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> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/completion.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/mempool.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/pci.h> | |
18 | #include <linux/delay.h> | |
faead26d | 19 | #include <linux/hardirq.h> |
1da177e4 LT |
20 | |
21 | #include <scsi/scsi.h> | |
beb40487 | 22 | #include <scsi/scsi_cmnd.h> |
1da177e4 LT |
23 | #include <scsi/scsi_dbg.h> |
24 | #include <scsi/scsi_device.h> | |
25 | #include <scsi/scsi_driver.h> | |
26 | #include <scsi/scsi_eh.h> | |
27 | #include <scsi/scsi_host.h> | |
1da177e4 LT |
28 | |
29 | #include "scsi_priv.h" | |
30 | #include "scsi_logging.h" | |
31 | ||
32 | ||
6391a113 | 33 | #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) |
1da177e4 LT |
34 | #define SG_MEMPOOL_SIZE 32 |
35 | ||
36 | struct scsi_host_sg_pool { | |
37 | size_t size; | |
38 | char *name; | |
39 | kmem_cache_t *slab; | |
40 | mempool_t *pool; | |
41 | }; | |
42 | ||
43 | #if (SCSI_MAX_PHYS_SEGMENTS < 32) | |
44 | #error SCSI_MAX_PHYS_SEGMENTS is too small | |
45 | #endif | |
46 | ||
47 | #define SP(x) { x, "sgpool-" #x } | |
52c1da39 | 48 | static struct scsi_host_sg_pool scsi_sg_pools[] = { |
1da177e4 LT |
49 | SP(8), |
50 | SP(16), | |
51 | SP(32), | |
52 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
53 | SP(64), | |
54 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
55 | SP(128), | |
56 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
57 | SP(256), | |
58 | #if (SCSI_MAX_PHYS_SEGMENTS > 256) | |
59 | #error SCSI_MAX_PHYS_SEGMENTS is too large | |
60 | #endif | |
61 | #endif | |
62 | #endif | |
63 | #endif | |
64 | }; | |
65 | #undef SP | |
66 | ||
a1bf9d1d | 67 | static void scsi_run_queue(struct request_queue *q); |
e91442b6 JB |
68 | |
69 | /* | |
70 | * Function: scsi_unprep_request() | |
71 | * | |
72 | * Purpose: Remove all preparation done for a request, including its | |
73 | * associated scsi_cmnd, so that it can be requeued. | |
74 | * | |
75 | * Arguments: req - request to unprepare | |
76 | * | |
77 | * Lock status: Assumed that no locks are held upon entry. | |
78 | * | |
79 | * Returns: Nothing. | |
80 | */ | |
81 | static void scsi_unprep_request(struct request *req) | |
82 | { | |
83 | struct scsi_cmnd *cmd = req->special; | |
84 | ||
85 | req->flags &= ~REQ_DONTPREP; | |
beb40487 | 86 | req->special = NULL; |
e91442b6 | 87 | |
e91442b6 JB |
88 | scsi_put_command(cmd); |
89 | } | |
a1bf9d1d | 90 | |
1da177e4 LT |
91 | /* |
92 | * Function: scsi_queue_insert() | |
93 | * | |
94 | * Purpose: Insert a command in the midlevel queue. | |
95 | * | |
96 | * Arguments: cmd - command that we are adding to queue. | |
97 | * reason - why we are inserting command to queue. | |
98 | * | |
99 | * Lock status: Assumed that lock is not held upon entry. | |
100 | * | |
101 | * Returns: Nothing. | |
102 | * | |
103 | * Notes: We do this for one of two cases. Either the host is busy | |
104 | * and it cannot accept any more commands for the time being, | |
105 | * or the device returned QUEUE_FULL and can accept no more | |
106 | * commands. | |
107 | * Notes: This could be called either from an interrupt context or a | |
108 | * normal process context. | |
109 | */ | |
110 | int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) | |
111 | { | |
112 | struct Scsi_Host *host = cmd->device->host; | |
113 | struct scsi_device *device = cmd->device; | |
a1bf9d1d TH |
114 | struct request_queue *q = device->request_queue; |
115 | unsigned long flags; | |
1da177e4 LT |
116 | |
117 | SCSI_LOG_MLQUEUE(1, | |
118 | printk("Inserting command %p into mlqueue\n", cmd)); | |
119 | ||
120 | /* | |
d8c37e7b | 121 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
122 | * |
123 | * If the host/device isn't busy, assume that something actually | |
124 | * completed, and that we should be able to queue a command now. | |
125 | * | |
126 | * Note that the prior mid-layer assumption that any host could | |
127 | * always queue at least one command is now broken. The mid-layer | |
128 | * will implement a user specifiable stall (see | |
129 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
130 | * if a command is requeued with no other commands outstanding | |
131 | * either for the device or for the host. | |
132 | */ | |
133 | if (reason == SCSI_MLQUEUE_HOST_BUSY) | |
134 | host->host_blocked = host->max_host_blocked; | |
135 | else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) | |
136 | device->device_blocked = device->max_device_blocked; | |
137 | ||
1da177e4 LT |
138 | /* |
139 | * Decrement the counters, since these commands are no longer | |
140 | * active on the host/device. | |
141 | */ | |
142 | scsi_device_unbusy(device); | |
143 | ||
144 | /* | |
a1bf9d1d TH |
145 | * Requeue this command. It will go before all other commands |
146 | * that are already in the queue. | |
1da177e4 LT |
147 | * |
148 | * NOTE: there is magic here about the way the queue is plugged if | |
149 | * we have no outstanding commands. | |
150 | * | |
a1bf9d1d | 151 | * Although we *don't* plug the queue, we call the request |
1da177e4 LT |
152 | * function. The SCSI request function detects the blocked condition |
153 | * and plugs the queue appropriately. | |
a1bf9d1d TH |
154 | */ |
155 | spin_lock_irqsave(q->queue_lock, flags); | |
59897dad | 156 | blk_requeue_request(q, cmd->request); |
a1bf9d1d TH |
157 | spin_unlock_irqrestore(q->queue_lock, flags); |
158 | ||
159 | scsi_run_queue(q); | |
160 | ||
1da177e4 LT |
161 | return 0; |
162 | } | |
163 | ||
39216033 | 164 | /** |
33aa687d | 165 | * scsi_execute - insert request and wait for the result |
39216033 JB |
166 | * @sdev: scsi device |
167 | * @cmd: scsi command | |
168 | * @data_direction: data direction | |
169 | * @buffer: data buffer | |
170 | * @bufflen: len of buffer | |
171 | * @sense: optional sense buffer | |
172 | * @timeout: request timeout in seconds | |
173 | * @retries: number of times to retry request | |
33aa687d | 174 | * @flags: or into request flags; |
39216033 | 175 | * |
ea73a9f2 JB |
176 | * returns the req->errors value which is the the scsi_cmnd result |
177 | * field. | |
39216033 | 178 | **/ |
33aa687d JB |
179 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
180 | int data_direction, void *buffer, unsigned bufflen, | |
181 | unsigned char *sense, int timeout, int retries, int flags) | |
39216033 JB |
182 | { |
183 | struct request *req; | |
184 | int write = (data_direction == DMA_TO_DEVICE); | |
185 | int ret = DRIVER_ERROR << 24; | |
186 | ||
187 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
188 | ||
189 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
190 | buffer, bufflen, __GFP_WAIT)) | |
191 | goto out; | |
192 | ||
193 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
194 | memcpy(req->cmd, cmd, req->cmd_len); | |
195 | req->sense = sense; | |
196 | req->sense_len = 0; | |
17e01f21 | 197 | req->retries = retries; |
39216033 | 198 | req->timeout = timeout; |
3173d8c3 | 199 | req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET; |
39216033 JB |
200 | |
201 | /* | |
202 | * head injection *required* here otherwise quiesce won't work | |
203 | */ | |
204 | blk_execute_rq(req->q, NULL, req, 1); | |
205 | ||
206 | ret = req->errors; | |
207 | out: | |
208 | blk_put_request(req); | |
209 | ||
210 | return ret; | |
211 | } | |
33aa687d | 212 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 213 | |
ea73a9f2 JB |
214 | |
215 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
216 | int data_direction, void *buffer, unsigned bufflen, | |
217 | struct scsi_sense_hdr *sshdr, int timeout, int retries) | |
218 | { | |
219 | char *sense = NULL; | |
1ccb48bb | 220 | int result; |
221 | ||
ea73a9f2 | 222 | if (sshdr) { |
24669f75 | 223 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
224 | if (!sense) |
225 | return DRIVER_ERROR << 24; | |
ea73a9f2 | 226 | } |
1ccb48bb | 227 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
24669f75 | 228 | sense, timeout, retries, 0); |
ea73a9f2 | 229 | if (sshdr) |
e514385b | 230 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
231 | |
232 | kfree(sense); | |
233 | return result; | |
234 | } | |
235 | EXPORT_SYMBOL(scsi_execute_req); | |
236 | ||
6e68af66 MC |
237 | struct scsi_io_context { |
238 | void *data; | |
239 | void (*done)(void *data, char *sense, int result, int resid); | |
240 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
241 | }; | |
242 | ||
aa7b5cd7 MC |
243 | static kmem_cache_t *scsi_io_context_cache; |
244 | ||
e650c305 | 245 | static void scsi_end_async(struct request *req, int uptodate) |
6e68af66 MC |
246 | { |
247 | struct scsi_io_context *sioc = req->end_io_data; | |
248 | ||
249 | if (sioc->done) | |
250 | sioc->done(sioc->data, sioc->sense, req->errors, req->data_len); | |
251 | ||
aa7b5cd7 | 252 | kmem_cache_free(scsi_io_context_cache, sioc); |
6e68af66 MC |
253 | __blk_put_request(req->q, req); |
254 | } | |
255 | ||
256 | static int scsi_merge_bio(struct request *rq, struct bio *bio) | |
257 | { | |
258 | struct request_queue *q = rq->q; | |
259 | ||
260 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
261 | if (rq_data_dir(rq) == WRITE) | |
262 | bio->bi_rw |= (1 << BIO_RW); | |
263 | blk_queue_bounce(q, &bio); | |
264 | ||
265 | if (!rq->bio) | |
266 | blk_rq_bio_prep(q, rq, bio); | |
267 | else if (!q->back_merge_fn(q, rq, bio)) | |
268 | return -EINVAL; | |
269 | else { | |
270 | rq->biotail->bi_next = bio; | |
271 | rq->biotail = bio; | |
272 | rq->hard_nr_sectors += bio_sectors(bio); | |
273 | rq->nr_sectors = rq->hard_nr_sectors; | |
274 | } | |
275 | ||
276 | return 0; | |
277 | } | |
278 | ||
279 | static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error) | |
280 | { | |
281 | if (bio->bi_size) | |
282 | return 1; | |
283 | ||
284 | bio_put(bio); | |
285 | return 0; | |
286 | } | |
287 | ||
288 | /** | |
289 | * scsi_req_map_sg - map a scatterlist into a request | |
290 | * @rq: request to fill | |
291 | * @sg: scatterlist | |
292 | * @nsegs: number of elements | |
293 | * @bufflen: len of buffer | |
294 | * @gfp: memory allocation flags | |
295 | * | |
296 | * scsi_req_map_sg maps a scatterlist into a request so that the | |
297 | * request can be sent to the block layer. We do not trust the scatterlist | |
298 | * sent to use, as some ULDs use that struct to only organize the pages. | |
299 | */ | |
300 | static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, | |
301 | int nsegs, unsigned bufflen, gfp_t gfp) | |
302 | { | |
303 | struct request_queue *q = rq->q; | |
f5235962 | 304 | int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT; |
6e68af66 MC |
305 | unsigned int data_len = 0, len, bytes, off; |
306 | struct page *page; | |
307 | struct bio *bio = NULL; | |
308 | int i, err, nr_vecs = 0; | |
309 | ||
310 | for (i = 0; i < nsegs; i++) { | |
311 | page = sgl[i].page; | |
312 | off = sgl[i].offset; | |
313 | len = sgl[i].length; | |
314 | data_len += len; | |
315 | ||
316 | while (len > 0) { | |
317 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
318 | ||
319 | if (!bio) { | |
320 | nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); | |
321 | nr_pages -= nr_vecs; | |
322 | ||
323 | bio = bio_alloc(gfp, nr_vecs); | |
324 | if (!bio) { | |
325 | err = -ENOMEM; | |
326 | goto free_bios; | |
327 | } | |
328 | bio->bi_end_io = scsi_bi_endio; | |
329 | } | |
330 | ||
331 | if (bio_add_pc_page(q, bio, page, bytes, off) != | |
332 | bytes) { | |
333 | bio_put(bio); | |
334 | err = -EINVAL; | |
335 | goto free_bios; | |
336 | } | |
337 | ||
338 | if (bio->bi_vcnt >= nr_vecs) { | |
339 | err = scsi_merge_bio(rq, bio); | |
340 | if (err) { | |
341 | bio_endio(bio, bio->bi_size, 0); | |
342 | goto free_bios; | |
343 | } | |
344 | bio = NULL; | |
345 | } | |
346 | ||
347 | page++; | |
348 | len -= bytes; | |
349 | off = 0; | |
350 | } | |
351 | } | |
352 | ||
353 | rq->buffer = rq->data = NULL; | |
354 | rq->data_len = data_len; | |
355 | return 0; | |
356 | ||
357 | free_bios: | |
358 | while ((bio = rq->bio) != NULL) { | |
359 | rq->bio = bio->bi_next; | |
360 | /* | |
361 | * call endio instead of bio_put incase it was bounced | |
362 | */ | |
363 | bio_endio(bio, bio->bi_size, 0); | |
364 | } | |
365 | ||
366 | return err; | |
367 | } | |
368 | ||
369 | /** | |
370 | * scsi_execute_async - insert request | |
371 | * @sdev: scsi device | |
372 | * @cmd: scsi command | |
bb1d1073 | 373 | * @cmd_len: length of scsi cdb |
6e68af66 MC |
374 | * @data_direction: data direction |
375 | * @buffer: data buffer (this can be a kernel buffer or scatterlist) | |
376 | * @bufflen: len of buffer | |
377 | * @use_sg: if buffer is a scatterlist this is the number of elements | |
378 | * @timeout: request timeout in seconds | |
379 | * @retries: number of times to retry request | |
380 | * @flags: or into request flags | |
381 | **/ | |
382 | int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, | |
bb1d1073 | 383 | int cmd_len, int data_direction, void *buffer, unsigned bufflen, |
6e68af66 MC |
384 | int use_sg, int timeout, int retries, void *privdata, |
385 | void (*done)(void *, char *, int, int), gfp_t gfp) | |
386 | { | |
387 | struct request *req; | |
388 | struct scsi_io_context *sioc; | |
389 | int err = 0; | |
390 | int write = (data_direction == DMA_TO_DEVICE); | |
391 | ||
aa7b5cd7 | 392 | sioc = kmem_cache_alloc(scsi_io_context_cache, gfp); |
6e68af66 MC |
393 | if (!sioc) |
394 | return DRIVER_ERROR << 24; | |
aa7b5cd7 | 395 | memset(sioc, 0, sizeof(*sioc)); |
6e68af66 MC |
396 | |
397 | req = blk_get_request(sdev->request_queue, write, gfp); | |
398 | if (!req) | |
399 | goto free_sense; | |
defd94b7 | 400 | req->flags |= REQ_BLOCK_PC | REQ_QUIET; |
6e68af66 MC |
401 | |
402 | if (use_sg) | |
403 | err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); | |
404 | else if (bufflen) | |
405 | err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); | |
406 | ||
407 | if (err) | |
408 | goto free_req; | |
409 | ||
bb1d1073 | 410 | req->cmd_len = cmd_len; |
6e68af66 MC |
411 | memcpy(req->cmd, cmd, req->cmd_len); |
412 | req->sense = sioc->sense; | |
413 | req->sense_len = 0; | |
414 | req->timeout = timeout; | |
17e01f21 | 415 | req->retries = retries; |
6e68af66 MC |
416 | req->end_io_data = sioc; |
417 | ||
418 | sioc->data = privdata; | |
419 | sioc->done = done; | |
420 | ||
421 | blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async); | |
422 | return 0; | |
423 | ||
424 | free_req: | |
425 | blk_put_request(req); | |
426 | free_sense: | |
427 | kfree(sioc); | |
428 | return DRIVER_ERROR << 24; | |
429 | } | |
430 | EXPORT_SYMBOL_GPL(scsi_execute_async); | |
431 | ||
1da177e4 LT |
432 | /* |
433 | * Function: scsi_init_cmd_errh() | |
434 | * | |
435 | * Purpose: Initialize cmd fields related to error handling. | |
436 | * | |
437 | * Arguments: cmd - command that is ready to be queued. | |
438 | * | |
1da177e4 LT |
439 | * Notes: This function has the job of initializing a number of |
440 | * fields related to error handling. Typically this will | |
441 | * be called once for each command, as required. | |
442 | */ | |
631c228c | 443 | static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) |
1da177e4 | 444 | { |
1da177e4 | 445 | cmd->serial_number = 0; |
1da177e4 | 446 | memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); |
1da177e4 LT |
447 | if (cmd->cmd_len == 0) |
448 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
1da177e4 LT |
449 | } |
450 | ||
451 | void scsi_device_unbusy(struct scsi_device *sdev) | |
452 | { | |
453 | struct Scsi_Host *shost = sdev->host; | |
454 | unsigned long flags; | |
455 | ||
456 | spin_lock_irqsave(shost->host_lock, flags); | |
457 | shost->host_busy--; | |
939647ee | 458 | if (unlikely(scsi_host_in_recovery(shost) && |
ee7863bc | 459 | (shost->host_failed || shost->host_eh_scheduled))) |
1da177e4 LT |
460 | scsi_eh_wakeup(shost); |
461 | spin_unlock(shost->host_lock); | |
152587de | 462 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 463 | sdev->device_busy--; |
152587de | 464 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
465 | } |
466 | ||
467 | /* | |
468 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
469 | * and call blk_run_queue for all the scsi_devices on the target - | |
470 | * including current_sdev first. | |
471 | * | |
472 | * Called with *no* scsi locks held. | |
473 | */ | |
474 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
475 | { | |
476 | struct Scsi_Host *shost = current_sdev->host; | |
477 | struct scsi_device *sdev, *tmp; | |
478 | struct scsi_target *starget = scsi_target(current_sdev); | |
479 | unsigned long flags; | |
480 | ||
481 | spin_lock_irqsave(shost->host_lock, flags); | |
482 | starget->starget_sdev_user = NULL; | |
483 | spin_unlock_irqrestore(shost->host_lock, flags); | |
484 | ||
485 | /* | |
486 | * Call blk_run_queue for all LUNs on the target, starting with | |
487 | * current_sdev. We race with others (to set starget_sdev_user), | |
488 | * but in most cases, we will be first. Ideally, each LU on the | |
489 | * target would get some limited time or requests on the target. | |
490 | */ | |
491 | blk_run_queue(current_sdev->request_queue); | |
492 | ||
493 | spin_lock_irqsave(shost->host_lock, flags); | |
494 | if (starget->starget_sdev_user) | |
495 | goto out; | |
496 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
497 | same_target_siblings) { | |
498 | if (sdev == current_sdev) | |
499 | continue; | |
500 | if (scsi_device_get(sdev)) | |
501 | continue; | |
502 | ||
503 | spin_unlock_irqrestore(shost->host_lock, flags); | |
504 | blk_run_queue(sdev->request_queue); | |
505 | spin_lock_irqsave(shost->host_lock, flags); | |
506 | ||
507 | scsi_device_put(sdev); | |
508 | } | |
509 | out: | |
510 | spin_unlock_irqrestore(shost->host_lock, flags); | |
511 | } | |
512 | ||
513 | /* | |
514 | * Function: scsi_run_queue() | |
515 | * | |
516 | * Purpose: Select a proper request queue to serve next | |
517 | * | |
518 | * Arguments: q - last request's queue | |
519 | * | |
520 | * Returns: Nothing | |
521 | * | |
522 | * Notes: The previous command was completely finished, start | |
523 | * a new one if possible. | |
524 | */ | |
525 | static void scsi_run_queue(struct request_queue *q) | |
526 | { | |
527 | struct scsi_device *sdev = q->queuedata; | |
528 | struct Scsi_Host *shost = sdev->host; | |
529 | unsigned long flags; | |
530 | ||
531 | if (sdev->single_lun) | |
532 | scsi_single_lun_run(sdev); | |
533 | ||
534 | spin_lock_irqsave(shost->host_lock, flags); | |
535 | while (!list_empty(&shost->starved_list) && | |
536 | !shost->host_blocked && !shost->host_self_blocked && | |
537 | !((shost->can_queue > 0) && | |
538 | (shost->host_busy >= shost->can_queue))) { | |
539 | /* | |
540 | * As long as shost is accepting commands and we have | |
541 | * starved queues, call blk_run_queue. scsi_request_fn | |
542 | * drops the queue_lock and can add us back to the | |
543 | * starved_list. | |
544 | * | |
545 | * host_lock protects the starved_list and starved_entry. | |
546 | * scsi_request_fn must get the host_lock before checking | |
547 | * or modifying starved_list or starved_entry. | |
548 | */ | |
549 | sdev = list_entry(shost->starved_list.next, | |
550 | struct scsi_device, starved_entry); | |
551 | list_del_init(&sdev->starved_entry); | |
552 | spin_unlock_irqrestore(shost->host_lock, flags); | |
553 | ||
04846f25 AH |
554 | |
555 | if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && | |
556 | !test_and_set_bit(QUEUE_FLAG_REENTER, | |
557 | &sdev->request_queue->queue_flags)) { | |
558 | blk_run_queue(sdev->request_queue); | |
559 | clear_bit(QUEUE_FLAG_REENTER, | |
560 | &sdev->request_queue->queue_flags); | |
561 | } else | |
562 | blk_run_queue(sdev->request_queue); | |
1da177e4 LT |
563 | |
564 | spin_lock_irqsave(shost->host_lock, flags); | |
565 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
566 | /* | |
567 | * sdev lost a race, and was put back on the | |
568 | * starved list. This is unlikely but without this | |
569 | * in theory we could loop forever. | |
570 | */ | |
571 | break; | |
572 | } | |
573 | spin_unlock_irqrestore(shost->host_lock, flags); | |
574 | ||
575 | blk_run_queue(q); | |
576 | } | |
577 | ||
578 | /* | |
579 | * Function: scsi_requeue_command() | |
580 | * | |
581 | * Purpose: Handle post-processing of completed commands. | |
582 | * | |
583 | * Arguments: q - queue to operate on | |
584 | * cmd - command that may need to be requeued. | |
585 | * | |
586 | * Returns: Nothing | |
587 | * | |
588 | * Notes: After command completion, there may be blocks left | |
589 | * over which weren't finished by the previous command | |
590 | * this can be for a number of reasons - the main one is | |
591 | * I/O errors in the middle of the request, in which case | |
592 | * we need to request the blocks that come after the bad | |
593 | * sector. | |
e91442b6 | 594 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
595 | */ |
596 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
597 | { | |
e91442b6 | 598 | struct request *req = cmd->request; |
283369cc TH |
599 | unsigned long flags; |
600 | ||
e91442b6 | 601 | scsi_unprep_request(req); |
283369cc | 602 | spin_lock_irqsave(q->queue_lock, flags); |
e91442b6 | 603 | blk_requeue_request(q, req); |
283369cc | 604 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
605 | |
606 | scsi_run_queue(q); | |
607 | } | |
608 | ||
609 | void scsi_next_command(struct scsi_cmnd *cmd) | |
610 | { | |
49d7bc64 LT |
611 | struct scsi_device *sdev = cmd->device; |
612 | struct request_queue *q = sdev->request_queue; | |
613 | ||
614 | /* need to hold a reference on the device before we let go of the cmd */ | |
615 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
616 | |
617 | scsi_put_command(cmd); | |
618 | scsi_run_queue(q); | |
49d7bc64 LT |
619 | |
620 | /* ok to remove device now */ | |
621 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
622 | } |
623 | ||
624 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
625 | { | |
626 | struct scsi_device *sdev; | |
627 | ||
628 | shost_for_each_device(sdev, shost) | |
629 | scsi_run_queue(sdev->request_queue); | |
630 | } | |
631 | ||
632 | /* | |
633 | * Function: scsi_end_request() | |
634 | * | |
635 | * Purpose: Post-processing of completed commands (usually invoked at end | |
636 | * of upper level post-processing and scsi_io_completion). | |
637 | * | |
638 | * Arguments: cmd - command that is complete. | |
639 | * uptodate - 1 if I/O indicates success, <= 0 for I/O error. | |
640 | * bytes - number of bytes of completed I/O | |
641 | * requeue - indicates whether we should requeue leftovers. | |
642 | * | |
643 | * Lock status: Assumed that lock is not held upon entry. | |
644 | * | |
e91442b6 | 645 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
646 | * |
647 | * Notes: This is called for block device requests in order to | |
648 | * mark some number of sectors as complete. | |
649 | * | |
650 | * We are guaranteeing that the request queue will be goosed | |
651 | * at some point during this call. | |
e91442b6 | 652 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 LT |
653 | */ |
654 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, | |
655 | int bytes, int requeue) | |
656 | { | |
657 | request_queue_t *q = cmd->device->request_queue; | |
658 | struct request *req = cmd->request; | |
659 | unsigned long flags; | |
660 | ||
661 | /* | |
662 | * If there are blocks left over at the end, set up the command | |
663 | * to queue the remainder of them. | |
664 | */ | |
665 | if (end_that_request_chunk(req, uptodate, bytes)) { | |
666 | int leftover = (req->hard_nr_sectors << 9); | |
667 | ||
668 | if (blk_pc_request(req)) | |
669 | leftover = req->data_len; | |
670 | ||
671 | /* kill remainder if no retrys */ | |
672 | if (!uptodate && blk_noretry_request(req)) | |
673 | end_that_request_chunk(req, 0, leftover); | |
674 | else { | |
e91442b6 | 675 | if (requeue) { |
1da177e4 LT |
676 | /* |
677 | * Bleah. Leftovers again. Stick the | |
678 | * leftovers in the front of the | |
679 | * queue, and goose the queue again. | |
680 | */ | |
681 | scsi_requeue_command(q, cmd); | |
e91442b6 JB |
682 | cmd = NULL; |
683 | } | |
1da177e4 LT |
684 | return cmd; |
685 | } | |
686 | } | |
687 | ||
688 | add_disk_randomness(req->rq_disk); | |
689 | ||
690 | spin_lock_irqsave(q->queue_lock, flags); | |
691 | if (blk_rq_tagged(req)) | |
692 | blk_queue_end_tag(q, req); | |
8ffdc655 | 693 | end_that_request_last(req, uptodate); |
1da177e4 LT |
694 | spin_unlock_irqrestore(q->queue_lock, flags); |
695 | ||
696 | /* | |
697 | * This will goose the queue request function at the end, so we don't | |
698 | * need to worry about launching another command. | |
699 | */ | |
700 | scsi_next_command(cmd); | |
701 | return NULL; | |
702 | } | |
703 | ||
c53033f6 | 704 | static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) |
1da177e4 LT |
705 | { |
706 | struct scsi_host_sg_pool *sgp; | |
707 | struct scatterlist *sgl; | |
708 | ||
709 | BUG_ON(!cmd->use_sg); | |
710 | ||
711 | switch (cmd->use_sg) { | |
712 | case 1 ... 8: | |
713 | cmd->sglist_len = 0; | |
714 | break; | |
715 | case 9 ... 16: | |
716 | cmd->sglist_len = 1; | |
717 | break; | |
718 | case 17 ... 32: | |
719 | cmd->sglist_len = 2; | |
720 | break; | |
721 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
722 | case 33 ... 64: | |
723 | cmd->sglist_len = 3; | |
724 | break; | |
725 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
726 | case 65 ... 128: | |
727 | cmd->sglist_len = 4; | |
728 | break; | |
729 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
730 | case 129 ... 256: | |
731 | cmd->sglist_len = 5; | |
732 | break; | |
733 | #endif | |
734 | #endif | |
735 | #endif | |
736 | default: | |
737 | return NULL; | |
738 | } | |
739 | ||
740 | sgp = scsi_sg_pools + cmd->sglist_len; | |
741 | sgl = mempool_alloc(sgp->pool, gfp_mask); | |
1da177e4 LT |
742 | return sgl; |
743 | } | |
744 | ||
745 | static void scsi_free_sgtable(struct scatterlist *sgl, int index) | |
746 | { | |
747 | struct scsi_host_sg_pool *sgp; | |
748 | ||
a77e3362 | 749 | BUG_ON(index >= SG_MEMPOOL_NR); |
1da177e4 LT |
750 | |
751 | sgp = scsi_sg_pools + index; | |
752 | mempool_free(sgl, sgp->pool); | |
753 | } | |
754 | ||
755 | /* | |
756 | * Function: scsi_release_buffers() | |
757 | * | |
758 | * Purpose: Completion processing for block device I/O requests. | |
759 | * | |
760 | * Arguments: cmd - command that we are bailing. | |
761 | * | |
762 | * Lock status: Assumed that no lock is held upon entry. | |
763 | * | |
764 | * Returns: Nothing | |
765 | * | |
766 | * Notes: In the event that an upper level driver rejects a | |
767 | * command, we must release resources allocated during | |
768 | * the __init_io() function. Primarily this would involve | |
769 | * the scatter-gather table, and potentially any bounce | |
770 | * buffers. | |
771 | */ | |
772 | static void scsi_release_buffers(struct scsi_cmnd *cmd) | |
773 | { | |
1da177e4 LT |
774 | if (cmd->use_sg) |
775 | scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); | |
1da177e4 LT |
776 | |
777 | /* | |
778 | * Zero these out. They now point to freed memory, and it is | |
779 | * dangerous to hang onto the pointers. | |
780 | */ | |
1da177e4 LT |
781 | cmd->request_buffer = NULL; |
782 | cmd->request_bufflen = 0; | |
783 | } | |
784 | ||
785 | /* | |
786 | * Function: scsi_io_completion() | |
787 | * | |
788 | * Purpose: Completion processing for block device I/O requests. | |
789 | * | |
790 | * Arguments: cmd - command that is finished. | |
791 | * | |
792 | * Lock status: Assumed that no lock is held upon entry. | |
793 | * | |
794 | * Returns: Nothing | |
795 | * | |
796 | * Notes: This function is matched in terms of capabilities to | |
797 | * the function that created the scatter-gather list. | |
798 | * In other words, if there are no bounce buffers | |
799 | * (the normal case for most drivers), we don't need | |
800 | * the logic to deal with cleaning up afterwards. | |
801 | * | |
802 | * We must do one of several things here: | |
803 | * | |
804 | * a) Call scsi_end_request. This will finish off the | |
805 | * specified number of sectors. If we are done, the | |
806 | * command block will be released, and the queue | |
807 | * function will be goosed. If we are not done, then | |
808 | * scsi_end_request will directly goose the queue. | |
809 | * | |
810 | * b) We can just use scsi_requeue_command() here. This would | |
811 | * be used if we just wanted to retry, for example. | |
812 | */ | |
03aba2f7 | 813 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
1da177e4 LT |
814 | { |
815 | int result = cmd->result; | |
631c228c | 816 | int this_count = cmd->request_bufflen; |
1da177e4 LT |
817 | request_queue_t *q = cmd->device->request_queue; |
818 | struct request *req = cmd->request; | |
819 | int clear_errors = 1; | |
820 | struct scsi_sense_hdr sshdr; | |
821 | int sense_valid = 0; | |
822 | int sense_deferred = 0; | |
823 | ||
631c228c | 824 | scsi_release_buffers(cmd); |
1da177e4 LT |
825 | |
826 | if (result) { | |
827 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
828 | if (sense_valid) | |
829 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
830 | } | |
631c228c | 831 | |
1da177e4 LT |
832 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ |
833 | req->errors = result; | |
834 | if (result) { | |
835 | clear_errors = 0; | |
836 | if (sense_valid && req->sense) { | |
837 | /* | |
838 | * SG_IO wants current and deferred errors | |
839 | */ | |
840 | int len = 8 + cmd->sense_buffer[7]; | |
841 | ||
842 | if (len > SCSI_SENSE_BUFFERSIZE) | |
843 | len = SCSI_SENSE_BUFFERSIZE; | |
844 | memcpy(req->sense, cmd->sense_buffer, len); | |
845 | req->sense_len = len; | |
846 | } | |
847 | } else | |
848 | req->data_len = cmd->resid; | |
849 | } | |
850 | ||
1da177e4 LT |
851 | /* |
852 | * Next deal with any sectors which we were able to correctly | |
853 | * handle. | |
854 | */ | |
d6b0c537 JB |
855 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, " |
856 | "%d bytes done.\n", | |
857 | req->nr_sectors, good_bytes)); | |
858 | SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); | |
859 | ||
860 | if (clear_errors) | |
861 | req->errors = 0; | |
862 | ||
863 | /* A number of bytes were successfully read. If there | |
864 | * are leftovers and there is some kind of error | |
865 | * (result != 0), retry the rest. | |
866 | */ | |
867 | if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) | |
868 | return; | |
03aba2f7 LT |
869 | |
870 | /* good_bytes = 0, or (inclusive) there were leftovers and | |
871 | * result = 0, so scsi_end_request couldn't retry. | |
1da177e4 LT |
872 | */ |
873 | if (sense_valid && !sense_deferred) { | |
874 | switch (sshdr.sense_key) { | |
875 | case UNIT_ATTENTION: | |
876 | if (cmd->device->removable) { | |
03aba2f7 | 877 | /* Detected disc change. Set a bit |
1da177e4 LT |
878 | * and quietly refuse further access. |
879 | */ | |
880 | cmd->device->changed = 1; | |
03aba2f7 | 881 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
882 | return; |
883 | } else { | |
03aba2f7 LT |
884 | /* Must have been a power glitch, or a |
885 | * bus reset. Could not have been a | |
886 | * media change, so we just retry the | |
887 | * request and see what happens. | |
888 | */ | |
1da177e4 LT |
889 | scsi_requeue_command(q, cmd); |
890 | return; | |
891 | } | |
892 | break; | |
893 | case ILLEGAL_REQUEST: | |
03aba2f7 LT |
894 | /* If we had an ILLEGAL REQUEST returned, then |
895 | * we may have performed an unsupported | |
896 | * command. The only thing this should be | |
897 | * would be a ten byte read where only a six | |
898 | * byte read was supported. Also, on a system | |
899 | * where READ CAPACITY failed, we may have | |
900 | * read past the end of the disk. | |
901 | */ | |
26a68019 JA |
902 | if ((cmd->device->use_10_for_rw && |
903 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
904 | (cmd->cmnd[0] == READ_10 || |
905 | cmd->cmnd[0] == WRITE_10)) { | |
906 | cmd->device->use_10_for_rw = 0; | |
03aba2f7 LT |
907 | /* This will cause a retry with a |
908 | * 6-byte command. | |
1da177e4 LT |
909 | */ |
910 | scsi_requeue_command(q, cmd); | |
03aba2f7 | 911 | return; |
1da177e4 | 912 | } else { |
e91442b6 | 913 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
914 | return; |
915 | } | |
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 */ | |
930 | scsi_requeue_command(q, cmd); | |
931 | return; | |
932 | default: | |
933 | break; | |
934 | } | |
1da177e4 | 935 | } |
f3e93f73 | 936 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 | 937 | scmd_printk(KERN_INFO, cmd, |
03aba2f7 | 938 | "Device not ready: "); |
f3e93f73 JB |
939 | scsi_print_sense_hdr("", &sshdr); |
940 | } | |
e91442b6 | 941 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
942 | return; |
943 | case VOLUME_OVERFLOW: | |
3173d8c3 | 944 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 | 945 | scmd_printk(KERN_INFO, cmd, |
03aba2f7 | 946 | "Volume overflow, CDB: "); |
631c228c | 947 | __scsi_print_command(cmd->cmnd); |
3173d8c3 JB |
948 | scsi_print_sense("", cmd); |
949 | } | |
03aba2f7 LT |
950 | /* See SSC3rXX or current. */ |
951 | scsi_end_request(cmd, 0, this_count, 1); | |
1da177e4 LT |
952 | return; |
953 | default: | |
954 | break; | |
955 | } | |
03aba2f7 | 956 | } |
1da177e4 | 957 | if (host_byte(result) == DID_RESET) { |
03aba2f7 LT |
958 | /* Third party bus reset or reset for error recovery |
959 | * reasons. Just retry the request and see what | |
960 | * happens. | |
1da177e4 LT |
961 | */ |
962 | scsi_requeue_command(q, cmd); | |
963 | return; | |
964 | } | |
965 | if (result) { | |
3173d8c3 | 966 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 | 967 | scmd_printk(KERN_INFO, cmd, |
03aba2f7 LT |
968 | "SCSI error: return code = 0x%08x\n", |
969 | result); | |
3173d8c3 JB |
970 | if (driver_byte(result) & DRIVER_SENSE) |
971 | scsi_print_sense("", cmd); | |
972 | } | |
1da177e4 | 973 | } |
03aba2f7 | 974 | scsi_end_request(cmd, 0, this_count, !result); |
1da177e4 LT |
975 | } |
976 | EXPORT_SYMBOL(scsi_io_completion); | |
977 | ||
978 | /* | |
979 | * Function: scsi_init_io() | |
980 | * | |
981 | * Purpose: SCSI I/O initialize function. | |
982 | * | |
983 | * Arguments: cmd - Command descriptor we wish to initialize | |
984 | * | |
985 | * Returns: 0 on success | |
986 | * BLKPREP_DEFER if the failure is retryable | |
987 | * BLKPREP_KILL if the failure is fatal | |
988 | */ | |
989 | static int scsi_init_io(struct scsi_cmnd *cmd) | |
990 | { | |
991 | struct request *req = cmd->request; | |
992 | struct scatterlist *sgpnt; | |
993 | int count; | |
994 | ||
995 | /* | |
996 | * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer | |
997 | */ | |
998 | if ((req->flags & REQ_BLOCK_PC) && !req->bio) { | |
999 | cmd->request_bufflen = req->data_len; | |
1000 | cmd->request_buffer = req->data; | |
1001 | req->buffer = req->data; | |
1002 | cmd->use_sg = 0; | |
1003 | return 0; | |
1004 | } | |
1005 | ||
1006 | /* | |
1007 | * we used to not use scatter-gather for single segment request, | |
1008 | * but now we do (it makes highmem I/O easier to support without | |
1009 | * kmapping pages) | |
1010 | */ | |
1011 | cmd->use_sg = req->nr_phys_segments; | |
1012 | ||
1013 | /* | |
1014 | * if sg table allocation fails, requeue request later. | |
1015 | */ | |
1016 | sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); | |
7c72ce81 AS |
1017 | if (unlikely(!sgpnt)) { |
1018 | scsi_unprep_request(req); | |
1da177e4 | 1019 | return BLKPREP_DEFER; |
7c72ce81 | 1020 | } |
1da177e4 LT |
1021 | |
1022 | cmd->request_buffer = (char *) sgpnt; | |
1023 | cmd->request_bufflen = req->nr_sectors << 9; | |
1024 | if (blk_pc_request(req)) | |
1025 | cmd->request_bufflen = req->data_len; | |
1026 | req->buffer = NULL; | |
1027 | ||
1028 | /* | |
1029 | * Next, walk the list, and fill in the addresses and sizes of | |
1030 | * each segment. | |
1031 | */ | |
1032 | count = blk_rq_map_sg(req->q, req, cmd->request_buffer); | |
1033 | ||
1034 | /* | |
1035 | * mapped well, send it off | |
1036 | */ | |
1037 | if (likely(count <= cmd->use_sg)) { | |
1038 | cmd->use_sg = count; | |
1039 | return 0; | |
1040 | } | |
1041 | ||
1042 | printk(KERN_ERR "Incorrect number of segments after building list\n"); | |
1043 | printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg); | |
1044 | printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, | |
1045 | req->current_nr_sectors); | |
1046 | ||
1047 | /* release the command and kill it */ | |
1048 | scsi_release_buffers(cmd); | |
1049 | scsi_put_command(cmd); | |
1050 | return BLKPREP_KILL; | |
1051 | } | |
1052 | ||
1da177e4 LT |
1053 | static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, |
1054 | sector_t *error_sector) | |
1055 | { | |
1056 | struct scsi_device *sdev = q->queuedata; | |
1057 | struct scsi_driver *drv; | |
1058 | ||
1059 | if (sdev->sdev_state != SDEV_RUNNING) | |
1060 | return -ENXIO; | |
1061 | ||
1062 | drv = *(struct scsi_driver **) disk->private_data; | |
1063 | if (drv->issue_flush) | |
1064 | return drv->issue_flush(&sdev->sdev_gendev, error_sector); | |
1065 | ||
1066 | return -EOPNOTSUPP; | |
1067 | } | |
1068 | ||
776b23a0 | 1069 | static void scsi_blk_pc_done(struct scsi_cmnd *cmd) |
e537a36d JB |
1070 | { |
1071 | BUG_ON(!blk_pc_request(cmd->request)); | |
0d95716d MC |
1072 | /* |
1073 | * This will complete the whole command with uptodate=1 so | |
1074 | * as far as the block layer is concerned the command completed | |
1075 | * successfully. Since this is a REQ_BLOCK_PC command the | |
1076 | * caller should check the request's errors value | |
1077 | */ | |
631c228c | 1078 | scsi_io_completion(cmd, cmd->request_bufflen); |
e537a36d JB |
1079 | } |
1080 | ||
776b23a0 | 1081 | static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) |
7b16318d JB |
1082 | { |
1083 | struct request *req = cmd->request; | |
1084 | ||
1085 | BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); | |
1086 | memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); | |
1087 | cmd->cmd_len = req->cmd_len; | |
1088 | if (!req->data_len) | |
1089 | cmd->sc_data_direction = DMA_NONE; | |
1090 | else if (rq_data_dir(req) == WRITE) | |
1091 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1092 | else | |
1093 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1094 | ||
1095 | cmd->transfersize = req->data_len; | |
1096 | cmd->allowed = req->retries; | |
1097 | cmd->timeout_per_command = req->timeout; | |
776b23a0 | 1098 | cmd->done = scsi_blk_pc_done; |
7b16318d | 1099 | } |
7b16318d | 1100 | |
1da177e4 LT |
1101 | static int scsi_prep_fn(struct request_queue *q, struct request *req) |
1102 | { | |
1103 | struct scsi_device *sdev = q->queuedata; | |
1104 | struct scsi_cmnd *cmd; | |
1105 | int specials_only = 0; | |
1106 | ||
1107 | /* | |
1108 | * Just check to see if the device is online. If it isn't, we | |
1109 | * refuse to process any commands. The device must be brought | |
1110 | * online before trying any recovery commands | |
1111 | */ | |
1112 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1113 | sdev_printk(KERN_ERR, sdev, |
1114 | "rejecting I/O to offline device\n"); | |
6f16b535 | 1115 | goto kill; |
1da177e4 LT |
1116 | } |
1117 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1118 | /* OK, we're not in a running state don't prep | |
1119 | * user commands */ | |
1120 | if (sdev->sdev_state == SDEV_DEL) { | |
1121 | /* Device is fully deleted, no commands | |
1122 | * at all allowed down */ | |
9ccfc756 JB |
1123 | sdev_printk(KERN_ERR, sdev, |
1124 | "rejecting I/O to dead device\n"); | |
6f16b535 | 1125 | goto kill; |
1da177e4 LT |
1126 | } |
1127 | /* OK, we only allow special commands (i.e. not | |
1128 | * user initiated ones */ | |
1129 | specials_only = sdev->sdev_state; | |
1130 | } | |
1131 | ||
1132 | /* | |
1133 | * Find the actual device driver associated with this command. | |
1134 | * The SPECIAL requests are things like character device or | |
1135 | * ioctls, which did not originate from ll_rw_blk. Note that | |
1136 | * the special field is also used to indicate the cmd for | |
1137 | * the remainder of a partially fulfilled request that can | |
1138 | * come up when there is a medium error. We have to treat | |
1139 | * these two cases differently. We differentiate by looking | |
1140 | * at request->cmd, as this tells us the real story. | |
1141 | */ | |
e537a36d | 1142 | if (req->flags & REQ_SPECIAL && req->special) { |
beb40487 | 1143 | cmd = req->special; |
1da177e4 LT |
1144 | } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { |
1145 | ||
e537a36d | 1146 | if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { |
1da177e4 LT |
1147 | if(specials_only == SDEV_QUIESCE || |
1148 | specials_only == SDEV_BLOCK) | |
6f16b535 | 1149 | goto defer; |
1da177e4 | 1150 | |
9ccfc756 JB |
1151 | sdev_printk(KERN_ERR, sdev, |
1152 | "rejecting I/O to device being removed\n"); | |
6f16b535 | 1153 | goto kill; |
1da177e4 LT |
1154 | } |
1155 | ||
1156 | ||
1157 | /* | |
1158 | * Now try and find a command block that we can use. | |
1159 | */ | |
1160 | if (!req->special) { | |
1161 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1162 | if (unlikely(!cmd)) | |
1163 | goto defer; | |
1164 | } else | |
1165 | cmd = req->special; | |
1166 | ||
1167 | /* pull a tag out of the request if we have one */ | |
1168 | cmd->tag = req->tag; | |
1169 | } else { | |
1170 | blk_dump_rq_flags(req, "SCSI bad req"); | |
6f16b535 | 1171 | goto kill; |
1da177e4 LT |
1172 | } |
1173 | ||
1174 | /* note the overloading of req->special. When the tag | |
1175 | * is active it always means cmd. If the tag goes | |
1176 | * back for re-queueing, it may be reset */ | |
1177 | req->special = cmd; | |
1178 | cmd->request = req; | |
1179 | ||
1180 | /* | |
1181 | * FIXME: drop the lock here because the functions below | |
1182 | * expect to be called without the queue lock held. Also, | |
1183 | * previously, we dequeued the request before dropping the | |
1184 | * lock. We hope REQ_STARTED prevents anything untoward from | |
1185 | * happening now. | |
1186 | */ | |
1187 | if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1da177e4 LT |
1188 | int ret; |
1189 | ||
1190 | /* | |
1191 | * This will do a couple of things: | |
1192 | * 1) Fill in the actual SCSI command. | |
1193 | * 2) Fill in any other upper-level specific fields | |
1194 | * (timeout). | |
1195 | * | |
1196 | * If this returns 0, it means that the request failed | |
1197 | * (reading past end of disk, reading offline device, | |
1198 | * etc). This won't actually talk to the device, but | |
1199 | * some kinds of consistency checking may cause the | |
1200 | * request to be rejected immediately. | |
1201 | */ | |
1202 | ||
1203 | /* | |
1204 | * This sets up the scatter-gather table (allocating if | |
1205 | * required). | |
1206 | */ | |
1207 | ret = scsi_init_io(cmd); | |
6f16b535 | 1208 | switch(ret) { |
7c72ce81 | 1209 | /* For BLKPREP_KILL/DEFER the cmd was released */ |
6f16b535 | 1210 | case BLKPREP_KILL: |
6f16b535 MC |
1211 | goto kill; |
1212 | case BLKPREP_DEFER: | |
1213 | goto defer; | |
1214 | } | |
1da177e4 LT |
1215 | |
1216 | /* | |
1217 | * Initialize the actual SCSI command for this request. | |
1218 | */ | |
776b23a0 CH |
1219 | if (req->flags & REQ_BLOCK_PC) { |
1220 | scsi_setup_blk_pc_cmnd(cmd); | |
1221 | } else if (req->rq_disk) { | |
1222 | struct scsi_driver *drv; | |
1223 | ||
e537a36d JB |
1224 | drv = *(struct scsi_driver **)req->rq_disk->private_data; |
1225 | if (unlikely(!drv->init_command(cmd))) { | |
1226 | scsi_release_buffers(cmd); | |
1227 | scsi_put_command(cmd); | |
6f16b535 | 1228 | goto kill; |
e537a36d | 1229 | } |
1da177e4 LT |
1230 | } |
1231 | } | |
1232 | ||
1233 | /* | |
1234 | * The request is now prepped, no need to come back here | |
1235 | */ | |
1236 | req->flags |= REQ_DONTPREP; | |
1237 | return BLKPREP_OK; | |
1238 | ||
1239 | defer: | |
1240 | /* If we defer, the elv_next_request() returns NULL, but the | |
1241 | * queue must be restarted, so we plug here if no returning | |
1242 | * command will automatically do that. */ | |
1243 | if (sdev->device_busy == 0) | |
1244 | blk_plug_device(q); | |
1245 | return BLKPREP_DEFER; | |
6f16b535 MC |
1246 | kill: |
1247 | req->errors = DID_NO_CONNECT << 16; | |
1248 | return BLKPREP_KILL; | |
1da177e4 LT |
1249 | } |
1250 | ||
1251 | /* | |
1252 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1253 | * return 0. | |
1254 | * | |
1255 | * Called with the queue_lock held. | |
1256 | */ | |
1257 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1258 | struct scsi_device *sdev) | |
1259 | { | |
1260 | if (sdev->device_busy >= sdev->queue_depth) | |
1261 | return 0; | |
1262 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1263 | /* | |
1264 | * unblock after device_blocked iterates to zero | |
1265 | */ | |
1266 | if (--sdev->device_blocked == 0) { | |
1267 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1268 | sdev_printk(KERN_INFO, sdev, |
1269 | "unblocking device at zero depth\n")); | |
1da177e4 LT |
1270 | } else { |
1271 | blk_plug_device(q); | |
1272 | return 0; | |
1273 | } | |
1274 | } | |
1275 | if (sdev->device_blocked) | |
1276 | return 0; | |
1277 | ||
1278 | return 1; | |
1279 | } | |
1280 | ||
1281 | /* | |
1282 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1283 | * return 0. We must end up running the queue again whenever 0 is | |
1284 | * returned, else IO can hang. | |
1285 | * | |
1286 | * Called with host_lock held. | |
1287 | */ | |
1288 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1289 | struct Scsi_Host *shost, | |
1290 | struct scsi_device *sdev) | |
1291 | { | |
939647ee | 1292 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1293 | return 0; |
1294 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1295 | /* | |
1296 | * unblock after host_blocked iterates to zero | |
1297 | */ | |
1298 | if (--shost->host_blocked == 0) { | |
1299 | SCSI_LOG_MLQUEUE(3, | |
1300 | printk("scsi%d unblocking host at zero depth\n", | |
1301 | shost->host_no)); | |
1302 | } else { | |
1303 | blk_plug_device(q); | |
1304 | return 0; | |
1305 | } | |
1306 | } | |
1307 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1308 | shost->host_blocked || shost->host_self_blocked) { | |
1309 | if (list_empty(&sdev->starved_entry)) | |
1310 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1311 | return 0; | |
1312 | } | |
1313 | ||
1314 | /* We're OK to process the command, so we can't be starved */ | |
1315 | if (!list_empty(&sdev->starved_entry)) | |
1316 | list_del_init(&sdev->starved_entry); | |
1317 | ||
1318 | return 1; | |
1319 | } | |
1320 | ||
1321 | /* | |
e91442b6 | 1322 | * Kill a request for a dead device |
1da177e4 | 1323 | */ |
e91442b6 | 1324 | static void scsi_kill_request(struct request *req, request_queue_t *q) |
1da177e4 | 1325 | { |
e91442b6 | 1326 | struct scsi_cmnd *cmd = req->special; |
e36e0c80 TH |
1327 | struct scsi_device *sdev = cmd->device; |
1328 | struct Scsi_Host *shost = sdev->host; | |
1da177e4 | 1329 | |
788ce43a JB |
1330 | blkdev_dequeue_request(req); |
1331 | ||
e91442b6 JB |
1332 | if (unlikely(cmd == NULL)) { |
1333 | printk(KERN_CRIT "impossible request in %s.\n", | |
1334 | __FUNCTION__); | |
1335 | BUG(); | |
1da177e4 | 1336 | } |
e91442b6 JB |
1337 | |
1338 | scsi_init_cmd_errh(cmd); | |
1339 | cmd->result = DID_NO_CONNECT << 16; | |
1340 | atomic_inc(&cmd->device->iorequest_cnt); | |
e36e0c80 TH |
1341 | |
1342 | /* | |
1343 | * SCSI request completion path will do scsi_device_unbusy(), | |
1344 | * bump busy counts. To bump the counters, we need to dance | |
1345 | * with the locks as normal issue path does. | |
1346 | */ | |
1347 | sdev->device_busy++; | |
1348 | spin_unlock(sdev->request_queue->queue_lock); | |
1349 | spin_lock(shost->host_lock); | |
1350 | shost->host_busy++; | |
1351 | spin_unlock(shost->host_lock); | |
1352 | spin_lock(sdev->request_queue->queue_lock); | |
1353 | ||
e91442b6 | 1354 | __scsi_done(cmd); |
1da177e4 LT |
1355 | } |
1356 | ||
1aea6434 JA |
1357 | static void scsi_softirq_done(struct request *rq) |
1358 | { | |
1359 | struct scsi_cmnd *cmd = rq->completion_data; | |
8884efab | 1360 | unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; |
1aea6434 JA |
1361 | int disposition; |
1362 | ||
1363 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1364 | ||
1365 | disposition = scsi_decide_disposition(cmd); | |
1366 | if (disposition != SUCCESS && | |
1367 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1368 | sdev_printk(KERN_ERR, cmd->device, | |
1369 | "timing out command, waited %lus\n", | |
1370 | wait_for/HZ); | |
1371 | disposition = SUCCESS; | |
1372 | } | |
1373 | ||
1374 | scsi_log_completion(cmd, disposition); | |
1375 | ||
1376 | switch (disposition) { | |
1377 | case SUCCESS: | |
1378 | scsi_finish_command(cmd); | |
1379 | break; | |
1380 | case NEEDS_RETRY: | |
1381 | scsi_retry_command(cmd); | |
1382 | break; | |
1383 | case ADD_TO_MLQUEUE: | |
1384 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1385 | break; | |
1386 | default: | |
1387 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1388 | scsi_finish_command(cmd); | |
1389 | } | |
1390 | } | |
1391 | ||
1da177e4 LT |
1392 | /* |
1393 | * Function: scsi_request_fn() | |
1394 | * | |
1395 | * Purpose: Main strategy routine for SCSI. | |
1396 | * | |
1397 | * Arguments: q - Pointer to actual queue. | |
1398 | * | |
1399 | * Returns: Nothing | |
1400 | * | |
1401 | * Lock status: IO request lock assumed to be held when called. | |
1402 | */ | |
1403 | static void scsi_request_fn(struct request_queue *q) | |
1404 | { | |
1405 | struct scsi_device *sdev = q->queuedata; | |
1406 | struct Scsi_Host *shost; | |
1407 | struct scsi_cmnd *cmd; | |
1408 | struct request *req; | |
1409 | ||
1410 | if (!sdev) { | |
1411 | printk("scsi: killing requests for dead queue\n"); | |
e91442b6 JB |
1412 | while ((req = elv_next_request(q)) != NULL) |
1413 | scsi_kill_request(req, q); | |
1da177e4 LT |
1414 | return; |
1415 | } | |
1416 | ||
1417 | if(!get_device(&sdev->sdev_gendev)) | |
1418 | /* We must be tearing the block queue down already */ | |
1419 | return; | |
1420 | ||
1421 | /* | |
1422 | * To start with, we keep looping until the queue is empty, or until | |
1423 | * the host is no longer able to accept any more requests. | |
1424 | */ | |
1425 | shost = sdev->host; | |
1426 | while (!blk_queue_plugged(q)) { | |
1427 | int rtn; | |
1428 | /* | |
1429 | * get next queueable request. We do this early to make sure | |
1430 | * that the request is fully prepared even if we cannot | |
1431 | * accept it. | |
1432 | */ | |
1433 | req = elv_next_request(q); | |
1434 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1435 | break; | |
1436 | ||
1437 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1438 | sdev_printk(KERN_ERR, sdev, |
1439 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1440 | scsi_kill_request(req, q); |
1da177e4 LT |
1441 | continue; |
1442 | } | |
1443 | ||
1444 | ||
1445 | /* | |
1446 | * Remove the request from the request list. | |
1447 | */ | |
1448 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1449 | blkdev_dequeue_request(req); | |
1450 | sdev->device_busy++; | |
1451 | ||
1452 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1453 | cmd = req->special; |
1454 | if (unlikely(cmd == NULL)) { | |
1455 | printk(KERN_CRIT "impossible request in %s.\n" | |
1456 | "please mail a stack trace to " | |
1457 | "linux-scsi@vger.kernel.org", | |
1458 | __FUNCTION__); | |
1459 | BUG(); | |
1460 | } | |
1da177e4 LT |
1461 | spin_lock(shost->host_lock); |
1462 | ||
1463 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1464 | goto not_ready; | |
1465 | if (sdev->single_lun) { | |
1466 | if (scsi_target(sdev)->starget_sdev_user && | |
1467 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1468 | goto not_ready; | |
1469 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1470 | } | |
1471 | shost->host_busy++; | |
1472 | ||
1473 | /* | |
1474 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1475 | * take the lock again. | |
1476 | */ | |
1477 | spin_unlock_irq(shost->host_lock); | |
1478 | ||
1da177e4 LT |
1479 | /* |
1480 | * Finally, initialize any error handling parameters, and set up | |
1481 | * the timers for timeouts. | |
1482 | */ | |
1483 | scsi_init_cmd_errh(cmd); | |
1484 | ||
1485 | /* | |
1486 | * Dispatch the command to the low-level driver. | |
1487 | */ | |
1488 | rtn = scsi_dispatch_cmd(cmd); | |
1489 | spin_lock_irq(q->queue_lock); | |
1490 | if(rtn) { | |
1491 | /* we're refusing the command; because of | |
1492 | * the way locks get dropped, we need to | |
1493 | * check here if plugging is required */ | |
1494 | if(sdev->device_busy == 0) | |
1495 | blk_plug_device(q); | |
1496 | ||
1497 | break; | |
1498 | } | |
1499 | } | |
1500 | ||
1501 | goto out; | |
1502 | ||
1503 | not_ready: | |
1504 | spin_unlock_irq(shost->host_lock); | |
1505 | ||
1506 | /* | |
1507 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1508 | * must return with queue_lock held. | |
1509 | * | |
1510 | * Decrementing device_busy without checking it is OK, as all such | |
1511 | * cases (host limits or settings) should run the queue at some | |
1512 | * later time. | |
1513 | */ | |
1514 | spin_lock_irq(q->queue_lock); | |
1515 | blk_requeue_request(q, req); | |
1516 | sdev->device_busy--; | |
1517 | if(sdev->device_busy == 0) | |
1518 | blk_plug_device(q); | |
1519 | out: | |
1520 | /* must be careful here...if we trigger the ->remove() function | |
1521 | * we cannot be holding the q lock */ | |
1522 | spin_unlock_irq(q->queue_lock); | |
1523 | put_device(&sdev->sdev_gendev); | |
1524 | spin_lock_irq(q->queue_lock); | |
1525 | } | |
1526 | ||
1527 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1528 | { | |
1529 | struct device *host_dev; | |
1530 | u64 bounce_limit = 0xffffffff; | |
1531 | ||
1532 | if (shost->unchecked_isa_dma) | |
1533 | return BLK_BOUNCE_ISA; | |
1534 | /* | |
1535 | * Platforms with virtual-DMA translation | |
1536 | * hardware have no practical limit. | |
1537 | */ | |
1538 | if (!PCI_DMA_BUS_IS_PHYS) | |
1539 | return BLK_BOUNCE_ANY; | |
1540 | ||
1541 | host_dev = scsi_get_device(shost); | |
1542 | if (host_dev && host_dev->dma_mask) | |
1543 | bounce_limit = *host_dev->dma_mask; | |
1544 | ||
1545 | return bounce_limit; | |
1546 | } | |
1547 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1548 | ||
1549 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1550 | { | |
1551 | struct Scsi_Host *shost = sdev->host; | |
1552 | struct request_queue *q; | |
1553 | ||
152587de | 1554 | q = blk_init_queue(scsi_request_fn, NULL); |
1da177e4 LT |
1555 | if (!q) |
1556 | return NULL; | |
1557 | ||
1558 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1559 | ||
1560 | blk_queue_max_hw_segments(q, shost->sg_tablesize); | |
1561 | blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); | |
1562 | blk_queue_max_sectors(q, shost->max_sectors); | |
1563 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1564 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1565 | blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); | |
1aea6434 | 1566 | blk_queue_softirq_done(q, scsi_softirq_done); |
1da177e4 | 1567 | |
1da177e4 LT |
1568 | if (!shost->use_clustering) |
1569 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
1570 | return q; | |
1571 | } | |
1572 | ||
1573 | void scsi_free_queue(struct request_queue *q) | |
1574 | { | |
1575 | blk_cleanup_queue(q); | |
1576 | } | |
1577 | ||
1578 | /* | |
1579 | * Function: scsi_block_requests() | |
1580 | * | |
1581 | * Purpose: Utility function used by low-level drivers to prevent further | |
1582 | * commands from being queued to the device. | |
1583 | * | |
1584 | * Arguments: shost - Host in question | |
1585 | * | |
1586 | * Returns: Nothing | |
1587 | * | |
1588 | * Lock status: No locks are assumed held. | |
1589 | * | |
1590 | * Notes: There is no timer nor any other means by which the requests | |
1591 | * get unblocked other than the low-level driver calling | |
1592 | * scsi_unblock_requests(). | |
1593 | */ | |
1594 | void scsi_block_requests(struct Scsi_Host *shost) | |
1595 | { | |
1596 | shost->host_self_blocked = 1; | |
1597 | } | |
1598 | EXPORT_SYMBOL(scsi_block_requests); | |
1599 | ||
1600 | /* | |
1601 | * Function: scsi_unblock_requests() | |
1602 | * | |
1603 | * Purpose: Utility function used by low-level drivers to allow further | |
1604 | * commands from being queued to the device. | |
1605 | * | |
1606 | * Arguments: shost - Host in question | |
1607 | * | |
1608 | * Returns: Nothing | |
1609 | * | |
1610 | * Lock status: No locks are assumed held. | |
1611 | * | |
1612 | * Notes: There is no timer nor any other means by which the requests | |
1613 | * get unblocked other than the low-level driver calling | |
1614 | * scsi_unblock_requests(). | |
1615 | * | |
1616 | * This is done as an API function so that changes to the | |
1617 | * internals of the scsi mid-layer won't require wholesale | |
1618 | * changes to drivers that use this feature. | |
1619 | */ | |
1620 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1621 | { | |
1622 | shost->host_self_blocked = 0; | |
1623 | scsi_run_host_queues(shost); | |
1624 | } | |
1625 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1626 | ||
1627 | int __init scsi_init_queue(void) | |
1628 | { | |
1629 | int i; | |
1630 | ||
aa7b5cd7 MC |
1631 | scsi_io_context_cache = kmem_cache_create("scsi_io_context", |
1632 | sizeof(struct scsi_io_context), | |
1633 | 0, 0, NULL, NULL); | |
1634 | if (!scsi_io_context_cache) { | |
1635 | printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); | |
1636 | return -ENOMEM; | |
1637 | } | |
1638 | ||
1da177e4 LT |
1639 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1640 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1641 | int size = sgp->size * sizeof(struct scatterlist); | |
1642 | ||
1643 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1644 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1645 | if (!sgp->slab) { | |
1646 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1647 | sgp->name); | |
1648 | } | |
1649 | ||
93d2341c MD |
1650 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
1651 | sgp->slab); | |
1da177e4 LT |
1652 | if (!sgp->pool) { |
1653 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1654 | sgp->name); | |
1655 | } | |
1656 | } | |
1657 | ||
1658 | return 0; | |
1659 | } | |
1660 | ||
1661 | void scsi_exit_queue(void) | |
1662 | { | |
1663 | int i; | |
1664 | ||
aa7b5cd7 MC |
1665 | kmem_cache_destroy(scsi_io_context_cache); |
1666 | ||
1da177e4 LT |
1667 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1668 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1669 | mempool_destroy(sgp->pool); | |
1670 | kmem_cache_destroy(sgp->slab); | |
1671 | } | |
1672 | } | |
5baba830 JB |
1673 | |
1674 | /** | |
1675 | * scsi_mode_select - issue a mode select | |
1676 | * @sdev: SCSI device to be queried | |
1677 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1678 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1679 | * @modepage: mode page being requested | |
1680 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1681 | * @len: length of request buffer. | |
1682 | * @timeout: command timeout | |
1683 | * @retries: number of retries before failing | |
1684 | * @data: returns a structure abstracting the mode header data | |
1685 | * @sense: place to put sense data (or NULL if no sense to be collected). | |
1686 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1687 | * | |
1688 | * Returns zero if successful; negative error number or scsi | |
1689 | * status on error | |
1690 | * | |
1691 | */ | |
1692 | int | |
1693 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1694 | unsigned char *buffer, int len, int timeout, int retries, | |
1695 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1696 | { | |
1697 | unsigned char cmd[10]; | |
1698 | unsigned char *real_buffer; | |
1699 | int ret; | |
1700 | ||
1701 | memset(cmd, 0, sizeof(cmd)); | |
1702 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1703 | ||
1704 | if (sdev->use_10_for_ms) { | |
1705 | if (len > 65535) | |
1706 | return -EINVAL; | |
1707 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1708 | if (!real_buffer) | |
1709 | return -ENOMEM; | |
1710 | memcpy(real_buffer + 8, buffer, len); | |
1711 | len += 8; | |
1712 | real_buffer[0] = 0; | |
1713 | real_buffer[1] = 0; | |
1714 | real_buffer[2] = data->medium_type; | |
1715 | real_buffer[3] = data->device_specific; | |
1716 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1717 | real_buffer[5] = 0; | |
1718 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1719 | real_buffer[7] = data->block_descriptor_length; | |
1720 | ||
1721 | cmd[0] = MODE_SELECT_10; | |
1722 | cmd[7] = len >> 8; | |
1723 | cmd[8] = len; | |
1724 | } else { | |
1725 | if (len > 255 || data->block_descriptor_length > 255 || | |
1726 | data->longlba) | |
1727 | return -EINVAL; | |
1728 | ||
1729 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1730 | if (!real_buffer) | |
1731 | return -ENOMEM; | |
1732 | memcpy(real_buffer + 4, buffer, len); | |
1733 | len += 4; | |
1734 | real_buffer[0] = 0; | |
1735 | real_buffer[1] = data->medium_type; | |
1736 | real_buffer[2] = data->device_specific; | |
1737 | real_buffer[3] = data->block_descriptor_length; | |
1738 | ||
1739 | ||
1740 | cmd[0] = MODE_SELECT; | |
1741 | cmd[4] = len; | |
1742 | } | |
1743 | ||
1744 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
1745 | sshdr, timeout, retries); | |
1746 | kfree(real_buffer); | |
1747 | return ret; | |
1748 | } | |
1749 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1750 | ||
1da177e4 | 1751 | /** |
ea73a9f2 | 1752 | * scsi_mode_sense - issue a mode sense, falling back from 10 to |
1da177e4 | 1753 | * six bytes if necessary. |
1cf72699 | 1754 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1755 | * @dbd: set if mode sense will allow block descriptors to be returned |
1756 | * @modepage: mode page being requested | |
1757 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1758 | * @len: length of request buffer. | |
1759 | * @timeout: command timeout | |
1760 | * @retries: number of retries before failing | |
1761 | * @data: returns a structure abstracting the mode header data | |
1cf72699 JB |
1762 | * @sense: place to put sense data (or NULL if no sense to be collected). |
1763 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1da177e4 LT |
1764 | * |
1765 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1766 | * or 8 depending on whether a six or ten byte command was | |
1767 | * issued) if successful. | |
1768 | **/ | |
1769 | int | |
1cf72699 | 1770 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1771 | unsigned char *buffer, int len, int timeout, int retries, |
5baba830 JB |
1772 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
1773 | { | |
1da177e4 LT |
1774 | unsigned char cmd[12]; |
1775 | int use_10_for_ms; | |
1776 | int header_length; | |
1cf72699 | 1777 | int result; |
ea73a9f2 | 1778 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1779 | |
1780 | memset(data, 0, sizeof(*data)); | |
1781 | memset(&cmd[0], 0, 12); | |
1782 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1783 | cmd[2] = modepage; | |
1784 | ||
ea73a9f2 JB |
1785 | /* caller might not be interested in sense, but we need it */ |
1786 | if (!sshdr) | |
1787 | sshdr = &my_sshdr; | |
1788 | ||
1da177e4 | 1789 | retry: |
1cf72699 | 1790 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1791 | |
1792 | if (use_10_for_ms) { | |
1793 | if (len < 8) | |
1794 | len = 8; | |
1795 | ||
1796 | cmd[0] = MODE_SENSE_10; | |
1797 | cmd[8] = len; | |
1798 | header_length = 8; | |
1799 | } else { | |
1800 | if (len < 4) | |
1801 | len = 4; | |
1802 | ||
1803 | cmd[0] = MODE_SENSE; | |
1804 | cmd[4] = len; | |
1805 | header_length = 4; | |
1806 | } | |
1807 | ||
1da177e4 LT |
1808 | memset(buffer, 0, len); |
1809 | ||
1cf72699 | 1810 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
ea73a9f2 | 1811 | sshdr, timeout, retries); |
1da177e4 LT |
1812 | |
1813 | /* This code looks awful: what it's doing is making sure an | |
1814 | * ILLEGAL REQUEST sense return identifies the actual command | |
1815 | * byte as the problem. MODE_SENSE commands can return | |
1816 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1817 | ||
1cf72699 JB |
1818 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1819 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1820 | if (scsi_sense_valid(sshdr)) { |
1821 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1822 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1823 | /* |
1824 | * Invalid command operation code | |
1825 | */ | |
1cf72699 | 1826 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1827 | goto retry; |
1828 | } | |
1829 | } | |
1830 | } | |
1831 | ||
1cf72699 | 1832 | if(scsi_status_is_good(result)) { |
6d73c851 AV |
1833 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
1834 | (modepage == 6 || modepage == 8))) { | |
1835 | /* Initio breakage? */ | |
1836 | header_length = 0; | |
1837 | data->length = 13; | |
1838 | data->medium_type = 0; | |
1839 | data->device_specific = 0; | |
1840 | data->longlba = 0; | |
1841 | data->block_descriptor_length = 0; | |
1842 | } else if(use_10_for_ms) { | |
1da177e4 LT |
1843 | data->length = buffer[0]*256 + buffer[1] + 2; |
1844 | data->medium_type = buffer[2]; | |
1845 | data->device_specific = buffer[3]; | |
1846 | data->longlba = buffer[4] & 0x01; | |
1847 | data->block_descriptor_length = buffer[6]*256 | |
1848 | + buffer[7]; | |
1849 | } else { | |
1850 | data->length = buffer[0] + 1; | |
1851 | data->medium_type = buffer[1]; | |
1852 | data->device_specific = buffer[2]; | |
1853 | data->block_descriptor_length = buffer[3]; | |
1854 | } | |
6d73c851 | 1855 | data->header_length = header_length; |
1da177e4 LT |
1856 | } |
1857 | ||
1cf72699 | 1858 | return result; |
1da177e4 LT |
1859 | } |
1860 | EXPORT_SYMBOL(scsi_mode_sense); | |
1861 | ||
1862 | int | |
1863 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) | |
1864 | { | |
1da177e4 LT |
1865 | char cmd[] = { |
1866 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
1867 | }; | |
ea73a9f2 | 1868 | struct scsi_sense_hdr sshdr; |
1da177e4 LT |
1869 | int result; |
1870 | ||
ea73a9f2 | 1871 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr, |
1cf72699 | 1872 | timeout, retries); |
1da177e4 | 1873 | |
1cf72699 | 1874 | if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { |
1da177e4 | 1875 | |
ea73a9f2 | 1876 | if ((scsi_sense_valid(&sshdr)) && |
1da177e4 LT |
1877 | ((sshdr.sense_key == UNIT_ATTENTION) || |
1878 | (sshdr.sense_key == NOT_READY))) { | |
1879 | sdev->changed = 1; | |
1cf72699 | 1880 | result = 0; |
1da177e4 LT |
1881 | } |
1882 | } | |
1da177e4 LT |
1883 | return result; |
1884 | } | |
1885 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
1886 | ||
1887 | /** | |
1888 | * scsi_device_set_state - Take the given device through the device | |
1889 | * state model. | |
1890 | * @sdev: scsi device to change the state of. | |
1891 | * @state: state to change to. | |
1892 | * | |
1893 | * Returns zero if unsuccessful or an error if the requested | |
1894 | * transition is illegal. | |
1895 | **/ | |
1896 | int | |
1897 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
1898 | { | |
1899 | enum scsi_device_state oldstate = sdev->sdev_state; | |
1900 | ||
1901 | if (state == oldstate) | |
1902 | return 0; | |
1903 | ||
1904 | switch (state) { | |
1905 | case SDEV_CREATED: | |
1906 | /* There are no legal states that come back to | |
1907 | * created. This is the manually initialised start | |
1908 | * state */ | |
1909 | goto illegal; | |
1910 | ||
1911 | case SDEV_RUNNING: | |
1912 | switch (oldstate) { | |
1913 | case SDEV_CREATED: | |
1914 | case SDEV_OFFLINE: | |
1915 | case SDEV_QUIESCE: | |
1916 | case SDEV_BLOCK: | |
1917 | break; | |
1918 | default: | |
1919 | goto illegal; | |
1920 | } | |
1921 | break; | |
1922 | ||
1923 | case SDEV_QUIESCE: | |
1924 | switch (oldstate) { | |
1925 | case SDEV_RUNNING: | |
1926 | case SDEV_OFFLINE: | |
1927 | break; | |
1928 | default: | |
1929 | goto illegal; | |
1930 | } | |
1931 | break; | |
1932 | ||
1933 | case SDEV_OFFLINE: | |
1934 | switch (oldstate) { | |
1935 | case SDEV_CREATED: | |
1936 | case SDEV_RUNNING: | |
1937 | case SDEV_QUIESCE: | |
1938 | case SDEV_BLOCK: | |
1939 | break; | |
1940 | default: | |
1941 | goto illegal; | |
1942 | } | |
1943 | break; | |
1944 | ||
1945 | case SDEV_BLOCK: | |
1946 | switch (oldstate) { | |
1947 | case SDEV_CREATED: | |
1948 | case SDEV_RUNNING: | |
1949 | break; | |
1950 | default: | |
1951 | goto illegal; | |
1952 | } | |
1953 | break; | |
1954 | ||
1955 | case SDEV_CANCEL: | |
1956 | switch (oldstate) { | |
1957 | case SDEV_CREATED: | |
1958 | case SDEV_RUNNING: | |
9ea72909 | 1959 | case SDEV_QUIESCE: |
1da177e4 LT |
1960 | case SDEV_OFFLINE: |
1961 | case SDEV_BLOCK: | |
1962 | break; | |
1963 | default: | |
1964 | goto illegal; | |
1965 | } | |
1966 | break; | |
1967 | ||
1968 | case SDEV_DEL: | |
1969 | switch (oldstate) { | |
309bd271 BK |
1970 | case SDEV_CREATED: |
1971 | case SDEV_RUNNING: | |
1972 | case SDEV_OFFLINE: | |
1da177e4 LT |
1973 | case SDEV_CANCEL: |
1974 | break; | |
1975 | default: | |
1976 | goto illegal; | |
1977 | } | |
1978 | break; | |
1979 | ||
1980 | } | |
1981 | sdev->sdev_state = state; | |
1982 | return 0; | |
1983 | ||
1984 | illegal: | |
1985 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
1986 | sdev_printk(KERN_ERR, sdev, |
1987 | "Illegal state transition %s->%s\n", | |
1988 | scsi_device_state_name(oldstate), | |
1989 | scsi_device_state_name(state)) | |
1da177e4 LT |
1990 | ); |
1991 | return -EINVAL; | |
1992 | } | |
1993 | EXPORT_SYMBOL(scsi_device_set_state); | |
1994 | ||
1995 | /** | |
1996 | * scsi_device_quiesce - Block user issued commands. | |
1997 | * @sdev: scsi device to quiesce. | |
1998 | * | |
1999 | * This works by trying to transition to the SDEV_QUIESCE state | |
2000 | * (which must be a legal transition). When the device is in this | |
2001 | * state, only special requests will be accepted, all others will | |
2002 | * be deferred. Since special requests may also be requeued requests, | |
2003 | * a successful return doesn't guarantee the device will be | |
2004 | * totally quiescent. | |
2005 | * | |
2006 | * Must be called with user context, may sleep. | |
2007 | * | |
2008 | * Returns zero if unsuccessful or an error if not. | |
2009 | **/ | |
2010 | int | |
2011 | scsi_device_quiesce(struct scsi_device *sdev) | |
2012 | { | |
2013 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2014 | if (err) | |
2015 | return err; | |
2016 | ||
2017 | scsi_run_queue(sdev->request_queue); | |
2018 | while (sdev->device_busy) { | |
2019 | msleep_interruptible(200); | |
2020 | scsi_run_queue(sdev->request_queue); | |
2021 | } | |
2022 | return 0; | |
2023 | } | |
2024 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2025 | ||
2026 | /** | |
2027 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2028 | * @sdev: scsi device to resume. | |
2029 | * | |
2030 | * Moves the device from quiesced back to running and restarts the | |
2031 | * queues. | |
2032 | * | |
2033 | * Must be called with user context, may sleep. | |
2034 | **/ | |
2035 | void | |
2036 | scsi_device_resume(struct scsi_device *sdev) | |
2037 | { | |
2038 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2039 | return; | |
2040 | scsi_run_queue(sdev->request_queue); | |
2041 | } | |
2042 | EXPORT_SYMBOL(scsi_device_resume); | |
2043 | ||
2044 | static void | |
2045 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2046 | { | |
2047 | scsi_device_quiesce(sdev); | |
2048 | } | |
2049 | ||
2050 | void | |
2051 | scsi_target_quiesce(struct scsi_target *starget) | |
2052 | { | |
2053 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2054 | } | |
2055 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2056 | ||
2057 | static void | |
2058 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2059 | { | |
2060 | scsi_device_resume(sdev); | |
2061 | } | |
2062 | ||
2063 | void | |
2064 | scsi_target_resume(struct scsi_target *starget) | |
2065 | { | |
2066 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2067 | } | |
2068 | EXPORT_SYMBOL(scsi_target_resume); | |
2069 | ||
2070 | /** | |
2071 | * scsi_internal_device_block - internal function to put a device | |
2072 | * temporarily into the SDEV_BLOCK state | |
2073 | * @sdev: device to block | |
2074 | * | |
2075 | * Block request made by scsi lld's to temporarily stop all | |
2076 | * scsi commands on the specified device. Called from interrupt | |
2077 | * or normal process context. | |
2078 | * | |
2079 | * Returns zero if successful or error if not | |
2080 | * | |
2081 | * Notes: | |
2082 | * This routine transitions the device to the SDEV_BLOCK state | |
2083 | * (which must be a legal transition). When the device is in this | |
2084 | * state, all commands are deferred until the scsi lld reenables | |
2085 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2086 | * This routine assumes the host_lock is held on entry. | |
2087 | **/ | |
2088 | int | |
2089 | scsi_internal_device_block(struct scsi_device *sdev) | |
2090 | { | |
2091 | request_queue_t *q = sdev->request_queue; | |
2092 | unsigned long flags; | |
2093 | int err = 0; | |
2094 | ||
2095 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2096 | if (err) | |
2097 | return err; | |
2098 | ||
2099 | /* | |
2100 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2101 | * block layer from calling the midlayer with this device's | |
2102 | * request queue. | |
2103 | */ | |
2104 | spin_lock_irqsave(q->queue_lock, flags); | |
2105 | blk_stop_queue(q); | |
2106 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2107 | ||
2108 | return 0; | |
2109 | } | |
2110 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2111 | ||
2112 | /** | |
2113 | * scsi_internal_device_unblock - resume a device after a block request | |
2114 | * @sdev: device to resume | |
2115 | * | |
2116 | * Called by scsi lld's or the midlayer to restart the device queue | |
2117 | * for the previously suspended scsi device. Called from interrupt or | |
2118 | * normal process context. | |
2119 | * | |
2120 | * Returns zero if successful or error if not. | |
2121 | * | |
2122 | * Notes: | |
2123 | * This routine transitions the device to the SDEV_RUNNING state | |
2124 | * (which must be a legal transition) allowing the midlayer to | |
2125 | * goose the queue for this device. This routine assumes the | |
2126 | * host_lock is held upon entry. | |
2127 | **/ | |
2128 | int | |
2129 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2130 | { | |
2131 | request_queue_t *q = sdev->request_queue; | |
2132 | int err; | |
2133 | unsigned long flags; | |
2134 | ||
2135 | /* | |
2136 | * Try to transition the scsi device to SDEV_RUNNING | |
2137 | * and goose the device queue if successful. | |
2138 | */ | |
2139 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
2140 | if (err) | |
2141 | return err; | |
2142 | ||
2143 | spin_lock_irqsave(q->queue_lock, flags); | |
2144 | blk_start_queue(q); | |
2145 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2146 | ||
2147 | return 0; | |
2148 | } | |
2149 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2150 | ||
2151 | static void | |
2152 | device_block(struct scsi_device *sdev, void *data) | |
2153 | { | |
2154 | scsi_internal_device_block(sdev); | |
2155 | } | |
2156 | ||
2157 | static int | |
2158 | target_block(struct device *dev, void *data) | |
2159 | { | |
2160 | if (scsi_is_target_device(dev)) | |
2161 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2162 | device_block); | |
2163 | return 0; | |
2164 | } | |
2165 | ||
2166 | void | |
2167 | scsi_target_block(struct device *dev) | |
2168 | { | |
2169 | if (scsi_is_target_device(dev)) | |
2170 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2171 | device_block); | |
2172 | else | |
2173 | device_for_each_child(dev, NULL, target_block); | |
2174 | } | |
2175 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2176 | ||
2177 | static void | |
2178 | device_unblock(struct scsi_device *sdev, void *data) | |
2179 | { | |
2180 | scsi_internal_device_unblock(sdev); | |
2181 | } | |
2182 | ||
2183 | static int | |
2184 | target_unblock(struct device *dev, void *data) | |
2185 | { | |
2186 | if (scsi_is_target_device(dev)) | |
2187 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2188 | device_unblock); | |
2189 | return 0; | |
2190 | } | |
2191 | ||
2192 | void | |
2193 | scsi_target_unblock(struct device *dev) | |
2194 | { | |
2195 | if (scsi_is_target_device(dev)) | |
2196 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2197 | device_unblock); | |
2198 | else | |
2199 | device_for_each_child(dev, NULL, target_unblock); | |
2200 | } | |
2201 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
cdb8c2a6 GL |
2202 | |
2203 | /** | |
2204 | * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt | |
2205 | * @sg: scatter-gather list | |
2206 | * @sg_count: number of segments in sg | |
2207 | * @offset: offset in bytes into sg, on return offset into the mapped area | |
2208 | * @len: bytes to map, on return number of bytes mapped | |
2209 | * | |
2210 | * Returns virtual address of the start of the mapped page | |
2211 | */ | |
2212 | void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count, | |
2213 | size_t *offset, size_t *len) | |
2214 | { | |
2215 | int i; | |
2216 | size_t sg_len = 0, len_complete = 0; | |
2217 | struct page *page; | |
2218 | ||
2219 | for (i = 0; i < sg_count; i++) { | |
2220 | len_complete = sg_len; /* Complete sg-entries */ | |
2221 | sg_len += sg[i].length; | |
2222 | if (sg_len > *offset) | |
2223 | break; | |
2224 | } | |
2225 | ||
2226 | if (unlikely(i == sg_count)) { | |
169e1a2a AM |
2227 | printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
2228 | "elements %d\n", | |
cdb8c2a6 GL |
2229 | __FUNCTION__, sg_len, *offset, sg_count); |
2230 | WARN_ON(1); | |
2231 | return NULL; | |
2232 | } | |
2233 | ||
2234 | /* Offset starting from the beginning of first page in this sg-entry */ | |
2235 | *offset = *offset - len_complete + sg[i].offset; | |
2236 | ||
2237 | /* Assumption: contiguous pages can be accessed as "page + i" */ | |
2238 | page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT)); | |
2239 | *offset &= ~PAGE_MASK; | |
2240 | ||
2241 | /* Bytes in this sg-entry from *offset to the end of the page */ | |
2242 | sg_len = PAGE_SIZE - *offset; | |
2243 | if (*len > sg_len) | |
2244 | *len = sg_len; | |
2245 | ||
2246 | return kmap_atomic(page, KM_BIO_SRC_IRQ); | |
2247 | } | |
2248 | EXPORT_SYMBOL(scsi_kmap_atomic_sg); | |
2249 | ||
2250 | /** | |
2251 | * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously | |
2252 | * mapped with scsi_kmap_atomic_sg | |
2253 | * @virt: virtual address to be unmapped | |
2254 | */ | |
2255 | void scsi_kunmap_atomic_sg(void *virt) | |
2256 | { | |
2257 | kunmap_atomic(virt, KM_BIO_SRC_IRQ); | |
2258 | } | |
2259 | EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |