Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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> | |
d3f46f39 | 11 | #include <linux/bitops.h> |
1da177e4 LT |
12 | #include <linux/blkdev.h> |
13 | #include <linux/completion.h> | |
14 | #include <linux/kernel.h> | |
09703660 | 15 | #include <linux/export.h> |
1da177e4 LT |
16 | #include <linux/mempool.h> |
17 | #include <linux/slab.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/pci.h> | |
20 | #include <linux/delay.h> | |
faead26d | 21 | #include <linux/hardirq.h> |
c6132da1 | 22 | #include <linux/scatterlist.h> |
1da177e4 LT |
23 | |
24 | #include <scsi/scsi.h> | |
beb40487 | 25 | #include <scsi/scsi_cmnd.h> |
1da177e4 LT |
26 | #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> | |
1da177e4 LT |
31 | |
32 | #include "scsi_priv.h" | |
33 | #include "scsi_logging.h" | |
34 | ||
35 | ||
6391a113 | 36 | #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) |
5972511b | 37 | #define SG_MEMPOOL_SIZE 2 |
1da177e4 LT |
38 | |
39 | struct scsi_host_sg_pool { | |
40 | size_t size; | |
a8474ce2 | 41 | char *name; |
e18b890b | 42 | struct kmem_cache *slab; |
1da177e4 LT |
43 | mempool_t *pool; |
44 | }; | |
45 | ||
d3f46f39 JB |
46 | #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 | |
52c1da39 | 50 | static struct scsi_host_sg_pool scsi_sg_pools[] = { |
1da177e4 LT |
51 | SP(8), |
52 | SP(16), | |
fd820f40 | 53 | #if (SCSI_MAX_SG_SEGMENTS > 32) |
d3f46f39 | 54 | SP(32), |
fd820f40 | 55 | #if (SCSI_MAX_SG_SEGMENTS > 64) |
d3f46f39 JB |
56 | SP(64), |
57 | #if (SCSI_MAX_SG_SEGMENTS > 128) | |
1da177e4 | 58 | SP(128), |
d3f46f39 JB |
59 | #if (SCSI_MAX_SG_SEGMENTS > 256) |
60 | #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX) | |
fd820f40 FT |
61 | #endif |
62 | #endif | |
63 | #endif | |
d3f46f39 JB |
64 | #endif |
65 | SP(SCSI_MAX_SG_SEGMENTS) | |
a8474ce2 | 66 | }; |
1da177e4 LT |
67 | #undef SP |
68 | ||
7027ad72 | 69 | struct kmem_cache *scsi_sdb_cache; |
6f9a35e2 | 70 | |
a488e749 JA |
71 | /* |
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 | ||
e91442b6 JB |
78 | /* |
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 | */ | |
90 | static void scsi_unprep_request(struct request *req) | |
91 | { | |
92 | struct scsi_cmnd *cmd = req->special; | |
93 | ||
28018c24 | 94 | blk_unprep_request(req); |
beb40487 | 95 | req->special = NULL; |
e91442b6 | 96 | |
e91442b6 JB |
97 | scsi_put_command(cmd); |
98 | } | |
a1bf9d1d | 99 | |
4f5299ac JB |
100 | /** |
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 | |
1da177e4 | 105 | * |
4f5299ac JB |
106 | * 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. | |
1da177e4 | 111 | */ |
84feb166 | 112 | static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) |
1da177e4 LT |
113 | { |
114 | struct Scsi_Host *host = cmd->device->host; | |
115 | struct scsi_device *device = cmd->device; | |
f0c0a376 | 116 | struct scsi_target *starget = scsi_target(device); |
a1bf9d1d TH |
117 | struct request_queue *q = device->request_queue; |
118 | unsigned long flags; | |
1da177e4 LT |
119 | |
120 | SCSI_LOG_MLQUEUE(1, | |
121 | printk("Inserting command %p into mlqueue\n", cmd)); | |
122 | ||
123 | /* | |
d8c37e7b | 124 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
125 | * |
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 | */ | |
f0c0a376 MC |
136 | switch (reason) { |
137 | case SCSI_MLQUEUE_HOST_BUSY: | |
1da177e4 | 138 | host->host_blocked = host->max_host_blocked; |
f0c0a376 MC |
139 | break; |
140 | case SCSI_MLQUEUE_DEVICE_BUSY: | |
573e5913 | 141 | case SCSI_MLQUEUE_EH_RETRY: |
1da177e4 | 142 | device->device_blocked = device->max_device_blocked; |
f0c0a376 MC |
143 | break; |
144 | case SCSI_MLQUEUE_TARGET_BUSY: | |
145 | starget->target_blocked = starget->max_target_blocked; | |
146 | break; | |
147 | } | |
1da177e4 | 148 | |
1da177e4 LT |
149 | /* |
150 | * Decrement the counters, since these commands are no longer | |
151 | * active on the host/device. | |
152 | */ | |
4f5299ac JB |
153 | if (unbusy) |
154 | scsi_device_unbusy(device); | |
1da177e4 LT |
155 | |
156 | /* | |
a1bf9d1d | 157 | * Requeue this command. It will go before all other commands |
b485462a BVA |
158 | * that are already in the queue. Schedule requeue work under |
159 | * lock such that the kblockd_schedule_work() call happens | |
160 | * before blk_cleanup_queue() finishes. | |
a488e749 | 161 | */ |
a1bf9d1d | 162 | spin_lock_irqsave(q->queue_lock, flags); |
59897dad | 163 | blk_requeue_request(q, cmd->request); |
9937a5e2 | 164 | kblockd_schedule_work(q, &device->requeue_work); |
b485462a | 165 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
166 | } |
167 | ||
4f5299ac JB |
168 | /* |
169 | * Function: scsi_queue_insert() | |
170 | * | |
171 | * Purpose: Insert a command in the midlevel queue. | |
172 | * | |
173 | * Arguments: cmd - command that we are adding to queue. | |
174 | * reason - why we are inserting command to queue. | |
175 | * | |
176 | * Lock status: Assumed that lock is not held upon entry. | |
177 | * | |
178 | * Returns: Nothing. | |
179 | * | |
180 | * Notes: We do this for one of two cases. Either the host is busy | |
181 | * and it cannot accept any more commands for the time being, | |
182 | * or the device returned QUEUE_FULL and can accept no more | |
183 | * commands. | |
184 | * Notes: This could be called either from an interrupt context or a | |
185 | * normal process context. | |
186 | */ | |
84feb166 | 187 | void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) |
4f5299ac | 188 | { |
84feb166 | 189 | __scsi_queue_insert(cmd, reason, 1); |
4f5299ac | 190 | } |
39216033 | 191 | /** |
33aa687d | 192 | * scsi_execute - insert request and wait for the result |
39216033 JB |
193 | * @sdev: scsi device |
194 | * @cmd: scsi command | |
195 | * @data_direction: data direction | |
196 | * @buffer: data buffer | |
197 | * @bufflen: len of buffer | |
198 | * @sense: optional sense buffer | |
199 | * @timeout: request timeout in seconds | |
200 | * @retries: number of times to retry request | |
33aa687d | 201 | * @flags: or into request flags; |
f4f4e47e | 202 | * @resid: optional residual length |
39216033 | 203 | * |
59c51591 | 204 | * returns the req->errors value which is the scsi_cmnd result |
ea73a9f2 | 205 | * field. |
eb44820c | 206 | */ |
33aa687d JB |
207 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
208 | int data_direction, void *buffer, unsigned bufflen, | |
f4f4e47e FT |
209 | unsigned char *sense, int timeout, int retries, int flags, |
210 | int *resid) | |
39216033 JB |
211 | { |
212 | struct request *req; | |
213 | int write = (data_direction == DMA_TO_DEVICE); | |
214 | int ret = DRIVER_ERROR << 24; | |
215 | ||
216 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
bfe159a5 JB |
217 | if (!req) |
218 | return ret; | |
39216033 JB |
219 | |
220 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
221 | buffer, bufflen, __GFP_WAIT)) | |
222 | goto out; | |
223 | ||
224 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
225 | memcpy(req->cmd, cmd, req->cmd_len); | |
226 | req->sense = sense; | |
227 | req->sense_len = 0; | |
17e01f21 | 228 | req->retries = retries; |
39216033 | 229 | req->timeout = timeout; |
4aff5e23 JA |
230 | req->cmd_type = REQ_TYPE_BLOCK_PC; |
231 | req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; | |
39216033 JB |
232 | |
233 | /* | |
234 | * head injection *required* here otherwise quiesce won't work | |
235 | */ | |
236 | blk_execute_rq(req->q, NULL, req, 1); | |
237 | ||
bdb2b8ca AS |
238 | /* |
239 | * Some devices (USB mass-storage in particular) may transfer | |
240 | * garbage data together with a residue indicating that the data | |
241 | * is invalid. Prevent the garbage from being misinterpreted | |
242 | * and prevent security leaks by zeroing out the excess data. | |
243 | */ | |
c3a4d78c TH |
244 | if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen)) |
245 | memset(buffer + (bufflen - req->resid_len), 0, req->resid_len); | |
bdb2b8ca | 246 | |
f4f4e47e | 247 | if (resid) |
c3a4d78c | 248 | *resid = req->resid_len; |
39216033 JB |
249 | ret = req->errors; |
250 | out: | |
251 | blk_put_request(req); | |
252 | ||
253 | return ret; | |
254 | } | |
33aa687d | 255 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 256 | |
9b21493c | 257 | int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd, |
ea73a9f2 | 258 | int data_direction, void *buffer, unsigned bufflen, |
f4f4e47e | 259 | struct scsi_sense_hdr *sshdr, int timeout, int retries, |
9b21493c | 260 | int *resid, int flags) |
ea73a9f2 JB |
261 | { |
262 | char *sense = NULL; | |
1ccb48bb | 263 | int result; |
264 | ||
ea73a9f2 | 265 | if (sshdr) { |
24669f75 | 266 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
267 | if (!sense) |
268 | return DRIVER_ERROR << 24; | |
ea73a9f2 | 269 | } |
1ccb48bb | 270 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
9b21493c | 271 | sense, timeout, retries, flags, resid); |
ea73a9f2 | 272 | if (sshdr) |
e514385b | 273 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
274 | |
275 | kfree(sense); | |
276 | return result; | |
277 | } | |
9b21493c | 278 | EXPORT_SYMBOL(scsi_execute_req_flags); |
ea73a9f2 | 279 | |
1da177e4 LT |
280 | /* |
281 | * Function: scsi_init_cmd_errh() | |
282 | * | |
283 | * Purpose: Initialize cmd fields related to error handling. | |
284 | * | |
285 | * Arguments: cmd - command that is ready to be queued. | |
286 | * | |
1da177e4 LT |
287 | * Notes: This function has the job of initializing a number of |
288 | * fields related to error handling. Typically this will | |
289 | * be called once for each command, as required. | |
290 | */ | |
631c228c | 291 | static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) |
1da177e4 | 292 | { |
1da177e4 | 293 | cmd->serial_number = 0; |
30b0c37b | 294 | scsi_set_resid(cmd, 0); |
b80ca4f7 | 295 | memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); |
1da177e4 | 296 | if (cmd->cmd_len == 0) |
db4742dd | 297 | cmd->cmd_len = scsi_command_size(cmd->cmnd); |
1da177e4 LT |
298 | } |
299 | ||
300 | void scsi_device_unbusy(struct scsi_device *sdev) | |
301 | { | |
302 | struct Scsi_Host *shost = sdev->host; | |
f0c0a376 | 303 | struct scsi_target *starget = scsi_target(sdev); |
1da177e4 LT |
304 | unsigned long flags; |
305 | ||
306 | spin_lock_irqsave(shost->host_lock, flags); | |
307 | shost->host_busy--; | |
f0c0a376 | 308 | starget->target_busy--; |
939647ee | 309 | if (unlikely(scsi_host_in_recovery(shost) && |
ee7863bc | 310 | (shost->host_failed || shost->host_eh_scheduled))) |
1da177e4 LT |
311 | scsi_eh_wakeup(shost); |
312 | spin_unlock(shost->host_lock); | |
152587de | 313 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 314 | sdev->device_busy--; |
152587de | 315 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
316 | } |
317 | ||
318 | /* | |
319 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
320 | * and call blk_run_queue for all the scsi_devices on the target - | |
321 | * including current_sdev first. | |
322 | * | |
323 | * Called with *no* scsi locks held. | |
324 | */ | |
325 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
326 | { | |
327 | struct Scsi_Host *shost = current_sdev->host; | |
328 | struct scsi_device *sdev, *tmp; | |
329 | struct scsi_target *starget = scsi_target(current_sdev); | |
330 | unsigned long flags; | |
331 | ||
332 | spin_lock_irqsave(shost->host_lock, flags); | |
333 | starget->starget_sdev_user = NULL; | |
334 | spin_unlock_irqrestore(shost->host_lock, flags); | |
335 | ||
336 | /* | |
337 | * Call blk_run_queue for all LUNs on the target, starting with | |
338 | * current_sdev. We race with others (to set starget_sdev_user), | |
339 | * but in most cases, we will be first. Ideally, each LU on the | |
340 | * target would get some limited time or requests on the target. | |
341 | */ | |
342 | blk_run_queue(current_sdev->request_queue); | |
343 | ||
344 | spin_lock_irqsave(shost->host_lock, flags); | |
345 | if (starget->starget_sdev_user) | |
346 | goto out; | |
