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 | |
de50ada5 HM |
71 | #ifdef CONFIG_ACPI |
72 | #include <acpi/acpi_bus.h> | |
73 | ||
74 | int scsi_register_acpi_bus_type(struct acpi_bus_type *bus) | |
75 | { | |
76 | bus->bus = &scsi_bus_type; | |
77 | return register_acpi_bus_type(bus); | |
78 | } | |
79 | EXPORT_SYMBOL_GPL(scsi_register_acpi_bus_type); | |
80 | ||
81 | void scsi_unregister_acpi_bus_type(struct acpi_bus_type *bus) | |
82 | { | |
83 | unregister_acpi_bus_type(bus); | |
84 | } | |
85 | EXPORT_SYMBOL_GPL(scsi_unregister_acpi_bus_type); | |
86 | #endif | |
87 | ||
a488e749 JA |
88 | /* |
89 | * When to reinvoke queueing after a resource shortage. It's 3 msecs to | |
90 | * not change behaviour from the previous unplug mechanism, experimentation | |
91 | * may prove this needs changing. | |
92 | */ | |
93 | #define SCSI_QUEUE_DELAY 3 | |
94 | ||
e91442b6 JB |
95 | /* |
96 | * Function: scsi_unprep_request() | |
97 | * | |
98 | * Purpose: Remove all preparation done for a request, including its | |
99 | * associated scsi_cmnd, so that it can be requeued. | |
100 | * | |
101 | * Arguments: req - request to unprepare | |
102 | * | |
103 | * Lock status: Assumed that no locks are held upon entry. | |
104 | * | |
105 | * Returns: Nothing. | |
106 | */ | |
107 | static void scsi_unprep_request(struct request *req) | |
108 | { | |
109 | struct scsi_cmnd *cmd = req->special; | |
110 | ||
28018c24 | 111 | blk_unprep_request(req); |
beb40487 | 112 | req->special = NULL; |
e91442b6 | 113 | |
e91442b6 JB |
114 | scsi_put_command(cmd); |
115 | } | |
a1bf9d1d | 116 | |
4f5299ac JB |
117 | /** |
118 | * __scsi_queue_insert - private queue insertion | |
119 | * @cmd: The SCSI command being requeued | |
120 | * @reason: The reason for the requeue | |
121 | * @unbusy: Whether the queue should be unbusied | |
1da177e4 | 122 | * |
4f5299ac JB |
123 | * This is a private queue insertion. The public interface |
124 | * scsi_queue_insert() always assumes the queue should be unbusied | |
125 | * because it's always called before the completion. This function is | |
126 | * for a requeue after completion, which should only occur in this | |
127 | * file. | |
1da177e4 | 128 | */ |
84feb166 | 129 | static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) |
1da177e4 LT |
130 | { |
131 | struct Scsi_Host *host = cmd->device->host; | |
132 | struct scsi_device *device = cmd->device; | |
f0c0a376 | 133 | struct scsi_target *starget = scsi_target(device); |
a1bf9d1d TH |
134 | struct request_queue *q = device->request_queue; |
135 | unsigned long flags; | |
1da177e4 LT |
136 | |
137 | SCSI_LOG_MLQUEUE(1, | |
138 | printk("Inserting command %p into mlqueue\n", cmd)); | |
139 | ||
140 | /* | |
d8c37e7b | 141 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
142 | * |
143 | * If the host/device isn't busy, assume that something actually | |
144 | * completed, and that we should be able to queue a command now. | |
145 | * | |
146 | * Note that the prior mid-layer assumption that any host could | |
147 | * always queue at least one command is now broken. The mid-layer | |
148 | * will implement a user specifiable stall (see | |
149 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
150 | * if a command is requeued with no other commands outstanding | |
151 | * either for the device or for the host. | |
152 | */ | |
f0c0a376 MC |
153 | switch (reason) { |
154 | case SCSI_MLQUEUE_HOST_BUSY: | |
1da177e4 | 155 | host->host_blocked = host->max_host_blocked; |
f0c0a376 MC |
156 | break; |
157 | case SCSI_MLQUEUE_DEVICE_BUSY: | |
573e5913 | 158 | case SCSI_MLQUEUE_EH_RETRY: |
1da177e4 | 159 | device->device_blocked = device->max_device_blocked; |
f0c0a376 MC |
160 | break; |
161 | case SCSI_MLQUEUE_TARGET_BUSY: | |
162 | starget->target_blocked = starget->max_target_blocked; | |
163 | break; | |
164 | } | |
1da177e4 | 165 | |
1da177e4 LT |
166 | /* |
167 | * Decrement the counters, since these commands are no longer | |
168 | * active on the host/device. | |
169 | */ | |
4f5299ac JB |
170 | if (unbusy) |
171 | scsi_device_unbusy(device); | |
1da177e4 LT |
172 | |
173 | /* | |
a1bf9d1d | 174 | * Requeue this command. It will go before all other commands |
b485462a BVA |
175 | * that are already in the queue. Schedule requeue work under |
176 | * lock such that the kblockd_schedule_work() call happens | |
177 | * before blk_cleanup_queue() finishes. | |
a488e749 | 178 | */ |
a1bf9d1d | 179 | spin_lock_irqsave(q->queue_lock, flags); |
59897dad | 180 | blk_requeue_request(q, cmd->request); |
9937a5e2 | 181 | kblockd_schedule_work(q, &device->requeue_work); |
b485462a | 182 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
183 | } |
184 | ||
4f5299ac JB |
185 | /* |
186 | * Function: scsi_queue_insert() | |
187 | * | |
188 | * Purpose: Insert a command in the midlevel queue. | |
189 | * | |
190 | * Arguments: cmd - command that we are adding to queue. | |
191 | * reason - why we are inserting command to queue. | |
192 | * | |
193 | * Lock status: Assumed that lock is not held upon entry. | |
194 | * | |
195 | * Returns: Nothing. | |
196 | * | |
197 | * Notes: We do this for one of two cases. Either the host is busy | |
198 | * and it cannot accept any more commands for the time being, | |
199 | * or the device returned QUEUE_FULL and can accept no more | |
200 | * commands. | |
201 | * Notes: This could be called either from an interrupt context or a | |
202 | * normal process context. | |
203 | */ | |
84feb166 | 204 | void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) |
4f5299ac | 205 | { |
84feb166 | 206 | __scsi_queue_insert(cmd, reason, 1); |
4f5299ac | 207 | } |
39216033 | 208 | /** |
33aa687d | 209 | * scsi_execute - insert request and wait for the result |
39216033 JB |
210 | * @sdev: scsi device |
211 | * @cmd: scsi command | |
212 | * @data_direction: data direction | |
213 | * @buffer: data buffer | |
214 | * @bufflen: len of buffer | |
215 | * @sense: optional sense buffer | |
216 | * @timeout: request timeout in seconds | |
217 | * @retries: number of times to retry request | |
33aa687d | 218 | * @flags: or into request flags; |
f4f4e47e | 219 | * @resid: optional residual length |
39216033 | 220 | * |
59c51591 | 221 | * returns the req->errors value which is the scsi_cmnd result |
ea73a9f2 | 222 | * field. |
eb44820c | 223 | */ |
33aa687d JB |
224 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
225 | int data_direction, void *buffer, unsigned bufflen, | |
f4f4e47e FT |
226 | unsigned char *sense, int timeout, int retries, int flags, |
227 | int *resid) | |
39216033 JB |
228 | { |
229 | struct request *req; | |
230 | int write = (data_direction == DMA_TO_DEVICE); | |
231 | int ret = DRIVER_ERROR << 24; | |
232 | ||
233 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
bfe159a5 JB |
234 | if (!req) |
235 | return ret; | |
39216033 JB |
236 | |
237 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
238 | buffer, bufflen, __GFP_WAIT)) | |
239 | goto out; | |
240 | ||
241 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
242 | memcpy(req->cmd, cmd, req->cmd_len); | |
243 | req->sense = sense; | |
244 | req->sense_len = 0; | |
17e01f21 | 245 | req->retries = retries; |
39216033 | 246 | req->timeout = timeout; |
4aff5e23 JA |
247 | req->cmd_type = REQ_TYPE_BLOCK_PC; |
248 | req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; | |
39216033 JB |
249 | |
250 | /* | |
251 | * head injection *required* here otherwise quiesce won't work | |
252 | */ | |
253 | blk_execute_rq(req->q, NULL, req, 1); | |
254 | ||
bdb2b8ca AS |
255 | /* |
256 | * Some devices (USB mass-storage in particular) may transfer | |
257 | * garbage data together with a residue indicating that the data | |
258 | * is invalid. Prevent the garbage from being misinterpreted | |
259 | * and prevent security leaks by zeroing out the excess data. | |
260 | */ | |
c3a4d78c TH |
261 | if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen)) |
262 | memset(buffer + (bufflen - req->resid_len), 0, req->resid_len); | |
bdb2b8ca | 263 | |
f4f4e47e | 264 | if (resid) |
c3a4d78c | 265 | *resid = req->resid_len; |
39216033 JB |
266 | ret = req->errors; |
267 | out: | |
268 | blk_put_request(req); | |
269 | ||
270 | return ret; | |
271 | } | |
33aa687d | 272 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 273 | |
ea73a9f2 JB |
274 | |
275 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
276 | int data_direction, void *buffer, unsigned bufflen, | |
f4f4e47e FT |
277 | struct scsi_sense_hdr *sshdr, int timeout, int retries, |
278 | int *resid) | |
ea73a9f2 JB |
279 | { |
280 | char *sense = NULL; | |
1ccb48bb | 281 | int result; |
282 | ||
ea73a9f2 | 283 | if (sshdr) { |
24669f75 | 284 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
285 | if (!sense) |
286 | return DRIVER_ERROR << 24; | |
ea73a9f2 | 287 | } |
1ccb48bb | 288 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
f4f4e47e | 289 | sense, timeout, retries, 0, resid); |
ea73a9f2 | 290 | if (sshdr) |
e514385b | 291 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
292 | |
293 | kfree(sense); | |
294 | return result; | |
295 | } | |
296 | EXPORT_SYMBOL(scsi_execute_req); | |
297 | ||
1da177e4 LT |
298 | /* |
299 | * Function: scsi_init_cmd_errh() | |
300 | * | |
301 | * Purpose: Initialize cmd fields related to error handling. | |
302 | * | |
303 | * Arguments: cmd - command that is ready to be queued. | |
304 | * | |
1da177e4 LT |
305 | * Notes: This function has the job of initializing a number of |
306 | * fields related to error handling. Typically this will | |
307 | * be called once for each command, as required. | |
308 | */ | |
631c228c | 309 | static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) |
1da177e4 | 310 | { |
1da177e4 | 311 | cmd->serial_number = 0; |
30b0c37b | 312 | scsi_set_resid(cmd, 0); |
b80ca4f7 | 313 | memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); |
1da177e4 | 314 | if (cmd->cmd_len == 0) |
db4742dd | 315 | cmd->cmd_len = scsi_command_size(cmd->cmnd); |
1da177e4 LT |
316 | } |
317 | ||
318 | void scsi_device_unbusy(struct scsi_device *sdev) | |
319 | { | |
320 | struct Scsi_Host *shost = sdev->host; | |
f0c0a376 | 321 | struct scsi_target *starget = scsi_target(sdev); |
1da177e4 LT |
322 | unsigned long flags; |
323 | ||
324 | spin_lock_irqsave(shost->host_lock, flags); | |
325 | shost->host_busy--; | |
f0c0a376 | 326 | starget->target_busy--; |
939647ee | 327 | if (unlikely(scsi_host_in_recovery(shost) && |
ee7863bc | 328 | (shost->host_failed || shost->host_eh_scheduled))) |
1da177e4 LT |
329 | scsi_eh_wakeup(shost); |
330 | spin_unlock(shost->host_lock); | |
152587de | 331 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 332 | sdev->device_busy--; |
152587de | 333 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
334 | } |
335 | ||
336 | /* | |
337 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
338 | * and call blk_run_queue for all the scsi_devices on the target - | |
339 | * including current_sdev first. | |
340 | * | |
341 | * Called with *no* scsi locks held. | |
342 | */ | |
343 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
344 | { | |
345 | struct Scsi_Host *shost = current_sdev->host; | |
346 | struct scsi_device *sdev, *tmp; | |
347 | struct scsi_target *starget = scsi_target(current_sdev); | |
348 | unsigned long flags; | |
349 | ||
350 | spin_lock_irqsave(shost->host_lock, flags); | |
351 | starget->starget_sdev_user = NULL; | |
352 | spin_unlock_irqrestore(shost->host_lock, flags); | |
353 | ||
354 | /* | |
355 | * Call blk_run_queue for all LUNs on the target, starting with | |
356 | * current_sdev. We race with others (to set starget_sdev_user), | |
357 | * but in most cases, we will be first. Ideally, each LU on the | |
358 | * target would get some limited time or requests on the target. | |
359 | */ | |
360 | blk_run_queue(current_sdev->request_queue); | |
361 | ||
362 | spin_lock_irqsave(shost->host_lock, flags); | |
363 | if (starget->starget_sdev_user) | |
364 | goto out; | |
365 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
366 | same_target_siblings) { | |
367 | if (sdev == current_sdev) | |
368 | continue; | |
369 | if (scsi_device_get(sdev)) | |
370 | continue; | |
371 | ||
372 | spin_unlock_irqrestore(shost->host_lock, flags); | |
373 | blk_run_queue(sdev->request_queue); | |
374 | spin_lock_irqsave(shost->host_lock, flags); | |
375 | ||
376 | scsi_device_put(sdev); | |
377 | } | |
378 | out: | |
379 | spin_unlock_irqrestore(shost->host_lock, flags); | |
380 | } | |
381 | ||
9d112517 KU |
382 | static inline int scsi_device_is_busy(struct scsi_device *sdev) |
383 | { | |
384 | if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) | |
385 | return 1; | |
386 | ||
387 | return 0; | |
388 | } | |
389 | ||
f0c0a376 MC |
390 | static inline int scsi_target_is_busy(struct scsi_target *starget) |
391 | { | |
392 | return ((starget->can_queue > 0 && | |
393 | starget->target_busy >= starget->can_queue) || | |
394 | starget->target_blocked); | |
395 | } | |
396 | ||
9d112517 KU |
397 | static inline int scsi_host_is_busy(struct Scsi_Host *shost) |
398 | { | |
399 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
400 | shost->host_blocked || shost->host_self_blocked) | |
401 | return 1; | |
402 | ||
403 | return 0; | |
404 | } | |
405 | ||
1da177e4 LT |
406 | /* |
407 | * Function: scsi_run_queue() | |
408 | * | |
409 | * Purpose: Select a proper request queue to serve next | |
410 | * | |
411 | * Arguments: q - last request's queue | |
412 | * | |
413 | * Returns: Nothing | |
414 | * | |
415 | * Notes: The previous command was completely finished, start | |
416 | * a new one if possible. | |
417 | */ | |
418 | static void scsi_run_queue(struct request_queue *q) | |
419 | { | |
2a3a59e5 | 420 | struct scsi_device *sdev = q->queuedata; |
c055f5b2 | 421 | struct Scsi_Host *shost; |
2a3a59e5 | 422 | LIST_HEAD(starved_list); |
1da177e4 LT |
423 | unsigned long flags; |
424 | ||
c055f5b2 | 425 | shost = sdev->host; |
25d7c363 | 426 | if (scsi_target(sdev)->single_lun) |
1da177e4 LT |
427 | scsi_single_lun_run(sdev); |
428 | ||
429 | spin_lock_irqsave(shost->host_lock, flags); | |
2a3a59e5 MC |
430 | list_splice_init(&shost->starved_list, &starved_list); |
431 | ||
432 | while (!list_empty(&starved_list)) { | |
1da177e4 LT |
433 | /* |
434 | * As long as shost is accepting commands and we have | |
435 | * starved queues, call blk_run_queue. scsi_request_fn | |
436 | * drops the queue_lock and can add us back to the | |
437 | * starved_list. | |
438 | * | |
439 | * host_lock protects the starved_list and starved_entry. | |
440 | * scsi_request_fn must get the host_lock before checking | |
441 | * or modifying starved_list or starved_entry. | |
442 | */ | |
2a3a59e5 | 443 | if (scsi_host_is_busy(shost)) |
f0c0a376 | 444 | break; |
f0c0a376 | 445 | |
2a3a59e5 MC |
446 | sdev = list_entry(starved_list.next, |
447 | struct scsi_device, starved_entry); | |
448 | list_del_init(&sdev->starved_entry); | |
f0c0a376 MC |
449 | if (scsi_target_is_busy(scsi_target(sdev))) { |
450 | list_move_tail(&sdev->starved_entry, | |
451 | &shost->starved_list); | |
452 | continue; | |
453 | } | |
454 | ||
9937a5e2 JA |
455 | spin_unlock(shost->host_lock); |
456 | spin_lock(sdev->request_queue->queue_lock); | |
457 | __blk_run_queue(sdev->request_queue); | |
458 | spin_unlock(sdev->request_queue->queue_lock); | |
459 | spin_lock(shost->host_lock); | |
1da177e4 | 460 | } |
2a3a59e5 MC |
461 | /* put any unprocessed entries back */ |
462 | list_splice(&starved_list, &shost->starved_list); | |
1da177e4 LT |
463 | spin_unlock_irqrestore(shost->host_lock, flags); |
464 | ||
465 | blk_run_queue(q); | |
466 | } | |
467 | ||
9937a5e2 JA |
468 | void scsi_requeue_run_queue(struct work_struct *work) |
469 | { | |
470 | struct scsi_device *sdev; | |
471 | struct request_queue *q; | |
472 | ||
473 | sdev = container_of(work, struct scsi_device, requeue_work); | |
474 | q = sdev->request_queue; | |
475 | scsi_run_queue(q); | |
476 | } | |
477 | ||
1da177e4 LT |
478 | /* |
479 | * Function: scsi_requeue_command() | |
480 | * | |
481 | * Purpose: Handle post-processing of completed commands. | |
482 | * | |
483 | * Arguments: q - queue to operate on | |
484 | * cmd - command that may need to be requeued. | |
485 | * | |
486 | * Returns: Nothing | |
487 | * | |
488 | * Notes: After command completion, there may be blocks left | |
489 | * over which weren't finished by the previous command | |
490 | * this can be for a number of reasons - the main one is | |
491 | * I/O errors in the middle of the request, in which case | |
492 | * we need to request the blocks that come after the bad | |
493 | * sector. | |
e91442b6 | 494 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
495 | */ |
496 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
497 | { | |
940f5d47 | 498 | struct scsi_device *sdev = cmd->device; |
e91442b6 | 499 | struct request *req = cmd->request; |
283369cc TH |
500 | unsigned long flags; |
501 | ||
940f5d47 BVA |
502 | /* |
503 | * We need to hold a reference on the device to avoid the queue being | |
504 | * killed after the unlock and before scsi_run_queue is invoked which | |
505 | * may happen because scsi_unprep_request() puts the command which | |
506 | * releases its reference on the device. | |
507 | */ | |
508 | get_device(&sdev->sdev_gendev); | |
509 | ||
283369cc | 510 | spin_lock_irqsave(q->queue_lock, flags); |
02bd3499 | 511 | scsi_unprep_request(req); |
e91442b6 | 512 | blk_requeue_request(q, req); |
283369cc | 513 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
514 | |
515 | scsi_run_queue(q); | |
940f5d47 BVA |
516 | |
517 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
518 | } |
519 | ||
520 | void scsi_next_command(struct scsi_cmnd *cmd) | |
521 | { | |
49d7bc64 LT |
522 | struct scsi_device *sdev = cmd->device; |
523 | struct request_queue *q = sdev->request_queue; | |
524 | ||
525 | /* need to hold a reference on the device before we let go of the cmd */ | |
526 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
527 | |
528 | scsi_put_command(cmd); | |
529 | scsi_run_queue(q); | |
49d7bc64 LT |
530 | |
531 | /* ok to remove device now */ | |
532 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
533 | } |
534 | ||
535 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
536 | { | |
537 | struct scsi_device *sdev; | |
538 | ||
539 | shost_for_each_device(sdev, shost) | |
540 | scsi_run_queue(sdev->request_queue); | |
541 | } | |
542 | ||
79ed2429 JB |
543 | static void __scsi_release_buffers(struct scsi_cmnd *, int); |
544 | ||
1da177e4 LT |
545 | /* |
546 | * Function: scsi_end_request() | |
547 | * | |
548 | * Purpose: Post-processing of completed commands (usually invoked at end | |
549 | * of upper level post-processing and scsi_io_completion). | |
550 | * | |
551 | * Arguments: cmd - command that is complete. | |
610d8b0c | 552 | * error - 0 if I/O indicates success, < 0 for I/O error. |
1da177e4 LT |
553 | * bytes - number of bytes of completed I/O |
554 | * requeue - indicates whether we should requeue leftovers. | |
555 | * | |
556 | * Lock status: Assumed that lock is not held upon entry. | |
557 | * | |
e91442b6 | 558 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
559 | * |
560 | * Notes: This is called for block device requests in order to | |
561 | * mark some number of sectors as complete. | |
562 | * | |
563 | * We are guaranteeing that the request queue will be goosed | |
564 | * at some point during this call. | |
e91442b6 | 565 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 | 566 | */ |
610d8b0c | 567 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, |
1da177e4 LT |
568 | int bytes, int requeue) |
569 | { | |
165125e1 | 570 | struct request_queue *q = cmd->device->request_queue; |
1da177e4 | 571 | struct request *req = cmd->request; |
1da177e4 LT |
572 | |
573 | /* | |
574 | * If there are blocks left over at the end, set up the command | |
575 | * to queue the remainder of them. | |
576 | */ | |
610d8b0c | 577 | if (blk_end_request(req, error, bytes)) { |
1da177e4 | 578 | /* kill remainder if no retrys */ |
4a27446f | 579 | if (error && scsi_noretry_cmd(cmd)) |
e458824f | 580 | blk_end_request_all(req, error); |
1da177e4 | 581 | else { |
e91442b6 | 582 | if (requeue) { |
1da177e4 LT |
583 | /* |
584 | * Bleah. Leftovers again. Stick the | |
585 | * leftovers in the front of the | |
586 | * queue, and goose the queue again. | |
587 | */ | |
79ed2429 | 588 | scsi_release_buffers(cmd); |
1da177e4 | 589 | scsi_requeue_command(q, cmd); |
e91442b6 JB |
590 | cmd = NULL; |
591 | } | |
1da177e4 LT |
592 | return cmd; |
593 | } | |
594 | } | |
595 | ||
1da177e4 LT |
596 | /* |
597 | * This will goose the queue request function at the end, so we don't | |
598 | * need to worry about launching another command. | |
599 | */ | |
79ed2429 | 600 | __scsi_release_buffers(cmd, 0); |
1da177e4 LT |
601 | scsi_next_command(cmd); |
602 | return NULL; | |
603 | } | |
604 | ||
a8474ce2 JA |
605 | static inline unsigned int scsi_sgtable_index(unsigned short nents) |
606 | { | |
607 | unsigned int index; | |
608 | ||
d3f46f39 JB |
609 | BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); |
610 | ||
611 | if (nents <= 8) | |
a8474ce2 | 612 | index = 0; |
d3f46f39 JB |
613 | else |
614 | index = get_count_order(nents) - 3; | |
1da177e4 | 615 | |
a8474ce2 JA |
616 | return index; |
617 | } | |
618 | ||
5ed7959e | 619 | static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) |
a8474ce2 JA |
620 | { |
621 | struct scsi_host_sg_pool *sgp; | |
a8474ce2 | 622 | |
5ed7959e JA |
623 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
624 | mempool_free(sgl, sgp->pool); | |
625 | } | |
a8474ce2 | 626 | |
5ed7959e JA |
627 | static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) |
628 | { | |
629 | struct scsi_host_sg_pool *sgp; | |
a8474ce2 | 630 | |
5ed7959e JA |
631 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
632 | return mempool_alloc(sgp->pool, gfp_mask); | |
633 | } | |
a3bec5c5 | 634 | |
30b0c37b BH |
635 | static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, |
636 | gfp_t gfp_mask) | |
5ed7959e JA |
637 | { |
638 | int ret; | |
a8474ce2 | 639 | |
30b0c37b | 640 | BUG_ON(!nents); |
a8474ce2 | 641 | |
30b0c37b BH |
642 | ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, |
643 | gfp_mask, scsi_sg_alloc); | |
5ed7959e | 644 | if (unlikely(ret)) |
30b0c37b | 645 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, |
7cedb1f1 | 646 | scsi_sg_free); |
45711f1a | 647 | |
a8474ce2 | 648 | return ret; |
1da177e4 LT |
649 | } |
650 | ||
30b0c37b | 651 | static void scsi_free_sgtable(struct scsi_data_buffer *sdb) |
1da177e4 | 652 | { |
30b0c37b | 653 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); |
1da177e4 LT |
654 | } |
655 | ||
79ed2429 JB |
656 | static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) |
657 | { | |
658 | ||
659 | if (cmd->sdb.table.nents) | |
660 | scsi_free_sgtable(&cmd->sdb); | |
661 | ||
662 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); | |
663 | ||
664 | if (do_bidi_check && scsi_bidi_cmnd(cmd)) { | |
665 | struct scsi_data_buffer *bidi_sdb = | |
666 | cmd->request->next_rq->special; | |
667 | scsi_free_sgtable(bidi_sdb); | |
668 | kmem_cache_free(scsi_sdb_cache, bidi_sdb); | |
669 | cmd->request->next_rq->special = NULL; | |
670 | } | |
671 | ||
672 | if (scsi_prot_sg_count(cmd)) | |
673 | scsi_free_sgtable(cmd->prot_sdb); | |
674 | } | |
675 | ||
1da177e4 LT |
676 | /* |
677 | * Function: scsi_release_buffers() | |
678 | * | |
679 | * Purpose: Completion processing for block device I/O requests. | |
