10:40 +02002049 if (!sshdr_external)
2050 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051 return result;
2052}
2053EXPORT_SYMBOL(scsi_test_unit_ready);
2054
2055/**
Rob Landleyeb448202007-11-03 13:30:39 -05002056 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002057 * @sdev: scsi device to change the state of.
2058 * @state: state to change to.
2059 *
2060 * Returns zero if unsuccessful or an error if the requested
2061 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002062 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002063int
2064scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2065{
2066 enum scsi_device_state oldstate = sdev->sdev_state;
2067
2068 if (state == oldstate)
2069 return 0;
2070
2071 switch (state) {
2072 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002073 switch (oldstate) {
2074 case SDEV_CREATED_BLOCK:
2075 break;
2076 default:
2077 goto illegal;
2078 }
2079 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080
2081 case SDEV_RUNNING:
2082 switch (oldstate) {
2083 case SDEV_CREATED:
2084 case SDEV_OFFLINE:
2085 case SDEV_QUIESCE:
2086 case SDEV_BLOCK:
2087 break;
2088 default:
2089 goto illegal;
2090 }
2091 break;
2092
2093 case SDEV_QUIESCE:
2094 switch (oldstate) {
2095 case SDEV_RUNNING:
2096 case SDEV_OFFLINE:
2097 break;
2098 default:
2099 goto illegal;
2100 }
2101 break;
2102
2103 case SDEV_OFFLINE:
2104 switch (oldstate) {
2105 case SDEV_CREATED:
2106 case SDEV_RUNNING:
2107 case SDEV_QUIESCE:
2108 case SDEV_BLOCK:
2109 break;
2110 default:
2111 goto illegal;
2112 }
2113 break;
2114
2115 case SDEV_BLOCK:
2116 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002117 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002118 case SDEV_CREATED_BLOCK:
2119 break;
2120 default:
2121 goto illegal;
2122 }
2123 break;
2124
2125 case SDEV_CREATED_BLOCK:
2126 switch (oldstate) {
2127 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128 break;
2129 default:
2130 goto illegal;
2131 }
2132 break;
2133
2134 case SDEV_CANCEL:
2135 switch (oldstate) {
2136 case SDEV_CREATED:
2137 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002138 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139 case SDEV_OFFLINE:
2140 case SDEV_BLOCK:
2141 break;
2142 default:
2143 goto illegal;
2144 }
2145 break;
2146
2147 case SDEV_DEL:
2148 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002149 case SDEV_CREATED:
2150 case SDEV_RUNNING:
2151 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002152 case SDEV_CANCEL:
2153 break;
2154 default:
2155 goto illegal;
2156 }
2157 break;
2158
2159 }
2160 sdev->sdev_state = state;
2161 return 0;
2162
2163 illegal:
2164 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002165 sdev_printk(KERN_ERR, sdev,
2166 "Illegal state transition %s->%s\n",
2167 scsi_device_state_name(oldstate),
2168 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169 );
2170 return -EINVAL;
2171}
2172EXPORT_SYMBOL(scsi_device_set_state);
2173
2174/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002175 * sdev_evt_emit - emit a single SCSI device uevent
2176 * @sdev: associated SCSI device
2177 * @evt: event to emit
2178 *
2179 * Send a single uevent (scsi_event) to the associated scsi_device.
2180 */
2181static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2182{
2183 int idx = 0;
2184 char *envp[3];
2185
2186 switch (evt->evt_type) {
2187 case SDEV_EVT_MEDIA_CHANGE:
2188 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2189 break;
2190
2191 default:
2192 /* do nothing */
2193 break;
2194 }
2195
2196 envp[idx++] = NULL;
2197
2198 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2199}
2200
2201/**
2202 * sdev_evt_thread - send a uevent for each scsi event
2203 * @work: work struct for scsi_device
2204 *
2205 * Dispatch queued events to their associated scsi_device kobjects
2206 * as uevents.
2207 */
2208void scsi_evt_thread(struct work_struct *work)
2209{
2210 struct scsi_device *sdev;
2211 LIST_HEAD(event_list);
2212
2213 sdev = container_of(work, struct scsi_device, event_work);
2214
2215 while (1) {
2216 struct scsi_event *evt;
2217 struct list_head *this, *tmp;
2218 unsigned long flags;
2219
2220 spin_lock_irqsave(&sdev->list_lock, flags);
2221 list_splice_init(&sdev->event_list, &event_list);
2222 spin_unlock_irqrestore(&sdev->list_lock, flags);
2223
2224 if (list_empty(&event_list))
2225 break;
2226
2227 list_for_each_safe(this, tmp, &event_list) {
2228 evt = list_entry(this, struct scsi_event, node);
2229 list_del(&evt->node);
2230 scsi_evt_emit(sdev, evt);
2231 kfree(evt);
2232 }
2233 }
2234}
2235
2236/**
2237 * sdev_evt_send - send asserted event to uevent thread
2238 * @sdev: scsi_device event occurred on
2239 * @evt: event to send
2240 *
2241 * Assert scsi device event asynchronously.
2242 */
2243void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2244{
2245 unsigned long flags;
2246
Kay Sievers4d1566e2008-03-19 13:04:47 +01002247#if 0
2248 /* FIXME: currently this check eliminates all media change events
2249 * for polled devices. Need to update to discriminate between AN
2250 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002251 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2252 kfree(evt);
2253 return;
2254 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002255#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002256
2257 spin_lock_irqsave(&sdev->list_lock, flags);
2258 list_add_tail(&evt->node, &sdev->event_list);
2259 schedule_work(&sdev->event_work);
2260 spin_unlock_irqrestore(&sdev->list_lock, flags);
2261}
2262EXPORT_SYMBOL_GPL(sdev_evt_send);
2263
2264/**
2265 * sdev_evt_alloc - allocate a new scsi event
2266 * @evt_type: type of event to allocate
2267 * @gfpflags: GFP flags for allocation
2268 *
2269 * Allocates and returns a new scsi_event.
2270 */
2271struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2272 gfp_t gfpflags)
2273{
2274 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2275 if (!evt)
2276 return NULL;
2277
2278 evt->evt_type = evt_type;
2279 INIT_LIST_HEAD(&evt->node);
2280
2281 /* evt_type-specific initialization, if any */
2282 switch (evt_type) {
2283 case SDEV_EVT_MEDIA_CHANGE:
2284 default:
2285 /* do nothing */
2286 break;
2287 }
2288
2289 return evt;
2290}
2291EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2292
2293/**
2294 * sdev_evt_send_simple - send asserted event to uevent thread
2295 * @sdev: scsi_device event occurred on
2296 * @evt_type: type of event to send
2297 * @gfpflags: GFP flags for allocation
2298 *
2299 * Assert scsi device event asynchronously, given an event type.
2300 */
2301void sdev_evt_send_simple(struct scsi_device *sdev,
2302 enum scsi_device_event evt_type, gfp_t gfpflags)
2303{
2304 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2305 if (!evt) {
2306 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2307 evt_type);
2308 return;
2309 }
2310
2311 sdev_evt_send(sdev, evt);
2312}
2313EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2314
2315/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316 * scsi_device_quiesce - Block user issued commands.
2317 * @sdev: scsi device to quiesce.
2318 *
2319 * This works by trying to transition to the SDEV_QUIESCE state
2320 * (which must be a legal transition). When the device is in this
2321 * state, only special requests will be accepted, all others will
2322 * be deferred. Since special requests may also be requeued requests,
2323 * a successful return doesn't guarantee the device will be
2324 * totally quiescent.
2325 *
2326 * Must be called with user context, may sleep.
2327 *
2328 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002329 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002330int
2331scsi_device_quiesce(struct scsi_device *sdev)
2332{
2333 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2334 if (err)
2335 return err;
2336
2337 scsi_run_queue(sdev->request_queue);
2338 while (sdev->device_busy) {
2339 msleep_interruptible(200);
2340 scsi_run_queue(sdev->request_queue);
2341 }
2342 return 0;
2343}
2344EXPORT_SYMBOL(scsi_device_quiesce);
2345
2346/**
2347 * scsi_device_resume - Restart user issued commands to a quiesced device.
2348 * @sdev: scsi device to resume.
2349 *
2350 * Moves the device from quiesced back to running and restarts the
2351 * queues.
2352 *
2353 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002354 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002355void
2356scsi_device_resume(struct scsi_device *sdev)
2357{
2358 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2359 return;
2360 scsi_run_queue(sdev->request_queue);
2361}
2362EXPORT_SYMBOL(scsi_device_resume);
2363
2364static void
2365device_quiesce_fn(struct scsi_device *sdev, void *data)
2366{
2367 scsi_device_quiesce(sdev);
2368}
2369
2370void
2371scsi_target_quiesce(struct scsi_target *starget)
2372{
2373 starget_for_each_device(starget, NULL, device_quiesce_fn);
2374}
2375EXPORT_SYMBOL(scsi_target_quiesce);
2376
2377static void
2378device_resume_fn(struct scsi_device *sdev, void *data)
2379{
2380 scsi_device_resume(sdev);
2381}
2382
2383void
2384scsi_target_resume(struct scsi_target *starget)
2385{
2386 starget_for_each_device(starget, NULL, device_resume_fn);
2387}
2388EXPORT_SYMBOL(scsi_target_resume);
2389
2390/**
Rob Landleyeb448202007-11-03 13:30:39 -05002391 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392 * @sdev: device to block
2393 *
2394 * Block request made by scsi lld's to temporarily stop all
2395 * scsi commands on the specified device. Called from interrupt
2396 * or normal process context.
2397 *
2398 * Returns zero if successful or error if not
2399 *
2400 * Notes:
2401 * This routine transitions the device to the SDEV_BLOCK state
2402 * (which must be a legal transition). When the device is in this
2403 * state, all commands are deferred until the scsi lld reenables
2404 * the device with scsi_device_unblock or device_block_tmo fires.
2405 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002406 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407int
2408scsi_internal_device_block(struct scsi_device *sdev)
2409{
Jens Axboe165125e2007-07-24 09:28:11 +02002410 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411 unsigned long flags;
2412 int err = 0;
2413
2414 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002415 if (err) {
2416 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2417
2418 if (err)
2419 return err;
2420 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002421
2422 /*
2423 * The device has transitioned to SDEV_BLOCK. Stop the
2424 * block layer from calling the midlayer with this device's
2425 * request queue.
2426 */
2427 spin_lock_irqsave(q->queue_lock, flags);
2428 blk_stop_queue(q);
2429 spin_unlock_irqrestore(q->queue_lock, flags);
2430
2431 return 0;
2432}
2433EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2434
2435/**
2436 * scsi_internal_device_unblock - resume a device after a block request
2437 * @sdev: device to resume
2438 *
2439 * Called by scsi lld's or the midlayer to restart the device queue
2440 * for the previously suspended scsi device. Called from interrupt or
2441 * normal process context.
2442 *
2443 * Returns zero if successful or error if not.
2444 *
2445 * Notes:
2446 * This routine transitions the device to the SDEV_RUNNING state
2447 * (which must be a legal transition) allowing the midlayer to
2448 * goose the queue for this device. This routine assumes the
2449 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002450 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451int
2452scsi_internal_device_unblock(struct scsi_device *sdev)
2453{
Jens Axboe165125e2007-07-24 09:28:11 +02002454 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455 unsigned long flags;
2456
2457 /*
2458 * Try to transition the scsi device to SDEV_RUNNING
2459 * and goose the device queue if successful.
2460 */
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002461 if (sdev->sdev_state == SDEV_BLOCK)
2462 sdev->sdev_state = SDEV_RUNNING;
2463 else if (sdev->sdev_state == SDEV_CREATED_BLOCK)
2464 sdev->sdev_state = SDEV_CREATED;
Mike Christie986fe6c2010-10-06 03:10:59 -05002465 else if (sdev->sdev_state != SDEV_CANCEL &&
2466 sdev->sdev_state != SDEV_OFFLINE)
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002467 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468
2469 spin_lock_irqsave(q->queue_lock, flags);
2470 blk_start_queue(q);
2471 spin_unlock_irqrestore(q->queue_lock, flags);
2472
2473 return 0;
2474}
2475EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2476
2477static void
2478device_block(struct scsi_device *sdev, void *data)
2479{
2480 scsi_internal_device_block(sdev);
2481}
2482
2483static int
2484target_block(struct device *dev, void *data)
2485{
2486 if (scsi_is_target_device(dev))
2487 starget_for_each_device(to_scsi_target(dev), NULL,
2488 device_block);
2489 return 0;
2490}
2491
2492void
2493scsi_target_block(struct device *dev)
2494{
2495 if (scsi_is_target_device(dev))
2496 starget_for_each_device(to_scsi_target(dev), NULL,
2497 device_block);
2498 else
2499 device_for_each_child(dev, NULL, target_block);
2500}
2501EXPORT_SYMBOL_GPL(scsi_target_block);
2502
2503static void
2504device_unblock(struct scsi_device *sdev, void *data)
2505{
2506 scsi_internal_device_unblock(sdev);
2507}
2508
2509static int
2510target_unblock(struct device *dev, void *data)
2511{
2512 if (scsi_is_target_device(dev))
2513 starget_for_each_device(to_scsi_target(dev), NULL,
2514 device_unblock);
2515 return 0;
2516}
2517
2518void
2519scsi_target_unblock(struct device *dev)
2520{
2521 if (scsi_is_target_device(dev))
2522 starget_for_each_device(to_scsi_target(dev), NULL,
2523 device_unblock);
2524 else
2525 device_for_each_child(dev, NULL, target_unblock);
2526}
2527EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002528
2529/**
2530 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002531 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002532 * @sg_count: number of segments in sg
2533 * @offset: offset in bytes into sg, on return offset into the mapped area
2534 * @len: bytes to map, on return number of bytes mapped
2535 *
2536 * Returns virtual address of the start of the mapped page
2537 */
Jens Axboec6132da2007-10-16 11:08:49 +02002538void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002539 size_t *offset, size_t *len)
2540{
2541 int i;
2542 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002543 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002544 struct page *page;
2545
Andrew Morton22cfefb2007-02-05 16:39:03 -08002546 WARN_ON(!irqs_disabled());
2547
Jens Axboec6132da2007-10-16 11:08:49 +02002548 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002549 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002550 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002551 if (sg_len > *offset)
2552 break;
2553 }
2554
2555 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002556 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2557 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002558 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002559 WARN_ON(1);
2560 return NULL;
2561 }
2562
2563 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002564 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002565
2566 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002567 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002568 *offset &= ~PAGE_MASK;
2569
2570 /* Bytes in this sg-entry from *offset to the end of the page */
2571 sg_len = PAGE_SIZE - *offset;
2572 if (*len > sg_len)
2573 *len = sg_len;
2574
2575 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2576}
2577EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2578
2579/**
Rob Landleyeb448202007-11-03 13:30:39 -05002580 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002581 * @virt: virtual address to be unmapped
2582 */
2583void scsi_kunmap_atomic_sg(void *virt)
2584{
2585 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2586}
2587EXPORT_SYMBOL(scsi_kunmap_atomic_sg);