347 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
348 | same_target_siblings) { | |
349 | if (sdev == current_sdev) | |
350 | continue; | |
351 | if (scsi_device_get(sdev)) | |
352 | continue; | |
353 | ||
354 | spin_unlock_irqrestore(shost->host_lock, flags); | |
355 | blk_run_queue(sdev->request_queue); | |
356 | spin_lock_irqsave(shost->host_lock, flags); | |
357 | ||
358 | scsi_device_put(sdev); | |
359 | } | |
360 | out: | |
361 | spin_unlock_irqrestore(shost->host_lock, flags); | |
362 | } | |
363 | ||
9d112517 KU |
364 | static inline int scsi_device_is_busy(struct scsi_device *sdev) |
365 | { | |
366 | if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) | |
367 | return 1; | |
368 | ||
369 | return 0; | |
370 | } | |
371 | ||
f0c0a376 MC |
372 | static inline int scsi_target_is_busy(struct scsi_target *starget) |
373 | { | |
374 | return ((starget->can_queue > 0 && | |
375 | starget->target_busy >= starget->can_queue) || | |
376 | starget->target_blocked); | |
377 | } | |
378 | ||
9d112517 KU |
379 | static inline int scsi_host_is_busy(struct Scsi_Host *shost) |
380 | { | |
381 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
382 | shost->host_blocked || shost->host_self_blocked) | |
383 | return 1; | |
384 | ||
385 | return 0; | |
386 | } | |
387 | ||
1da177e4 LT |
388 | /* |
389 | * Function: scsi_run_queue() | |
390 | * | |
391 | * Purpose: Select a proper request queue to serve next | |
392 | * | |
393 | * Arguments: q - last request's queue | |
394 | * | |
395 | * Returns: Nothing | |
396 | * | |
397 | * Notes: The previous command was completely finished, start | |
398 | * a new one if possible. | |
399 | */ | |
400 | static void scsi_run_queue(struct request_queue *q) | |
401 | { | |
2a3a59e5 | 402 | struct scsi_device *sdev = q->queuedata; |
c055f5b2 | 403 | struct Scsi_Host *shost; |
2a3a59e5 | 404 | LIST_HEAD(starved_list); |
1da177e4 LT |
405 | unsigned long flags; |
406 | ||
c055f5b2 | 407 | shost = sdev->host; |
25d7c363 | 408 | if (scsi_target(sdev)->single_lun) |
1da177e4 LT |
409 | scsi_single_lun_run(sdev); |
410 | ||
411 | spin_lock_irqsave(shost->host_lock, flags); | |
2a3a59e5 MC |
412 | list_splice_init(&shost->starved_list, &starved_list); |
413 | ||
414 | while (!list_empty(&starved_list)) { | |
e2eb7244 JB |
415 | struct request_queue *slq; |
416 | ||
1da177e4 LT |
417 | /* |
418 | * As long as shost is accepting commands and we have | |
419 | * starved queues, call blk_run_queue. scsi_request_fn | |
420 | * drops the queue_lock and can add us back to the | |
421 | * starved_list. | |
422 | * | |
423 | * host_lock protects the starved_list and starved_entry. | |
424 | * scsi_request_fn must get the host_lock before checking | |
425 | * or modifying starved_list or starved_entry. | |
426 | */ | |
2a3a59e5 | 427 | if (scsi_host_is_busy(shost)) |
f0c0a376 | 428 | break; |
f0c0a376 | 429 | |
2a3a59e5 MC |
430 | sdev = list_entry(starved_list.next, |
431 | struct scsi_device, starved_entry); | |
432 | list_del_init(&sdev->starved_entry); | |
f0c0a376 MC |
433 | if (scsi_target_is_busy(scsi_target(sdev))) { |
434 | list_move_tail(&sdev->starved_entry, | |
435 | &shost->starved_list); | |
436 | continue; | |
437 | } | |
438 | ||
e2eb7244 JB |
439 | /* |
440 | * Once we drop the host lock, a racing scsi_remove_device() | |
441 | * call may remove the sdev from the starved list and destroy | |
442 | * it and the queue. Mitigate by taking a reference to the | |
443 | * queue and never touching the sdev again after we drop the | |
444 | * host lock. Note: if __scsi_remove_device() invokes | |
445 | * blk_cleanup_queue() before the queue is run from this | |
446 | * function then blk_run_queue() will return immediately since | |
447 | * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING. | |
448 | */ | |
449 | slq = sdev->request_queue; | |
450 | if (!blk_get_queue(slq)) | |
451 | continue; | |
452 | spin_unlock_irqrestore(shost->host_lock, flags); | |
453 | ||
454 | blk_run_queue(slq); | |
455 | blk_put_queue(slq); | |
456 | ||
457 | spin_lock_irqsave(shost->host_lock, flags); | |
1da177e4 | 458 | } |
2a3a59e5 MC |
459 | /* put any unprocessed entries back */ |
460 | list_splice(&starved_list, &shost->starved_list); | |
1da177e4 LT |
461 | spin_unlock_irqrestore(shost->host_lock, flags); |
462 | ||
463 | blk_run_queue(q); | |
464 | } | |
465 | ||
9937a5e2 JA |
466 | void scsi_requeue_run_queue(struct work_struct *work) |
467 | { | |
468 | struct scsi_device *sdev; | |
469 | struct request_queue *q; | |
470 | ||
471 | sdev = container_of(work, struct scsi_device, requeue_work); | |
472 | q = sdev->request_queue; | |
473 | scsi_run_queue(q); | |
474 | } | |
475 | ||
1da177e4 LT |
476 | /* |
477 | * Function: scsi_requeue_command() | |
478 | * | |
479 | * Purpose: Handle post-processing of completed commands. | |
480 | * | |
481 | * Arguments: q - queue to operate on | |
482 | * cmd - command that may need to be requeued. | |
483 | * | |
484 | * Returns: Nothing | |
485 | * | |
486 | * Notes: After command completion, there may be blocks left | |
487 | * over which weren't finished by the previous command | |
488 | * this can be for a number of reasons - the main one is | |
489 | * I/O errors in the middle of the request, in which case | |
490 | * we need to request the blocks that come after the bad | |
491 | * sector. | |
e91442b6 | 492 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
493 | */ |
494 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
495 | { | |
940f5d47 | 496 | struct scsi_device *sdev = cmd->device; |
e91442b6 | 497 | struct request *req = cmd->request; |
283369cc TH |
498 | unsigned long flags; |
499 | ||
940f5d47 BVA |
500 | /* |
501 | * We need to hold a reference on the device to avoid the queue being | |
502 | * killed after the unlock and before scsi_run_queue is invoked which | |
503 | * may happen because scsi_unprep_request() puts the command which | |
504 | * releases its reference on the device. | |
505 | */ | |
506 | get_device(&sdev->sdev_gendev); | |
507 | ||
283369cc | 508 | spin_lock_irqsave(q->queue_lock, flags); |
02bd3499 | 509 | scsi_unprep_request(req); |
e91442b6 | 510 | blk_requeue_request(q, req); |
283369cc | 511 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
512 | |
513 | scsi_run_queue(q); | |
940f5d47 BVA |
514 | |
515 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
516 | } |
517 | ||
518 | void scsi_next_command(struct scsi_cmnd *cmd) | |
519 | { | |
49d7bc64 LT |
520 | struct scsi_device *sdev = cmd->device; |
521 | struct request_queue *q = sdev->request_queue; | |
522 | ||
523 | /* need to hold a reference on the device before we let go of the cmd */ | |
524 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
525 | |
526 | scsi_put_command(cmd); | |
527 | scsi_run_queue(q); | |
49d7bc64 LT |
528 | |
529 | /* ok to remove device now */ | |
530 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
531 | } |
532 | ||
533 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
534 | { | |
535 | struct scsi_device *sdev; | |
536 | ||
537 | shost_for_each_device(sdev, shost) | |
538 | scsi_run_queue(sdev->request_queue); | |
539 | } | |
540 | ||
79ed2429 JB |
541 | static void __scsi_release_buffers(struct scsi_cmnd *, int); |
542 | ||
1da177e4 LT |
543 | /* |
544 | * Function: scsi_end_request() | |
545 | * | |
546 | * Purpose: Post-processing of completed commands (usually invoked at end | |
547 | * of upper level post-processing and scsi_io_completion). | |
548 | * | |
549 | * Arguments: cmd - command that is complete. | |
610d8b0c | 550 | * error - 0 if I/O indicates success, < 0 for I/O error. |
1da177e4 LT |
551 | * bytes - number of bytes of completed I/O |
552 | * requeue - indicates whether we should requeue leftovers. | |
553 | * | |
554 | * Lock status: Assumed that lock is not held upon entry. | |
555 | * | |
e91442b6 | 556 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
557 | * |
558 | * Notes: This is called for block device requests in order to | |
559 | * mark some number of sectors as complete. | |
560 | * | |
561 | * We are guaranteeing that the request queue will be goosed | |
562 | * at some point during this call. | |
e91442b6 | 563 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 | 564 | */ |
610d8b0c | 565 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, |
1da177e4 LT |
566 | int bytes, int requeue) |
567 | { | |
165125e1 | 568 | struct request_queue *q = cmd->device->request_queue; |
1da177e4 | 569 | struct request *req = cmd->request; |
1da177e4 LT |
570 | |
571 | /* | |
572 | * If there are blocks left over at the end, set up the command | |
573 | * to queue the remainder of them. | |
574 | */ | |
610d8b0c | 575 | if (blk_end_request(req, error, bytes)) { |
1da177e4 | 576 | /* kill remainder if no retrys */ |
4a27446f | 577 | if (error && scsi_noretry_cmd(cmd)) |
e458824f | 578 | blk_end_request_all(req, error); |
1da177e4 | 579 | else { |
e91442b6 | 580 | if (requeue) { |
1da177e4 LT |
581 | /* |
582 | * Bleah. Leftovers again. Stick the | |
583 | * leftovers in the front of the | |
584 | * queue, and goose the queue again. | |
585 | */ | |
79ed2429 | 586 | scsi_release_buffers(cmd); |
1da177e4 | 587 | scsi_requeue_command(q, cmd); |
e91442b6 JB |
588 | cmd = NULL; |
589 | } | |
1da177e4 LT |
590 | return cmd; |
591 | } | |
592 | } | |
593 | ||
1da177e4 LT |
594 | /* |
595 | * This will goose the queue request function at the end, so we don't | |
596 | * need to worry about launching another command. | |
597 | */ | |
79ed2429 | 598 | __scsi_release_buffers(cmd, 0); |
1da177e4 LT |
599 | scsi_next_command(cmd); |
600 | return NULL; | |
601 | } | |
602 | ||
a8474ce2 JA |
603 | static inline unsigned int scsi_sgtable_index(unsigned short nents) |
604 | { | |
605 | unsigned int index; | |
606 | ||
d3f46f39 JB |
607 | BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); |
608 | ||
609 | if (nents <= 8) | |
a8474ce2 | 610 | index = 0; |
d3f46f39 JB |
611 | else |
612 | index = get_count_order(nents) - 3; | |
1da177e4 | 613 | |
a8474ce2 JA |
614 | return index; |
615 | } | |
616 | ||
5ed7959e | 617 | static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) |
a8474ce2 JA |
618 | { |
619 | struct scsi_host_sg_pool *sgp; | |
a8474ce2 | 620 | |
5ed7959e JA |
621 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
622 | mempool_free(sgl, sgp->pool); | |
623 | } | |
a8474ce2 | 624 | |
5ed7959e JA |
625 | static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) |
626 | { | |
627 | struct scsi_host_sg_pool *sgp; | |
a8474ce2 | 628 | |
5ed7959e JA |
629 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
630 | return mempool_alloc(sgp->pool, gfp_mask); | |
631 | } | |
a3bec5c5 | 632 | |
30b0c37b BH |
633 | static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, |
634 | gfp_t gfp_mask) | |
5ed7959e JA |
635 | { |
636 | int ret; | |
a8474ce2 | 637 | |
30b0c37b | 638 | BUG_ON(!nents); |
a8474ce2 | 639 | |
30b0c37b BH |
640 | ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, |
641 | gfp_mask, scsi_sg_alloc); | |
5ed7959e | 642 | if (unlikely(ret)) |
30b0c37b | 643 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, |
7cedb1f1 | 644 | scsi_sg_free); |
45711f1a | 645 | |
a8474ce2 | 646 | return ret; |
1da177e4 LT |
647 | } |
648 | ||
30b0c37b | 649 | static void scsi_free_sgtable(struct scsi_data_buffer *sdb) |
1da177e4 | 650 | { |
30b0c37b | 651 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); |
1da177e4 LT |
652 | } |
653 | ||
79ed2429 JB |
654 | static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) |
655 | { | |
656 | ||
657 | if (cmd->sdb.table.nents) | |
658 | scsi_free_sgtable(&cmd->sdb); | |
659 | ||
660 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); | |
661 | ||
662 | if (do_bidi_check && scsi_bidi_cmnd(cmd)) { | |
663 | struct scsi_data_buffer *bidi_sdb = | |
664 | cmd->request->next_rq->special; | |
665 | scsi_free_sgtable(bidi_sdb); | |
666 | kmem_cache_free(scsi_sdb_cache, bidi_sdb); | |
667 | cmd->request->next_rq->special = NULL; | |