680 | * | |
681 | * Arguments: cmd - command that we are bailing. | |
682 | * | |
683 | * Lock status: Assumed that no lock is held upon entry. | |
684 | * | |
685 | * Returns: Nothing | |
686 | * | |
687 | * Notes: In the event that an upper level driver rejects a | |
688 | * command, we must release resources allocated during | |
689 | * the __init_io() function. Primarily this would involve | |
690 | * the scatter-gather table, and potentially any bounce | |
691 | * buffers. | |
692 | */ | |
bb52d82f | 693 | void scsi_release_buffers(struct scsi_cmnd *cmd) |
1da177e4 | 694 | { |
79ed2429 | 695 | __scsi_release_buffers(cmd, 1); |
1da177e4 | 696 | } |
bb52d82f | 697 | EXPORT_SYMBOL(scsi_release_buffers); |
1da177e4 | 698 | |
63583cca HR |
699 | static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result) |
700 | { | |
701 | int error = 0; | |
702 | ||
703 | switch(host_byte(result)) { | |
704 | case DID_TRANSPORT_FAILFAST: | |
705 | error = -ENOLINK; | |
706 | break; | |
707 | case DID_TARGET_FAILURE: | |
2082ebc4 | 708 | set_host_byte(cmd, DID_OK); |
63583cca HR |
709 | error = -EREMOTEIO; |
710 | break; | |
711 | case DID_NEXUS_FAILURE: | |
2082ebc4 | 712 | set_host_byte(cmd, DID_OK); |
63583cca HR |
713 | error = -EBADE; |
714 | break; | |
715 | default: | |
716 | error = -EIO; | |
717 | break; | |
718 | } | |
719 | ||
720 | return error; | |
721 | } | |
722 | ||
1da177e4 LT |
723 | /* |
724 | * Function: scsi_io_completion() | |
725 | * | |
726 | * Purpose: Completion processing for block device I/O requests. | |
727 | * | |
728 | * Arguments: cmd - command that is finished. | |
729 | * | |
730 | * Lock status: Assumed that no lock is held upon entry. | |
731 | * | |
732 | * Returns: Nothing | |
733 | * | |
734 | * Notes: This function is matched in terms of capabilities to | |
735 | * the function that created the scatter-gather list. | |
736 | * In other words, if there are no bounce buffers | |
737 | * (the normal case for most drivers), we don't need | |
738 | * the logic to deal with cleaning up afterwards. | |
739 | * | |
b60af5b0 AS |
740 | * We must call scsi_end_request(). This will finish off |
741 | * the specified number of sectors. If we are done, the | |
742 | * command block will be released and the queue function | |
743 | * will be goosed. If we are not done then we have to | |
744 | * figure out what to do next: | |
1da177e4 | 745 | * |
b60af5b0 AS |
746 | * a) We can call scsi_requeue_command(). The request |
747 | * will be unprepared and put back on the queue. Then | |
748 | * a new command will be created for it. This should | |
749 | * be used if we made forward progress, or if we want | |
750 | * to switch from READ(10) to READ(6) for example. | |
1da177e4 | 751 | * |
b60af5b0 AS |
752 | * b) We can call scsi_queue_insert(). The request will |
753 | * be put back on the queue and retried using the same | |
754 | * command as before, possibly after a delay. | |
755 | * | |
756 | * c) We can call blk_end_request() with -EIO to fail | |
757 | * the remainder of the request. | |
1da177e4 | 758 | */ |
03aba2f7 | 759 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
1da177e4 LT |
760 | { |
761 | int result = cmd->result; | |
165125e1 | 762 | struct request_queue *q = cmd->device->request_queue; |
1da177e4 | 763 | struct request *req = cmd->request; |
fa8e36c3 | 764 | int error = 0; |
1da177e4 LT |
765 | struct scsi_sense_hdr sshdr; |
766 | int sense_valid = 0; | |
767 | int sense_deferred = 0; | |
b60af5b0 AS |
768 | enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, |
769 | ACTION_DELAYED_RETRY} action; | |
770 | char *description = NULL; | |
1da177e4 | 771 | |
1da177e4 LT |
772 | if (result) { |
773 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
774 | if (sense_valid) | |
775 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
776 | } | |
631c228c | 777 | |
33659ebb | 778 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */ |
1da177e4 LT |
779 | req->errors = result; |
780 | if (result) { | |
1da177e4 LT |
781 | if (sense_valid && req->sense) { |
782 | /* | |
783 | * SG_IO wants current and deferred errors | |
784 | */ | |
785 | int len = 8 + cmd->sense_buffer[7]; | |
786 | ||
787 | if (len > SCSI_SENSE_BUFFERSIZE) | |
788 | len = SCSI_SENSE_BUFFERSIZE; | |
789 | memcpy(req->sense, cmd->sense_buffer, len); | |
790 | req->sense_len = len; | |
791 | } | |
fa8e36c3 | 792 | if (!sense_deferred) |
63583cca | 793 | error = __scsi_error_from_host_byte(cmd, result); |
b22f687d | 794 | } |
e6bb7a96 FT |
795 | |
796 | req->resid_len = scsi_get_resid(cmd); | |
797 | ||
6f9a35e2 | 798 | if (scsi_bidi_cmnd(cmd)) { |
e6bb7a96 FT |
799 | /* |
800 | * Bidi commands Must be complete as a whole, | |
801 | * both sides at once. | |
802 | */ | |
803 | req->next_rq->resid_len = scsi_in(cmd)->resid; | |
804 | ||
63c43b0e | 805 | scsi_release_buffers(cmd); |
e6bb7a96 FT |
806 | blk_end_request_all(req, 0); |
807 | ||
e6bb7a96 | 808 | scsi_next_command(cmd); |
6f9a35e2 BH |
809 | return; |
810 | } | |
1da177e4 LT |
811 | } |
812 | ||
33659ebb CH |
813 | /* no bidi support for !REQ_TYPE_BLOCK_PC yet */ |
814 | BUG_ON(blk_bidi_rq(req)); | |
30b0c37b | 815 | |
1da177e4 LT |
816 | /* |
817 | * Next deal with any sectors which we were able to correctly | |
818 | * handle. | |
819 | */ | |
83096ebf | 820 | SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, " |
d6b0c537 | 821 | "%d bytes done.\n", |
83096ebf | 822 | blk_rq_sectors(req), good_bytes)); |
d6b0c537 | 823 | |
a9bddd74 JB |
824 | /* |
825 | * Recovered errors need reporting, but they're always treated | |
826 | * as success, so fiddle the result code here. For BLOCK_PC | |
827 | * we already took a copy of the original into rq->errors which | |
828 | * is what gets returned to the user | |
829 | */ | |
e7efe593 DG |
830 | if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { |
831 | /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip | |
832 | * print since caller wants ATA registers. Only occurs on | |
833 | * SCSI ATA PASS_THROUGH commands when CK_COND=1 | |
834 | */ | |
835 | if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) | |
836 | ; | |
837 | else if (!(req->cmd_flags & REQ_QUIET)) | |
a9bddd74 JB |
838 | scsi_print_sense("", cmd); |
839 | result = 0; | |
840 | /* BLOCK_PC may have set error */ | |
841 | error = 0; | |
842 | } | |
843 | ||
844 | /* | |
845 | * A number of bytes were successfully read. If there | |
d6b0c537 JB |
846 | * are leftovers and there is some kind of error |
847 | * (result != 0), retry the rest. | |
848 | */ | |
fa8e36c3 | 849 | if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) |
d6b0c537 | 850 | return; |
03aba2f7 | 851 | |
63583cca | 852 | error = __scsi_error_from_host_byte(cmd, result); |
3e695f89 | 853 | |
b60af5b0 AS |
854 | if (host_byte(result) == DID_RESET) { |
855 | /* Third party bus reset or reset for error recovery | |
856 | * reasons. Just retry the command and see what | |
857 | * happens. | |
858 | */ | |
859 | action = ACTION_RETRY; | |
860 | } else if (sense_valid && !sense_deferred) { | |
1da177e4 LT |
861 | switch (sshdr.sense_key) { |
862 | case UNIT_ATTENTION: | |
863 | if (cmd->device->removable) { | |
03aba2f7 | 864 | /* Detected disc change. Set a bit |
1da177e4 LT |
865 | * and quietly refuse further access. |
866 | */ | |
867 | cmd->device->changed = 1; | |
b60af5b0 AS |
868 | description = "Media Changed"; |
869 | action = ACTION_FAIL; | |
1da177e4 | 870 | } else { |
03aba2f7 LT |
871 | /* Must have been a power glitch, or a |
872 | * bus reset. Could not have been a | |
873 | * media change, so we just retry the | |
b60af5b0 | 874 | * command and see what happens. |
03aba2f7 | 875 | */ |
b60af5b0 | 876 | action = ACTION_RETRY; |
1da177e4 LT |
877 | } |
878 | break; | |
879 | case ILLEGAL_REQUEST: | |
03aba2f7 LT |
880 | /* If we had an ILLEGAL REQUEST returned, then |
881 | * we may have performed an unsupported | |
882 | * command. The only thing this should be | |
883 | * would be a ten byte read where only a six | |
884 | * byte read was supported. Also, on a system | |
885 | * where READ CAPACITY failed, we may have | |
886 | * read past the end of the disk. | |
887 | */ | |
26a68019 JA |
888 | if ((cmd->device->use_10_for_rw && |
889 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
890 | (cmd->cmnd[0] == READ_10 || |
891 | cmd->cmnd[0] == WRITE_10)) { | |
b60af5b0 | 892 | /* This will issue a new 6-byte command. */ |
1da177e4 | 893 | cmd->device->use_10_for_rw = 0; |
b60af5b0 | 894 | action = ACTION_REPREP; |
3e695f89 MP |
895 | } else if (sshdr.asc == 0x10) /* DIX */ { |
896 | description = "Host Data Integrity Failure"; | |
897 | action = ACTION_FAIL; | |
898 | error = -EILSEQ; | |
c98a0eb0 MP |
899 | /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ |
900 | } else if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) && | |
901 | (cmd->cmnd[0] == UNMAP || | |
902 | cmd->cmnd[0] == WRITE_SAME_16 || | |
903 | cmd->cmnd[0] == WRITE_SAME)) { | |
904 | description = "Discard failure"; | |
905 | action = ACTION_FAIL; | |
66a651aa | 906 | error = -EREMOTEIO; |
b60af5b0 AS |
907 | } else |
908 | action = ACTION_FAIL; | |
909 | break; | |
511e44f4 | 910 | case ABORTED_COMMAND: |
126c0982 | 911 | action = ACTION_FAIL; |
511e44f4 | 912 | if (sshdr.asc == 0x10) { /* DIF */ |
3e695f89 | 913 | description = "Target Data Integrity Failure"; |
3e695f89 | 914 | error = -EILSEQ; |
126c0982 | 915 | } |
1da177e4 LT |
916 | break; |
917 | case NOT_READY: | |
03aba2f7 | 918 | /* If the device is in the process of becoming |
f3e93f73 | 919 | * ready, or has a temporary blockage, retry. |
1da177e4 | 920 | */ |
f3e93f73 JB |
921 | if (sshdr.asc == 0x04) { |
922 | switch (sshdr.ascq) { | |
923 | case 0x01: /* becoming ready */ | |
924 | case 0x04: /* format in progress */ | |
925 | case 0x05: /* rebuild in progress */ | |
926 | case 0x06: /* recalculation in progress */ | |
927 | case 0x07: /* operation in progress */ | |
928 | case 0x08: /* Long write in progress */ | |
929 | case 0x09: /* self test in progress */ | |
d8705f11 | 930 | case 0x14: /* space allocation in progress */ |
b60af5b0 | 931 | action = ACTION_DELAYED_RETRY; |
f3e93f73 | 932 | break; |
3dbf6a54 AS |
933 | default: |
934 | description = "Device not ready"; | |
935 | action = ACTION_FAIL; | |
936 | break; | |
f3e93f73 | 937 | } |
b60af5b0 AS |
938 | } else { |
939 | description = "Device not ready"; | |
940 | action = ACTION_FAIL; | |
1da177e4 | 941 | } |
b60af5b0 | 942 | break; |
1da177e4 | 943 | case VOLUME_OVERFLOW: |
03aba2f7 | 944 | /* See SSC3rXX or current. */ |
b60af5b0 AS |
945 | action = ACTION_FAIL; |
946 | break; | |
1da177e4 | 947 | default: |
b60af5b0 AS |
948 | description = "Unhandled sense code"; |
949 | action = ACTION_FAIL; | |
1da177e4 LT |
950 | break; |
951 | } | |
b60af5b0 AS |
952 | } else { |
953 | description = "Unhandled error code"; | |
954 | action = ACTION_FAIL; | |
03aba2f7 | 955 | } |
b60af5b0 AS |
956 | |
957 | switch (action) { | |
958 | case ACTION_FAIL: | |
959 | /* Give up and fail the remainder of the request */ | |
79ed2429 | 960 | scsi_release_buffers(cmd); |
4aff5e23 | 961 | if (!(req->cmd_flags & REQ_QUIET)) { |
b60af5b0 | 962 | if (description) |
3dbf6a54 | 963 | scmd_printk(KERN_INFO, cmd, "%s\n", |
b60af5b0 | 964 | description); |
a4d04a4c | 965 | scsi_print_result(cmd); |
3173d8c3 JB |
966 | if (driver_byte(result) & DRIVER_SENSE) |
967 | scsi_print_sense("", cmd); | |
002b1eb2 | 968 | scsi_print_command(cmd); |
3173d8c3 | 969 | } |
ad630826 | 970 | if (blk_end_request_err(req, error)) |
da6c5c72 TH |
971 | scsi_requeue_command(q, cmd); |
972 | else | |
973 | scsi_next_command(cmd); | |
b60af5b0 AS |
974 | break; |
975 | case ACTION_REPREP: | |
976 | /* Unprep the request and put it back at the head of the queue. | |