668 | } | |
669 | ||
670 | if (scsi_prot_sg_count(cmd)) | |
671 | scsi_free_sgtable(cmd->prot_sdb); | |
672 | } | |
673 | ||
1da177e4 LT |
674 | /* |
675 | * Function: scsi_release_buffers() | |
676 | * | |
677 | * Purpose: Completion processing for block device I/O requests. | |
678 | * | |
679 | * Arguments: cmd - command that we are bailing. | |
680 | * | |
681 | * Lock status: Assumed that no lock is held upon entry. | |
682 | * | |
683 | * Returns: Nothing | |
684 | * | |
685 | * Notes: In the event that an upper level driver rejects a | |
686 | * command, we must release resources allocated during | |
687 | * the __init_io() function. Primarily this would involve | |
688 | * the scatter-gather table, and potentially any bounce | |
689 | * buffers. | |
690 | */ | |
bb52d82f | 691 | void scsi_release_buffers(struct scsi_cmnd *cmd) |
1da177e4 | 692 | { |
79ed2429 | 693 | __scsi_release_buffers(cmd, 1); |
1da177e4 | 694 | } |
bb52d82f | 695 | EXPORT_SYMBOL(scsi_release_buffers); |
1da177e4 | 696 | |
63583cca HR |
697 | static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result) |
698 | { | |
699 | int error = 0; | |
700 | ||
701 | switch(host_byte(result)) { | |
702 | case DID_TRANSPORT_FAILFAST: | |
703 | error = -ENOLINK; | |
704 | break; | |
705 | case DID_TARGET_FAILURE: | |
2082ebc4 | 706 | set_host_byte(cmd, DID_OK); |
63583cca HR |
707 | error = -EREMOTEIO; |
708 | break; | |
709 | case DID_NEXUS_FAILURE: | |
2082ebc4 | 710 | set_host_byte(cmd, DID_OK); |
63583cca HR |
711 | error = -EBADE; |
712 | break; | |
713 | default: | |
714 | error = -EIO; | |
715 | break; | |
716 | } | |
717 | ||
718 | return error; | |
719 | } | |
720 | ||
1da177e4 LT |
721 | /* |
722 | * Function: scsi_io_completion() | |
723 | * | |
724 | * Purpose: Completion processing for block device I/O requests. | |
725 | * | |
726 | * Arguments: cmd - command that is finished. | |
727 | * | |
728 | * Lock status: Assumed that no lock is held upon entry. | |
729 | * | |
730 | * Returns: Nothing | |
731 | * | |
732 | * Notes: This function is matched in terms of capabilities to | |
733 | * the function that created the scatter-gather list. | |
734 | * In other words, if there are no bounce buffers | |
735 | * (the normal case for most drivers), we don't need | |
736 | * the logic to deal with cleaning up afterwards. | |
737 | * | |
b60af5b0 AS |
738 | * We must call scsi_end_request(). This will finish off |
739 | * the specified number of sectors. If we are done, the | |
740 | * command block will be released and the queue function | |
741 | * will be goosed. If we are not done then we have to | |
742 | * figure out what to do next: | |
1da177e4 | 743 | * |
b60af5b0 AS |
744 | * a) We can call scsi_requeue_command(). The request |
745 | * will be unprepared and put back on the queue. Then | |
746 | * a new command will be created for it. This should | |
747 | * be used if we made forward progress, or if we want | |
748 | * to switch from READ(10) to READ(6) for example. | |
1da177e4 | 749 | * |
b60af5b0 AS |
750 | * b) We can call scsi_queue_insert(). The request will |
751 | * be put back on the queue and retried using the same | |
752 | * command as before, possibly after a delay. | |
753 | * | |
754 | * c) We can call blk_end_request() with -EIO to fail | |
755 | * the remainder of the request. | |
1da177e4 | 756 | */ |
03aba2f7 | 757 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
1da177e4 LT |
758 | { |
759 | int result = cmd->result; | |
165125e1 | 760 | struct request_queue *q = cmd->device->request_queue; |
1da177e4 | 761 | struct request *req = cmd->request; |
fa8e36c3 | 762 | int error = 0; |
1da177e4 LT |
763 | struct scsi_sense_hdr sshdr; |
764 | int sense_valid = 0; | |
765 | int sense_deferred = 0; | |
b60af5b0 AS |
766 | enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, |
767 | ACTION_DELAYED_RETRY} action; | |
768 | char *description = NULL; | |
1da177e4 | 769 | |
1da177e4 LT |
770 | if (result) { |
771 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
772 | if (sense_valid) | |
773 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
774 | } | |
631c228c | 775 | |
33659ebb | 776 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */ |
1da177e4 | 777 | if (result) { |
1da177e4 LT |
778 | if (sense_valid && req->sense) { |
779 | /* | |
780 | * SG_IO wants current and deferred errors | |
781 | */ | |
782 | int len = 8 + cmd->sense_buffer[7]; | |
783 | ||
784 | if (len > SCSI_SENSE_BUFFERSIZE) | |
785 | len = SCSI_SENSE_BUFFERSIZE; | |
786 | memcpy(req->sense, cmd->sense_buffer, len); | |
787 | req->sense_len = len; | |
788 | } | |
fa8e36c3 | 789 | if (!sense_deferred) |
63583cca | 790 | error = __scsi_error_from_host_byte(cmd, result); |
b22f687d | 791 | } |
27c41973 MS |
792 | /* |
793 | * __scsi_error_from_host_byte may have reset the host_byte | |
794 | */ | |
795 | req->errors = cmd->result; | |
e6bb7a96 FT |
796 | |
797 | req->resid_len = scsi_get_resid(cmd); | |
798 | ||
6f9a35e2 | 799 | if (scsi_bidi_cmnd(cmd)) { |
e6bb7a96 FT |
800 | /* |
801 | * Bidi commands Must be complete as a whole, | |
802 | * both sides at once. | |
803 | */ | |
804 | req->next_rq->resid_len = scsi_in(cmd)->resid; | |
805 | ||
63c43b0e | 806 | scsi_release_buffers(cmd); |
e6bb7a96 FT |
807 | blk_end_request_all(req, 0); |
808 | ||
e6bb7a96 | 809 | scsi_next_command(cmd); |
6f9a35e2 BH |
810 | return; |
811 | } | |
1da177e4 LT |
812 | } |
813 | ||
33659ebb CH |
814 | /* no bidi support for !REQ_TYPE_BLOCK_PC yet */ |
815 | BUG_ON(blk_bidi_rq(req)); | |
30b0c37b | 816 | |
1da177e4 LT |
817 | /* |
818 | * Next deal with any sectors which we were able to correctly | |
819 | * handle. | |
820 | */ | |
83096ebf | 821 | SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, " |
d6b0c537 | 822 | "%d bytes done.\n", |
83096ebf | 823 | blk_rq_sectors(req), good_bytes)); |
d6b0c537 | 824 | |
a9bddd74 JB |
825 | /* |
826 | * Recovered errors need reporting, but they're always treated | |
827 | * as success, so fiddle the result code here. For BLOCK_PC | |
828 | * we already took a copy of the original into rq->errors which | |
829 | * is what gets returned to the user | |
830 | */ | |
e7efe593 DG |
831 | if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { |
832 | /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip | |
833 | * print since caller wants ATA registers. Only occurs on | |
834 | * SCSI ATA PASS_THROUGH commands when CK_COND=1 | |
835 | */ | |
836 | if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) | |
837 | ; | |
838 | else if (!(req->cmd_flags & REQ_QUIET)) | |
a9bddd74 JB |
839 | scsi_print_sense("", cmd); |
840 | result = 0; | |
841 | /* BLOCK_PC may have set error */ | |
842 | error = 0; | |
843 | } | |
844 | ||
845 | /* | |
846 | * A number of bytes were successfully read. If there | |
d6b0c537 JB |
847 | * are leftovers and there is some kind of error |
848 | * (result != 0), retry the rest. | |
849 | */ | |
fa8e36c3 | 850 | if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) |
d6b0c537 | 851 | return; |
03aba2f7 | 852 | |
63583cca | 853 | error = __scsi_error_from_host_byte(cmd, result); |
3e695f89 | 854 | |
b60af5b0 AS |
855 | if (host_byte(result) == DID_RESET) { |
856 | /* Third party bus reset or reset for error recovery | |
857 | * reasons. Just retry the command and see what | |
858 | * happens. | |
859 | */ | |
860 | action = ACTION_RETRY; | |
861 | } else if (sense_valid && !sense_deferred) { | |
1da177e4 LT |
862 | switch (sshdr.sense_key) { |
863 | case UNIT_ATTENTION: | |
864 | if (cmd->device->removable) { | |
03aba2f7 | 865 | /* Detected disc change. Set a bit |
1da177e4 LT |
866 | * and quietly refuse further access. |
867 | */ | |
868 | cmd->device->changed = 1; | |
b60af5b0 AS |
869 | description = "Media Changed"; |
870 | action = ACTION_FAIL; | |
1da177e4 | 871 | } else { |
03aba2f7 LT |
872 | /* Must have been a power glitch, or a |
873 | * bus reset. Could not have been a | |
874 | * media change, so we just retry the | |
b60af5b0 | 875 | * command and see what happens. |
03aba2f7 | 876 | */ |
b60af5b0 | 877 | action = ACTION_RETRY; |
1da177e4 LT |
878 | } |
879 | break; | |
880 | case ILLEGAL_REQUEST: | |
03aba2f7 LT |
881 | /* If we had an ILLEGAL REQUEST returned, then |
882 | * we may have performed an unsupported | |
883 | * command. The only thing this should be | |
884 | * would be a ten byte read where only a six | |
885 | * byte read was supported. Also, on a system | |
886 | * where READ CAPACITY failed, we may have | |
887 | * read past the end of the disk. | |
888 | */ | |
26a68019 JA |
889 | if ((cmd->device->use_10_for_rw && |
890 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
891 | (cmd->cmnd[0] == READ_10 || |
892 | cmd->cmnd[0] == WRITE_10)) { | |
b60af5b0 | 893 | /* This will issue a new 6-byte command. */ |
1da177e4 | 894 | cmd->device->use_10_for_rw = 0; |
b60af5b0 | 895 | action = ACTION_REPREP; |
3e695f89 MP |
896 | } else if (sshdr.asc == 0x10) /* DIX */ { |
897 | description = "Host Data Integrity Failure"; | |
898 | action = ACTION_FAIL; | |
899 | error = -EILSEQ; | |
c98a0eb0 | 900 | /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ |
5db44863 MP |
901 | } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { |
902 | switch (cmd->cmnd[0]) { | |
903 | case UNMAP: | |
904 | description = "Discard failure"; | |
905 | break; | |
906 | case WRITE_SAME: | |
907 | case WRITE_SAME_16: | |
908 | if (cmd->cmnd[1] & 0x8) | |
909 | description = "Discard failure"; | |
910 | else | |
911 | description = | |
912 | "Write same failure"; | |
913 | break; | |
914 | default: | |
915 | description = "Invalid command failure"; | |
916 | break; | |
917 | } | |
c98a0eb0 | 918 | action = ACTION_FAIL; |
66a651aa | 919 | error = -EREMOTEIO; |
b60af5b0 AS |
920 | } else |
921 | action = ACTION_FAIL; | |
922 | break; | |
511e44f4 | 923 | case ABORTED_COMMAND: |
126c0982 | 924 | action = ACTION_FAIL; |
511e44f4 | 925 | if (sshdr.asc == 0x10) { /* DIF */ |
3e695f89 | 926 | description = "Target Data Integrity Failure"; |
3e695f89 | 927 | error = -EILSEQ; |
126c0982 | 928 | } |
1da177e4 LT |
929 | break; |
930 | case NOT_READY: | |
03aba2f7 | 931 | /* If the device is in the process of becoming |
f3e93f73 | 932 | * ready, or has a temporary blockage, retry. |
1da177e4 | 933 | */ |
f3e93f73 JB |
934 | if (sshdr.asc == 0x04) { |
935 | switch (sshdr.ascq) { | |
936 | case 0x01: /* becoming ready */ | |
937 | case 0x04: /* format in progress */ | |
938 | case 0x05: /* rebuild in progress */ | |
939 | case 0x06: /* recalculation in progress */ | |
940 | case 0x07: /* operation in progress */ | |
941 | case 0x08: /* Long write in progress */ | |
942 | case 0x09: /* self test in progress */ | |
d8705f11 | 943 | case 0x14: /* space allocation in progress */ |
b60af5b0 | 944 | action = ACTION_DELAYED_RETRY; |
f3e93f73 | 945 | break; |
3dbf6a54 AS |
946 | default: |
947 | description = "Device not ready"; | |
948 | action = ACTION_FAIL; | |
949 | break; | |
f3e93f73 | 950 | } |
b60af5b0 AS |
951 | } else { |
952 | description = "Device not ready"; | |
953 | action = ACTION_FAIL; | |
1da177e4 | 954 | } |
b60af5b0 | 955 | break; |
1da177e4 | 956 | case VOLUME_OVERFLOW: |
03aba2f7 | 957 | /* See SSC3rXX or current. */ |
b60af5b0 AS |
958 | action = ACTION_FAIL; |
959 | break; | |
1da177e4 | 960 | default: |
b60af5b0 AS |
961 | description = "Unhandled sense code"; |
962 | action = ACTION_FAIL; | |
1da177e4 LT |
963 | break; |
964 | } | |
b60af5b0 AS |
965 | } else { |
966 | description = "Unhandled error code"; | |
967 | action = ACTION_FAIL; | |
03aba2f7 | 968 | } |
b60af5b0 AS |
969 | |
970 | switch (action) { | |
971 | case ACTION_FAIL: | |
972 | /* Give up and fail the remainder of the request */ | |
79ed2429 | 973 | scsi_release_buffers(cmd); |
4aff5e23 | 974 | if (!(req->cmd_flags & REQ_QUIET)) { |
b60af5b0 | 975 | if (description) |
3dbf6a54 | 976 | scmd_printk(KERN_INFO, cmd, "%s\n", |
b60af5b0 | 977 | description); |
a4d04a4c | 978 | scsi_print_result(cmd); |
3173d8c3 JB |
979 | if (driver_byte(result) & DRIVER_SENSE) |
980 | scsi_print_sense("", cmd); | |
002b1eb2 | 981 | scsi_print_command(cmd); |
3173d8c3 | 982 | } |
ad630826 | 983 | if (blk_end_request_err(req, error)) |
da6c5c72 TH |
984 | scsi_requeue_command(q, cmd); |
985 | else | |
986 | scsi_next_command(cmd); | |
b60af5b0 AS |
987 | break; |
988 | case ACTION_REPREP: | |
989 | /* Unprep the request and put it back at the head of the queue. | |
990 | * A new command will be prepared and issued. | |
991 | */ | |
79ed2429 | 992 | scsi_release_buffers(cmd); |
b60af5b0 AS |
993 | scsi_requeue_command(q, cmd); |
994 | break; | |
995 | case ACTION_RETRY: | |
996 | /* Retry the same command immediately */ | |
4f5299ac | 997 | __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); |
b60af5b0 AS |
998 | break; |
999 | case ACTION_DELAYED_RETRY: | |
1000 | /* Retry the same command after a delay */ | |
4f5299ac | 1001 | __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); |
b60af5b0 | 1002 | break; |
1da177e4 LT |
1003 | } |
1004 | } | |
1da177e4 | 1005 | |
6f9a35e2 BH |
1006 | static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, |
1007 | gfp_t gfp_mask) | |
1da177e4 | 1008 | { |
6f9a35e2 | 1009 | int count; |
1da177e4 LT |
1010 | |
1011 | /* | |
3b003157 | 1012 | * If sg table allocation fails, requeue request later. |
1da177e4 | 1013 | */ |
30b0c37b BH |
1014 | if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, |
1015 | gfp_mask))) { | |
1da177e4 | 1016 | return BLKPREP_DEFER; |
7c72ce81 | 1017 | } |
1da177e4 | 1018 | |
3b003157 | 1019 | req->buffer = NULL; |
1da177e4 LT |
1020 | |
1021 | /* | |
1022 | * Next, walk the list, and fill in the addresses and sizes of | |
1023 | * each segment. | |
1024 | */ | |
30b0c37b BH |
1025 | count = blk_rq_map_sg(req->q, req, sdb->table.sgl); |
1026 | BUG_ON(count > sdb->table.nents); | |
1027 | sdb->table.nents = count; | |
1011c1b9 | 1028 | sdb->length = blk_rq_bytes(req); |
4a03d90e | 1029 | return BLKPREP_OK; |
1da177e4 | 1030 | } |
6f9a35e2 BH |
1031 | |
1032 | /* | |
1033 | * Function: scsi_init_io() | |
1034 | * | |
1035 | * Purpose: SCSI I/O initialize function. | |
1036 | * | |
1037 | * Arguments: cmd - Command descriptor we wish to initialize | |
1038 | * | |
1039 | * Returns: 0 on success | |
1040 | * BLKPREP_DEFER if the failure is retryable | |
1041 | * BLKPREP_KILL if the failure is fatal | |
1042 | */ | |
1043 | int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) | |
1044 | { | |
13f05c8d MP |
1045 | struct request *rq = cmd->request; |
1046 | ||
1047 | int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask); | |
6f9a35e2 BH |
1048 | if (error) |
1049 | goto err_exit; | |
1050 | ||
13f05c8d | 1051 | if (blk_bidi_rq(rq)) { |
6f9a35e2 | 1052 | struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( |
6362abd3 | 1053 | scsi_sdb_cache, GFP_ATOMIC); |
6f9a35e2 BH |
1054 | if (!bidi_sdb) { |
1055 | error = BLKPREP_DEFER; | |
1056 | goto err_exit; | |
1057 | } | |
1058 | ||
13f05c8d MP |
1059 | rq->next_rq->special = bidi_sdb; |
1060 | error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC); | |
6f9a35e2 BH |
1061 | if (error) |
1062 | goto err_exit; | |
1063 | } | |
1064 | ||
13f05c8d | 1065 | if (blk_integrity_rq(rq)) { |
7027ad72 MP |
1066 | struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; |
1067 | int ivecs, count; | |
1068 | ||
1069 | BUG_ON(prot_sdb == NULL); | |
13f05c8d | 1070 | ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); |
7027ad72 MP |
1071 | |
1072 | if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { | |
1073 | error = BLKPREP_DEFER; | |
1074 | goto err_exit; | |
1075 | } | |
1076 | ||
13f05c8d | 1077 | count = blk_rq_map_integrity_sg(rq->q, rq->bio, |
7027ad72 MP |
1078 | prot_sdb->table.sgl); |
1079 | BUG_ON(unlikely(count > ivecs)); | |
13f05c8d | 1080 | BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q))); |
7027ad72 MP |
1081 | |
1082 | cmd->prot_sdb = prot_sdb; | |
1083 | cmd->prot_sdb->table.nents = count; | |
1084 | } | |
1085 | ||
6f9a35e2 BH |
1086 | return BLKPREP_OK ; |
1087 | ||
1088 | err_exit: | |
1089 | scsi_release_buffers(cmd); | |
610a6349 | 1090 | cmd->request->special = NULL; |
3a5c19c2 | 1091 | scsi_put_command(cmd); |
6f9a35e2 BH |
1092 | return error; |
1093 | } | |
bb52d82f | 1094 | EXPORT_SYMBOL(scsi_init_io); |
1da177e4 | 1095 | |
3b003157 CH |
1096 | static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, |
1097 | struct request *req) | |
1098 | { | |
1099 | struct scsi_cmnd *cmd; | |
1100 | ||
1101 | if (!req->special) { | |
1102 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1103 | if (unlikely(!cmd)) | |
1104 | return NULL; | |
1105 | req->special = cmd; | |
1106 | } else { | |
1107 | cmd = req->special; | |
1108 | } | |
1109 | ||
1110 | /* pull a tag out of the request if we have one */ | |
1111 | cmd->tag = req->tag; | |
1112 | cmd->request = req; | |
1113 | ||
64a87b24 | 1114 | cmd->cmnd = req->cmd; |
72f7d322 | 1115 | cmd->prot_op = SCSI_PROT_NORMAL; |
64a87b24 | 1116 | |
3b003157 CH |
1117 | return cmd; |
1118 | } | |
1119 | ||
7f9a6bc4 | 1120 | int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) |
7b16318d | 1121 | { |
3b003157 | 1122 | struct scsi_cmnd *cmd; |
7f9a6bc4 JB |
1123 | int ret = scsi_prep_state_check(sdev, req); |
1124 | ||
1125 | if (ret != BLKPREP_OK) | |
1126 | return ret; | |
3b003157 CH |
1127 | |
1128 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1129 | if (unlikely(!cmd)) | |
1130 | return BLKPREP_DEFER; | |
1131 | ||
1132 | /* | |
1133 | * BLOCK_PC requests may transfer data, in which case they must | |
1134 | * a bio attached to them. Or they might contain a SCSI command | |
1135 | * that does not transfer data, in which case they may optionally | |
1136 | * submit a request without an attached bio. | |
1137 | */ | |
1138 | if (req->bio) { | |
1139 | int ret; | |
1140 | ||
1141 | BUG_ON(!req->nr_phys_segments); | |
1142 | ||
bb52d82f | 1143 | ret = scsi_init_io(cmd, GFP_ATOMIC); |
3b003157 CH |
1144 | if (unlikely(ret)) |
1145 | return ret; | |
1146 | } else { | |
b0790410 | 1147 | BUG_ON(blk_rq_bytes(req)); |
3b003157 | 1148 | |
30b0c37b | 1149 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
3b003157 CH |
1150 | req->buffer = NULL; |
1151 | } | |
7b16318d | 1152 | |
7b16318d | 1153 | cmd->cmd_len = req->cmd_len; |
b0790410 | 1154 | if (!blk_rq_bytes(req)) |
7b16318d JB |
1155 | cmd->sc_data_direction = DMA_NONE; |
1156 | else if (rq_data_dir(req) == WRITE) | |
1157 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1158 | else | |
1159 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1160 | ||
b0790410 | 1161 | cmd->transfersize = blk_rq_bytes(req); |
7b16318d | 1162 | cmd->allowed = req->retries; |
3b003157 | 1163 | return BLKPREP_OK; |
7b16318d | 1164 | } |
7f9a6bc4 | 1165 | EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); |
7b16318d | 1166 | |
3b003157 CH |
1167 | /* |
1168 | * Setup a REQ_TYPE_FS command. These are simple read/write request | |
1169 | * from filesystems that still need to be translated to SCSI CDBs from | |
1170 | * the ULD. | |
1171 | */ | |
7f9a6bc4 | 1172 | int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) |
1da177e4 | 1173 | { |
1da177e4 | 1174 | struct scsi_cmnd *cmd; |
7f9a6bc4 | 1175 | int ret = scsi_prep_state_check(sdev, req); |
1da177e4 | 1176 | |
7f9a6bc4 JB |
1177 | if (ret != BLKPREP_OK) |
1178 | return ret; | |
a6a8d9f8 CS |
1179 | |
1180 | if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh | |
1181 | && sdev->scsi_dh_data->scsi_dh->prep_fn)) { | |
1182 | ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); | |
1183 | if (ret != BLKPREP_OK) | |
1184 | return ret; | |
1185 | } | |
1186 | ||
1da177e4 | 1187 | /* |
3b003157 | 1188 | * Filesystem requests must transfer data. |
1da177e4 | 1189 | */ |
3b003157 CH |
1190 | BUG_ON(!req->nr_phys_segments); |
1191 | ||
1192 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1193 | if (unlikely(!cmd)) | |
1194 | return BLKPREP_DEFER; | |
1195 | ||
64a87b24 | 1196 | memset(cmd->cmnd, 0, BLK_MAX_CDB); |
bb52d82f | 1197 | return scsi_init_io(cmd, GFP_ATOMIC); |
3b003157 | 1198 | } |
7f9a6bc4 | 1199 | EXPORT_SYMBOL(scsi_setup_fs_cmnd); |
3b003157 | 1200 | |
7f9a6bc4 | 1201 | int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) |
3b003157 | 1202 | { |
3b003157 CH |
1203 | int ret = BLKPREP_OK; |
1204 | ||
1da177e4 | 1205 | /* |
3b003157 CH |
1206 | * If the device is not in running state we will reject some |
1207 | * or all commands. | |
1da177e4 | 1208 | */ |
3b003157 CH |
1209 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { |
1210 | switch (sdev->sdev_state) { | |
1211 | case SDEV_OFFLINE: | |
1b8d2620 | 1212 | case SDEV_TRANSPORT_OFFLINE: |
3b003157 CH |
1213 | /* |
1214 | * If the device is offline we refuse to process any | |
1215 | * commands. The device must be brought online | |
1216 | * before trying any recovery commands. | |
1217 | */ | |
1218 | sdev_printk(KERN_ERR, sdev, | |
1219 | "rejecting I/O to offline device\n"); | |
1220 | ret = BLKPREP_KILL; | |
1221 | break; | |
1222 | case SDEV_DEL: | |
1223 | /* | |
1224 | * If the device is fully deleted, we refuse to | |
1225 | * process any commands as well. | |
1226 | */ | |
9ccfc756 | 1227 | sdev_printk(KERN_ERR, sdev, |
3b003157 CH |
1228 | "rejecting I/O to dead device\n"); |
1229 | ret = BLKPREP_KILL; | |
1230 | break; | |
1231 | case SDEV_QUIESCE: | |
1232 | case SDEV_BLOCK: | |
6f4267e3 | 1233 | case SDEV_CREATED_BLOCK: |
3b003157 CH |
1234 | /* |
1235 | * If the devices is blocked we defer normal commands. | |
1236 | */ | |
1237 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1238 | ret = BLKPREP_DEFER; | |
1239 | break; | |
1240 | default: | |
1241 | /* | |
1242 | * For any other not fully online state we only allow | |
1243 | * special commands. In particular any user initiated | |
1244 | * command is not allowed. | |
1245 | */ | |
1246 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1247 | ret = BLKPREP_KILL; | |
1248 | break; | |
1da177e4 | 1249 | } |
1da177e4 | 1250 | } |
7f9a6bc4 JB |
1251 | return ret; |
1252 | } | |
1253 | EXPORT_SYMBOL(scsi_prep_state_check); | |
1da177e4 | 1254 | |
7f9a6bc4 JB |
1255 | int scsi_prep_return(struct request_queue *q, struct request *req, int ret) |
1256 | { | |
1257 | struct scsi_device *sdev = q->queuedata; | |
1da177e4 | 1258 | |
3b003157 CH |
1259 | switch (ret) { |
1260 | case BLKPREP_KILL: | |
1261 | req->errors = DID_NO_CONNECT << 16; | |
7f9a6bc4 JB |
1262 | /* release the command and kill it */ |
1263 | if (req->special) { | |
1264 | struct scsi_cmnd *cmd = req->special; | |
1265 | scsi_release_buffers(cmd); | |
1266 | scsi_put_command(cmd); | |
1267 | req->special = NULL; | |
1268 | } | |
3b003157 CH |
1269 | break; |
1270 | case BLKPREP_DEFER: | |
1da177e4 | 1271 | /* |
9934c8c0 | 1272 | * If we defer, the blk_peek_request() returns NULL, but the |
a488e749 JA |
1273 | * queue must be restarted, so we schedule a callback to happen |
1274 | * shortly. | |
1da177e4 | 1275 | */ |
3b003157 | 1276 | if (sdev->device_busy == 0) |
a488e749 | 1277 | blk_delay_queue(q, SCSI_QUEUE_DELAY); |
3b003157 CH |
1278 | break; |
1279 | default: | |
1280 | req->cmd_flags |= REQ_DONTPREP; | |
1da177e4 LT |
1281 | } |
1282 | ||
3b003157 | 1283 | return ret; |
1da177e4 | 1284 | } |
7f9a6bc4 JB |
1285 | EXPORT_SYMBOL(scsi_prep_return); |
1286 | ||
751bf4d7 | 1287 | int scsi_prep_fn(struct request_queue *q, struct request *req) |
7f9a6bc4 JB |
1288 | { |
1289 | struct scsi_device *sdev = q->queuedata; | |
1290 | int ret = BLKPREP_KILL; | |
1291 | ||
1292 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) | |
1293 | ret = scsi_setup_blk_pc_cmnd(sdev, req); | |
1294 | return scsi_prep_return(q, req, ret); | |
1295 | } | |
b391277a | 1296 | EXPORT_SYMBOL(scsi_prep_fn); |
1da177e4 LT |
1297 | |
1298 | /* | |
1299 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1300 | * return 0. | |
1301 | * | |
1302 | * Called with the queue_lock held. | |
1303 | */ | |
1304 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1305 | struct scsi_device *sdev) | |
1306 | { | |
1da177e4 LT |
1307 | if (sdev->device_busy == 0 && sdev->device_blocked) { |
1308 | /* | |
1309 | * unblock after device_blocked iterates to zero | |
1310 | */ | |
1311 | if (--sdev->device_blocked == 0) { | |
1312 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1313 | sdev_printk(KERN_INFO, sdev, |
1314 | "unblocking device at zero depth\n")); | |
1da177e4 | 1315 | } else { |
a488e749 | 1316 | blk_delay_queue(q, SCSI_QUEUE_DELAY); |
1da177e4 LT |
1317 | return 0; |
1318 | } | |
1319 | } | |
9d112517 | 1320 | if (scsi_device_is_busy(sdev)) |
1da177e4 LT |
1321 | return 0; |
1322 | ||
1323 | return 1; | |
1324 | } | |
1325 | ||
f0c0a376 MC |
1326 | |
1327 | /* | |
1328 | * scsi_target_queue_ready: checks if there we can send commands to target | |
1329 | * @sdev: scsi device on starget to check. | |
1330 | * | |
1331 | * Called with the host lock held. | |
1332 | */ | |
1333 | static inline int scsi_target_queue_ready(struct Scsi_Host *shost, | |
1334 | struct scsi_device *sdev) | |
1335 | { | |
1336 | struct scsi_target *starget = scsi_target(sdev); | |
1337 | ||
1338 | if (starget->single_lun) { | |
1339 | if (starget->starget_sdev_user && | |
1340 | starget->starget_sdev_user != sdev) | |
1341 | return 0; | |
1342 | starget->starget_sdev_user = sdev; | |
1343 | } | |
1344 | ||
1345 | if (starget->target_busy == 0 && starget->target_blocked) { | |
1346 | /* | |
1347 | * unblock after target_blocked iterates to zero | |
1348 | */ | |
1349 | if (--starget->target_blocked == 0) { | |
1350 | SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, | |
1351 | "unblocking target at zero depth\n")); | |
b4efdd58 | 1352 | } else |
f0c0a376 | 1353 | return 0; |
f0c0a376 MC |
1354 | } |
1355 | ||
1356 | if (scsi_target_is_busy(starget)) { | |
466c08c7 | 1357 | list_move_tail(&sdev->starved_entry, &shost->starved_list); |
fd01a663 | 1358 | return 0; |
f0c0a376 MC |
1359 | } |
1360 | ||
f0c0a376 MC |
1361 | return 1; |
1362 | } | |
1363 | ||
1da177e4 LT |
1364 | /* |
1365 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1366 | * return 0. We must end up running the queue again whenever 0 is | |
1367 | * returned, else IO can hang. | |
1368 | * | |
1369 | * Called with host_lock held. | |
1370 | */ | |
1371 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1372 | struct Scsi_Host *shost, | |
1373 | struct scsi_device *sdev) | |
1374 | { | |
939647ee | 1375 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1376 | return 0; |
1377 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1378 | /* | |
1379 | * unblock after host_blocked iterates to zero | |
1380 | */ | |
1381 | if (--shost->host_blocked == 0) { | |
1382 | SCSI_LOG_MLQUEUE(3, | |
1383 | printk("scsi%d unblocking host at zero depth\n", | |
1384 | shost->host_no)); | |
1385 | } else { | |
1da177e4 LT |
1386 | return 0; |
1387 | } | |
1388 | } | |
9d112517 | 1389 | if (scsi_host_is_busy(shost)) { |
1da177e4 LT |
1390 | if (list_empty(&sdev->starved_entry)) |
1391 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1392 | return 0; | |
1393 | } | |
1394 | ||
1395 | /* We're OK to process the command, so we can't be starved */ | |
1396 | if (!list_empty(&sdev->starved_entry)) | |
1397 | list_del_init(&sdev->starved_entry); | |
1398 | ||
1399 | return 1; | |
1400 | } | |
1401 | ||
6c5121b7 KU |
1402 | /* |
1403 | * Busy state exporting function for request stacking drivers. | |
1404 | * | |
1405 | * For efficiency, no lock is taken to check the busy state of | |
1406 | * shost/starget/sdev, since the returned value is not guaranteed and | |
1407 | * may be changed after request stacking drivers call the function, | |
1408 | * regardless of taking lock or not. | |
1409 | * | |
67bd9413 BVA |
1410 | * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi |
1411 | * needs to return 'not busy'. Otherwise, request stacking drivers | |
1412 | * may hold requests forever. | |
6c5121b7 KU |
1413 | */ |
1414 | static int scsi_lld_busy(struct request_queue *q) | |
1415 | { | |
1416 | struct scsi_device *sdev = q->queuedata; | |
1417 | struct Scsi_Host *shost; | |
6c5121b7 | 1418 | |
3f3299d5 | 1419 | if (blk_queue_dying(q)) |
6c5121b7 KU |
1420 | return 0; |
1421 | ||
1422 | shost = sdev->host; | |
6c5121b7 | 1423 | |
b7e94a16 JN |
1424 | /* |
1425 | * Ignore host/starget busy state. | |
1426 | * Since block layer does not have a concept of fairness across | |
1427 | * multiple queues, congestion of host/starget needs to be handled | |
1428 | * in SCSI layer. | |
1429 | */ | |
1430 | if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) | |
6c5121b7 KU |
1431 | return 1; |
1432 | ||
1433 | return 0; | |
1434 | } | |
1435 | ||
1da177e4 | 1436 | /* |
e91442b6 | 1437 | * Kill a request for a dead device |
1da177e4 | 1438 | */ |
165125e1 | 1439 | static void scsi_kill_request(struct request *req, struct request_queue *q) |
1da177e4 | 1440 | { |
e91442b6 | 1441 | struct scsi_cmnd *cmd = req->special; |
03b14708 JS |
1442 | struct scsi_device *sdev; |
1443 | struct scsi_target *starget; | |
1444 | struct Scsi_Host *shost; | |
1da177e4 | 1445 | |
9934c8c0 | 1446 | blk_start_request(req); |
788ce43a | 1447 | |
74571813 HR |
1448 | scmd_printk(KERN_INFO, cmd, "killing request\n"); |
1449 | ||
03b14708 JS |
1450 | sdev = cmd->device; |
1451 | starget = scsi_target(sdev); | |
1452 | shost = sdev->host; | |
e91442b6 JB |
1453 | scsi_init_cmd_errh(cmd); |
1454 | cmd->result = DID_NO_CONNECT << 16; | |
1455 | atomic_inc(&cmd->device->iorequest_cnt); | |
e36e0c80 TH |
1456 | |
1457 | /* | |
1458 | * SCSI request completion path will do scsi_device_unbusy(), | |
1459 | * bump busy counts. To bump the counters, we need to dance | |
1460 | * with the locks as normal issue path does. | |
1461 | */ | |
1462 | sdev->device_busy++; | |
1463 | spin_unlock(sdev->request_queue->queue_lock); | |
1464 | spin_lock(shost->host_lock); | |
1465 | shost->host_busy++; | |
f0c0a376 | 1466 | starget->target_busy++; |
e36e0c80 TH |
1467 | spin_unlock(shost->host_lock); |
1468 | spin_lock(sdev->request_queue->queue_lock); | |
1469 | ||
242f9dcb | 1470 | blk_complete_request(req); |
1da177e4 LT |
1471 | } |
1472 | ||
1aea6434 JA |
1473 | static void scsi_softirq_done(struct request *rq) |
1474 | { | |
242f9dcb JA |
1475 | struct scsi_cmnd *cmd = rq->special; |
1476 | unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; | |
1aea6434 JA |
1477 | int disposition; |
1478 | ||
1479 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1480 | ||
242f9dcb JA |
1481 | atomic_inc(&cmd->device->iodone_cnt); |
1482 | if (cmd->result) | |
1483 | atomic_inc(&cmd->device->ioerr_cnt); | |
1484 | ||
1aea6434 JA |
1485 | disposition = scsi_decide_disposition(cmd); |
1486 | if (disposition != SUCCESS && | |
1487 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1488 | sdev_printk(KERN_ERR, cmd->device, | |
1489 | "timing out command, waited %lus\n", | |
1490 | wait_for/HZ); | |
1491 | disposition = SUCCESS; | |
1492 | } | |
1493 | ||
1494 | scsi_log_completion(cmd, disposition); | |
1495 | ||
1496 | switch (disposition) { | |
1497 | case SUCCESS: | |
1498 | scsi_finish_command(cmd); | |
1499 | break; | |
1500 | case NEEDS_RETRY: | |
596f482a | 1501 | scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); |
1aea6434 JA |
1502 | break; |
1503 | case ADD_TO_MLQUEUE: | |
1504 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1505 | break; | |
1506 | default: | |
1507 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1508 | scsi_finish_command(cmd); | |
1509 | } | |
1510 | } | |
1511 | ||
1da177e4 LT |
1512 | /* |
1513 | * Function: scsi_request_fn() | |
1514 | * | |
1515 | * Purpose: Main strategy routine for SCSI. | |
1516 | * | |
1517 | * Arguments: q - Pointer to actual queue. | |
1518 | * | |
1519 | * Returns: Nothing | |
1520 | * | |
1521 | * Lock status: IO request lock assumed to be held when called. | |
1522 | */ | |
1523 | static void scsi_request_fn(struct request_queue *q) | |
1524 | { | |
1525 | struct scsi_device *sdev = q->queuedata; | |
1526 | struct Scsi_Host *shost; | |
1527 | struct scsi_cmnd *cmd; | |
1528 | struct request *req; | |
1529 | ||
1da177e4 LT |
1530 | if(!get_device(&sdev->sdev_gendev)) |
1531 | /* We must be tearing the block queue down already */ | |
1532 | return; | |
1533 | ||
1534 | /* | |
1535 | * To start with, we keep looping until the queue is empty, or until | |
1536 | * the host is no longer able to accept any more requests. | |
1537 | */ | |
1538 | shost = sdev->host; | |
a488e749 | 1539 | for (;;) { |
1da177e4 LT |
1540 | int rtn; |
1541 | /* | |
1542 | * get next queueable request. We do this early to make sure | |
1543 | * that the request is fully prepared even if we cannot | |
1544 | * accept it. | |
1545 | */ | |
9934c8c0 | 1546 | req = blk_peek_request(q); |
1da177e4 LT |
1547 | if (!req || !scsi_dev_queue_ready(q, sdev)) |
1548 | break; | |
1549 | ||
1550 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1551 | sdev_printk(KERN_ERR, sdev, |
1552 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1553 | scsi_kill_request(req, q); |
1da177e4 LT |
1554 | continue; |
1555 | } | |
1556 | ||
1557 | ||
1558 | /* | |
1559 | * Remove the request from the request list. | |
1560 | */ | |
1561 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
9934c8c0 | 1562 | blk_start_request(req); |
1da177e4 LT |
1563 | sdev->device_busy++; |
1564 | ||
1565 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1566 | cmd = req->special; |
1567 | if (unlikely(cmd == NULL)) { | |
1568 | printk(KERN_CRIT "impossible request in %s.\n" | |
1569 | "please mail a stack trace to " | |
4aff5e23 | 1570 | "linux-scsi@vger.kernel.org\n", |
cadbd4a5 | 1571 | __func__); |
4aff5e23 | 1572 | blk_dump_rq_flags(req, "foo"); |
e91442b6 JB |
1573 | BUG(); |
1574 | } | |
1da177e4 LT |
1575 | spin_lock(shost->host_lock); |
1576 | ||
ecefe8a9 MC |
1577 | /* |
1578 | * We hit this when the driver is using a host wide | |
1579 | * tag map. For device level tag maps the queue_depth check | |
1580 | * in the device ready fn would prevent us from trying | |
1581 | * to allocate a tag. Since the map is a shared host resource | |
1582 | * we add the dev to the starved list so it eventually gets | |
1583 | * a run when a tag is freed. | |
1584 | */ | |
6bd522f6 | 1585 | if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { |
ecefe8a9 MC |
1586 | if (list_empty(&sdev->starved_entry)) |
1587 | list_add_tail(&sdev->starved_entry, | |
1588 | &shost->starved_list); | |
1589 | goto not_ready; | |
1590 | } | |
1591 | ||
f0c0a376 MC |
1592 | if (!scsi_target_queue_ready(shost, sdev)) |
1593 | goto not_ready; | |
1594 | ||
1da177e4 LT |
1595 | if (!scsi_host_queue_ready(q, shost, sdev)) |
1596 | goto not_ready; | |
f0c0a376 MC |
1597 | |
1598 | scsi_target(sdev)->target_busy++; | |
1da177e4 LT |
1599 | shost->host_busy++; |
1600 | ||
1601 | /* | |
1602 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1603 | * take the lock again. | |
1604 | */ | |
1605 | spin_unlock_irq(shost->host_lock); | |
1606 | ||
1da177e4 LT |
1607 | /* |
1608 | * Finally, initialize any error handling parameters, and set up | |
1609 | * the timers for timeouts. | |
1610 | */ | |
1611 | scsi_init_cmd_errh(cmd); | |
1612 | ||
1613 | /* | |
1614 | * Dispatch the command to the low-level driver. | |
1615 | */ | |
1616 | rtn = scsi_dispatch_cmd(cmd); | |
1617 | spin_lock_irq(q->queue_lock); | |
a488e749 JA |
1618 | if (rtn) |
1619 | goto out_delay; | |
1da177e4 LT |
1620 | } |
1621 | ||
1622 | goto out; | |
1623 | ||
1624 | not_ready: | |
1625 | spin_unlock_irq(shost->host_lock); | |
1626 | ||
1627 | /* | |
1628 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1629 | * must return with queue_lock held. | |
1630 | * | |
1631 | * Decrementing device_busy without checking it is OK, as all such | |
1632 | * cases (host limits or settings) should run the queue at some | |
1633 | * later time. | |
1634 | */ | |
1635 | spin_lock_irq(q->queue_lock); | |
1636 | blk_requeue_request(q, req); | |
1637 | sdev->device_busy--; | |
a488e749 JA |
1638 | out_delay: |
1639 | if (sdev->device_busy == 0) | |
1640 | blk_delay_queue(q, SCSI_QUEUE_DELAY); | |
1641 | out: | |
1da177e4 LT |
1642 | /* must be careful here...if we trigger the ->remove() function |
1643 | * we cannot be holding the q lock */ | |
1644 | spin_unlock_irq(q->queue_lock); | |
1645 | put_device(&sdev->sdev_gendev); | |
1646 | spin_lock_irq(q->queue_lock); | |
1647 | } | |
1648 | ||
1649 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1650 | { | |
1651 | struct device *host_dev; | |
1652 | u64 bounce_limit = 0xffffffff; | |
1653 | ||
1654 | if (shost->unchecked_isa_dma) | |
1655 | return BLK_BOUNCE_ISA; | |
1656 | /* | |
1657 | * Platforms with virtual-DMA translation | |
1658 | * hardware have no practical limit. | |
1659 | */ | |
1660 | if (!PCI_DMA_BUS_IS_PHYS) | |
1661 | return BLK_BOUNCE_ANY; | |
1662 | ||
1663 | host_dev = scsi_get_device(shost); | |
1664 | if (host_dev && host_dev->dma_mask) | |
1665 | bounce_limit = *host_dev->dma_mask; | |
1666 | ||
1667 | return bounce_limit; | |
1668 | } | |
1669 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1670 | ||
b58d9154 FT |
1671 | struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, |
1672 | request_fn_proc *request_fn) | |
1da177e4 | 1673 | { |
1da177e4 | 1674 | struct request_queue *q; |
6f381fa3 | 1675 | struct device *dev = shost->dma_dev; |
1da177e4 | 1676 | |
b58d9154 | 1677 | q = blk_init_queue(request_fn, NULL); |
1da177e4 LT |
1678 | if (!q) |
1679 | return NULL; | |
1680 | ||
a8474ce2 JA |
1681 | /* |
1682 | * this limit is imposed by hardware restrictions | |
1683 | */ | |
8a78362c MP |
1684 | blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, |
1685 | SCSI_MAX_SG_CHAIN_SEGMENTS)); | |
a8474ce2 | 1686 | |
13f05c8d MP |
1687 | if (scsi_host_prot_dma(shost)) { |
1688 | shost->sg_prot_tablesize = | |
1689 | min_not_zero(shost->sg_prot_tablesize, | |
1690 | (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); | |
1691 | BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); | |
1692 | blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); | |
1693 | } | |
1694 | ||
086fa5ff | 1695 | blk_queue_max_hw_sectors(q, shost->max_sectors); |
1da177e4 LT |
1696 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); |
1697 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
99c84dbd | 1698 | dma_set_seg_boundary(dev, shost->dma_boundary); |
1da177e4 | 1699 | |
860ac568 FT |
1700 | blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); |
1701 | ||
1da177e4 | 1702 | if (!shost->use_clustering) |
e692cb66 | 1703 | q->limits.cluster = 0; |
465ff318 JB |
1704 | |
1705 | /* | |
1706 | * set a reasonable default alignment on word boundaries: the | |
1707 | * host and device may alter it using | |
1708 | * blk_queue_update_dma_alignment() later. | |
1709 | */ | |
1710 | blk_queue_dma_alignment(q, 0x03); | |
1711 | ||
1da177e4 LT |
1712 | return q; |
1713 | } | |
b58d9154 FT |
1714 | EXPORT_SYMBOL(__scsi_alloc_queue); |
1715 | ||
1716 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1717 | { | |
1718 | struct request_queue *q; | |
1719 | ||
1720 | q = __scsi_alloc_queue(sdev->host, scsi_request_fn); | |
1721 | if (!q) | |
1722 | return NULL; | |
1723 | ||
1724 | blk_queue_prep_rq(q, scsi_prep_fn); | |
b58d9154 | 1725 | blk_queue_softirq_done(q, scsi_softirq_done); |
242f9dcb | 1726 | blk_queue_rq_timed_out(q, scsi_times_out); |
6c5121b7 | 1727 | blk_queue_lld_busy(q, scsi_lld_busy); |
b58d9154 FT |
1728 | return q; |
1729 | } | |
1da177e4 | 1730 | |
1da177e4 LT |
1731 | /* |
1732 | * Function: scsi_block_requests() | |
1733 | * | |
1734 | * Purpose: Utility function used by low-level drivers to prevent further | |
1735 | * commands from being queued to the device. | |
1736 | * | |
1737 | * Arguments: shost - Host in question | |
1738 | * | |
1739 | * Returns: Nothing | |
1740 | * | |
1741 | * Lock status: No locks are assumed held. | |
1742 | * | |
1743 | * Notes: There is no timer nor any other means by which the requests | |
1744 | * get unblocked other than the low-level driver calling | |
1745 | * scsi_unblock_requests(). | |
1746 | */ | |
1747 | void scsi_block_requests(struct Scsi_Host *shost) | |
1748 | { | |
1749 | shost->host_self_blocked = 1; | |
1750 | } | |
1751 | EXPORT_SYMBOL(scsi_block_requests); | |
1752 | ||
1753 | /* | |
1754 | * Function: scsi_unblock_requests() | |
1755 | * | |
1756 | * Purpose: Utility function used by low-level drivers to allow further | |
1757 | * commands from being queued to the device. | |
1758 | * | |
1759 | * Arguments: shost - Host in question | |
1760 | * | |
1761 | * Returns: Nothing | |
1762 | * | |
1763 | * Lock status: No locks are assumed held. | |
1764 | * | |
1765 | * Notes: There is no timer nor any other means by which the requests | |
1766 | * get unblocked other than the low-level driver calling | |
1767 | * scsi_unblock_requests(). | |
1768 | * | |
1769 | * This is done as an API function so that changes to the | |
1770 | * internals of the scsi mid-layer won't require wholesale | |
1771 | * changes to drivers that use this feature. | |
1772 | */ | |
1773 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1774 | { | |
1775 | shost->host_self_blocked = 0; | |
1776 | scsi_run_host_queues(shost); | |
1777 | } | |
1778 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1779 | ||
1780 | int __init scsi_init_queue(void) | |
1781 | { | |
1782 | int i; | |
1783 | ||
6362abd3 MP |
1784 | scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", |
1785 | sizeof(struct scsi_data_buffer), | |
1786 | 0, 0, NULL); | |
1787 | if (!scsi_sdb_cache) { | |
1788 | printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); | |
f078727b | 1789 | return -ENOMEM; |
6f9a35e2 BH |
1790 | } |
1791 | ||
1da177e4 LT |
1792 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1793 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1794 | int size = sgp->size * sizeof(struct scatterlist); | |
1795 | ||
1796 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
20c2df83 | 1797 | SLAB_HWCACHE_ALIGN, NULL); |
1da177e4 LT |
1798 | if (!sgp->slab) { |
1799 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1800 | sgp->name); | |
6362abd3 | 1801 | goto cleanup_sdb; |
1da177e4 LT |
1802 | } |
1803 | ||
93d2341c MD |
1804 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
1805 | sgp->slab); | |
1da177e4 LT |
1806 | if (!sgp->pool) { |
1807 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1808 | sgp->name); | |
6362abd3 | 1809 | goto cleanup_sdb; |
1da177e4 LT |
1810 | } |
1811 | } | |
1812 | ||
1813 | return 0; | |
3d9dd6ee | 1814 | |
6362abd3 | 1815 | cleanup_sdb: |
3d9dd6ee FT |
1816 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1817 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1818 | if (sgp->pool) | |
1819 | mempool_destroy(sgp->pool); | |
1820 | if (sgp->slab) | |
1821 | kmem_cache_destroy(sgp->slab); | |
1822 | } | |
6362abd3 | 1823 | kmem_cache_destroy(scsi_sdb_cache); |
3d9dd6ee FT |
1824 | |
1825 | return -ENOMEM; | |
1da177e4 LT |
1826 | } |
1827 | ||
1828 | void scsi_exit_queue(void) | |
1829 | { | |
1830 | int i; | |
1831 | ||
6362abd3 | 1832 | kmem_cache_destroy(scsi_sdb_cache); |
aa7b5cd7 | 1833 | |
1da177e4 LT |
1834 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1835 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1836 | mempool_destroy(sgp->pool); | |
1837 | kmem_cache_destroy(sgp->slab); | |
1838 | } | |
1839 | } | |
5baba830 JB |
1840 | |
1841 | /** | |
1842 | * scsi_mode_select - issue a mode select | |
1843 | * @sdev: SCSI device to be queried | |
1844 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1845 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1846 | * @modepage: mode page being requested | |
1847 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1848 | * @len: length of request buffer. | |
1849 | * @timeout: command timeout | |
1850 | * @retries: number of retries before failing | |
1851 | * @data: returns a structure abstracting the mode header data | |
eb44820c | 1852 | * @sshdr: place to put sense data (or NULL if no sense to be collected). |
5baba830 JB |
1853 | * must be SCSI_SENSE_BUFFERSIZE big. |
1854 | * | |
1855 | * Returns zero if successful; negative error number or scsi | |
1856 | * status on error | |
1857 | * | |
1858 | */ | |
1859 | int | |
1860 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1861 | unsigned char *buffer, int len, int timeout, int retries, | |
1862 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1863 | { | |
1864 | unsigned char cmd[10]; | |
1865 | unsigned char *real_buffer; | |
1866 | int ret; | |
1867 | ||
1868 | memset(cmd, 0, sizeof(cmd)); | |
1869 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1870 | ||
1871 | if (sdev->use_10_for_ms) { | |
1872 | if (len > 65535) | |
1873 | return -EINVAL; | |
1874 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1875 | if (!real_buffer) | |
1876 | return -ENOMEM; | |
1877 | memcpy(real_buffer + 8, buffer, len); | |
1878 | len += 8; | |
1879 | real_buffer[0] = 0; | |
1880 | real_buffer[1] = 0; | |
1881 | real_buffer[2] = data->medium_type; | |
1882 | real_buffer[3] = data->device_specific; | |
1883 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1884 | real_buffer[5] = 0; | |
1885 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1886 | real_buffer[7] = data->block_descriptor_length; | |
1887 | ||
1888 | cmd[0] = MODE_SELECT_10; | |
1889 | cmd[7] = len >> 8; | |
1890 | cmd[8] = len; | |
1891 | } else { | |
1892 | if (len > 255 || data->block_descriptor_length > 255 || | |
1893 | data->longlba) | |
1894 | return -EINVAL; | |
1895 | ||
1896 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1897 | if (!real_buffer) | |
1898 | return -ENOMEM; | |
1899 | memcpy(real_buffer + 4, buffer, len); | |
1900 | len += 4; | |
1901 | real_buffer[0] = 0; | |
1902 | real_buffer[1] = data->medium_type; | |
1903 | real_buffer[2] = data->device_specific; | |
1904 | real_buffer[3] = data->block_descriptor_length; | |
1905 | ||
1906 | ||
1907 | cmd[0] = MODE_SELECT; | |
1908 | cmd[4] = len; | |
1909 | } | |
1910 | ||
1911 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
f4f4e47e | 1912 | sshdr, timeout, retries, NULL); |
5baba830 JB |
1913 | kfree(real_buffer); |
1914 | return ret; | |
1915 | } | |
1916 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1917 | ||
1da177e4 | 1918 | /** |
eb44820c | 1919 | * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. |
1cf72699 | 1920 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1921 | * @dbd: set if mode sense will allow block descriptors to be returned |
1922 | * @modepage: mode page being requested | |
1923 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1924 | * @len: length of request buffer. | |
1925 | * @timeout: command timeout | |
1926 | * @retries: number of retries before failing | |
1927 | * @data: returns a structure abstracting the mode header data | |
eb44820c | 1928 | * @sshdr: place to put sense data (or NULL if no sense to be collected). |
1cf72699 | 1929 | * must be SCSI_SENSE_BUFFERSIZE big. |
1da177e4 LT |
1930 | * |
1931 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1932 | * or 8 depending on whether a six or ten byte command was | |
1933 | * issued) if successful. | |
eb44820c | 1934 | */ |
1da177e4 | 1935 | int |
1cf72699 | 1936 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1937 | unsigned char *buffer, int len, int timeout, int retries, |
5baba830 JB |
1938 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
1939 | { | |
1da177e4 LT |
1940 | unsigned char cmd[12]; |
1941 | int use_10_for_ms; | |
1942 | int header_length; | |
1cf72699 | 1943 | int result; |
ea73a9f2 | 1944 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1945 | |
1946 | memset(data, 0, sizeof(*data)); | |
1947 | memset(&cmd[0], 0, 12); | |
1948 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1949 | cmd[2] = modepage; | |
1950 | ||
ea73a9f2 JB |
1951 | /* caller might not be interested in sense, but we need it */ |
1952 | if (!sshdr) | |
1953 | sshdr = &my_sshdr; | |
1954 | ||
1da177e4 | 1955 | retry: |
1cf72699 | 1956 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1957 | |
1958 | if (use_10_for_ms) { | |
1959 | if (len < 8) | |
1960 | len = 8; | |
1961 | ||
1962 | cmd[0] = MODE_SENSE_10; | |
1963 | cmd[8] = len; | |
1964 | header_length = 8; | |
1965 | } else { | |
1966 | if (len < 4) | |
1967 | len = 4; | |
1968 | ||
1969 | cmd[0] = MODE_SENSE; | |
1970 | cmd[4] = len; | |
1971 | header_length = 4; | |
1972 | } | |
1973 | ||
1da177e4 LT |
1974 | memset(buffer, 0, len); |
1975 | ||
1cf72699 | 1976 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
f4f4e47e | 1977 | sshdr, timeout, retries, NULL); |
1da177e4 LT |
1978 | |
1979 | /* This code looks awful: what it's doing is making sure an | |
1980 | * ILLEGAL REQUEST sense return identifies the actual command | |
1981 | * byte as the problem. MODE_SENSE commands can return | |
1982 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1983 | ||
1cf72699 JB |
1984 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1985 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1986 | if (scsi_sense_valid(sshdr)) { |
1987 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1988 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1989 | /* |
1990 | * Invalid command operation code | |
1991 | */ | |
1cf72699 | 1992 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1993 | goto retry; |
1994 | } | |
1995 | } | |
1996 | } | |
1997 | ||
1cf72699 | 1998 | if(scsi_status_is_good(result)) { |
6d73c851 AV |
1999 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
2000 | (modepage == 6 || modepage == 8))) { | |
2001 | /* Initio breakage? */ | |
2002 | header_length = 0; | |
2003 | data->length = 13; | |
2004 | data->medium_type = 0; | |
2005 | data->device_specific = 0; | |
2006 | data->longlba = 0; | |
2007 | data->block_descriptor_length = 0; | |
2008 | } else if(use_10_for_ms) { | |
1da177e4 LT |
2009 | data->length = buffer[0]*256 + buffer[1] + 2; |
2010 | data->medium_type = buffer[2]; | |
2011 | data->device_specific = buffer[3]; | |
2012 | data->longlba = buffer[4] & 0x01; | |
2013 | data->block_descriptor_length = buffer[6]*256 | |
2014 | + buffer[7]; | |
2015 | } else { | |
2016 | data->length = buffer[0] + 1; | |
2017 | data->medium_type = buffer[1]; | |
2018 | data->device_specific = buffer[2]; | |
2019 | data->block_descriptor_length = buffer[3]; | |
2020 | } | |
6d73c851 | 2021 | data->header_length = header_length; |
1da177e4 LT |
2022 | } |
2023 | ||
1cf72699 | 2024 | return result; |
1da177e4 LT |
2025 | } |
2026 | EXPORT_SYMBOL(scsi_mode_sense); | |
2027 | ||
001aac25 JB |
2028 | /** |
2029 | * scsi_test_unit_ready - test if unit is ready | |
2030 | * @sdev: scsi device to change the state of. | |
2031 | * @timeout: command timeout | |
2032 | * @retries: number of retries before failing | |
2033 | * @sshdr_external: Optional pointer to struct scsi_sense_hdr for | |
2034 | * returning sense. Make sure that this is cleared before passing | |
2035 | * in. | |
2036 | * | |
2037 | * Returns zero if unsuccessful or an error if TUR failed. For | |
9f8a2c23 | 2038 | * removable media, UNIT_ATTENTION sets ->changed flag. |
001aac25 | 2039 | **/ |
1da177e4 | 2040 | int |
001aac25 JB |
2041 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, |
2042 | struct scsi_sense_hdr *sshdr_external) | |
1da177e4 | 2043 | { |
1da177e4 LT |
2044 | char cmd[] = { |
2045 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
2046 | }; | |
001aac25 | 2047 | struct scsi_sense_hdr *sshdr; |
1da177e4 | 2048 | int result; |
001aac25 JB |
2049 | |
2050 | if (!sshdr_external) | |
2051 | sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); | |
2052 | else | |
2053 | sshdr = sshdr_external; | |
2054 | ||
2055 | /* try to eat the UNIT_ATTENTION if there are enough retries */ | |
2056 | do { | |
2057 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, | |
f4f4e47e | 2058 | timeout, retries, NULL); |
32c356d7 JB |
2059 | if (sdev->removable && scsi_sense_valid(sshdr) && |
2060 | sshdr->sense_key == UNIT_ATTENTION) | |
2061 | sdev->changed = 1; | |
2062 | } while (scsi_sense_valid(sshdr) && | |
2063 | sshdr->sense_key == UNIT_ATTENTION && --retries); | |
001aac25 | 2064 | |
001aac25 JB |
2065 | if (!sshdr_external) |
2066 | kfree(sshdr); | |
1da177e4 LT |
2067 | return result; |
2068 | } | |
2069 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
2070 | ||
2071 | /** | |
eb44820c | 2072 | * scsi_device_set_state - Take the given device through the device state model. |
1da177e4 LT |
2073 | * @sdev: scsi device to change the state of. |
2074 | * @state: state to change to. | |
2075 | * | |
2076 | * Returns zero if unsuccessful or an error if the requested | |
2077 | * transition is illegal. | |
eb44820c | 2078 | */ |
1da177e4 LT |
2079 | int |
2080 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
2081 | { | |
2082 | enum scsi_device_state oldstate = sdev->sdev_state; | |
2083 | ||
2084 | if (state == oldstate) | |
2085 | return 0; | |
2086 | ||
2087 | switch (state) { | |
2088 | case SDEV_CREATED: | |
6f4267e3 JB |
2089 | switch (oldstate) { |
2090 | case SDEV_CREATED_BLOCK: | |
2091 | break; | |
2092 | default: | |
2093 | goto illegal; | |
2094 | } | |
2095 | break; | |
1da177e4 LT |
2096 | |
2097 | case SDEV_RUNNING: | |
2098 | switch (oldstate) { | |
2099 | case SDEV_CREATED: | |
2100 | case SDEV_OFFLINE: | |
1b8d2620 | 2101 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2102 | case SDEV_QUIESCE: |
2103 | case SDEV_BLOCK: | |
2104 | break; | |
2105 | default: | |
2106 | goto illegal; | |
2107 | } | |
2108 | break; | |
2109 | ||
2110 | case SDEV_QUIESCE: | |
2111 | switch (oldstate) { | |
2112 | case SDEV_RUNNING: | |
2113 | case SDEV_OFFLINE: | |
1b8d2620 | 2114 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2115 | break; |
2116 | default: | |
2117 | goto illegal; | |
2118 | } | |
2119 | break; | |
2120 | ||
2121 | case SDEV_OFFLINE: | |
1b8d2620 | 2122 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2123 | switch (oldstate) { |
2124 | case SDEV_CREATED: | |
2125 | case SDEV_RUNNING: | |
2126 | case SDEV_QUIESCE: | |
2127 | case SDEV_BLOCK: | |
2128 | break; | |
2129 | default: | |
2130 | goto illegal; | |
2131 | } | |
2132 | break; | |
2133 | ||
2134 | case SDEV_BLOCK: | |
2135 | switch (oldstate) { | |
1da177e4 | 2136 | case SDEV_RUNNING: |
6f4267e3 JB |
2137 | case SDEV_CREATED_BLOCK: |
2138 | break; | |
2139 | default: | |
2140 | goto illegal; | |
2141 | } | |
2142 | break; | |
2143 | ||
2144 | case SDEV_CREATED_BLOCK: | |
2145 | switch (oldstate) { | |
2146 | case SDEV_CREATED: | |
1da177e4 LT |
2147 | break; |
2148 | default: | |
2149 | goto illegal; | |
2150 | } | |
2151 | break; | |
2152 | ||
2153 | case SDEV_CANCEL: | |
2154 | switch (oldstate) { | |
2155 | case SDEV_CREATED: | |
2156 | case SDEV_RUNNING: | |
9ea72909 | 2157 | case SDEV_QUIESCE: |
1da177e4 | 2158 | case SDEV_OFFLINE: |
1b8d2620 | 2159 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2160 | case SDEV_BLOCK: |
2161 | break; | |
2162 | default: | |
2163 | goto illegal; | |
2164 | } | |
2165 | break; | |
2166 | ||
2167 | case SDEV_DEL: | |
2168 | switch (oldstate) { | |
309bd271 BK |
2169 | case SDEV_CREATED: |
2170 | case SDEV_RUNNING: | |
2171 | case SDEV_OFFLINE: | |
1b8d2620 | 2172 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 | 2173 | case SDEV_CANCEL: |
0516c08d | 2174 | case SDEV_CREATED_BLOCK: |
1da177e4 LT |
2175 | break; |
2176 | default: | |
2177 | goto illegal; | |
2178 | } | |
2179 | break; | |
2180 | ||
2181 | } | |
2182 | sdev->sdev_state = state; | |
2183 | return 0; | |
2184 | ||
2185 | illegal: | |
2186 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2187 | sdev_printk(KERN_ERR, sdev, |
2188 | "Illegal state transition %s->%s\n", | |
2189 | scsi_device_state_name(oldstate), | |
2190 | scsi_device_state_name(state)) | |
1da177e4 LT |
2191 | ); |
2192 | return -EINVAL; | |
2193 | } | |
2194 | EXPORT_SYMBOL(scsi_device_set_state); | |
2195 | ||
a341cd0f JG |
2196 | /** |
2197 | * sdev_evt_emit - emit a single SCSI device uevent | |
2198 | * @sdev: associated SCSI device | |
2199 | * @evt: event to emit | |
2200 | * | |
2201 | * Send a single uevent (scsi_event) to the associated scsi_device. | |
2202 | */ | |
2203 | static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) | |
2204 | { | |
2205 | int idx = 0; | |
2206 | char *envp[3]; | |
2207 | ||
2208 | switch (evt->evt_type) { | |
2209 | case SDEV_EVT_MEDIA_CHANGE: | |
2210 | envp[idx++] = "SDEV_MEDIA_CHANGE=1"; | |
2211 | break; | |
2212 | ||
2213 | default: | |
2214 | /* do nothing */ | |
2215 | break; | |
2216 | } | |
2217 | ||
2218 | envp[idx++] = NULL; | |
2219 | ||
2220 | kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); | |
2221 | } | |
2222 | ||
2223 | /** | |
2224 | * sdev_evt_thread - send a uevent for each scsi event | |
2225 | * @work: work struct for scsi_device | |
2226 | * | |
2227 | * Dispatch queued events to their associated scsi_device kobjects | |
2228 | * as uevents. | |
2229 | */ | |
2230 | void scsi_evt_thread(struct work_struct *work) | |
2231 | { | |
2232 | struct scsi_device *sdev; | |
2233 | LIST_HEAD(event_list); | |
2234 | ||
2235 | sdev = container_of(work, struct scsi_device, event_work); | |
2236 | ||
2237 | while (1) { | |
2238 | struct scsi_event *evt; | |
2239 | struct list_head *this, *tmp; | |
2240 | unsigned long flags; | |
2241 | ||
2242 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2243 | list_splice_init(&sdev->event_list, &event_list); | |
2244 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2245 | ||
2246 | if (list_empty(&event_list)) | |
2247 | break; | |
2248 | ||
2249 | list_for_each_safe(this, tmp, &event_list) { | |
2250 | evt = list_entry(this, struct scsi_event, node); | |
2251 | list_del(&evt->node); | |
2252 | scsi_evt_emit(sdev, evt); | |
2253 | kfree(evt); | |
2254 | } | |
2255 | } | |
2256 | } | |
2257 | ||
2258 | /** | |
2259 | * sdev_evt_send - send asserted event to uevent thread | |
2260 | * @sdev: scsi_device event occurred on | |
2261 | * @evt: event to send | |
2262 | * | |
2263 | * Assert scsi device event asynchronously. | |
2264 | */ | |
2265 | void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) | |
2266 | { | |
2267 | unsigned long flags; | |
2268 | ||
4d1566ed KS |
2269 | #if 0 |
2270 | /* FIXME: currently this check eliminates all media change events | |
2271 | * for polled devices. Need to update to discriminate between AN | |
2272 | * and polled events */ | |
a341cd0f JG |
2273 | if (!test_bit(evt->evt_type, sdev->supported_events)) { |
2274 | kfree(evt); | |
2275 | return; | |
2276 | } | |
4d1566ed | 2277 | #endif |
a341cd0f JG |
2278 | |
2279 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2280 | list_add_tail(&evt->node, &sdev->event_list); | |
2281 | schedule_work(&sdev->event_work); | |
2282 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2283 | } | |
2284 | EXPORT_SYMBOL_GPL(sdev_evt_send); | |
2285 | ||
2286 | /** | |
2287 | * sdev_evt_alloc - allocate a new scsi event | |
2288 | * @evt_type: type of event to allocate | |
2289 | * @gfpflags: GFP flags for allocation | |
2290 | * | |
2291 | * Allocates and returns a new scsi_event. | |
2292 | */ | |
2293 | struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, | |
2294 | gfp_t gfpflags) | |
2295 | { | |
2296 | struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); | |
2297 | if (!evt) | |
2298 | return NULL; | |
2299 | ||
2300 | evt->evt_type = evt_type; | |
2301 | INIT_LIST_HEAD(&evt->node); | |
2302 | ||
2303 | /* evt_type-specific initialization, if any */ | |
2304 | switch (evt_type) { | |
2305 | case SDEV_EVT_MEDIA_CHANGE: | |
2306 | default: | |
2307 | /* do nothing */ | |
2308 | break; | |
2309 | } | |
2310 | ||
2311 | return evt; | |
2312 | } | |
2313 | EXPORT_SYMBOL_GPL(sdev_evt_alloc); | |
2314 | ||
2315 | /** | |
2316 | * sdev_evt_send_simple - send asserted event to uevent thread | |
2317 | * @sdev: scsi_device event occurred on | |
2318 | * @evt_type: type of event to send | |
2319 | * @gfpflags: GFP flags for allocation | |
2320 | * | |
2321 | * Assert scsi device event asynchronously, given an event type. | |
2322 | */ | |
2323 | void sdev_evt_send_simple(struct scsi_device *sdev, | |
2324 | enum scsi_device_event evt_type, gfp_t gfpflags) | |
2325 | { | |
2326 | struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); | |
2327 | if (!evt) { | |
2328 | sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", | |
2329 | evt_type); | |
2330 | return; | |
2331 | } | |
2332 | ||
2333 | sdev_evt_send(sdev, evt); | |
2334 | } | |
2335 | EXPORT_SYMBOL_GPL(sdev_evt_send_simple); | |
2336 | ||
1da177e4 LT |
2337 | /** |
2338 | * scsi_device_quiesce - Block user issued commands. | |
2339 | * @sdev: scsi device to quiesce. | |
2340 | * | |
2341 | * This works by trying to transition to the SDEV_QUIESCE state | |
2342 | * (which must be a legal transition). When the device is in this | |
2343 | * state, only special requests will be accepted, all others will | |
2344 | * be deferred. Since special requests may also be requeued requests, | |
2345 | * a successful return doesn't guarantee the device will be | |
2346 | * totally quiescent. | |
2347 | * | |
2348 | * Must be called with user context, may sleep. | |
2349 | * | |
2350 | * Returns zero if unsuccessful or an error if not. | |
eb44820c | 2351 | */ |
1da177e4 LT |
2352 | int |
2353 | scsi_device_quiesce(struct scsi_device *sdev) | |
2354 | { | |
2355 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2356 | if (err) | |
2357 | return err; | |
2358 | ||
2359 | scsi_run_queue(sdev->request_queue); | |
2360 | while (sdev->device_busy) { | |
2361 | msleep_interruptible(200); | |
2362 | scsi_run_queue(sdev->request_queue); | |
2363 | } | |
2364 | return 0; | |
2365 | } | |
2366 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2367 | ||
2368 | /** | |
2369 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2370 | * @sdev: scsi device to resume. | |
2371 | * | |
2372 | * Moves the device from quiesced back to running and restarts the | |
2373 | * queues. | |
2374 | * | |
2375 | * Must be called with user context, may sleep. | |
eb44820c | 2376 | */ |
a7a20d10 | 2377 | void scsi_device_resume(struct scsi_device *sdev) |
1da177e4 | 2378 | { |
a7a20d10 DW |
2379 | /* check if the device state was mutated prior to resume, and if |
2380 | * so assume the state is being managed elsewhere (for example | |
2381 | * device deleted during suspend) | |
2382 | */ | |
2383 | if (sdev->sdev_state != SDEV_QUIESCE || | |
2384 | scsi_device_set_state(sdev, SDEV_RUNNING)) | |
1da177e4 LT |
2385 | return; |
2386 | scsi_run_queue(sdev->request_queue); | |
2387 | } | |
2388 | EXPORT_SYMBOL(scsi_device_resume); | |
2389 | ||
2390 | static void | |
2391 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2392 | { | |
2393 | scsi_device_quiesce(sdev); | |
2394 | } | |
2395 | ||
2396 | void | |
2397 | scsi_target_quiesce(struct scsi_target *starget) | |
2398 | { | |
2399 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2400 | } | |
2401 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2402 | ||
2403 | static void | |
2404 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2405 | { | |
2406 | scsi_device_resume(sdev); | |
2407 | } | |
2408 | ||
2409 | void | |
2410 | scsi_target_resume(struct scsi_target *starget) | |
2411 | { | |
2412 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2413 | } | |
2414 | EXPORT_SYMBOL(scsi_target_resume); | |
2415 | ||
2416 | /** | |
eb44820c | 2417 | * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state |
1da177e4 LT |
2418 | * @sdev: device to block |
2419 | * | |
2420 | * Block request made by scsi lld's to temporarily stop all | |
2421 | * scsi commands on the specified device. Called from interrupt | |
2422 | * or normal process context. | |
2423 | * | |
2424 | * Returns zero if successful or error if not | |
2425 | * | |
2426 | * Notes: | |
2427 | * This routine transitions the device to the SDEV_BLOCK state | |
2428 | * (which must be a legal transition). When the device is in this | |
2429 | * state, all commands are deferred until the scsi lld reenables | |
2430 | * the device with scsi_device_unblock or device_block_tmo fires. | |
eb44820c | 2431 | */ |
1da177e4 LT |
2432 | int |
2433 | scsi_internal_device_block(struct scsi_device *sdev) | |
2434 | { | |
165125e1 | 2435 | struct request_queue *q = sdev->request_queue; |
1da177e4 LT |
2436 | unsigned long flags; |
2437 | int err = 0; | |
2438 | ||
2439 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
6f4267e3 JB |
2440 | if (err) { |
2441 | err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); | |
2442 | ||
2443 | if (err) | |
2444 | return err; | |
2445 | } | |
1da177e4 LT |
2446 | |
2447 | /* | |
2448 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2449 | * block layer from calling the midlayer with this device's | |
2450 | * request queue. | |
2451 | */ | |
2452 | spin_lock_irqsave(q->queue_lock, flags); | |
2453 | blk_stop_queue(q); | |
2454 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2455 | ||
2456 | return 0; | |
2457 | } | |
2458 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2459 | ||
2460 | /** | |
2461 | * scsi_internal_device_unblock - resume a device after a block request | |
2462 | * @sdev: device to resume | |
5d9fb5cc | 2463 | * @new_state: state to set devices to after unblocking |
1da177e4 LT |
2464 | * |
2465 | * Called by scsi lld's or the midlayer to restart the device queue | |
2466 | * for the previously suspended scsi device. Called from interrupt or | |
2467 | * normal process context. | |
2468 | * | |
2469 | * Returns zero if successful or error if not. | |
2470 | * | |
2471 | * Notes: | |
2472 | * This routine transitions the device to the SDEV_RUNNING state | |
5d9fb5cc | 2473 | * or to one of the offline states (which must be a legal transition) |
d075498c | 2474 | * allowing the midlayer to goose the queue for this device. |
eb44820c | 2475 | */ |
1da177e4 | 2476 | int |
5d9fb5cc MC |
2477 | scsi_internal_device_unblock(struct scsi_device *sdev, |
2478 | enum scsi_device_state new_state) | |
1da177e4 | 2479 | { |
165125e1 | 2480 | struct request_queue *q = sdev->request_queue; |
1da177e4 | 2481 | unsigned long flags; |
5d9fb5cc MC |
2482 | |
2483 | /* | |
2484 | * Try to transition the scsi device to SDEV_RUNNING or one of the | |
2485 | * offlined states and goose the device queue if successful. | |
1da177e4 | 2486 | */ |
0e58076b VC |
2487 | if ((sdev->sdev_state == SDEV_BLOCK) || |
2488 | (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE)) | |
5d9fb5cc MC |
2489 | sdev->sdev_state = new_state; |
2490 | else if (sdev->sdev_state == SDEV_CREATED_BLOCK) { | |
2491 | if (new_state == SDEV_TRANSPORT_OFFLINE || | |
2492 | new_state == SDEV_OFFLINE) | |
2493 | sdev->sdev_state = new_state; | |
2494 | else | |
2495 | sdev->sdev_state = SDEV_CREATED; | |
2496 | } else if (sdev->sdev_state != SDEV_CANCEL && | |
986fe6c7 | 2497 | sdev->sdev_state != SDEV_OFFLINE) |
5c10e63c | 2498 | return -EINVAL; |
1da177e4 LT |
2499 | |
2500 | spin_lock_irqsave(q->queue_lock, flags); | |
2501 | blk_start_queue(q); | |
2502 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2503 | ||
2504 | return 0; | |
2505 | } | |
2506 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2507 | ||
2508 | static void | |
2509 | device_block(struct scsi_device *sdev, void *data) | |
2510 | { | |
2511 | scsi_internal_device_block(sdev); | |
2512 | } | |
2513 | ||
2514 | static int | |
2515 | target_block(struct device *dev, void *data) | |
2516 | { | |
2517 | if (scsi_is_target_device(dev)) | |
2518 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2519 | device_block); | |
2520 | return 0; | |
2521 | } | |
2522 | ||
2523 | void | |
2524 | scsi_target_block(struct device *dev) | |
2525 | { | |
2526 | if (scsi_is_target_device(dev)) | |
2527 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2528 | device_block); | |
2529 | else | |
2530 | device_for_each_child(dev, NULL, target_block); | |
2531 | } | |
2532 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2533 | ||
2534 | static void | |
2535 | device_unblock(struct scsi_device *sdev, void *data) | |
2536 | { | |
5d9fb5cc | 2537 | scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); |
1da177e4 LT |
2538 | } |
2539 | ||
2540 | static int | |
2541 | target_unblock(struct device *dev, void *data) | |
2542 | { | |
2543 | if (scsi_is_target_device(dev)) | |
5d9fb5cc | 2544 | starget_for_each_device(to_scsi_target(dev), data, |
1da177e4 LT |
2545 | device_unblock); |
2546 | return 0; | |
2547 | } | |
2548 | ||
2549 | void | |
5d9fb5cc | 2550 | scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) |
1da177e4 LT |
2551 | { |
2552 | if (scsi_is_target_device(dev)) | |
5d9fb5cc | 2553 | starget_for_each_device(to_scsi_target(dev), &new_state, |
1da177e4 LT |
2554 | device_unblock); |
2555 | else | |
5d9fb5cc | 2556 | device_for_each_child(dev, &new_state, target_unblock); |
1da177e4 LT |
2557 | } |
2558 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
cdb8c2a6 GL |
2559 | |
2560 | /** | |
2561 | * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt | |
eb44820c | 2562 | * @sgl: scatter-gather list |
cdb8c2a6 GL |
2563 | * @sg_count: number of segments in sg |
2564 | * @offset: offset in bytes into sg, on return offset into the mapped area | |
2565 | * @len: bytes to map, on return number of bytes mapped | |
2566 | * | |
2567 | * Returns virtual address of the start of the mapped page | |
2568 | */ | |
c6132da1 | 2569 | void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, |
cdb8c2a6 GL |
2570 | size_t *offset, size_t *len) |
2571 | { | |
2572 | int i; | |
2573 | size_t sg_len = 0, len_complete = 0; | |
c6132da1 | 2574 | struct scatterlist *sg; |
cdb8c2a6 GL |
2575 | struct page *page; |
2576 | ||
22cfefb5 AM |
2577 | WARN_ON(!irqs_disabled()); |
2578 | ||
c6132da1 | 2579 | for_each_sg(sgl, sg, sg_count, i) { |
cdb8c2a6 | 2580 | len_complete = sg_len; /* Complete sg-entries */ |
c6132da1 | 2581 | sg_len += sg->length; |
cdb8c2a6 GL |
2582 | if (sg_len > *offset) |
2583 | break; | |
2584 | } | |
2585 | ||
2586 | if (unlikely(i == sg_count)) { | |
169e1a2a AM |
2587 | printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
2588 | "elements %d\n", | |
cadbd4a5 | 2589 | __func__, sg_len, *offset, sg_count); |
cdb8c2a6 GL |
2590 | WARN_ON(1); |
2591 | return NULL; | |
2592 | } | |
2593 | ||
2594 | /* Offset starting from the beginning of first page in this sg-entry */ | |
c6132da1 | 2595 | *offset = *offset - len_complete + sg->offset; |
cdb8c2a6 GL |
2596 | |
2597 | /* Assumption: contiguous pages can be accessed as "page + i" */ | |
45711f1a | 2598 | page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); |
cdb8c2a6 GL |
2599 | *offset &= ~PAGE_MASK; |
2600 | ||
2601 | /* Bytes in this sg-entry from *offset to the end of the page */ | |
2602 | sg_len = PAGE_SIZE - *offset; | |
2603 | if (*len > sg_len) | |
2604 | *len = sg_len; | |
2605 | ||
77dfce07 | 2606 | return kmap_atomic(page); |
cdb8c2a6 GL |
2607 | } |
2608 | EXPORT_SYMBOL(scsi_kmap_atomic_sg); | |
2609 | ||
2610 | /** | |
eb44820c | 2611 | * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg |
cdb8c2a6 GL |
2612 | * @virt: virtual address to be unmapped |
2613 | */ | |
2614 | void scsi_kunmap_atomic_sg(void *virt) | |
2615 | { | |
77dfce07 | 2616 | kunmap_atomic(virt); |
cdb8c2a6 GL |
2617 | } |
2618 | EXPORT_SYMBOL(scsi_kunmap_atomic_sg); | |
6f4c827e AL |
2619 | |
2620 | void sdev_disable_disk_events(struct scsi_device *sdev) | |
2621 | { | |
2622 | atomic_inc(&sdev->disk_events_disable_depth); | |
2623 | } | |
2624 | EXPORT_SYMBOL(sdev_disable_disk_events); | |
2625 | ||
2626 | void sdev_enable_disk_events(struct scsi_device *sdev) | |
2627 | { | |
2628 | if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) | |
2629 | return; | |
2630 | atomic_dec(&sdev->disk_events_disable_depth); | |
2631 | } | |
2632 | EXPORT_SYMBOL(sdev_enable_disk_events); |