977 | * A new command will be prepared and issued. | |
978 | */ | |
79ed2429 | 979 | scsi_release_buffers(cmd); |
b60af5b0 AS |
980 | scsi_requeue_command(q, cmd); |
981 | break; | |
982 | case ACTION_RETRY: | |
983 | /* Retry the same command immediately */ | |
4f5299ac | 984 | __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); |
b60af5b0 AS |
985 | break; |
986 | case ACTION_DELAYED_RETRY: | |
987 | /* Retry the same command after a delay */ | |
4f5299ac | 988 | __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); |
b60af5b0 | 989 | break; |
1da177e4 LT |
990 | } |
991 | } | |
1da177e4 | 992 | |
6f9a35e2 BH |
993 | static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, |
994 | gfp_t gfp_mask) | |
1da177e4 | 995 | { |
6f9a35e2 | 996 | int count; |
1da177e4 LT |
997 | |
998 | /* | |
3b003157 | 999 | * If sg table allocation fails, requeue request later. |
1da177e4 | 1000 | */ |
30b0c37b BH |
1001 | if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, |
1002 | gfp_mask))) { | |
1da177e4 | 1003 | return BLKPREP_DEFER; |
7c72ce81 | 1004 | } |
1da177e4 | 1005 | |
3b003157 | 1006 | req->buffer = NULL; |
1da177e4 LT |
1007 | |
1008 | /* | |
1009 | * Next, walk the list, and fill in the addresses and sizes of | |
1010 | * each segment. | |
1011 | */ | |
30b0c37b BH |
1012 | count = blk_rq_map_sg(req->q, req, sdb->table.sgl); |
1013 | BUG_ON(count > sdb->table.nents); | |
1014 | sdb->table.nents = count; | |
1011c1b9 | 1015 | sdb->length = blk_rq_bytes(req); |
4a03d90e | 1016 | return BLKPREP_OK; |
1da177e4 | 1017 | } |
6f9a35e2 BH |
1018 | |
1019 | /* | |
1020 | * Function: scsi_init_io() | |
1021 | * | |
1022 | * Purpose: SCSI I/O initialize function. | |
1023 | * | |
1024 | * Arguments: cmd - Command descriptor we wish to initialize | |
1025 | * | |
1026 | * Returns: 0 on success | |
1027 | * BLKPREP_DEFER if the failure is retryable | |
1028 | * BLKPREP_KILL if the failure is fatal | |
1029 | */ | |
1030 | int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) | |
1031 | { | |
13f05c8d MP |
1032 | struct request *rq = cmd->request; |
1033 | ||
1034 | int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask); | |
6f9a35e2 BH |
1035 | if (error) |
1036 | goto err_exit; | |
1037 | ||
13f05c8d | 1038 | if (blk_bidi_rq(rq)) { |
6f9a35e2 | 1039 | struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( |
6362abd3 | 1040 | scsi_sdb_cache, GFP_ATOMIC); |
6f9a35e2 BH |
1041 | if (!bidi_sdb) { |
1042 | error = BLKPREP_DEFER; | |
1043 | goto err_exit; | |
1044 | } | |
1045 | ||
13f05c8d MP |
1046 | rq->next_rq->special = bidi_sdb; |
1047 | error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC); | |
6f9a35e2 BH |
1048 | if (error) |
1049 | goto err_exit; | |
1050 | } | |
1051 | ||
13f05c8d | 1052 | if (blk_integrity_rq(rq)) { |
7027ad72 MP |
1053 | struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; |
1054 | int ivecs, count; | |
1055 | ||
1056 | BUG_ON(prot_sdb == NULL); | |
13f05c8d | 1057 | ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); |
7027ad72 MP |
1058 | |
1059 | if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { | |
1060 | error = BLKPREP_DEFER; | |
1061 | goto err_exit; | |
1062 | } | |
1063 | ||
13f05c8d | 1064 | count = blk_rq_map_integrity_sg(rq->q, rq->bio, |
7027ad72 MP |
1065 | prot_sdb->table.sgl); |
1066 | BUG_ON(unlikely(count > ivecs)); | |
13f05c8d | 1067 | BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q))); |
7027ad72 MP |
1068 | |
1069 | cmd->prot_sdb = prot_sdb; | |
1070 | cmd->prot_sdb->table.nents = count; | |
1071 | } | |
1072 | ||
6f9a35e2 BH |
1073 | return BLKPREP_OK ; |
1074 | ||
1075 | err_exit: | |
1076 | scsi_release_buffers(cmd); | |
610a6349 | 1077 | cmd->request->special = NULL; |
3a5c19c2 | 1078 | scsi_put_command(cmd); |
6f9a35e2 BH |
1079 | return error; |
1080 | } | |
bb52d82f | 1081 | EXPORT_SYMBOL(scsi_init_io); |
1da177e4 | 1082 | |
3b003157 CH |
1083 | static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, |
1084 | struct request *req) | |
1085 | { | |
1086 | struct scsi_cmnd *cmd; | |
1087 | ||
1088 | if (!req->special) { | |
1089 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1090 | if (unlikely(!cmd)) | |
1091 | return NULL; | |
1092 | req->special = cmd; | |
1093 | } else { | |
1094 | cmd = req->special; | |
1095 | } | |
1096 | ||
1097 | /* pull a tag out of the request if we have one */ | |
1098 | cmd->tag = req->tag; | |
1099 | cmd->request = req; | |
1100 | ||
64a87b24 | 1101 | cmd->cmnd = req->cmd; |
72f7d322 | 1102 | cmd->prot_op = SCSI_PROT_NORMAL; |
64a87b24 | 1103 | |
3b003157 CH |
1104 | return cmd; |
1105 | } | |
1106 | ||
7f9a6bc4 | 1107 | int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) |
7b16318d | 1108 | { |
3b003157 | 1109 | struct scsi_cmnd *cmd; |
7f9a6bc4 JB |
1110 | int ret = scsi_prep_state_check(sdev, req); |
1111 | ||
1112 | if (ret != BLKPREP_OK) | |
1113 | return ret; | |
3b003157 CH |
1114 | |
1115 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1116 | if (unlikely(!cmd)) | |
1117 | return BLKPREP_DEFER; | |
1118 | ||
1119 | /* | |
1120 | * BLOCK_PC requests may transfer data, in which case they must | |
1121 | * a bio attached to them. Or they might contain a SCSI command | |
1122 | * that does not transfer data, in which case they may optionally | |
1123 | * submit a request without an attached bio. | |
1124 | */ | |
1125 | if (req->bio) { | |
1126 | int ret; | |
1127 | ||
1128 | BUG_ON(!req->nr_phys_segments); | |
1129 | ||
bb52d82f | 1130 | ret = scsi_init_io(cmd, GFP_ATOMIC); |
3b003157 CH |
1131 | if (unlikely(ret)) |
1132 | return ret; | |
1133 | } else { | |
b0790410 | 1134 | BUG_ON(blk_rq_bytes(req)); |
3b003157 | 1135 | |
30b0c37b | 1136 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
3b003157 CH |
1137 | req->buffer = NULL; |
1138 | } | |
7b16318d | 1139 | |
7b16318d | 1140 | cmd->cmd_len = req->cmd_len; |
b0790410 | 1141 | if (!blk_rq_bytes(req)) |
7b16318d JB |
1142 | cmd->sc_data_direction = DMA_NONE; |
1143 | else if (rq_data_dir(req) == WRITE) | |
1144 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1145 | else | |
1146 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1147 | ||
b0790410 | 1148 | cmd->transfersize = blk_rq_bytes(req); |
7b16318d | 1149 | cmd->allowed = req->retries; |
3b003157 | 1150 | return BLKPREP_OK; |
7b16318d | 1151 | } |
7f9a6bc4 | 1152 | EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); |
7b16318d | 1153 | |
3b003157 CH |
1154 | /* |
1155 | * Setup a REQ_TYPE_FS command. These are simple read/write request | |
1156 | * from filesystems that still need to be translated to SCSI CDBs from | |
1157 | * the ULD. | |
1158 | */ | |
7f9a6bc4 | 1159 | int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) |
1da177e4 | 1160 | { |
1da177e4 | 1161 | struct scsi_cmnd *cmd; |
7f9a6bc4 | 1162 | int ret = scsi_prep_state_check(sdev, req); |
1da177e4 | 1163 | |
7f9a6bc4 JB |
1164 | if (ret != BLKPREP_OK) |
1165 | return ret; | |
a6a8d9f8 CS |
1166 | |
1167 | if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh | |
1168 | && sdev->scsi_dh_data->scsi_dh->prep_fn)) { | |
1169 | ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); | |
1170 | if (ret != BLKPREP_OK) | |
1171 | return ret; | |
1172 | } | |
1173 | ||
1da177e4 | 1174 | /* |
3b003157 | 1175 | * Filesystem requests must transfer data. |
1da177e4 | 1176 | */ |
3b003157 CH |
1177 | BUG_ON(!req->nr_phys_segments); |
1178 | ||
1179 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1180 | if (unlikely(!cmd)) | |
1181 | return BLKPREP_DEFER; | |
1182 | ||
64a87b24 | 1183 | memset(cmd->cmnd, 0, BLK_MAX_CDB); |
bb52d82f | 1184 | return scsi_init_io(cmd, GFP_ATOMIC); |
3b003157 | 1185 | } |
7f9a6bc4 | 1186 | EXPORT_SYMBOL(scsi_setup_fs_cmnd); |
3b003157 | 1187 | |
7f9a6bc4 | 1188 | int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) |
3b003157 | 1189 | { |
3b003157 CH |
1190 | int ret = BLKPREP_OK; |
1191 | ||
1da177e4 | 1192 | /* |
3b003157 CH |
1193 | * If the device is not in running state we will reject some |
1194 | * or all commands. | |
1da177e4 | 1195 | */ |
3b003157 CH |
1196 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { |
1197 | switch (sdev->sdev_state) { | |
1198 | case SDEV_OFFLINE: | |
1b8d2620 | 1199 | case SDEV_TRANSPORT_OFFLINE: |
3b003157 CH |
1200 | /* |
1201 | * If the device is offline we refuse to process any | |
1202 | * commands. The device must be brought online | |
1203 | * before trying any recovery commands. | |
1204 | */ | |
1205 | sdev_printk(KERN_ERR, sdev, | |
1206 | "rejecting I/O to offline device\n"); | |
1207 | ret = BLKPREP_KILL; | |
1208 | break; | |
1209 | case SDEV_DEL: | |
1210 | /* | |
1211 | * If the device is fully deleted, we refuse to | |
1212 | * process any commands as well. | |
1213 | */ | |
9ccfc756 | 1214 | sdev_printk(KERN_ERR, sdev, |
3b003157 CH |
1215 | "rejecting I/O to dead device\n"); |
1216 | ret = BLKPREP_KILL; | |
1217 | break; | |
1218 | case SDEV_QUIESCE: | |
1219 | case SDEV_BLOCK: | |
6f4267e3 | 1220 | case SDEV_CREATED_BLOCK: |
3b003157 CH |
1221 | /* |
1222 | * If the devices is blocked we defer normal commands. | |
1223 | */ | |
1224 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1225 | ret = BLKPREP_DEFER; | |
1226 | break; | |
1227 | default: | |
1228 | /* | |
1229 | * For any other not fully online state we only allow | |
1230 | * special commands. In particular any user initiated | |
1231 | * command is not allowed. | |
1232 | */ | |
1233 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1234 | ret = BLKPREP_KILL; | |
1235 | break; | |
1da177e4 | 1236 | } |
1da177e4 | 1237 | } |
7f9a6bc4 JB |
1238 | return ret; |
1239 | } | |
1240 | EXPORT_SYMBOL(scsi_prep_state_check); | |
1da177e4 | 1241 | |
7f9a6bc4 JB |
1242 | int scsi_prep_return(struct request_queue *q, struct request *req, int ret) |
1243 | { | |
1244 | struct scsi_device *sdev = q->queuedata; | |
1da177e4 | 1245 | |
3b003157 CH |
1246 | switch (ret) { |
1247 | case BLKPREP_KILL: | |
1248 | req->errors = DID_NO_CONNECT << 16; | |
7f9a6bc4 JB |
1249 | /* release the command and kill it */ |
1250 | if (req->special) { | |
1251 | struct scsi_cmnd *cmd = req->special; | |
1252 | scsi_release_buffers(cmd); | |
1253 | scsi_put_command(cmd); | |
1254 | req->special = NULL; | |
1255 | } | |
3b003157 CH |
1256 | break; |
1257 | case BLKPREP_DEFER: | |
1da177e4 | 1258 | /* |
9934c8c0 | 1259 | * If we defer, the blk_peek_request() returns NULL, but the |
a488e749 JA |
1260 | * queue must be restarted, so we schedule a callback to happen |
1261 | * shortly. | |
1da177e4 | 1262 | */ |
3b003157 | 1263 | if (sdev->device_busy == 0) |
a488e749 | 1264 | blk_delay_queue(q, SCSI_QUEUE_DELAY); |
3b003157 CH |
1265 | break; |
1266 | default: | |
1267 | req->cmd_flags |= REQ_DONTPREP; | |
1da177e4 LT |
1268 | } |
1269 | ||
3b003157 | 1270 | return ret; |
1da177e4 | 1271 | } |
7f9a6bc4 JB |
1272 | EXPORT_SYMBOL(scsi_prep_return); |
1273 | ||
751bf4d7 | 1274 | int scsi_prep_fn(struct request_queue *q, struct request *req) |
7f9a6bc4 JB |
1275 | { |
1276 | struct scsi_device *sdev = q->queuedata; | |
1277 | int ret = BLKPREP_KILL; | |
1278 | ||
1279 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) | |
1280 | ret = scsi_setup_blk_pc_cmnd(sdev, req); | |
1281 | return scsi_prep_return(q, req, ret); | |
1282 | } | |
b391277a | 1283 | EXPORT_SYMBOL(scsi_prep_fn); |
1da177e4 LT |
1284 | |
1285 | /* | |
1286 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1287 | * return 0. | |
1288 | * | |
1289 | * Called with the queue_lock held. | |
1290 | */ | |
1291 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1292 | struct scsi_device *sdev) | |
1293 | { | |
1da177e4 LT |
1294 | if (sdev->device_busy == 0 && sdev->device_blocked) { |
1295 | /* | |
1296 | * unblock after device_blocked iterates to zero | |
1297 | */ | |
1298 | if (--sdev->device_blocked == 0) { | |
1299 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1300 | sdev_printk(KERN_INFO, sdev, |
1301 | "unblocking device at zero depth\n")); | |
1da177e4 | 1302 | } else { |
a488e749 | 1303 | blk_delay_queue(q, SCSI_QUEUE_DELAY); |
1da177e4 LT |
1304 | return 0; |
1305 | } | |
1306 | } | |
9d112517 | 1307 | if (scsi_device_is_busy(sdev)) |
1da177e4 LT |
1308 | return 0; |
1309 | ||
1310 | return 1; | |
1311 | } | |
1312 | ||
f0c0a376 MC |
1313 | |
1314 | /* | |
1315 | * scsi_target_queue_ready: checks if there we can send commands to target | |
1316 | * @sdev: scsi device on starget to check. | |
1317 | * | |
1318 | * Called with the host lock held. | |
1319 | */ | |
1320 | static inline int scsi_target_queue_ready(struct Scsi_Host *shost, | |
1321 | struct scsi_device *sdev) | |
1322 | { | |
1323 | struct scsi_target *starget = scsi_target(sdev); | |
1324 | ||
1325 | if (starget->single_lun) { | |
1326 | if (starget->starget_sdev_user && | |
1327 | starget->starget_sdev_user != sdev) | |
1328 | return 0; | |
1329 | starget->starget_sdev_user = sdev; | |
1330 | } | |
1331 | ||
1332 | if (starget->target_busy == 0 && starget->target_blocked) { | |
1333 | /* | |
1334 | * unblock after target_blocked iterates to zero | |
1335 | */ | |
1336 | if (--starget->target_blocked == 0) { | |
1337 | SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, | |
1338 | "unblocking target at zero depth\n")); | |
b4efdd58 | 1339 | } else |
f0c0a376 | 1340 | return 0; |
f0c0a376 MC |
1341 | } |
1342 | ||
1343 | if (scsi_target_is_busy(starget)) { | |
466c08c7 | 1344 | list_move_tail(&sdev->starved_entry, &shost->starved_list); |
fd01a663 | 1345 | return 0; |
f0c0a376 MC |
1346 | } |
1347 | ||
f0c0a376 MC |
1348 | return 1; |
1349 | } | |
1350 | ||
1da177e4 LT |
1351 | /* |
1352 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1353 | * return 0. We must end up running the queue again whenever 0 is | |
1354 | * returned, else IO can hang. | |
1355 | * | |
1356 | * Called with host_lock held. | |
1357 | */ | |
1358 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1359 | struct Scsi_Host *shost, | |
1360 | struct scsi_device *sdev) | |
1361 | { | |
939647ee | 1362 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1363 | return 0; |
1364 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1365 | /* | |
1366 | * unblock after host_blocked iterates to zero | |
1367 | */ | |
1368 | if (--shost->host_blocked == 0) { | |
1369 | SCSI_LOG_MLQUEUE(3, | |
1370 | printk("scsi%d unblocking host at zero depth\n", | |
1371 | shost->host_no)); | |
1372 | } else { | |
1da177e4 LT |
1373 | return 0; |
1374 | } | |
1375 | } | |
9d112517 | 1376 | if (scsi_host_is_busy(shost)) { |
1da177e4 LT |
1377 | if (list_empty(&sdev->starved_entry)) |
1378 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1379 | return 0; | |
1380 | } | |
1381 | ||
1382 | /* We're OK to process the command, so we can't be starved */ | |
1383 | if (!list_empty(&sdev->starved_entry)) | |
1384 | list_del_init(&sdev->starved_entry); | |
1385 | ||
1386 | return 1; | |
1387 | } | |
1388 | ||
6c5121b7 KU |
1389 | /* |
1390 | * Busy state exporting function for request stacking drivers. | |
1391 | * | |
1392 | * For efficiency, no lock is taken to check the busy state of | |
1393 | * shost/starget/sdev, since the returned value is not guaranteed and | |
1394 | * may be changed after request stacking drivers call the function, | |
1395 | * regardless of taking lock or not. | |
1396 | * | |
67bd9413 BVA |
1397 | * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi |
1398 | * needs to return 'not busy'. Otherwise, request stacking drivers | |
1399 | * may hold requests forever. | |
6c5121b7 KU |
1400 | */ |
1401 | static int scsi_lld_busy(struct request_queue *q) | |
1402 | { | |
1403 | struct scsi_device *sdev = q->queuedata; | |
1404 | struct Scsi_Host *shost; | |
6c5121b7 | 1405 | |
67bd9413 | 1406 | if (blk_queue_dead(q)) |
6c5121b7 KU |
1407 | return 0; |
1408 | ||
1409 | shost = sdev->host; | |
6c5121b7 | 1410 | |
b7e94a16 JN |
1411 | /* |
1412 | * Ignore host/starget busy state. | |
1413 | * Since block layer does not have a concept of fairness across | |
1414 | * multiple queues, congestion of host/starget needs to be handled | |
1415 | * in SCSI layer. | |
1416 | */ | |
1417 | if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) | |
6c5121b7 KU |
1418 | return 1; |
1419 | ||
1420 | return 0; | |
1421 | } | |
1422 | ||
1da177e4 | 1423 | /* |
e91442b6 | 1424 | * Kill a request for a dead device |
1da177e4 | 1425 | */ |
165125e1 | 1426 | static void scsi_kill_request(struct request *req, struct request_queue *q) |
1da177e4 | 1427 | { |
e91442b6 | 1428 | struct scsi_cmnd *cmd = req->special; |
03b14708 JS |
1429 | struct scsi_device *sdev; |
1430 | struct scsi_target *starget; | |
1431 | struct Scsi_Host *shost; | |
1da177e4 | 1432 | |
9934c8c0 | 1433 | blk_start_request(req); |
788ce43a | 1434 | |
74571813 HR |
1435 | scmd_printk(KERN_INFO, cmd, "killing request\n"); |
1436 | ||
03b14708 JS |
1437 | sdev = cmd->device; |
1438 | starget = scsi_target(sdev); | |
1439 | shost = sdev->host; | |
e91442b6 JB |
1440 | scsi_init_cmd_errh(cmd); |
1441 | cmd->result = DID_NO_CONNECT << 16; | |
1442 | atomic_inc(&cmd->device->iorequest_cnt); | |
e36e0c80 TH |
1443 | |
1444 | /* | |
1445 | * SCSI request completion path will do scsi_device_unbusy(), | |
1446 | * bump busy counts. To bump the counters, we need to dance | |
1447 | * with the locks as normal issue path does. | |
1448 | */ | |
1449 | sdev->device_busy++; | |
1450 | spin_unlock(sdev->request_queue->queue_lock); | |
1451 | spin_lock(shost->host_lock); | |
1452 | shost->host_busy++; | |
f0c0a376 | 1453 | starget->target_busy++; |
e36e0c80 TH |
1454 | spin_unlock(shost->host_lock); |
1455 | spin_lock(sdev->request_queue->queue_lock); | |
1456 | ||
242f9dcb | 1457 | blk_complete_request(req); |
1da177e4 LT |
1458 | } |
1459 | ||
1aea6434 JA |
1460 | static void scsi_softirq_done(struct request *rq) |
1461 | { | |
242f9dcb JA |
1462 | struct scsi_cmnd *cmd = rq->special; |
1463 | unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; | |
1aea6434 JA |
1464 | int disposition; |
1465 | ||
1466 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1467 | ||
242f9dcb JA |
1468 | atomic_inc(&cmd->device->iodone_cnt); |
1469 | if (cmd->result) | |
1470 | atomic_inc(&cmd->device->ioerr_cnt); | |
1471 | ||
1aea6434 JA |
1472 | disposition = scsi_decide_disposition(cmd); |
1473 | if (disposition != SUCCESS && | |
1474 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1475 | sdev_printk(KERN_ERR, cmd->device, | |
1476 | "timing out command, waited %lus\n", | |
1477 | wait_for/HZ); | |
1478 | disposition = SUCCESS; | |
1479 | } | |
1480 | ||
1481 | scsi_log_completion(cmd, disposition); | |
1482 | ||
1483 | switch (disposition) { | |
1484 | case SUCCESS: | |
1485 | scsi_finish_command(cmd); | |
1486 | break; | |
1487 | case NEEDS_RETRY: | |
596f482a | 1488 | scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); |
1aea6434 JA |
1489 | break; |
1490 | case ADD_TO_MLQUEUE: | |
1491 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1492 | break; | |
1493 | default: | |
1494 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1495 | scsi_finish_command(cmd); | |
1496 | } | |
1497 | } | |
1498 | ||
1da177e4 LT |
1499 | /* |
1500 | * Function: scsi_request_fn() | |
1501 | * | |
1502 | * Purpose: Main strategy routine for SCSI. | |
1503 | * | |
1504 | * Arguments: q - Pointer to actual queue. | |
1505 | * | |
1506 | * Returns: Nothing | |
1507 | * | |
1508 | * Lock status: IO request lock assumed to be held when called. | |
1509 | */ | |
1510 | static void scsi_request_fn(struct request_queue *q) | |
1511 | { | |
1512 | struct scsi_device *sdev = q->queuedata; | |
1513 | struct Scsi_Host *shost; | |
1514 | struct scsi_cmnd *cmd; | |
1515 | struct request *req; | |
1516 | ||
1da177e4 LT |
1517 | if(!get_device(&sdev->sdev_gendev)) |
1518 | /* We must be tearing the block queue down already */ | |
1519 | return; | |
1520 | ||
1521 | /* | |
1522 | * To start with, we keep looping until the queue is empty, or until | |
1523 | * the host is no longer able to accept any more requests. | |
1524 | */ | |
1525 | shost = sdev->host; | |
a488e749 | 1526 | for (;;) { |
1da177e4 LT |
1527 | int rtn; |
1528 | /* | |
1529 | * get next queueable request. We do this early to make sure | |
1530 | * that the request is fully prepared even if we cannot | |
1531 | * accept it. | |
1532 | */ | |
9934c8c0 | 1533 | req = blk_peek_request(q); |
1da177e4 LT |
1534 | if (!req || !scsi_dev_queue_ready(q, sdev)) |
1535 | break; | |
1536 | ||
1537 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1538 | sdev_printk(KERN_ERR, sdev, |
1539 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1540 | scsi_kill_request(req, q); |
1da177e4 LT |
1541 | continue; |
1542 | } | |
1543 | ||
1544 | ||
1545 | /* | |
1546 | * Remove the request from the request list. | |
1547 | */ | |
1548 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
9934c8c0 | 1549 | blk_start_request(req); |
1da177e4 LT |
1550 | sdev->device_busy++; |
1551 | ||
1552 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1553 | cmd = req->special; |
1554 | if (unlikely(cmd == NULL)) { | |
1555 | printk(KERN_CRIT "impossible request in %s.\n" | |
1556 | "please mail a stack trace to " | |
4aff5e23 | 1557 | "linux-scsi@vger.kernel.org\n", |
cadbd4a5 | 1558 | __func__); |
4aff5e23 | 1559 | blk_dump_rq_flags(req, "foo"); |
e91442b6 JB |
1560 | BUG(); |
1561 | } | |
1da177e4 LT |
1562 | spin_lock(shost->host_lock); |
1563 | ||
ecefe8a9 MC |
1564 | /* |
1565 | * We hit this when the driver is using a host wide | |
1566 | * tag map. For device level tag maps the queue_depth check | |
1567 | * in the device ready fn would prevent us from trying | |
1568 | * to allocate a tag. Since the map is a shared host resource | |
1569 | * we add the dev to the starved list so it eventually gets | |
1570 | * a run when a tag is freed. | |
1571 | */ | |
6bd522f6 | 1572 | if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { |
ecefe8a9 MC |
1573 | if (list_empty(&sdev->starved_entry)) |
1574 | list_add_tail(&sdev->starved_entry, | |
1575 | &shost->starved_list); | |
1576 | goto not_ready; | |
1577 | } | |
1578 | ||
f0c0a376 MC |
1579 | if (!scsi_target_queue_ready(shost, sdev)) |
1580 | goto not_ready; | |
1581 | ||
1da177e4 LT |
1582 | if (!scsi_host_queue_ready(q, shost, sdev)) |
1583 | goto not_ready; | |
f0c0a376 MC |
1584 | |
1585 | scsi_target(sdev)->target_busy++; | |
1da177e4 LT |
1586 | shost->host_busy++; |
1587 | ||
1588 | /* | |
1589 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1590 | * take the lock again. | |
1591 | */ | |
1592 | spin_unlock_irq(shost->host_lock); | |
1593 | ||
1da177e4 LT |
1594 | /* |
1595 | * Finally, initialize any error handling parameters, and set up | |
1596 | * the timers for timeouts. | |
1597 | */ | |
1598 | scsi_init_cmd_errh(cmd); | |
1599 | ||
1600 | /* | |
1601 | * Dispatch the command to the low-level driver. | |
1602 | */ | |
1603 | rtn = scsi_dispatch_cmd(cmd); | |
1604 | spin_lock_irq(q->queue_lock); | |
a488e749 JA |
1605 | if (rtn) |
1606 | goto out_delay; | |
1da177e4 LT |
1607 | } |
1608 | ||
1609 | goto out; | |
1610 | ||
1611 | not_ready: | |
1612 | spin_unlock_irq(shost->host_lock); | |
1613 | ||
1614 | /* | |
1615 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1616 | * must return with queue_lock held. | |
1617 | * | |
1618 | * Decrementing device_busy without checking it is OK, as all such | |
1619 | * cases (host limits or settings) should run the queue at some | |
1620 | * later time. | |
1621 | */ | |
1622 | spin_lock_irq(q->queue_lock); | |
1623 | blk_requeue_request(q, req); | |
1624 | sdev->device_busy--; | |
a488e749 JA |
1625 | out_delay: |
1626 | if (sdev->device_busy == 0) | |
1627 | blk_delay_queue(q, SCSI_QUEUE_DELAY); | |
1628 | out: | |
1da177e4 LT |
1629 | /* must be careful here...if we trigger the ->remove() function |
1630 | * we cannot be holding the q lock */ | |
1631 | spin_unlock_irq(q->queue_lock); | |
1632 | put_device(&sdev->sdev_gendev); | |
1633 | spin_lock_irq(q->queue_lock); | |
1634 | } | |
1635 | ||
1636 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1637 | { | |
1638 | struct device *host_dev; | |
1639 | u64 bounce_limit = 0xffffffff; | |
1640 | ||
1641 | if (shost->unchecked_isa_dma) | |
1642 | return BLK_BOUNCE_ISA; | |
1643 | /* | |
1644 | * Platforms with virtual-DMA translation | |
1645 | * hardware have no practical limit. | |
1646 | */ | |
1647 | if (!PCI_DMA_BUS_IS_PHYS) | |
1648 | return BLK_BOUNCE_ANY; | |
1649 | ||
1650 | host_dev = scsi_get_device(shost); | |
1651 | if (host_dev && host_dev->dma_mask) | |
1652 | bounce_limit = *host_dev->dma_mask; | |
1653 | ||
1654 | return bounce_limit; | |
1655 | } | |
1656 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1657 | ||
b58d9154 FT |
1658 | struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, |
1659 | request_fn_proc *request_fn) | |
1da177e4 | 1660 | { |
1da177e4 | 1661 | struct request_queue *q; |
6f381fa3 | 1662 | struct device *dev = shost->dma_dev; |
1da177e4 | 1663 | |
b58d9154 | 1664 | q = blk_init_queue(request_fn, NULL); |
1da177e4 LT |
1665 | if (!q) |
1666 | return NULL; | |
1667 | ||
a8474ce2 JA |
1668 | /* |
1669 | * this limit is imposed by hardware restrictions | |
1670 | */ | |
8a78362c MP |
1671 | blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, |
1672 | SCSI_MAX_SG_CHAIN_SEGMENTS)); | |
a8474ce2 | 1673 | |
13f05c8d MP |
1674 | if (scsi_host_prot_dma(shost)) { |
1675 | shost->sg_prot_tablesize = | |
1676 | min_not_zero(shost->sg_prot_tablesize, | |
1677 | (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); | |
1678 | BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); | |
1679 | blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); | |
1680 | } | |
1681 | ||
086fa5ff | 1682 | blk_queue_max_hw_sectors(q, shost->max_sectors); |
1da177e4 LT |
1683 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); |
1684 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
99c84dbd | 1685 | dma_set_seg_boundary(dev, shost->dma_boundary); |
1da177e4 | 1686 | |
860ac568 FT |
1687 | blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); |
1688 | ||
1da177e4 | 1689 | if (!shost->use_clustering) |
e692cb66 | 1690 | q->limits.cluster = 0; |
465ff318 JB |
1691 | |
1692 | /* | |
1693 | * set a reasonable default alignment on word boundaries: the | |
1694 | * host and device may alter it using | |
1695 | * blk_queue_update_dma_alignment() later. | |
1696 | */ | |
1697 | blk_queue_dma_alignment(q, 0x03); | |
1698 | ||
1da177e4 LT |
1699 | return q; |
1700 | } | |
b58d9154 FT |
1701 | EXPORT_SYMBOL(__scsi_alloc_queue); |
1702 | ||
1703 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1704 | { | |
1705 | struct request_queue *q; | |
1706 | ||
1707 | q = __scsi_alloc_queue(sdev->host, scsi_request_fn); | |
1708 | if (!q) | |
1709 | return NULL; | |
1710 | ||
1711 | blk_queue_prep_rq(q, scsi_prep_fn); | |
b58d9154 | 1712 | blk_queue_softirq_done(q, scsi_softirq_done); |
242f9dcb | 1713 | blk_queue_rq_timed_out(q, scsi_times_out); |
6c5121b7 | 1714 | blk_queue_lld_busy(q, scsi_lld_busy); |
b58d9154 FT |
1715 | return q; |
1716 | } | |
1da177e4 | 1717 | |
1da177e4 LT |
1718 | /* |
1719 | * Function: scsi_block_requests() | |
1720 | * | |
1721 | * Purpose: Utility function used by low-level drivers to prevent further | |
1722 | * commands from being queued to the device. | |
1723 | * | |
1724 | * Arguments: shost - Host in question | |
1725 | * | |
1726 | * Returns: Nothing | |
1727 | * | |
1728 | * Lock status: No locks are assumed held. | |
1729 | * | |
1730 | * Notes: There is no timer nor any other means by which the requests | |
1731 | * get unblocked other than the low-level driver calling | |
1732 | * scsi_unblock_requests(). | |
1733 | */ | |
1734 | void scsi_block_requests(struct Scsi_Host *shost) | |
1735 | { | |
1736 | shost->host_self_blocked = 1; | |
1737 | } | |
1738 | EXPORT_SYMBOL(scsi_block_requests); | |
1739 | ||
1740 | /* | |
1741 | * Function: scsi_unblock_requests() | |
1742 | * | |
1743 | * Purpose: Utility function used by low-level drivers to allow further | |
1744 | * commands from being queued to the device. | |
1745 | * | |
1746 | * Arguments: shost - Host in question | |
1747 | * | |
1748 | * Returns: Nothing | |
1749 | * | |
1750 | * Lock status: No locks are assumed held. | |
1751 | * | |
1752 | * Notes: There is no timer nor any other means by which the requests | |
1753 | * get unblocked other than the low-level driver calling | |
1754 | * scsi_unblock_requests(). | |
1755 | * | |
1756 | * This is done as an API function so that changes to the | |
1757 | * internals of the scsi mid-layer won't require wholesale | |
1758 | * changes to drivers that use this feature. | |
1759 | */ | |
1760 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1761 | { | |
1762 | shost->host_self_blocked = 0; | |
1763 | scsi_run_host_queues(shost); | |
1764 | } | |
1765 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1766 | ||
1767 | int __init scsi_init_queue(void) | |
1768 | { | |
1769 | int i; | |
1770 | ||
6362abd3 MP |
1771 | scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", |
1772 | sizeof(struct scsi_data_buffer), | |
1773 | 0, 0, NULL); | |
1774 | if (!scsi_sdb_cache) { | |
1775 | printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); | |
f078727b | 1776 | return -ENOMEM; |
6f9a35e2 BH |
1777 | } |
1778 | ||
1da177e4 LT |
1779 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1780 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1781 | int size = sgp->size * sizeof(struct scatterlist); | |
1782 | ||
1783 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
20c2df83 | 1784 | SLAB_HWCACHE_ALIGN, NULL); |
1da177e4 LT |
1785 | if (!sgp->slab) { |
1786 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1787 | sgp->name); | |
6362abd3 | 1788 | goto cleanup_sdb; |
1da177e4 LT |
1789 | } |
1790 | ||
93d2341c MD |
1791 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
1792 | sgp->slab); | |
1da177e4 LT |
1793 | if (!sgp->pool) { |
1794 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1795 | sgp->name); | |
6362abd3 | 1796 | goto cleanup_sdb; |
1da177e4 LT |
1797 | } |
1798 | } | |
1799 | ||
1800 | return 0; | |
3d9dd6ee | 1801 | |
6362abd3 | 1802 | cleanup_sdb: |
3d9dd6ee FT |
1803 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1804 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1805 | if (sgp->pool) | |
1806 | mempool_destroy(sgp->pool); | |
1807 | if (sgp->slab) | |
1808 | kmem_cache_destroy(sgp->slab); | |
1809 | } | |
6362abd3 | 1810 | kmem_cache_destroy(scsi_sdb_cache); |
3d9dd6ee FT |
1811 | |
1812 | return -ENOMEM; | |
1da177e4 LT |
1813 | } |
1814 | ||
1815 | void scsi_exit_queue(void) | |
1816 | { | |
1817 | int i; | |
1818 | ||
6362abd3 | 1819 | kmem_cache_destroy(scsi_sdb_cache); |
aa7b5cd7 | 1820 | |
1da177e4 LT |
1821 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1822 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1823 | mempool_destroy(sgp->pool); | |
1824 | kmem_cache_destroy(sgp->slab); | |
1825 | } | |
1826 | } | |
5baba830 JB |
1827 | |
1828 | /** | |
1829 | * scsi_mode_select - issue a mode select | |
1830 | * @sdev: SCSI device to be queried | |
1831 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1832 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1833 | * @modepage: mode page being requested | |
1834 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1835 | * @len: length of request buffer. | |
1836 | * @timeout: command timeout | |
1837 | * @retries: number of retries before failing | |
1838 | * @data: returns a structure abstracting the mode header data | |
eb44820c | 1839 | * @sshdr: place to put sense data (or NULL if no sense to be collected). |
5baba830 JB |
1840 | * must be SCSI_SENSE_BUFFERSIZE big. |
1841 | * | |
1842 | * Returns zero if successful; negative error number or scsi | |
1843 | * status on error | |
1844 | * | |
1845 | */ | |
1846 | int | |
1847 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1848 | unsigned char *buffer, int len, int timeout, int retries, | |
1849 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1850 | { | |
1851 | unsigned char cmd[10]; | |
1852 | unsigned char *real_buffer; | |
1853 | int ret; | |
1854 | ||
1855 | memset(cmd, 0, sizeof(cmd)); | |
1856 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1857 | ||
1858 | if (sdev->use_10_for_ms) { | |
1859 | if (len > 65535) | |
1860 | return -EINVAL; | |
1861 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1862 | if (!real_buffer) | |
1863 | return -ENOMEM; | |
1864 | memcpy(real_buffer + 8, buffer, len); | |
1865 | len += 8; | |
1866 | real_buffer[0] = 0; | |
1867 | real_buffer[1] = 0; | |
1868 | real_buffer[2] = data->medium_type; | |
1869 | real_buffer[3] = data->device_specific; | |
1870 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1871 | real_buffer[5] = 0; | |
1872 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1873 | real_buffer[7] = data->block_descriptor_length; | |
1874 | ||
1875 | cmd[0] = MODE_SELECT_10; | |
1876 | cmd[7] = len >> 8; | |
1877 | cmd[8] = len; | |
1878 | } else { | |
1879 | if (len > 255 || data->block_descriptor_length > 255 || | |
1880 | data->longlba) | |
1881 | return -EINVAL; | |
1882 | ||
1883 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1884 | if (!real_buffer) | |
1885 | return -ENOMEM; | |
1886 | memcpy(real_buffer + 4, buffer, len); | |
1887 | len += 4; | |
1888 | real_buffer[0] = 0; | |
1889 | real_buffer[1] = data->medium_type; | |
1890 | real_buffer[2] = data->device_specific; | |
1891 | real_buffer[3] = data->block_descriptor_length; | |
1892 | ||
1893 | ||
1894 | cmd[0] = MODE_SELECT; | |
1895 | cmd[4] = len; | |
1896 | } | |
1897 | ||
1898 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
f4f4e47e | 1899 | sshdr, timeout, retries, NULL); |
5baba830 JB |
1900 | kfree(real_buffer); |
1901 | return ret; | |
1902 | } | |
1903 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1904 | ||
1da177e4 | 1905 | /** |
eb44820c | 1906 | * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. |
1cf72699 | 1907 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1908 | * @dbd: set if mode sense will allow block descriptors to be returned |
1909 | * @modepage: mode page being requested | |
1910 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1911 | * @len: length of request buffer. | |
1912 | * @timeout: command timeout | |
1913 | * @retries: number of retries before failing | |
1914 | * @data: returns a structure abstracting the mode header data | |
eb44820c | 1915 | * @sshdr: place to put sense data (or NULL if no sense to be collected). |
1cf72699 | 1916 | * must be SCSI_SENSE_BUFFERSIZE big. |
1da177e4 LT |
1917 | * |
1918 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1919 | * or 8 depending on whether a six or ten byte command was | |
1920 | * issued) if successful. | |
eb44820c | 1921 | */ |
1da177e4 | 1922 | int |
1cf72699 | 1923 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1924 | unsigned char *buffer, int len, int timeout, int retries, |
5baba830 JB |
1925 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
1926 | { | |
1da177e4 LT |
1927 | unsigned char cmd[12]; |
1928 | int use_10_for_ms; | |
1929 | int header_length; | |
1cf72699 | 1930 | int result; |
ea73a9f2 | 1931 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1932 | |
1933 | memset(data, 0, sizeof(*data)); | |
1934 | memset(&cmd[0], 0, 12); | |
1935 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1936 | cmd[2] = modepage; | |
1937 | ||
ea73a9f2 JB |
1938 | /* caller might not be interested in sense, but we need it */ |
1939 | if (!sshdr) | |
1940 | sshdr = &my_sshdr; | |
1941 | ||
1da177e4 | 1942 | retry: |
1cf72699 | 1943 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1944 | |
1945 | if (use_10_for_ms) { | |
1946 | if (len < 8) | |
1947 | len = 8; | |
1948 | ||
1949 | cmd[0] = MODE_SENSE_10; | |
1950 | cmd[8] = len; | |
1951 | header_length = 8; | |
1952 | } else { | |
1953 | if (len < 4) | |
1954 | len = 4; | |
1955 | ||
1956 | cmd[0] = MODE_SENSE; | |
1957 | cmd[4] = len; | |
1958 | header_length = 4; | |
1959 | } | |
1960 | ||
1da177e4 LT |
1961 | memset(buffer, 0, len); |
1962 | ||
1cf72699 | 1963 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
f4f4e47e | 1964 | sshdr, timeout, retries, NULL); |
1da177e4 LT |
1965 | |
1966 | /* This code looks awful: what it's doing is making sure an | |
1967 | * ILLEGAL REQUEST sense return identifies the actual command | |
1968 | * byte as the problem. MODE_SENSE commands can return | |
1969 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1970 | ||
1cf72699 JB |
1971 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1972 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1973 | if (scsi_sense_valid(sshdr)) { |
1974 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1975 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1976 | /* |
1977 | * Invalid command operation code | |
1978 | */ | |
1cf72699 | 1979 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1980 | goto retry; |
1981 | } | |
1982 | } | |
1983 | } | |
1984 | ||
1cf72699 | 1985 | if(scsi_status_is_good(result)) { |
6d73c851 AV |
1986 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
1987 | (modepage == 6 || modepage == 8))) { | |
1988 | /* Initio breakage? */ | |
1989 | header_length = 0; | |
1990 | data->length = 13; | |
1991 | data->medium_type = 0; | |
1992 | data->device_specific = 0; | |
1993 | data->longlba = 0; | |
1994 | data->block_descriptor_length = 0; | |
1995 | } else if(use_10_for_ms) { | |
1da177e4 LT |
1996 | data->length = buffer[0]*256 + buffer[1] + 2; |
1997 | data->medium_type = buffer[2]; | |
1998 | data->device_specific = buffer[3]; | |
1999 | data->longlba = buffer[4] & 0x01; | |
2000 | data->block_descriptor_length = buffer[6]*256 | |
2001 | + buffer[7]; | |
2002 | } else { | |
2003 | data->length = buffer[0] + 1; | |
2004 | data->medium_type = buffer[1]; | |
2005 | data->device_specific = buffer[2]; | |
2006 | data->block_descriptor_length = buffer[3]; | |
2007 | } | |
6d73c851 | 2008 | data->header_length = header_length; |
1da177e4 LT |
2009 | } |
2010 | ||
1cf72699 | 2011 | return result; |
1da177e4 LT |
2012 | } |
2013 | EXPORT_SYMBOL(scsi_mode_sense); | |
2014 | ||
001aac25 JB |
2015 | /** |
2016 | * scsi_test_unit_ready - test if unit is ready | |
2017 | * @sdev: scsi device to change the state of. | |
2018 | * @timeout: command timeout | |
2019 | * @retries: number of retries before failing | |
2020 | * @sshdr_external: Optional pointer to struct scsi_sense_hdr for | |
2021 | * returning sense. Make sure that this is cleared before passing | |
2022 | * in. | |
2023 | * | |
2024 | * Returns zero if unsuccessful or an error if TUR failed. For | |
9f8a2c23 | 2025 | * removable media, UNIT_ATTENTION sets ->changed flag. |
001aac25 | 2026 | **/ |
1da177e4 | 2027 | int |
001aac25 JB |
2028 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, |
2029 | struct scsi_sense_hdr *sshdr_external) | |
1da177e4 | 2030 | { |
1da177e4 LT |
2031 | char cmd[] = { |
2032 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
2033 | }; | |
001aac25 | 2034 | struct scsi_sense_hdr *sshdr; |
1da177e4 | 2035 | int result; |
001aac25 JB |
2036 | |
2037 | if (!sshdr_external) | |
2038 | sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); | |
2039 | else | |
2040 | sshdr = sshdr_external; | |
2041 | ||
2042 | /* try to eat the UNIT_ATTENTION if there are enough retries */ | |
2043 | do { | |
2044 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, | |
f4f4e47e | 2045 | timeout, retries, NULL); |
32c356d7 JB |
2046 | if (sdev->removable && scsi_sense_valid(sshdr) && |
2047 | sshdr->sense_key == UNIT_ATTENTION) | |
2048 | sdev->changed = 1; | |
2049 | } while (scsi_sense_valid(sshdr) && | |
2050 | sshdr->sense_key == UNIT_ATTENTION && --retries); | |
001aac25 | 2051 | |
001aac25 JB |
2052 | if (!sshdr_external) |
2053 | kfree(sshdr); | |
1da177e4 LT |
2054 | return result; |
2055 | } | |
2056 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
2057 | ||
2058 | /** | |
eb44820c | 2059 | * scsi_device_set_state - Take the given device through the device state model. |
1da177e4 LT |
2060 | * @sdev: scsi device to change the state of. |
2061 | * @state: state to change to. | |
2062 | * | |
2063 | * Returns zero if unsuccessful or an error if the requested | |
2064 | * transition is illegal. | |
eb44820c | 2065 | */ |
1da177e4 LT |
2066 | int |
2067 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
2068 | { | |
2069 | enum scsi_device_state oldstate = sdev->sdev_state; | |
2070 | ||
2071 | if (state == oldstate) | |
2072 | return 0; | |
2073 | ||
2074 | switch (state) { | |
2075 | case SDEV_CREATED: | |
6f4267e3 JB |
2076 | switch (oldstate) { |
2077 | case SDEV_CREATED_BLOCK: | |
2078 | break; | |
2079 | default: | |
2080 | goto illegal; | |
2081 | } | |
2082 | break; | |
1da177e4 LT |
2083 | |
2084 | case SDEV_RUNNING: | |
2085 | switch (oldstate) { | |
2086 | case SDEV_CREATED: | |
2087 | case SDEV_OFFLINE: | |
1b8d2620 | 2088 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2089 | case SDEV_QUIESCE: |
2090 | case SDEV_BLOCK: | |
2091 | break; | |
2092 | default: | |
2093 | goto illegal; | |
2094 | } | |
2095 | break; | |
2096 | ||
2097 | case SDEV_QUIESCE: | |
2098 | switch (oldstate) { | |
2099 | case SDEV_RUNNING: | |
2100 | case SDEV_OFFLINE: | |
1b8d2620 | 2101 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2102 | break; |
2103 | default: | |
2104 | goto illegal; | |
2105 | } | |
2106 | break; | |
2107 | ||
2108 | case SDEV_OFFLINE: | |
1b8d2620 | 2109 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2110 | switch (oldstate) { |
2111 | case SDEV_CREATED: | |
2112 | case SDEV_RUNNING: | |
2113 | case SDEV_QUIESCE: | |
2114 | case SDEV_BLOCK: | |
2115 | break; | |
2116 | default: | |
2117 | goto illegal; | |
2118 | } | |
2119 | break; | |
2120 | ||
2121 | case SDEV_BLOCK: | |
2122 | switch (oldstate) { | |
1da177e4 | 2123 | case SDEV_RUNNING: |
6f4267e3 JB |
2124 | case SDEV_CREATED_BLOCK: |
2125 | break; | |
2126 | default: | |
2127 | goto illegal; | |
2128 | } | |
2129 | break; | |
2130 | ||
2131 | case SDEV_CREATED_BLOCK: | |
2132 | switch (oldstate) { | |
2133 | case SDEV_CREATED: | |
1da177e4 LT |
2134 | break; |
2135 | default: | |
2136 | goto illegal; | |
2137 | } | |
2138 | break; | |
2139 | ||
2140 | case SDEV_CANCEL: | |
2141 | switch (oldstate) { | |
2142 | case SDEV_CREATED: | |
2143 | case SDEV_RUNNING: | |
9ea72909 | 2144 | case SDEV_QUIESCE: |
1da177e4 | 2145 | case SDEV_OFFLINE: |
1b8d2620 | 2146 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2147 | case SDEV_BLOCK: |
2148 | break; | |
2149 | default: | |
2150 | goto illegal; | |
2151 | } | |
2152 | break; | |
2153 | ||
2154 | case SDEV_DEL: | |
2155 | switch (oldstate) { | |
309bd271 BK |
2156 | case SDEV_CREATED: |
2157 | case SDEV_RUNNING: | |
2158 | case SDEV_OFFLINE: | |
1b8d2620 | 2159 | case SDEV_TRANSPORT_OFFLINE: |
1da177e4 LT |
2160 | case SDEV_CANCEL: |
2161 | break; | |
2162 | default: | |
2163 | goto illegal; | |
2164 | } | |
2165 | break; | |
2166 | ||
2167 | } | |
2168 | sdev->sdev_state = state; | |
2169 | return 0; | |
2170 | ||
2171 | illegal: | |
2172 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2173 | sdev_printk(KERN_ERR, sdev, |
2174 | "Illegal state transition %s->%s\n", | |
2175 | scsi_device_state_name(oldstate), | |
2176 | scsi_device_state_name(state)) | |
1da177e4 LT |
2177 | ); |
2178 | return -EINVAL; | |
2179 | } | |
2180 | EXPORT_SYMBOL(scsi_device_set_state); | |
2181 | ||
a341cd0f JG |
2182 | /** |
2183 | * sdev_evt_emit - emit a single SCSI device uevent | |
2184 | * @sdev: associated SCSI device | |
2185 | * @evt: event to emit | |
2186 | * | |
2187 | * Send a single uevent (scsi_event) to the associated scsi_device. | |
2188 | */ | |
2189 | static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) | |
2190 | { | |
2191 | int idx = 0; | |
2192 | char *envp[3]; | |
2193 | ||
2194 | switch (evt->evt_type) { | |
2195 | case SDEV_EVT_MEDIA_CHANGE: | |
2196 | envp[idx++] = "SDEV_MEDIA_CHANGE=1"; | |
2197 | break; | |
2198 | ||
2199 | default: | |
2200 | /* do nothing */ | |
2201 | break; | |
2202 | } | |
2203 | ||
2204 | envp[idx++] = NULL; | |
2205 | ||
2206 | kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); | |
2207 | } | |
2208 | ||
2209 | /** | |
2210 | * sdev_evt_thread - send a uevent for each scsi event | |
2211 | * @work: work struct for scsi_device | |
2212 | * | |
2213 | * Dispatch queued events to their associated scsi_device kobjects | |
2214 | * as uevents. | |
2215 | */ | |
2216 | void scsi_evt_thread(struct work_struct *work) | |
2217 | { | |
2218 | struct scsi_device *sdev; | |
2219 | LIST_HEAD(event_list); | |
2220 | ||
2221 | sdev = container_of(work, struct scsi_device, event_work); | |
2222 | ||
2223 | while (1) { | |
2224 | struct scsi_event *evt; | |
2225 | struct list_head *this, *tmp; | |
2226 | unsigned long flags; | |
2227 | ||
2228 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2229 | list_splice_init(&sdev->event_list, &event_list); | |
2230 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2231 | ||
2232 | if (list_empty(&event_list)) | |
2233 | break; | |
2234 | ||
2235 | list_for_each_safe(this, tmp, &event_list) { | |
2236 | evt = list_entry(this, struct scsi_event, node); | |
2237 | list_del(&evt->node); | |
2238 | scsi_evt_emit(sdev, evt); | |
2239 | kfree(evt); | |
2240 | } | |
2241 | } | |
2242 | } | |
2243 | ||
2244 | /** | |
2245 | * sdev_evt_send - send asserted event to uevent thread | |
2246 | * @sdev: scsi_device event occurred on | |
2247 | * @evt: event to send | |
2248 | * | |
2249 | * Assert scsi device event asynchronously. | |
2250 | */ | |
2251 | void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) | |
2252 | { | |
2253 | unsigned long flags; | |
2254 | ||
4d1566ed KS |
2255 | #if 0 |
2256 | /* FIXME: currently this check eliminates all media change events | |
2257 | * for polled devices. Need to update to discriminate between AN | |
2258 | * and polled events */ | |
a341cd0f JG |
2259 | if (!test_bit(evt->evt_type, sdev->supported_events)) { |
2260 | kfree(evt); | |
2261 | return; | |
2262 | } | |
4d1566ed | 2263 | #endif |
a341cd0f JG |
2264 | |
2265 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2266 | list_add_tail(&evt->node, &sdev->event_list); | |
2267 | schedule_work(&sdev->event_work); | |
2268 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2269 | } | |
2270 | EXPORT_SYMBOL_GPL(sdev_evt_send); | |
2271 | ||
2272 | /** | |
2273 | * sdev_evt_alloc - allocate a new scsi event | |
2274 | * @evt_type: type of event to allocate | |
2275 | * @gfpflags: GFP flags for allocation | |
2276 | * | |
2277 | * Allocates and returns a new scsi_event. | |
2278 | */ | |
2279 | struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, | |
2280 | gfp_t gfpflags) | |
2281 | { | |
2282 | struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); | |
2283 | if (!evt) | |
2284 | return NULL; | |
2285 | ||
2286 | evt->evt_type = evt_type; | |
2287 | INIT_LIST_HEAD(&evt->node); | |
2288 | ||
2289 | /* evt_type-specific initialization, if any */ | |
2290 | switch (evt_type) { | |
2291 | case SDEV_EVT_MEDIA_CHANGE: | |
2292 | default: | |
2293 | /* do nothing */ | |
2294 | break; | |
2295 | } | |
2296 | ||
2297 | return evt; | |
2298 | } | |
2299 | EXPORT_SYMBOL_GPL(sdev_evt_alloc); | |
2300 | ||
2301 | /** | |
2302 | * sdev_evt_send_simple - send asserted event to uevent thread | |
2303 | * @sdev: scsi_device event occurred on | |
2304 | * @evt_type: type of event to send | |
2305 | * @gfpflags: GFP flags for allocation | |
2306 | * | |
2307 | * Assert scsi device event asynchronously, given an event type. | |
2308 | */ | |
2309 | void sdev_evt_send_simple(struct scsi_device *sdev, | |
2310 | enum scsi_device_event evt_type, gfp_t gfpflags) | |
2311 | { | |
2312 | struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); | |
2313 | if (!evt) { | |
2314 | sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", | |
2315 | evt_type); | |
2316 | return; | |
2317 | } | |
2318 | ||
2319 | sdev_evt_send(sdev, evt); | |
2320 | } | |
2321 | EXPORT_SYMBOL_GPL(sdev_evt_send_simple); | |
2322 | ||
1da177e4 LT |
2323 | /** |
2324 | * scsi_device_quiesce - Block user issued commands. | |
2325 | * @sdev: scsi device to quiesce. | |
2326 | * | |
2327 | * This works by trying to transition to the SDEV_QUIESCE state | |
2328 | * (which must be a legal transition). When the device is in this | |
2329 | * state, only special requests will be accepted, all others will | |
2330 | * be deferred. Since special requests may also be requeued requests, | |
2331 | * a successful return doesn't guarantee the device will be | |
2332 | * totally quiescent. | |
2333 | * | |
2334 | * Must be called with user context, may sleep. | |
2335 | * | |
2336 | * Returns zero if unsuccessful or an error if not. | |
eb44820c | 2337 | */ |
1da177e4 LT |
2338 | int |
2339 | scsi_device_quiesce(struct scsi_device *sdev) | |
2340 | { | |
2341 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2342 | if (err) | |
2343 | return err; | |
2344 | ||
2345 | scsi_run_queue(sdev->request_queue); | |
2346 | while (sdev->device_busy) { | |
2347 | msleep_interruptible(200); | |
2348 | scsi_run_queue(sdev->request_queue); | |
2349 | } | |
2350 | return 0; | |
2351 | } | |
2352 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2353 | ||
2354 | /** | |
2355 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2356 | * @sdev: scsi device to resume. | |
2357 | * | |
2358 | * Moves the device from quiesced back to running and restarts the | |
2359 | * queues. | |
2360 | * | |
2361 | * Must be called with user context, may sleep. | |
eb44820c | 2362 | */ |
a7a20d10 | 2363 | void scsi_device_resume(struct scsi_device *sdev) |
1da177e4 | 2364 | { |
a7a20d10 DW |
2365 | /* check if the device state was mutated prior to resume, and if |
2366 | * so assume the state is being managed elsewhere (for example | |
2367 | * device deleted during suspend) | |
2368 | */ | |
2369 | if (sdev->sdev_state != SDEV_QUIESCE || | |
2370 | scsi_device_set_state(sdev, SDEV_RUNNING)) | |
1da177e4 LT |
2371 | return; |
2372 | scsi_run_queue(sdev->request_queue); | |
2373 | } | |
2374 | EXPORT_SYMBOL(scsi_device_resume); | |
2375 | ||
2376 | static void | |
2377 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2378 | { | |
2379 | scsi_device_quiesce(sdev); | |
2380 | } | |
2381 | ||
2382 | void | |
2383 | scsi_target_quiesce(struct scsi_target *starget) | |
2384 | { | |
2385 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2386 | } | |
2387 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2388 | ||
2389 | static void | |
2390 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2391 | { | |
2392 | scsi_device_resume(sdev); | |
2393 | } | |
2394 | ||
2395 | void | |
2396 | scsi_target_resume(struct scsi_target *starget) | |
2397 | { | |
2398 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2399 | } | |
2400 | EXPORT_SYMBOL(scsi_target_resume); | |
2401 | ||
2402 | /** | |
eb44820c | 2403 | * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state |
1da177e4 LT |
2404 | * @sdev: device to block |
2405 | * | |
2406 | * Block request made by scsi lld's to temporarily stop all | |
2407 | * scsi commands on the specified device. Called from interrupt | |
2408 | * or normal process context. | |
2409 | * | |
2410 | * Returns zero if successful or error if not | |
2411 | * | |
2412 | * Notes: | |
2413 | * This routine transitions the device to the SDEV_BLOCK state | |
2414 | * (which must be a legal transition). When the device is in this | |
2415 | * state, all commands are deferred until the scsi lld reenables | |
2416 | * the device with scsi_device_unblock or device_block_tmo fires. | |
eb44820c | 2417 | */ |
1da177e4 LT |
2418 | int |
2419 | scsi_internal_device_block(struct scsi_device *sdev) | |
2420 | { | |
165125e1 | 2421 | struct request_queue *q = sdev->request_queue; |
1da177e4 LT |
2422 | unsigned long flags; |
2423 | int err = 0; | |
2424 | ||
2425 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
6f4267e3 JB |
2426 | if (err) { |
2427 | err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); | |
2428 | ||
2429 | if (err) | |
2430 | return err; | |
2431 | } | |
1da177e4 LT |
2432 | |
2433 | /* | |
2434 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2435 | * block layer from calling the midlayer with this device's | |
2436 | * request queue. | |
2437 | */ | |
2438 | spin_lock_irqsave(q->queue_lock, flags); | |
2439 | blk_stop_queue(q); | |
2440 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2441 | ||
2442 | return 0; | |
2443 | } | |
2444 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2445 | ||
2446 | /** | |
2447 | * scsi_internal_device_unblock - resume a device after a block request | |
2448 | * @sdev: device to resume | |
5d9fb5cc | 2449 | * @new_state: state to set devices to after unblocking |
1da177e4 LT |
2450 | * |
2451 | * Called by scsi lld's or the midlayer to restart the device queue | |
2452 | * for the previously suspended scsi device. Called from interrupt or | |
2453 | * normal process context. | |
2454 | * | |
2455 | * Returns zero if successful or error if not. | |
2456 | * | |
2457 | * Notes: | |
2458 | * This routine transitions the device to the SDEV_RUNNING state | |
5d9fb5cc | 2459 | * or to one of the offline states (which must be a legal transition) |
d075498c | 2460 | * allowing the midlayer to goose the queue for this device. |
eb44820c | 2461 | */ |
1da177e4 | 2462 | int |
5d9fb5cc MC |
2463 | scsi_internal_device_unblock(struct scsi_device *sdev, |
2464 | enum scsi_device_state new_state) | |
1da177e4 | 2465 | { |
165125e1 | 2466 | struct request_queue *q = sdev->request_queue; |
1da177e4 | 2467 | unsigned long flags; |
5d9fb5cc MC |
2468 | |
2469 | /* | |
2470 | * Try to transition the scsi device to SDEV_RUNNING or one of the | |
2471 | * offlined states and goose the device queue if successful. | |
1da177e4 | 2472 | */ |
5c10e63c | 2473 | if (sdev->sdev_state == SDEV_BLOCK) |
5d9fb5cc MC |
2474 | sdev->sdev_state = new_state; |
2475 | else if (sdev->sdev_state == SDEV_CREATED_BLOCK) { | |
2476 | if (new_state == SDEV_TRANSPORT_OFFLINE || | |
2477 | new_state == SDEV_OFFLINE) | |
2478 | sdev->sdev_state = new_state; | |
2479 | else | |
2480 | sdev->sdev_state = SDEV_CREATED; | |
2481 | } else if (sdev->sdev_state != SDEV_CANCEL && | |
986fe6c7 | 2482 | sdev->sdev_state != SDEV_OFFLINE) |
5c10e63c | 2483 | return -EINVAL; |
1da177e4 LT |
2484 | |
2485 | spin_lock_irqsave(q->queue_lock, flags); | |
2486 | blk_start_queue(q); | |
2487 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2488 | ||
2489 | return 0; | |
2490 | } | |
2491 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2492 | ||
2493 | static void | |
2494 | device_block(struct scsi_device *sdev, void *data) | |
2495 | { | |
2496 | scsi_internal_device_block(sdev); | |
2497 | } | |
2498 | ||
2499 | static int | |
2500 | target_block(struct device *dev, void *data) | |
2501 | { | |
2502 | if (scsi_is_target_device(dev)) | |
2503 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2504 | device_block); | |
2505 | return 0; | |
2506 | } | |
2507 | ||
2508 | void | |
2509 | scsi_target_block(struct device *dev) | |
2510 | { | |
2511 | if (scsi_is_target_device(dev)) | |
2512 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2513 | device_block); | |
2514 | else | |
2515 | device_for_each_child(dev, NULL, target_block); | |
2516 | } | |
2517 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2518 | ||
2519 | static void | |
2520 | device_unblock(struct scsi_device *sdev, void *data) | |
2521 | { | |
5d9fb5cc | 2522 | scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); |
1da177e4 LT |
2523 | } |
2524 | ||
2525 | static int | |
2526 | target_unblock(struct device *dev, void *data) | |
2527 | { | |
2528 | if (scsi_is_target_device(dev)) | |
5d9fb5cc | 2529 | starget_for_each_device(to_scsi_target(dev), data, |
1da177e4 LT |
2530 | device_unblock); |
2531 | return 0; | |
2532 | } | |
2533 | ||
2534 | void | |
5d9fb5cc | 2535 | scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) |
1da177e4 LT |
2536 | { |
2537 | if (scsi_is_target_device(dev)) | |
5d9fb5cc | 2538 | starget_for_each_device(to_scsi_target(dev), &new_state, |
1da177e4 LT |
2539 | device_unblock); |
2540 | else | |
5d9fb5cc | 2541 | device_for_each_child(dev, &new_state, target_unblock); |
1da177e4 LT |
2542 | } |
2543 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
cdb8c2a6 GL |
2544 | |
2545 | /** | |
2546 | * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt | |
eb44820c | 2547 | * @sgl: scatter-gather list |
cdb8c2a6 GL |
2548 | * @sg_count: number of segments in sg |
2549 | * @offset: offset in bytes into sg, on return offset into the mapped area | |
2550 | * @len: bytes to map, on return number of bytes mapped | |
2551 | * | |
2552 | * Returns virtual address of the start of the mapped page | |
2553 | */ | |
c6132da1 | 2554 | void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, |
cdb8c2a6 GL |
2555 | size_t *offset, size_t *len) |
2556 | { | |
2557 | int i; | |
2558 | size_t sg_len = 0, len_complete = 0; | |
c6132da1 | 2559 | struct scatterlist *sg; |
cdb8c2a6 GL |
2560 | struct page *page; |
2561 | ||
22cfefb5 AM |
2562 | WARN_ON(!irqs_disabled()); |
2563 | ||
c6132da1 | 2564 | for_each_sg(sgl, sg, sg_count, i) { |
cdb8c2a6 | 2565 | len_complete = sg_len; /* Complete sg-entries */ |
c6132da1 | 2566 | sg_len += sg->length; |
cdb8c2a6 GL |
2567 | if (sg_len > *offset) |
2568 | break; | |
2569 | } | |
2570 | ||
2571 | if (unlikely(i == sg_count)) { | |
169e1a2a AM |
2572 | printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
2573 | "elements %d\n", | |
cadbd4a5 | 2574 | __func__, sg_len, *offset, sg_count); |
cdb8c2a6 GL |
2575 | WARN_ON(1); |
2576 | return NULL; | |
2577 | } | |
2578 | ||
2579 | /* Offset starting from the beginning of first page in this sg-entry */ | |
c6132da1 | 2580 | *offset = *offset - len_complete + sg->offset; |
cdb8c2a6 GL |
2581 | |
2582 | /* Assumption: contiguous pages can be accessed as "page + i" */ | |
45711f1a | 2583 | page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); |
cdb8c2a6 GL |
2584 | *offset &= ~PAGE_MASK; |
2585 | ||
2586 | /* Bytes in this sg-entry from *offset to the end of the page */ | |
2587 | sg_len = PAGE_SIZE - *offset; | |
2588 | if (*len > sg_len) | |
2589 | *len = sg_len; | |
2590 | ||
77dfce07 | 2591 | return kmap_atomic(page); |
cdb8c2a6 GL |
2592 | } |
2593 | EXPORT_SYMBOL(scsi_kmap_atomic_sg); | |
2594 | ||
2595 | /** | |
eb44820c | 2596 | * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg |
cdb8c2a6 GL |
2597 | * @virt: virtual address to be unmapped |
2598 | */ | |
2599 | void scsi_kunmap_atomic_sg(void *virt) | |
2600 | { | |
77dfce07 | 2601 | kunmap_atomic(virt); |
cdb8c2a6 GL |
2602 | } |
2603 | EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |