blob: 98ee55ced5922c4ff14634bd320725eb2d3b5db0 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
3 *
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
8 */
9
10#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060011#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/blkdev.h>
13#include <linux/completion.h>
14#include <linux/kernel.h>
15#include <linux/mempool.h>
16#include <linux/slab.h>
17#include <linux/init.h>
18#include <linux/pci.h>
19#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060020#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020021#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020024#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <scsi/scsi_dbg.h>
26#include <scsi/scsi_device.h>
27#include <scsi/scsi_driver.h>
28#include <scsi/scsi_eh.h>
29#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include "scsi_priv.h"
32#include "scsi_logging.h"
33
34
Tobias Klauser6391a112006-06-08 22:23:48 -070035#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020036#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38struct scsi_host_sg_pool {
39 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020040 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080041 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 mempool_t *pool;
43};
44
James Bottomleyd3f46f32008-01-15 11:11:46 -060045#define SP(x) { x, "sgpool-" __stringify(x) }
46#if (SCSI_MAX_SG_SEGMENTS < 32)
47#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
48#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070049static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 SP(8),
51 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020052#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060053 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020054#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060055 SP(64),
56#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060058#if (SCSI_MAX_SG_SEGMENTS > 256)
59#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020060#endif
61#endif
62#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060063#endif
64 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020065};
Linus Torvalds1da177e2005-04-16 15:20:36 -070066#undef SP
67
Martin K. Petersen7027ad72008-07-17 17:08:48 -040068struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020069
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -050070static void scsi_run_queue(struct request_queue *q);
James Bottomleye91442b2005-09-09 10:44:16 -050071
72/*
73 * Function: scsi_unprep_request()
74 *
75 * Purpose: Remove all preparation done for a request, including its
76 * associated scsi_cmnd, so that it can be requeued.
77 *
78 * Arguments: req - request to unprepare
79 *
80 * Lock status: Assumed that no locks are held upon entry.
81 *
82 * Returns: Nothing.
83 */
84static void scsi_unprep_request(struct request *req)
85{
86 struct scsi_cmnd *cmd = req->special;
87
Jens Axboe4aff5e22006-08-10 08:44:47 +020088 req->cmd_flags &= ~REQ_DONTPREP;
Christoph Hellwigbeb40482006-06-10 18:01:03 +020089 req->special = NULL;
James Bottomleye91442b2005-09-09 10:44:16 -050090
James Bottomleye91442b2005-09-09 10:44:16 -050091 scsi_put_command(cmd);
92}
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -050093
Linus Torvalds1da177e2005-04-16 15:20:36 -070094/*
95 * Function: scsi_queue_insert()
96 *
97 * Purpose: Insert a command in the midlevel queue.
98 *
99 * Arguments: cmd - command that we are adding to queue.
100 * reason - why we are inserting command to queue.
101 *
102 * Lock status: Assumed that lock is not held upon entry.
103 *
104 * Returns: Nothing.
105 *
106 * Notes: We do this for one of two cases. Either the host is busy
107 * and it cannot accept any more commands for the time being,
108 * or the device returned QUEUE_FULL and can accept no more
109 * commands.
110 * Notes: This could be called either from an interrupt context or a
111 * normal process context.
112 */
113int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
114{
115 struct Scsi_Host *host = cmd->device->host;
116 struct scsi_device *device = cmd->device;
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500117 struct request_queue *q = device->request_queue;
118 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120 SCSI_LOG_MLQUEUE(1,
121 printk("Inserting command %p into mlqueue\n", cmd));
122
123 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +0900124 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 *
126 * If the host/device isn't busy, assume that something actually
127 * completed, and that we should be able to queue a command now.
128 *
129 * Note that the prior mid-layer assumption that any host could
130 * always queue at least one command is now broken. The mid-layer
131 * will implement a user specifiable stall (see
132 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
133 * if a command is requeued with no other commands outstanding
134 * either for the device or for the host.
135 */
136 if (reason == SCSI_MLQUEUE_HOST_BUSY)
137 host->host_blocked = host->max_host_blocked;
138 else if (reason == SCSI_MLQUEUE_DEVICE_BUSY)
139 device->device_blocked = device->max_device_blocked;
140
141 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 * Decrement the counters, since these commands are no longer
143 * active on the host/device.
144 */
145 scsi_device_unbusy(device);
146
147 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500148 * Requeue this command. It will go before all other commands
149 * that are already in the queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 *
151 * NOTE: there is magic here about the way the queue is plugged if
152 * we have no outstanding commands.
153 *
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500154 * Although we *don't* plug the queue, we call the request
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 * function. The SCSI request function detects the blocked condition
156 * and plugs the queue appropriately.
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500157 */
158 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400159 blk_requeue_request(q, cmd->request);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500160 spin_unlock_irqrestore(q->queue_lock, flags);
161
162 scsi_run_queue(q);
163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 return 0;
165}
166
James Bottomley39216032005-06-15 18:48:29 -0500167/**
James Bottomley33aa6872005-08-28 11:31:14 -0500168 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500169 * @sdev: scsi device
170 * @cmd: scsi command
171 * @data_direction: data direction
172 * @buffer: data buffer
173 * @bufflen: len of buffer
174 * @sense: optional sense buffer
175 * @timeout: request timeout in seconds
176 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500177 * @flags: or into request flags;
James Bottomley39216032005-06-15 18:48:29 -0500178 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200179 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500180 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500181 */
James Bottomley33aa6872005-08-28 11:31:14 -0500182int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
183 int data_direction, void *buffer, unsigned bufflen,
184 unsigned char *sense, int timeout, int retries, int flags)
James Bottomley39216032005-06-15 18:48:29 -0500185{
186 struct request *req;
187 int write = (data_direction == DMA_TO_DEVICE);
188 int ret = DRIVER_ERROR << 24;
189
190 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
191
192 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
193 buffer, bufflen, __GFP_WAIT))
194 goto out;
195
196 req->cmd_len = COMMAND_SIZE(cmd[0]);
197 memcpy(req->cmd, cmd, req->cmd_len);
198 req->sense = sense;
199 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600200 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500201 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200202 req->cmd_type = REQ_TYPE_BLOCK_PC;
203 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500204
205 /*
206 * head injection *required* here otherwise quiesce won't work
207 */
208 blk_execute_rq(req->q, NULL, req, 1);
209
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400210 /*
211 * Some devices (USB mass-storage in particular) may transfer
212 * garbage data together with a residue indicating that the data
213 * is invalid. Prevent the garbage from being misinterpreted
214 * and prevent security leaks by zeroing out the excess data.
215 */
216 if (unlikely(req->data_len > 0 && req->data_len <= bufflen))
217 memset(buffer + (bufflen - req->data_len), 0, req->data_len);
218
James Bottomley39216032005-06-15 18:48:29 -0500219 ret = req->errors;
220 out:
221 blk_put_request(req);
222
223 return ret;
224}
James Bottomley33aa6872005-08-28 11:31:14 -0500225EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500226
James Bottomleyea73a9f2005-08-28 11:33:52 -0500227
228int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
229 int data_direction, void *buffer, unsigned bufflen,
230 struct scsi_sense_hdr *sshdr, int timeout, int retries)
231{
232 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700233 int result;
234
James Bottomleyea73a9f2005-08-28 11:33:52 -0500235 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500236 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500237 if (!sense)
238 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500239 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700240 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Jes Sorensen24669f752006-01-16 10:31:18 -0500241 sense, timeout, retries, 0);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500242 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500243 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500244
245 kfree(sense);
246 return result;
247}
248EXPORT_SYMBOL(scsi_execute_req);
249
Mike Christie6e68af62005-11-11 05:30:27 -0600250struct scsi_io_context {
251 void *data;
252 void (*done)(void *data, char *sense, int result, int resid);
253 char sense[SCSI_SENSE_BUFFERSIZE];
254};
255
Christoph Lametere18b8902006-12-06 20:33:20 -0800256static struct kmem_cache *scsi_io_context_cache;
Mike Christieaa7b5cd2005-11-11 05:31:41 -0600257
Jens Axboee650c302006-01-06 12:38:30 +0100258static void scsi_end_async(struct request *req, int uptodate)
Mike Christie6e68af62005-11-11 05:30:27 -0600259{
260 struct scsi_io_context *sioc = req->end_io_data;
261
262 if (sioc->done)
263 sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
264
Mike Christieaa7b5cd2005-11-11 05:31:41 -0600265 kmem_cache_free(scsi_io_context_cache, sioc);
Mike Christie6e68af62005-11-11 05:30:27 -0600266 __blk_put_request(req->q, req);
267}
268
269static int scsi_merge_bio(struct request *rq, struct bio *bio)
270{
271 struct request_queue *q = rq->q;
272
273 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
274 if (rq_data_dir(rq) == WRITE)
275 bio->bi_rw |= (1 << BIO_RW);
276 blk_queue_bounce(q, &bio);
277
NeilBrown3001ca72007-08-16 13:31:27 +0200278 return blk_rq_append_bio(q, rq, bio);
Mike Christie6e68af62005-11-11 05:30:27 -0600279}
280
NeilBrown6712ecf2007-09-27 12:47:43 +0200281static void scsi_bi_endio(struct bio *bio, int error)
Mike Christie6e68af62005-11-11 05:30:27 -0600282{
Mike Christie6e68af62005-11-11 05:30:27 -0600283 bio_put(bio);
Mike Christie6e68af62005-11-11 05:30:27 -0600284}
285
286/**
287 * scsi_req_map_sg - map a scatterlist into a request
288 * @rq: request to fill
Rob Landleyeb448202007-11-03 13:30:39 -0500289 * @sgl: scatterlist
Mike Christie6e68af62005-11-11 05:30:27 -0600290 * @nsegs: number of elements
291 * @bufflen: len of buffer
292 * @gfp: memory allocation flags
293 *
294 * scsi_req_map_sg maps a scatterlist into a request so that the
295 * request can be sent to the block layer. We do not trust the scatterlist
296 * sent to use, as some ULDs use that struct to only organize the pages.
297 */
298static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
299 int nsegs, unsigned bufflen, gfp_t gfp)
300{
301 struct request_queue *q = rq->q;
Bryan Holtyf5235962006-03-22 06:35:39 -0600302 int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
Mike Christiebd441de2007-03-13 12:52:29 -0500303 unsigned int data_len = bufflen, len, bytes, off;
Jens Axboec6132da2007-10-16 11:08:49 +0200304 struct scatterlist *sg;
Mike Christie6e68af62005-11-11 05:30:27 -0600305 struct page *page;
306 struct bio *bio = NULL;
307 int i, err, nr_vecs = 0;
308
Jens Axboec6132da2007-10-16 11:08:49 +0200309 for_each_sg(sgl, sg, nsegs, i) {
Jens Axboe45711f12007-10-22 21:19:53 +0200310 page = sg_page(sg);
Jens Axboec6132da2007-10-16 11:08:49 +0200311 off = sg->offset;
312 len = sg->length;
Mike Christie6e68af62005-11-11 05:30:27 -0600313
Mike Christiebd441de2007-03-13 12:52:29 -0500314 while (len > 0 && data_len > 0) {
315 /*
316 * sg sends a scatterlist that is larger than
317 * the data_len it wants transferred for certain
318 * IO sizes
319 */
Mike Christie6e68af62005-11-11 05:30:27 -0600320 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
Mike Christiebd441de2007-03-13 12:52:29 -0500321 bytes = min(bytes, data_len);
Mike Christie6e68af62005-11-11 05:30:27 -0600322
323 if (!bio) {
324 nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
325 nr_pages -= nr_vecs;
326
327 bio = bio_alloc(gfp, nr_vecs);
328 if (!bio) {
329 err = -ENOMEM;
330 goto free_bios;
331 }
332 bio->bi_end_io = scsi_bi_endio;
333 }
334
335 if (bio_add_pc_page(q, bio, page, bytes, off) !=
336 bytes) {
337 bio_put(bio);
338 err = -EINVAL;
339 goto free_bios;
340 }
341
342 if (bio->bi_vcnt >= nr_vecs) {
343 err = scsi_merge_bio(rq, bio);
344 if (err) {
NeilBrown6712ecf2007-09-27 12:47:43 +0200345 bio_endio(bio, 0);
Mike Christie6e68af62005-11-11 05:30:27 -0600346 goto free_bios;
347 }
348 bio = NULL;
349 }
350
351 page++;
352 len -= bytes;
Mike Christiebd441de2007-03-13 12:52:29 -0500353 data_len -=bytes;
Mike Christie6e68af62005-11-11 05:30:27 -0600354 off = 0;
355 }
356 }
357
358 rq->buffer = rq->data = NULL;
Mike Christiebd441de2007-03-13 12:52:29 -0500359 rq->data_len = bufflen;
Mike Christie6e68af62005-11-11 05:30:27 -0600360 return 0;
361
362free_bios:
363 while ((bio = rq->bio) != NULL) {
364 rq->bio = bio->bi_next;
365 /*
366 * call endio instead of bio_put incase it was bounced
367 */
NeilBrown6712ecf2007-09-27 12:47:43 +0200368 bio_endio(bio, 0);
Mike Christie6e68af62005-11-11 05:30:27 -0600369 }
370
371 return err;
372}
373
374/**
375 * scsi_execute_async - insert request
376 * @sdev: scsi device
377 * @cmd: scsi command
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600378 * @cmd_len: length of scsi cdb
Rob Landleyeb448202007-11-03 13:30:39 -0500379 * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE
Mike Christie6e68af62005-11-11 05:30:27 -0600380 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
381 * @bufflen: len of buffer
382 * @use_sg: if buffer is a scatterlist this is the number of elements
383 * @timeout: request timeout in seconds
384 * @retries: number of times to retry request
Rob Landleyeb448202007-11-03 13:30:39 -0500385 * @privdata: data passed to done()
386 * @done: callback function when done
387 * @gfp: memory allocation flags
388 */
Mike Christie6e68af62005-11-11 05:30:27 -0600389int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600390 int cmd_len, int data_direction, void *buffer, unsigned bufflen,
Mike Christie6e68af62005-11-11 05:30:27 -0600391 int use_sg, int timeout, int retries, void *privdata,
392 void (*done)(void *, char *, int, int), gfp_t gfp)
393{
394 struct request *req;
395 struct scsi_io_context *sioc;
396 int err = 0;
397 int write = (data_direction == DMA_TO_DEVICE);
398
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800399 sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp);
Mike Christie6e68af62005-11-11 05:30:27 -0600400 if (!sioc)
401 return DRIVER_ERROR << 24;
402
403 req = blk_get_request(sdev->request_queue, write, gfp);
404 if (!req)
405 goto free_sense;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200406 req->cmd_type = REQ_TYPE_BLOCK_PC;
407 req->cmd_flags |= REQ_QUIET;
Mike Christie6e68af62005-11-11 05:30:27 -0600408
409 if (use_sg)
410 err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
411 else if (bufflen)
412 err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
413
414 if (err)
415 goto free_req;
416
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600417 req->cmd_len = cmd_len;
Tejun Heo097b8452006-11-16 01:19:31 -0800418 memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
Mike Christie6e68af62005-11-11 05:30:27 -0600419 memcpy(req->cmd, cmd, req->cmd_len);
420 req->sense = sioc->sense;
421 req->sense_len = 0;
422 req->timeout = timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600423 req->retries = retries;
Mike Christie6e68af62005-11-11 05:30:27 -0600424 req->end_io_data = sioc;
425
426 sioc->data = privdata;
427 sioc->done = done;
428
429 blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
430 return 0;
431
432free_req:
433 blk_put_request(req);
434free_sense:
Arne Redlich6470f2b2006-09-30 15:49:40 +0200435 kmem_cache_free(scsi_io_context_cache, sioc);
Mike Christie6e68af62005-11-11 05:30:27 -0600436 return DRIVER_ERROR << 24;
437}
438EXPORT_SYMBOL_GPL(scsi_execute_async);
439
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440/*
441 * Function: scsi_init_cmd_errh()
442 *
443 * Purpose: Initialize cmd fields related to error handling.
444 *
445 * Arguments: cmd - command that is ready to be queued.
446 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 * Notes: This function has the job of initializing a number of
448 * fields related to error handling. Typically this will
449 * be called once for each command, as required.
450 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200451static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200454 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900455 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300457 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458}
459
460void scsi_device_unbusy(struct scsi_device *sdev)
461{
462 struct Scsi_Host *shost = sdev->host;
463 unsigned long flags;
464
465 spin_lock_irqsave(shost->host_lock, flags);
466 shost->host_busy--;
James Bottomley939647e2005-09-18 15:05:20 -0500467 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900468 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 scsi_eh_wakeup(shost);
470 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500471 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500473 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474}
475
476/*
477 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
478 * and call blk_run_queue for all the scsi_devices on the target -
479 * including current_sdev first.
480 *
481 * Called with *no* scsi locks held.
482 */
483static void scsi_single_lun_run(struct scsi_device *current_sdev)
484{
485 struct Scsi_Host *shost = current_sdev->host;
486 struct scsi_device *sdev, *tmp;
487 struct scsi_target *starget = scsi_target(current_sdev);
488 unsigned long flags;
489
490 spin_lock_irqsave(shost->host_lock, flags);
491 starget->starget_sdev_user = NULL;
492 spin_unlock_irqrestore(shost->host_lock, flags);
493
494 /*
495 * Call blk_run_queue for all LUNs on the target, starting with
496 * current_sdev. We race with others (to set starget_sdev_user),
497 * but in most cases, we will be first. Ideally, each LU on the
498 * target would get some limited time or requests on the target.
499 */
500 blk_run_queue(current_sdev->request_queue);
501
502 spin_lock_irqsave(shost->host_lock, flags);
503 if (starget->starget_sdev_user)
504 goto out;
505 list_for_each_entry_safe(sdev, tmp, &starget->devices,
506 same_target_siblings) {
507 if (sdev == current_sdev)
508 continue;
509 if (scsi_device_get(sdev))
510 continue;
511
512 spin_unlock_irqrestore(shost->host_lock, flags);
513 blk_run_queue(sdev->request_queue);
514 spin_lock_irqsave(shost->host_lock, flags);
515
516 scsi_device_put(sdev);
517 }
518 out:
519 spin_unlock_irqrestore(shost->host_lock, flags);
520}
521
522/*
523 * Function: scsi_run_queue()
524 *
525 * Purpose: Select a proper request queue to serve next
526 *
527 * Arguments: q - last request's queue
528 *
529 * Returns: Nothing
530 *
531 * Notes: The previous command was completely finished, start
532 * a new one if possible.
533 */
534static void scsi_run_queue(struct request_queue *q)
535{
536 struct scsi_device *sdev = q->queuedata;
537 struct Scsi_Host *shost = sdev->host;
538 unsigned long flags;
539
Tony Battersby25d7c362007-11-12 10:00:44 -0500540 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 scsi_single_lun_run(sdev);
542
543 spin_lock_irqsave(shost->host_lock, flags);
544 while (!list_empty(&shost->starved_list) &&
545 !shost->host_blocked && !shost->host_self_blocked &&
546 !((shost->can_queue > 0) &&
547 (shost->host_busy >= shost->can_queue))) {
Nick Piggin75ad23b2008-04-29 14:48:33 +0200548
549 int flagset;
550
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 /*
552 * As long as shost is accepting commands and we have
553 * starved queues, call blk_run_queue. scsi_request_fn
554 * drops the queue_lock and can add us back to the
555 * starved_list.
556 *
557 * host_lock protects the starved_list and starved_entry.
558 * scsi_request_fn must get the host_lock before checking
559 * or modifying starved_list or starved_entry.
560 */
561 sdev = list_entry(shost->starved_list.next,
562 struct scsi_device, starved_entry);
563 list_del_init(&sdev->starved_entry);
Nick Piggin75ad23b2008-04-29 14:48:33 +0200564 spin_unlock(shost->host_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
Nick Piggin75ad23b2008-04-29 14:48:33 +0200566 spin_lock(sdev->request_queue->queue_lock);
567 flagset = test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) &&
568 !test_bit(QUEUE_FLAG_REENTER,
569 &sdev->request_queue->queue_flags);
570 if (flagset)
571 queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue);
572 __blk_run_queue(sdev->request_queue);
573 if (flagset)
574 queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue);
575 spin_unlock(sdev->request_queue->queue_lock);
Andreas Herrmann04846f22006-08-09 17:31:16 +0200576
Nick Piggin75ad23b2008-04-29 14:48:33 +0200577 spin_lock(shost->host_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 if (unlikely(!list_empty(&sdev->starved_entry)))
579 /*
580 * sdev lost a race, and was put back on the
581 * starved list. This is unlikely but without this
582 * in theory we could loop forever.
583 */
584 break;
585 }
586 spin_unlock_irqrestore(shost->host_lock, flags);
587
588 blk_run_queue(q);
589}
590
591/*
592 * Function: scsi_requeue_command()
593 *
594 * Purpose: Handle post-processing of completed commands.
595 *
596 * Arguments: q - queue to operate on
597 * cmd - command that may need to be requeued.
598 *
599 * Returns: Nothing
600 *
601 * Notes: After command completion, there may be blocks left
602 * over which weren't finished by the previous command
603 * this can be for a number of reasons - the main one is
604 * I/O errors in the middle of the request, in which case
605 * we need to request the blocks that come after the bad
606 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500607 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 */
609static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
610{
James Bottomleye91442b2005-09-09 10:44:16 -0500611 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500612 unsigned long flags;
613
James Bottomleye91442b2005-09-09 10:44:16 -0500614 scsi_unprep_request(req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500615 spin_lock_irqsave(q->queue_lock, flags);
James Bottomleye91442b2005-09-09 10:44:16 -0500616 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500617 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
619 scsi_run_queue(q);
620}
621
622void scsi_next_command(struct scsi_cmnd *cmd)
623{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800624 struct scsi_device *sdev = cmd->device;
625 struct request_queue *q = sdev->request_queue;
626
627 /* need to hold a reference on the device before we let go of the cmd */
628 get_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629
630 scsi_put_command(cmd);
631 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800632
633 /* ok to remove device now */
634 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635}
636
637void scsi_run_host_queues(struct Scsi_Host *shost)
638{
639 struct scsi_device *sdev;
640
641 shost_for_each_device(sdev, shost)
642 scsi_run_queue(sdev->request_queue);
643}
644
645/*
646 * Function: scsi_end_request()
647 *
648 * Purpose: Post-processing of completed commands (usually invoked at end
649 * of upper level post-processing and scsi_io_completion).
650 *
651 * Arguments: cmd - command that is complete.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500652 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 * bytes - number of bytes of completed I/O
654 * requeue - indicates whether we should requeue leftovers.
655 *
656 * Lock status: Assumed that lock is not held upon entry.
657 *
James Bottomleye91442b2005-09-09 10:44:16 -0500658 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 *
660 * Notes: This is called for block device requests in order to
661 * mark some number of sectors as complete.
662 *
663 * We are guaranteeing that the request queue will be goosed
664 * at some point during this call.
James Bottomleye91442b2005-09-09 10:44:16 -0500665 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500667static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 int bytes, int requeue)
669{
Jens Axboe165125e2007-07-24 09:28:11 +0200670 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672
673 /*
674 * If there are blocks left over at the end, set up the command
675 * to queue the remainder of them.
676 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500677 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 int leftover = (req->hard_nr_sectors << 9);
679
680 if (blk_pc_request(req))
681 leftover = req->data_len;
682
683 /* kill remainder if no retrys */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500684 if (error && blk_noretry_request(req))
685 blk_end_request(req, error, leftover);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500687 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 /*
689 * Bleah. Leftovers again. Stick the
690 * leftovers in the front of the
691 * queue, and goose the queue again.
692 */
693 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500694 cmd = NULL;
695 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 return cmd;
697 }
698 }
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 /*
701 * This will goose the queue request function at the end, so we don't
702 * need to worry about launching another command.
703 */
704 scsi_next_command(cmd);
705 return NULL;
706}
707
Jens Axboea8474ce2007-08-07 09:02:51 +0200708static inline unsigned int scsi_sgtable_index(unsigned short nents)
709{
710 unsigned int index;
711
James Bottomleyd3f46f32008-01-15 11:11:46 -0600712 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
713
714 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200715 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600716 else
717 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200718
719 return index;
720}
721
Jens Axboe5ed79592007-11-15 09:13:11 +0100722static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723{
724 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100725
726 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
727 mempool_free(sgl, sgp->pool);
728}
729
730static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
731{
732 struct scsi_host_sg_pool *sgp;
733
734 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
735 return mempool_alloc(sgp->pool, gfp_mask);
736}
737
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200738static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
739 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100740{
741 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200743 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200745 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
746 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100747 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200748 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600749 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750
Jens Axboea8474ce2007-08-07 09:02:51 +0200751 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752}
753
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200754static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200756 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757}
758
759/*
760 * Function: scsi_release_buffers()
761 *
762 * Purpose: Completion processing for block device I/O requests.
763 *
764 * Arguments: cmd - command that we are bailing.
765 *
766 * Lock status: Assumed that no lock is held upon entry.
767 *
768 * Returns: Nothing
769 *
770 * Notes: In the event that an upper level driver rejects a
771 * command, we must release resources allocated during
772 * the __init_io() function. Primarily this would involve
773 * the scatter-gather table, and potentially any bounce
774 * buffers.
775 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800776void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200778 if (cmd->sdb.table.nents)
779 scsi_free_sgtable(&cmd->sdb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200781 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200782
783 if (scsi_bidi_cmnd(cmd)) {
784 struct scsi_data_buffer *bidi_sdb =
785 cmd->request->next_rq->special;
786 scsi_free_sgtable(bidi_sdb);
Martin K. Petersen6362abd2008-06-05 23:30:03 -0400787 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200788 cmd->request->next_rq->special = NULL;
789 }
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400790
791 if (scsi_prot_sg_count(cmd))
792 scsi_free_sgtable(cmd->prot_sdb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800794EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795
796/*
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200797 * Bidi commands Must be complete as a whole, both sides at once.
798 * If part of the bytes were written and lld returned
799 * scsi_in()->resid and/or scsi_out()->resid this information will be left
800 * in req->data_len and req->next_rq->data_len. The upper-layer driver can
801 * decide what to do with this information.
802 */
Adrian Bunk8c5e03d2008-03-31 01:53:55 +0300803static void scsi_end_bidi_request(struct scsi_cmnd *cmd)
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200804{
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500805 struct request *req = cmd->request;
806 unsigned int dlen = req->data_len;
807 unsigned int next_dlen = req->next_rq->data_len;
808
809 req->data_len = scsi_out(cmd)->resid;
810 req->next_rq->data_len = scsi_in(cmd)->resid;
811
812 /* The req and req->next_rq have not been completed */
813 BUG_ON(blk_end_bidi_request(req, 0, dlen, next_dlen));
814
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200815 scsi_release_buffers(cmd);
816
817 /*
818 * This will goose the queue request function at the end, so we don't
819 * need to worry about launching another command.
820 */
821 scsi_next_command(cmd);
822}
823
824/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 * Function: scsi_io_completion()
826 *
827 * Purpose: Completion processing for block device I/O requests.
828 *
829 * Arguments: cmd - command that is finished.
830 *
831 * Lock status: Assumed that no lock is held upon entry.
832 *
833 * Returns: Nothing
834 *
835 * Notes: This function is matched in terms of capabilities to
836 * the function that created the scatter-gather list.
837 * In other words, if there are no bounce buffers
838 * (the normal case for most drivers), we don't need
839 * the logic to deal with cleaning up afterwards.
840 *
841 * We must do one of several things here:
842 *
843 * a) Call scsi_end_request. This will finish off the
844 * specified number of sectors. If we are done, the
845 * command block will be released, and the queue
846 * function will be goosed. If we are not done, then
847 * scsi_end_request will directly goose the queue.
848 *
849 * b) We can just use scsi_requeue_command() here. This would
850 * be used if we just wanted to retry, for example.
851 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700852void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853{
854 int result = cmd->result;
James Bottomley44ea91c2008-09-20 00:31:50 +0000855 int this_count;
Jens Axboe165125e2007-07-24 09:28:11 +0200856 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500858 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 struct scsi_sense_hdr sshdr;
860 int sense_valid = 0;
861 int sense_deferred = 0;
862
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 if (result) {
864 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
865 if (sense_valid)
866 sense_deferred = scsi_sense_is_deferred(&sshdr);
867 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200868
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
870 req->errors = result;
871 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 if (sense_valid && req->sense) {
873 /*
874 * SG_IO wants current and deferred errors
875 */
876 int len = 8 + cmd->sense_buffer[7];
877
878 if (len > SCSI_SENSE_BUFFERSIZE)
879 len = SCSI_SENSE_BUFFERSIZE;
880 memcpy(req->sense, cmd->sense_buffer, len);
881 req->sense_len = len;
882 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500883 if (!sense_deferred)
884 error = -EIO;
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400885 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200886 if (scsi_bidi_cmnd(cmd)) {
887 /* will also release_buffers */
888 scsi_end_bidi_request(cmd);
889 return;
890 }
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200891 req->data_len = scsi_get_resid(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 }
893
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200894 BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200895 scsi_release_buffers(cmd);
896
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 * Next deal with any sectors which we were able to correctly
899 * handle.
900 */
James Bottomleyd6b0c532006-07-02 10:06:28 -0500901 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
902 "%d bytes done.\n",
903 req->nr_sectors, good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904
James Bottomleyd6b0c532006-07-02 10:06:28 -0500905 /* A number of bytes were successfully read. If there
906 * are leftovers and there is some kind of error
907 * (result != 0), retry the rest.
908 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500909 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500910 return;
James Bottomley44ea91c2008-09-20 00:31:50 +0000911 this_count = blk_rq_bytes(req);
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700912
913 /* good_bytes = 0, or (inclusive) there were leftovers and
914 * result = 0, so scsi_end_request couldn't retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 */
916 if (sense_valid && !sense_deferred) {
917 switch (sshdr.sense_key) {
918 case UNIT_ATTENTION:
919 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700920 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 * and quietly refuse further access.
922 */
923 cmd->device->changed = 1;
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500924 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 return;
926 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700927 /* Must have been a power glitch, or a
928 * bus reset. Could not have been a
929 * media change, so we just retry the
930 * request and see what happens.
931 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 scsi_requeue_command(q, cmd);
933 return;
934 }
935 break;
936 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700937 /* If we had an ILLEGAL REQUEST returned, then
938 * we may have performed an unsupported
939 * command. The only thing this should be
940 * would be a ten byte read where only a six
941 * byte read was supported. Also, on a system
942 * where READ CAPACITY failed, we may have
943 * read past the end of the disk.
944 */
Jens Axboe26a68012005-11-29 21:03:34 +0100945 if ((cmd->device->use_10_for_rw &&
946 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 (cmd->cmnd[0] == READ_10 ||
948 cmd->cmnd[0] == WRITE_10)) {
949 cmd->device->use_10_for_rw = 0;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700950 /* This will cause a retry with a
951 * 6-byte command.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 */
953 scsi_requeue_command(q, cmd);
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400954 } else if (sshdr.asc == 0x10) /* DIX */
955 scsi_end_request(cmd, -EIO, this_count, 0);
956 else
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500957 scsi_end_request(cmd, -EIO, this_count, 1);
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400958 return;
959 case ABORTED_COMMAND:
960 if (sshdr.asc == 0x10) { /* DIF */
961 scsi_end_request(cmd, -EIO, this_count, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 return;
963 }
964 break;
965 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700966 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500967 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500969 if (sshdr.asc == 0x04) {
970 switch (sshdr.ascq) {
971 case 0x01: /* becoming ready */
972 case 0x04: /* format in progress */
973 case 0x05: /* rebuild in progress */
974 case 0x06: /* recalculation in progress */
975 case 0x07: /* operation in progress */
976 case 0x08: /* Long write in progress */
977 case 0x09: /* self test in progress */
978 scsi_requeue_command(q, cmd);
979 return;
980 default:
981 break;
982 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 }
James Bottomley311b5812007-09-23 09:08:46 -0500984 if (!(req->cmd_flags & REQ_QUIET))
985 scsi_cmd_print_sense_hdr(cmd,
986 "Device not ready",
987 &sshdr);
988
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500989 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990 return;
991 case VOLUME_OVERFLOW:
Jens Axboe4aff5e22006-08-10 08:44:47 +0200992 if (!(req->cmd_flags & REQ_QUIET)) {
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400993 scmd_printk(KERN_INFO, cmd,
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700994 "Volume overflow, CDB: ");
Christoph Hellwig631c2282006-07-08 20:42:15 +0200995 __scsi_print_command(cmd->cmnd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500996 scsi_print_sense("", cmd);
997 }
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700998 /* See SSC3rXX or current. */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500999 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 return;
1001 default:
1002 break;
1003 }
Luben Tuikov03aba2f2006-06-23 09:39:09 -07001004 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 if (host_byte(result) == DID_RESET) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -07001006 /* Third party bus reset or reset for error recovery
1007 * reasons. Just retry the request and see what
1008 * happens.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 */
1010 scsi_requeue_command(q, cmd);
1011 return;
1012 }
1013 if (result) {
Jens Axboe4aff5e22006-08-10 08:44:47 +02001014 if (!(req->cmd_flags & REQ_QUIET)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -05001015 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -05001016 if (driver_byte(result) & DRIVER_SENSE)
1017 scsi_print_sense("", cmd);
1018 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 }
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -05001020 scsi_end_request(cmd, -EIO, this_count, !result);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001023static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1024 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001026 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
1028 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001029 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001031 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1032 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -04001034 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035
Christoph Hellwig3b003152006-11-04 20:10:55 +01001036 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037
1038 /*
1039 * Next, walk the list, and fill in the addresses and sizes of
1040 * each segment.
1041 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001042 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1043 BUG_ON(count > sdb->table.nents);
1044 sdb->table.nents = count;
Tejun Heo6b007692008-02-19 11:36:35 +01001045 if (blk_pc_request(req))
1046 sdb->length = req->data_len;
1047 else
1048 sdb->length = req->nr_sectors << 9;
Rusty Russell4a03d902007-11-19 11:28:48 +11001049 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001051
1052/*
1053 * Function: scsi_init_io()
1054 *
1055 * Purpose: SCSI I/O initialize function.
1056 *
1057 * Arguments: cmd - Command descriptor we wish to initialize
1058 *
1059 * Returns: 0 on success
1060 * BLKPREP_DEFER if the failure is retryable
1061 * BLKPREP_KILL if the failure is fatal
1062 */
1063int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1064{
1065 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
1066 if (error)
1067 goto err_exit;
1068
1069 if (blk_bidi_rq(cmd->request)) {
1070 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001071 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001072 if (!bidi_sdb) {
1073 error = BLKPREP_DEFER;
1074 goto err_exit;
1075 }
1076
1077 cmd->request->next_rq->special = bidi_sdb;
1078 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
1079 GFP_ATOMIC);
1080 if (error)
1081 goto err_exit;
1082 }
1083
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001084 if (blk_integrity_rq(cmd->request)) {
1085 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1086 int ivecs, count;
1087
1088 BUG_ON(prot_sdb == NULL);
1089 ivecs = blk_rq_count_integrity_sg(cmd->request);
1090
1091 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1092 error = BLKPREP_DEFER;
1093 goto err_exit;
1094 }
1095
1096 count = blk_rq_map_integrity_sg(cmd->request,
1097 prot_sdb->table.sgl);
1098 BUG_ON(unlikely(count > ivecs));
1099
1100 cmd->prot_sdb = prot_sdb;
1101 cmd->prot_sdb->table.nents = count;
1102 }
1103
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001104 return BLKPREP_OK ;
1105
1106err_exit:
1107 scsi_release_buffers(cmd);
1108 if (error == BLKPREP_KILL)
1109 scsi_put_command(cmd);
1110 else /* BLKPREP_DEFER */
1111 scsi_unprep_request(cmd->request);
1112
1113 return error;
1114}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001115EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116
Christoph Hellwig3b003152006-11-04 20:10:55 +01001117static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1118 struct request *req)
1119{
1120 struct scsi_cmnd *cmd;
1121
1122 if (!req->special) {
1123 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1124 if (unlikely(!cmd))
1125 return NULL;
1126 req->special = cmd;
1127 } else {
1128 cmd = req->special;
1129 }
1130
1131 /* pull a tag out of the request if we have one */
1132 cmd->tag = req->tag;
1133 cmd->request = req;
1134
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001135 cmd->cmnd = req->cmd;
1136
Christoph Hellwig3b003152006-11-04 20:10:55 +01001137 return cmd;
1138}
1139
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001140int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001141{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001142 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001143 int ret = scsi_prep_state_check(sdev, req);
1144
1145 if (ret != BLKPREP_OK)
1146 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001147
1148 cmd = scsi_get_cmd_from_req(sdev, req);
1149 if (unlikely(!cmd))
1150 return BLKPREP_DEFER;
1151
1152 /*
1153 * BLOCK_PC requests may transfer data, in which case they must
1154 * a bio attached to them. Or they might contain a SCSI command
1155 * that does not transfer data, in which case they may optionally
1156 * submit a request without an attached bio.
1157 */
1158 if (req->bio) {
1159 int ret;
1160
1161 BUG_ON(!req->nr_phys_segments);
1162
Boaz Harroshbb52d822007-12-13 16:14:27 -08001163 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001164 if (unlikely(ret))
1165 return ret;
1166 } else {
1167 BUG_ON(req->data_len);
1168 BUG_ON(req->data);
1169
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001170 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001171 req->buffer = NULL;
1172 }
James Bottomley7b163182005-12-15 20:17:02 -06001173
James Bottomley7b163182005-12-15 20:17:02 -06001174 cmd->cmd_len = req->cmd_len;
1175 if (!req->data_len)
1176 cmd->sc_data_direction = DMA_NONE;
1177 else if (rq_data_dir(req) == WRITE)
1178 cmd->sc_data_direction = DMA_TO_DEVICE;
1179 else
1180 cmd->sc_data_direction = DMA_FROM_DEVICE;
1181
1182 cmd->transfersize = req->data_len;
1183 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001184 return BLKPREP_OK;
1185}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001186EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001187
1188/*
1189 * Setup a REQ_TYPE_FS command. These are simple read/write request
1190 * from filesystems that still need to be translated to SCSI CDBs from
1191 * the ULD.
1192 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001193int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001194{
1195 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001196 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001197
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001198 if (ret != BLKPREP_OK)
1199 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001200
1201 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1202 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1203 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1204 if (ret != BLKPREP_OK)
1205 return ret;
1206 }
1207
Christoph Hellwig3b003152006-11-04 20:10:55 +01001208 /*
1209 * Filesystem requests must transfer data.
1210 */
1211 BUG_ON(!req->nr_phys_segments);
1212
1213 cmd = scsi_get_cmd_from_req(sdev, req);
1214 if (unlikely(!cmd))
1215 return BLKPREP_DEFER;
1216
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001217 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001218 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001219}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001220EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001221
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001222int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001224 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
1226 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001227 * If the device is not in running state we will reject some
1228 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001231 switch (sdev->sdev_state) {
1232 case SDEV_OFFLINE:
1233 /*
1234 * If the device is offline we refuse to process any
1235 * commands. The device must be brought online
1236 * before trying any recovery commands.
1237 */
1238 sdev_printk(KERN_ERR, sdev,
1239 "rejecting I/O to offline device\n");
1240 ret = BLKPREP_KILL;
1241 break;
1242 case SDEV_DEL:
1243 /*
1244 * If the device is fully deleted, we refuse to
1245 * process any commands as well.
1246 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001247 sdev_printk(KERN_ERR, sdev,
1248 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001249 ret = BLKPREP_KILL;
1250 break;
1251 case SDEV_QUIESCE:
1252 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001253 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001254 /*
1255 * If the devices is blocked we defer normal commands.
1256 */
1257 if (!(req->cmd_flags & REQ_PREEMPT))
1258 ret = BLKPREP_DEFER;
1259 break;
1260 default:
1261 /*
1262 * For any other not fully online state we only allow
1263 * special commands. In particular any user initiated
1264 * command is not allowed.
1265 */
1266 if (!(req->cmd_flags & REQ_PREEMPT))
1267 ret = BLKPREP_KILL;
1268 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001271 return ret;
1272}
1273EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001275int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1276{
1277 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278
Christoph Hellwig3b003152006-11-04 20:10:55 +01001279 switch (ret) {
1280 case BLKPREP_KILL:
1281 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001282 /* release the command and kill it */
1283 if (req->special) {
1284 struct scsi_cmnd *cmd = req->special;
1285 scsi_release_buffers(cmd);
1286 scsi_put_command(cmd);
1287 req->special = NULL;
1288 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001289 break;
1290 case BLKPREP_DEFER:
1291 /*
1292 * If we defer, the elv_next_request() returns NULL, but the
1293 * queue must be restarted, so we plug here if no returning
1294 * command will automatically do that.
1295 */
1296 if (sdev->device_busy == 0)
1297 blk_plug_device(q);
1298 break;
1299 default:
1300 req->cmd_flags |= REQ_DONTPREP;
1301 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302
Christoph Hellwig3b003152006-11-04 20:10:55 +01001303 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001305EXPORT_SYMBOL(scsi_prep_return);
1306
James Bottomley751bf4d2008-01-02 11:14:30 -06001307int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001308{
1309 struct scsi_device *sdev = q->queuedata;
1310 int ret = BLKPREP_KILL;
1311
1312 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1313 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1314 return scsi_prep_return(q, req, ret);
1315}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316
1317/*
1318 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1319 * return 0.
1320 *
1321 * Called with the queue_lock held.
1322 */
1323static inline int scsi_dev_queue_ready(struct request_queue *q,
1324 struct scsi_device *sdev)
1325{
1326 if (sdev->device_busy >= sdev->queue_depth)
1327 return 0;
1328 if (sdev->device_busy == 0 && sdev->device_blocked) {
1329 /*
1330 * unblock after device_blocked iterates to zero
1331 */
1332 if (--sdev->device_blocked == 0) {
1333 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001334 sdev_printk(KERN_INFO, sdev,
1335 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 } else {
1337 blk_plug_device(q);
1338 return 0;
1339 }
1340 }
1341 if (sdev->device_blocked)
1342 return 0;
1343
1344 return 1;
1345}
1346
1347/*
1348 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1349 * return 0. We must end up running the queue again whenever 0 is
1350 * returned, else IO can hang.
1351 *
1352 * Called with host_lock held.
1353 */
1354static inline int scsi_host_queue_ready(struct request_queue *q,
1355 struct Scsi_Host *shost,
1356 struct scsi_device *sdev)
1357{
James Bottomley939647e2005-09-18 15:05:20 -05001358 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 return 0;
1360 if (shost->host_busy == 0 && shost->host_blocked) {
1361 /*
1362 * unblock after host_blocked iterates to zero
1363 */
1364 if (--shost->host_blocked == 0) {
1365 SCSI_LOG_MLQUEUE(3,
1366 printk("scsi%d unblocking host at zero depth\n",
1367 shost->host_no));
1368 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 return 0;
1370 }
1371 }
1372 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
1373 shost->host_blocked || shost->host_self_blocked) {
1374 if (list_empty(&sdev->starved_entry))
1375 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1376 return 0;
1377 }
1378
1379 /* We're OK to process the command, so we can't be starved */
1380 if (!list_empty(&sdev->starved_entry))
1381 list_del_init(&sdev->starved_entry);
1382
1383 return 1;
1384}
1385
1386/*
James Bottomleye91442b2005-09-09 10:44:16 -05001387 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 */
Jens Axboe165125e2007-07-24 09:28:11 +02001389static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390{
James Bottomleye91442b2005-09-09 10:44:16 -05001391 struct scsi_cmnd *cmd = req->special;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001392 struct scsi_device *sdev = cmd->device;
1393 struct Scsi_Host *shost = sdev->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394
James Bottomley788ce432005-09-09 13:40:23 -05001395 blkdev_dequeue_request(req);
1396
James Bottomleye91442b2005-09-09 10:44:16 -05001397 if (unlikely(cmd == NULL)) {
1398 printk(KERN_CRIT "impossible request in %s.\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001399 __func__);
James Bottomleye91442b2005-09-09 10:44:16 -05001400 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 }
James Bottomleye91442b2005-09-09 10:44:16 -05001402
1403 scsi_init_cmd_errh(cmd);
1404 cmd->result = DID_NO_CONNECT << 16;
1405 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001406
1407 /*
1408 * SCSI request completion path will do scsi_device_unbusy(),
1409 * bump busy counts. To bump the counters, we need to dance
1410 * with the locks as normal issue path does.
1411 */
1412 sdev->device_busy++;
1413 spin_unlock(sdev->request_queue->queue_lock);
1414 spin_lock(shost->host_lock);
1415 shost->host_busy++;
1416 spin_unlock(shost->host_lock);
1417 spin_lock(sdev->request_queue->queue_lock);
1418
Jens Axboe242f9dc2008-09-14 05:55:09 -07001419 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420}
1421
Jens Axboe1aea6432006-01-09 16:03:03 +01001422static void scsi_softirq_done(struct request *rq)
1423{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001424 struct scsi_cmnd *cmd = rq->special;
1425 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001426 int disposition;
1427
1428 INIT_LIST_HEAD(&cmd->eh_entry);
1429
Jens Axboe242f9dc2008-09-14 05:55:09 -07001430 /*
1431 * Set the serial numbers back to zero
1432 */
1433 cmd->serial_number = 0;
1434
1435 atomic_inc(&cmd->device->iodone_cnt);
1436 if (cmd->result)
1437 atomic_inc(&cmd->device->ioerr_cnt);
1438
Jens Axboe1aea6432006-01-09 16:03:03 +01001439 disposition = scsi_decide_disposition(cmd);
1440 if (disposition != SUCCESS &&
1441 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1442 sdev_printk(KERN_ERR, cmd->device,
1443 "timing out command, waited %lus\n",
1444 wait_for/HZ);
1445 disposition = SUCCESS;
1446 }
1447
1448 scsi_log_completion(cmd, disposition);
1449
1450 switch (disposition) {
1451 case SUCCESS:
1452 scsi_finish_command(cmd);
1453 break;
1454 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001455 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001456 break;
1457 case ADD_TO_MLQUEUE:
1458 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1459 break;
1460 default:
1461 if (!scsi_eh_scmd_add(cmd, 0))
1462 scsi_finish_command(cmd);
1463 }
1464}
1465
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466/*
1467 * Function: scsi_request_fn()
1468 *
1469 * Purpose: Main strategy routine for SCSI.
1470 *
1471 * Arguments: q - Pointer to actual queue.
1472 *
1473 * Returns: Nothing
1474 *
1475 * Lock status: IO request lock assumed to be held when called.
1476 */
1477static void scsi_request_fn(struct request_queue *q)
1478{
1479 struct scsi_device *sdev = q->queuedata;
1480 struct Scsi_Host *shost;
1481 struct scsi_cmnd *cmd;
1482 struct request *req;
1483
1484 if (!sdev) {
1485 printk("scsi: killing requests for dead queue\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001486 while ((req = elv_next_request(q)) != NULL)
1487 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 return;
1489 }
1490
1491 if(!get_device(&sdev->sdev_gendev))
1492 /* We must be tearing the block queue down already */
1493 return;
1494
1495 /*
1496 * To start with, we keep looping until the queue is empty, or until
1497 * the host is no longer able to accept any more requests.
1498 */
1499 shost = sdev->host;
1500 while (!blk_queue_plugged(q)) {
1501 int rtn;
1502 /*
1503 * get next queueable request. We do this early to make sure
1504 * that the request is fully prepared even if we cannot
1505 * accept it.
1506 */
1507 req = elv_next_request(q);
1508 if (!req || !scsi_dev_queue_ready(q, sdev))
1509 break;
1510
1511 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001512 sdev_printk(KERN_ERR, sdev,
1513 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001514 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001515 continue;
1516 }
1517
1518
1519 /*
1520 * Remove the request from the request list.
1521 */
1522 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1523 blkdev_dequeue_request(req);
1524 sdev->device_busy++;
1525
1526 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001527 cmd = req->special;
1528 if (unlikely(cmd == NULL)) {
1529 printk(KERN_CRIT "impossible request in %s.\n"
1530 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001531 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001532 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001533 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001534 BUG();
1535 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 spin_lock(shost->host_lock);
1537
Mike Christieecefe8a2008-07-11 19:50:35 -05001538 /*
1539 * We hit this when the driver is using a host wide
1540 * tag map. For device level tag maps the queue_depth check
1541 * in the device ready fn would prevent us from trying
1542 * to allocate a tag. Since the map is a shared host resource
1543 * we add the dev to the starved list so it eventually gets
1544 * a run when a tag is freed.
1545 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001546 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001547 if (list_empty(&sdev->starved_entry))
1548 list_add_tail(&sdev->starved_entry,
1549 &shost->starved_list);
1550 goto not_ready;
1551 }
1552
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 if (!scsi_host_queue_ready(q, shost, sdev))
1554 goto not_ready;
Tony Battersby25d7c362007-11-12 10:00:44 -05001555 if (scsi_target(sdev)->single_lun) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 if (scsi_target(sdev)->starget_sdev_user &&
1557 scsi_target(sdev)->starget_sdev_user != sdev)
1558 goto not_ready;
1559 scsi_target(sdev)->starget_sdev_user = sdev;
1560 }
1561 shost->host_busy++;
1562
1563 /*
1564 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1565 * take the lock again.
1566 */
1567 spin_unlock_irq(shost->host_lock);
1568
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 /*
1570 * Finally, initialize any error handling parameters, and set up
1571 * the timers for timeouts.
1572 */
1573 scsi_init_cmd_errh(cmd);
1574
1575 /*
1576 * Dispatch the command to the low-level driver.
1577 */
1578 rtn = scsi_dispatch_cmd(cmd);
1579 spin_lock_irq(q->queue_lock);
1580 if(rtn) {
1581 /* we're refusing the command; because of
1582 * the way locks get dropped, we need to
1583 * check here if plugging is required */
1584 if(sdev->device_busy == 0)
1585 blk_plug_device(q);
1586
1587 break;
1588 }
1589 }
1590
1591 goto out;
1592
1593 not_ready:
1594 spin_unlock_irq(shost->host_lock);
1595
1596 /*
1597 * lock q, handle tag, requeue req, and decrement device_busy. We
1598 * must return with queue_lock held.
1599 *
1600 * Decrementing device_busy without checking it is OK, as all such
1601 * cases (host limits or settings) should run the queue at some
1602 * later time.
1603 */
1604 spin_lock_irq(q->queue_lock);
1605 blk_requeue_request(q, req);
1606 sdev->device_busy--;
1607 if(sdev->device_busy == 0)
1608 blk_plug_device(q);
1609 out:
1610 /* must be careful here...if we trigger the ->remove() function
1611 * we cannot be holding the q lock */
1612 spin_unlock_irq(q->queue_lock);
1613 put_device(&sdev->sdev_gendev);
1614 spin_lock_irq(q->queue_lock);
1615}
1616
1617u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1618{
1619 struct device *host_dev;
1620 u64 bounce_limit = 0xffffffff;
1621
1622 if (shost->unchecked_isa_dma)
1623 return BLK_BOUNCE_ISA;
1624 /*
1625 * Platforms with virtual-DMA translation
1626 * hardware have no practical limit.
1627 */
1628 if (!PCI_DMA_BUS_IS_PHYS)
1629 return BLK_BOUNCE_ANY;
1630
1631 host_dev = scsi_get_device(shost);
1632 if (host_dev && host_dev->dma_mask)
1633 bounce_limit = *host_dev->dma_mask;
1634
1635 return bounce_limit;
1636}
1637EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1638
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001639struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1640 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001641{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001643 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001645 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646 if (!q)
1647 return NULL;
1648
Jens Axboea8474ce2007-08-07 09:02:51 +02001649 /*
1650 * this limit is imposed by hardware restrictions
1651 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652 blk_queue_max_hw_segments(q, shost->sg_tablesize);
James Bottomleyd3f46f32008-01-15 11:11:46 -06001653 blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
Jens Axboea8474ce2007-08-07 09:02:51 +02001654
Linus Torvalds1da177e2005-04-16 15:20:36 -07001655 blk_queue_max_sectors(q, shost->max_sectors);
1656 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1657 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001658 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001660 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1661
Nick Piggin75ad23b2008-04-29 14:48:33 +02001662 /* New queue, no concurrency on queue_flags */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 if (!shost->use_clustering)
Nick Piggin75ad23b2008-04-29 14:48:33 +02001664 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
James Bottomley465ff312008-01-01 10:00:10 -06001665
1666 /*
1667 * set a reasonable default alignment on word boundaries: the
1668 * host and device may alter it using
1669 * blk_queue_update_dma_alignment() later.
1670 */
1671 blk_queue_dma_alignment(q, 0x03);
1672
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673 return q;
1674}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001675EXPORT_SYMBOL(__scsi_alloc_queue);
1676
1677struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1678{
1679 struct request_queue *q;
1680
1681 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1682 if (!q)
1683 return NULL;
1684
1685 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001686 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001687 blk_queue_rq_timed_out(q, scsi_times_out);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001688 return q;
1689}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690
1691void scsi_free_queue(struct request_queue *q)
1692{
1693 blk_cleanup_queue(q);
1694}
1695
1696/*
1697 * Function: scsi_block_requests()
1698 *
1699 * Purpose: Utility function used by low-level drivers to prevent further
1700 * commands from being queued to the device.
1701 *
1702 * Arguments: shost - Host in question
1703 *
1704 * Returns: Nothing
1705 *
1706 * Lock status: No locks are assumed held.
1707 *
1708 * Notes: There is no timer nor any other means by which the requests
1709 * get unblocked other than the low-level driver calling
1710 * scsi_unblock_requests().
1711 */
1712void scsi_block_requests(struct Scsi_Host *shost)
1713{
1714 shost->host_self_blocked = 1;
1715}
1716EXPORT_SYMBOL(scsi_block_requests);
1717
1718/*
1719 * Function: scsi_unblock_requests()
1720 *
1721 * Purpose: Utility function used by low-level drivers to allow 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 * This is done as an API function so that changes to the
1735 * internals of the scsi mid-layer won't require wholesale
1736 * changes to drivers that use this feature.
1737 */
1738void scsi_unblock_requests(struct Scsi_Host *shost)
1739{
1740 shost->host_self_blocked = 0;
1741 scsi_run_host_queues(shost);
1742}
1743EXPORT_SYMBOL(scsi_unblock_requests);
1744
1745int __init scsi_init_queue(void)
1746{
1747 int i;
1748
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001749 scsi_io_context_cache = kmem_cache_create("scsi_io_context",
1750 sizeof(struct scsi_io_context),
Paul Mundt20c2df82007-07-20 10:11:58 +09001751 0, 0, NULL);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001752 if (!scsi_io_context_cache) {
1753 printk(KERN_ERR "SCSI: can't init scsi io context cache\n");
1754 return -ENOMEM;
1755 }
1756
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001757 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1758 sizeof(struct scsi_data_buffer),
1759 0, 0, NULL);
1760 if (!scsi_sdb_cache) {
1761 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001762 goto cleanup_io_context;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001763 }
1764
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1766 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1767 int size = sgp->size * sizeof(struct scatterlist);
1768
1769 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001770 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 if (!sgp->slab) {
1772 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1773 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001774 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 }
1776
Matthew Dobson93d23412006-03-26 01:37:50 -08001777 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1778 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 if (!sgp->pool) {
1780 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1781 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001782 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 }
1784 }
1785
1786 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001787
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001788cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001789 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1790 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1791 if (sgp->pool)
1792 mempool_destroy(sgp->pool);
1793 if (sgp->slab)
1794 kmem_cache_destroy(sgp->slab);
1795 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001796 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001797cleanup_io_context:
1798 kmem_cache_destroy(scsi_io_context_cache);
1799
1800 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801}
1802
1803void scsi_exit_queue(void)
1804{
1805 int i;
1806
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001807 kmem_cache_destroy(scsi_io_context_cache);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001808 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001809
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1811 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1812 mempool_destroy(sgp->pool);
1813 kmem_cache_destroy(sgp->slab);
1814 }
1815}
James Bottomley5baba832006-03-18 14:10:35 -06001816
1817/**
1818 * scsi_mode_select - issue a mode select
1819 * @sdev: SCSI device to be queried
1820 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1821 * @sp: Save page bit (0 == don't save, 1 == save)
1822 * @modepage: mode page being requested
1823 * @buffer: request buffer (may not be smaller than eight bytes)
1824 * @len: length of request buffer.
1825 * @timeout: command timeout
1826 * @retries: number of retries before failing
1827 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001828 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001829 * must be SCSI_SENSE_BUFFERSIZE big.
1830 *
1831 * Returns zero if successful; negative error number or scsi
1832 * status on error
1833 *
1834 */
1835int
1836scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1837 unsigned char *buffer, int len, int timeout, int retries,
1838 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1839{
1840 unsigned char cmd[10];
1841 unsigned char *real_buffer;
1842 int ret;
1843
1844 memset(cmd, 0, sizeof(cmd));
1845 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1846
1847 if (sdev->use_10_for_ms) {
1848 if (len > 65535)
1849 return -EINVAL;
1850 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1851 if (!real_buffer)
1852 return -ENOMEM;
1853 memcpy(real_buffer + 8, buffer, len);
1854 len += 8;
1855 real_buffer[0] = 0;
1856 real_buffer[1] = 0;
1857 real_buffer[2] = data->medium_type;
1858 real_buffer[3] = data->device_specific;
1859 real_buffer[4] = data->longlba ? 0x01 : 0;
1860 real_buffer[5] = 0;
1861 real_buffer[6] = data->block_descriptor_length >> 8;
1862 real_buffer[7] = data->block_descriptor_length;
1863
1864 cmd[0] = MODE_SELECT_10;
1865 cmd[7] = len >> 8;
1866 cmd[8] = len;
1867 } else {
1868 if (len > 255 || data->block_descriptor_length > 255 ||
1869 data->longlba)
1870 return -EINVAL;
1871
1872 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1873 if (!real_buffer)
1874 return -ENOMEM;
1875 memcpy(real_buffer + 4, buffer, len);
1876 len += 4;
1877 real_buffer[0] = 0;
1878 real_buffer[1] = data->medium_type;
1879 real_buffer[2] = data->device_specific;
1880 real_buffer[3] = data->block_descriptor_length;
1881
1882
1883 cmd[0] = MODE_SELECT;
1884 cmd[4] = len;
1885 }
1886
1887 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1888 sshdr, timeout, retries);
1889 kfree(real_buffer);
1890 return ret;
1891}
1892EXPORT_SYMBOL_GPL(scsi_mode_select);
1893
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894/**
Rob Landleyeb448202007-11-03 13:30:39 -05001895 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001896 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897 * @dbd: set if mode sense will allow block descriptors to be returned
1898 * @modepage: mode page being requested
1899 * @buffer: request buffer (may not be smaller than eight bytes)
1900 * @len: length of request buffer.
1901 * @timeout: command timeout
1902 * @retries: number of retries before failing
1903 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001904 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001905 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906 *
1907 * Returns zero if unsuccessful, or the header offset (either 4
1908 * or 8 depending on whether a six or ten byte command was
1909 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001910 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911int
James Bottomley1cf72692005-08-28 11:27:01 -05001912scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001914 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1915{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001916 unsigned char cmd[12];
1917 int use_10_for_ms;
1918 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001919 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001920 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921
1922 memset(data, 0, sizeof(*data));
1923 memset(&cmd[0], 0, 12);
1924 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1925 cmd[2] = modepage;
1926
James Bottomleyea73a9f2005-08-28 11:33:52 -05001927 /* caller might not be interested in sense, but we need it */
1928 if (!sshdr)
1929 sshdr = &my_sshdr;
1930
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001932 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933
1934 if (use_10_for_ms) {
1935 if (len < 8)
1936 len = 8;
1937
1938 cmd[0] = MODE_SENSE_10;
1939 cmd[8] = len;
1940 header_length = 8;
1941 } else {
1942 if (len < 4)
1943 len = 4;
1944
1945 cmd[0] = MODE_SENSE;
1946 cmd[4] = len;
1947 header_length = 4;
1948 }
1949
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 memset(buffer, 0, len);
1951
James Bottomley1cf72692005-08-28 11:27:01 -05001952 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
James Bottomleyea73a9f2005-08-28 11:33:52 -05001953 sshdr, timeout, retries);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954
1955 /* This code looks awful: what it's doing is making sure an
1956 * ILLEGAL REQUEST sense return identifies the actual command
1957 * byte as the problem. MODE_SENSE commands can return
1958 * ILLEGAL REQUEST if the code page isn't supported */
1959
James Bottomley1cf72692005-08-28 11:27:01 -05001960 if (use_10_for_ms && !scsi_status_is_good(result) &&
1961 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001962 if (scsi_sense_valid(sshdr)) {
1963 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1964 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001965 /*
1966 * Invalid command operation code
1967 */
James Bottomley1cf72692005-08-28 11:27:01 -05001968 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001969 goto retry;
1970 }
1971 }
1972 }
1973
James Bottomley1cf72692005-08-28 11:27:01 -05001974 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001975 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1976 (modepage == 6 || modepage == 8))) {
1977 /* Initio breakage? */
1978 header_length = 0;
1979 data->length = 13;
1980 data->medium_type = 0;
1981 data->device_specific = 0;
1982 data->longlba = 0;
1983 data->block_descriptor_length = 0;
1984 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 data->length = buffer[0]*256 + buffer[1] + 2;
1986 data->medium_type = buffer[2];
1987 data->device_specific = buffer[3];
1988 data->longlba = buffer[4] & 0x01;
1989 data->block_descriptor_length = buffer[6]*256
1990 + buffer[7];
1991 } else {
1992 data->length = buffer[0] + 1;
1993 data->medium_type = buffer[1];
1994 data->device_specific = buffer[2];
1995 data->block_descriptor_length = buffer[3];
1996 }
Al Viro6d73c852006-02-23 02:03:16 +01001997 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998 }
1999
James Bottomley1cf72692005-08-28 11:27:01 -05002000 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001}
2002EXPORT_SYMBOL(scsi_mode_sense);
2003
James Bottomley001aac22007-12-02 19:10:40 +02002004/**
2005 * scsi_test_unit_ready - test if unit is ready
2006 * @sdev: scsi device to change the state of.
2007 * @timeout: command timeout
2008 * @retries: number of retries before failing
2009 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2010 * returning sense. Make sure that this is cleared before passing
2011 * in.
2012 *
2013 * Returns zero if unsuccessful or an error if TUR failed. For
2014 * removable media, a return of NOT_READY or UNIT_ATTENTION is
2015 * translated to success, with the ->changed flag updated.
2016 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002017int
James Bottomley001aac22007-12-02 19:10:40 +02002018scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2019 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021 char cmd[] = {
2022 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2023 };
James Bottomley001aac22007-12-02 19:10:40 +02002024 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002025 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002026
2027 if (!sshdr_external)
2028 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2029 else
2030 sshdr = sshdr_external;
2031
2032 /* try to eat the UNIT_ATTENTION if there are enough retries */
2033 do {
2034 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2035 timeout, retries);
2036 } while ((driver_byte(result) & DRIVER_SENSE) &&
2037 sshdr && sshdr->sense_key == UNIT_ATTENTION &&
2038 --retries);
2039
2040 if (!sshdr)
2041 /* could not allocate sense buffer, so can't process it */
2042 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043
James Bottomley1cf72692005-08-28 11:27:01 -05002044 if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002045
James Bottomley001aac22007-12-02 19:10:40 +02002046 if ((scsi_sense_valid(sshdr)) &&
2047 ((sshdr->sense_key == UNIT_ATTENTION) ||
2048 (sshdr->sense_key == NOT_READY))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 sdev->changed = 1;
James Bottomley1cf72692005-08-28 11:27:01 -05002050 result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051 }
2052 }
James Bottomley001aac22007-12-02 19:10:40 +02002053 if (!sshdr_external)
2054 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 return result;
2056}
2057EXPORT_SYMBOL(scsi_test_unit_ready);
2058
2059/**
Rob Landleyeb448202007-11-03 13:30:39 -05002060 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061 * @sdev: scsi device to change the state of.
2062 * @state: state to change to.
2063 *
2064 * Returns zero if unsuccessful or an error if the requested
2065 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002066 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067int
2068scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2069{
2070 enum scsi_device_state oldstate = sdev->sdev_state;
2071
2072 if (state == oldstate)
2073 return 0;
2074
2075 switch (state) {
2076 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002077 switch (oldstate) {
2078 case SDEV_CREATED_BLOCK:
2079 break;
2080 default:
2081 goto illegal;
2082 }
2083 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002084
2085 case SDEV_RUNNING:
2086 switch (oldstate) {
2087 case SDEV_CREATED:
2088 case SDEV_OFFLINE:
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:
2101 break;
2102 default:
2103 goto illegal;
2104 }
2105 break;
2106
2107 case SDEV_OFFLINE:
2108 switch (oldstate) {
2109 case SDEV_CREATED:
2110 case SDEV_RUNNING:
2111 case SDEV_QUIESCE:
2112 case SDEV_BLOCK:
2113 break;
2114 default:
2115 goto illegal;
2116 }
2117 break;
2118
2119 case SDEV_BLOCK:
2120 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002122 case SDEV_CREATED_BLOCK:
2123 break;
2124 default:
2125 goto illegal;
2126 }
2127 break;
2128
2129 case SDEV_CREATED_BLOCK:
2130 switch (oldstate) {
2131 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132 break;
2133 default:
2134 goto illegal;
2135 }
2136 break;
2137
2138 case SDEV_CANCEL:
2139 switch (oldstate) {
2140 case SDEV_CREATED:
2141 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002142 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002143 case SDEV_OFFLINE:
2144 case SDEV_BLOCK:
2145 break;
2146 default:
2147 goto illegal;
2148 }
2149 break;
2150
2151 case SDEV_DEL:
2152 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002153 case SDEV_CREATED:
2154 case SDEV_RUNNING:
2155 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 case SDEV_CANCEL:
2157 break;
2158 default:
2159 goto illegal;
2160 }
2161 break;
2162
2163 }
2164 sdev->sdev_state = state;
2165 return 0;
2166
2167 illegal:
2168 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002169 sdev_printk(KERN_ERR, sdev,
2170 "Illegal state transition %s->%s\n",
2171 scsi_device_state_name(oldstate),
2172 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002173 );
2174 return -EINVAL;
2175}
2176EXPORT_SYMBOL(scsi_device_set_state);
2177
2178/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002179 * sdev_evt_emit - emit a single SCSI device uevent
2180 * @sdev: associated SCSI device
2181 * @evt: event to emit
2182 *
2183 * Send a single uevent (scsi_event) to the associated scsi_device.
2184 */
2185static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2186{
2187 int idx = 0;
2188 char *envp[3];
2189
2190 switch (evt->evt_type) {
2191 case SDEV_EVT_MEDIA_CHANGE:
2192 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2193 break;
2194
2195 default:
2196 /* do nothing */
2197 break;
2198 }
2199
2200 envp[idx++] = NULL;
2201
2202 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2203}
2204
2205/**
2206 * sdev_evt_thread - send a uevent for each scsi event
2207 * @work: work struct for scsi_device
2208 *
2209 * Dispatch queued events to their associated scsi_device kobjects
2210 * as uevents.
2211 */
2212void scsi_evt_thread(struct work_struct *work)
2213{
2214 struct scsi_device *sdev;
2215 LIST_HEAD(event_list);
2216
2217 sdev = container_of(work, struct scsi_device, event_work);
2218
2219 while (1) {
2220 struct scsi_event *evt;
2221 struct list_head *this, *tmp;
2222 unsigned long flags;
2223
2224 spin_lock_irqsave(&sdev->list_lock, flags);
2225 list_splice_init(&sdev->event_list, &event_list);
2226 spin_unlock_irqrestore(&sdev->list_lock, flags);
2227
2228 if (list_empty(&event_list))
2229 break;
2230
2231 list_for_each_safe(this, tmp, &event_list) {
2232 evt = list_entry(this, struct scsi_event, node);
2233 list_del(&evt->node);
2234 scsi_evt_emit(sdev, evt);
2235 kfree(evt);
2236 }
2237 }
2238}
2239
2240/**
2241 * sdev_evt_send - send asserted event to uevent thread
2242 * @sdev: scsi_device event occurred on
2243 * @evt: event to send
2244 *
2245 * Assert scsi device event asynchronously.
2246 */
2247void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2248{
2249 unsigned long flags;
2250
Kay Sievers4d1566e2008-03-19 13:04:47 +01002251#if 0
2252 /* FIXME: currently this check eliminates all media change events
2253 * for polled devices. Need to update to discriminate between AN
2254 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002255 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2256 kfree(evt);
2257 return;
2258 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002259#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002260
2261 spin_lock_irqsave(&sdev->list_lock, flags);
2262 list_add_tail(&evt->node, &sdev->event_list);
2263 schedule_work(&sdev->event_work);
2264 spin_unlock_irqrestore(&sdev->list_lock, flags);
2265}
2266EXPORT_SYMBOL_GPL(sdev_evt_send);
2267
2268/**
2269 * sdev_evt_alloc - allocate a new scsi event
2270 * @evt_type: type of event to allocate
2271 * @gfpflags: GFP flags for allocation
2272 *
2273 * Allocates and returns a new scsi_event.
2274 */
2275struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2276 gfp_t gfpflags)
2277{
2278 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2279 if (!evt)
2280 return NULL;
2281
2282 evt->evt_type = evt_type;
2283 INIT_LIST_HEAD(&evt->node);
2284
2285 /* evt_type-specific initialization, if any */
2286 switch (evt_type) {
2287 case SDEV_EVT_MEDIA_CHANGE:
2288 default:
2289 /* do nothing */
2290 break;
2291 }
2292
2293 return evt;
2294}
2295EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2296
2297/**
2298 * sdev_evt_send_simple - send asserted event to uevent thread
2299 * @sdev: scsi_device event occurred on
2300 * @evt_type: type of event to send
2301 * @gfpflags: GFP flags for allocation
2302 *
2303 * Assert scsi device event asynchronously, given an event type.
2304 */
2305void sdev_evt_send_simple(struct scsi_device *sdev,
2306 enum scsi_device_event evt_type, gfp_t gfpflags)
2307{
2308 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2309 if (!evt) {
2310 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2311 evt_type);
2312 return;
2313 }
2314
2315 sdev_evt_send(sdev, evt);
2316}
2317EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2318
2319/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320 * scsi_device_quiesce - Block user issued commands.
2321 * @sdev: scsi device to quiesce.
2322 *
2323 * This works by trying to transition to the SDEV_QUIESCE state
2324 * (which must be a legal transition). When the device is in this
2325 * state, only special requests will be accepted, all others will
2326 * be deferred. Since special requests may also be requeued requests,
2327 * a successful return doesn't guarantee the device will be
2328 * totally quiescent.
2329 *
2330 * Must be called with user context, may sleep.
2331 *
2332 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002333 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002334int
2335scsi_device_quiesce(struct scsi_device *sdev)
2336{
2337 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2338 if (err)
2339 return err;
2340
2341 scsi_run_queue(sdev->request_queue);
2342 while (sdev->device_busy) {
2343 msleep_interruptible(200);
2344 scsi_run_queue(sdev->request_queue);
2345 }
2346 return 0;
2347}
2348EXPORT_SYMBOL(scsi_device_quiesce);
2349
2350/**
2351 * scsi_device_resume - Restart user issued commands to a quiesced device.
2352 * @sdev: scsi device to resume.
2353 *
2354 * Moves the device from quiesced back to running and restarts the
2355 * queues.
2356 *
2357 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002358 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359void
2360scsi_device_resume(struct scsi_device *sdev)
2361{
2362 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2363 return;
2364 scsi_run_queue(sdev->request_queue);
2365}
2366EXPORT_SYMBOL(scsi_device_resume);
2367
2368static void
2369device_quiesce_fn(struct scsi_device *sdev, void *data)
2370{
2371 scsi_device_quiesce(sdev);
2372}
2373
2374void
2375scsi_target_quiesce(struct scsi_target *starget)
2376{
2377 starget_for_each_device(starget, NULL, device_quiesce_fn);
2378}
2379EXPORT_SYMBOL(scsi_target_quiesce);
2380
2381static void
2382device_resume_fn(struct scsi_device *sdev, void *data)
2383{
2384 scsi_device_resume(sdev);
2385}
2386
2387void
2388scsi_target_resume(struct scsi_target *starget)
2389{
2390 starget_for_each_device(starget, NULL, device_resume_fn);
2391}
2392EXPORT_SYMBOL(scsi_target_resume);
2393
2394/**
Rob Landleyeb448202007-11-03 13:30:39 -05002395 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002396 * @sdev: device to block
2397 *
2398 * Block request made by scsi lld's to temporarily stop all
2399 * scsi commands on the specified device. Called from interrupt
2400 * or normal process context.
2401 *
2402 * Returns zero if successful or error if not
2403 *
2404 * Notes:
2405 * This routine transitions the device to the SDEV_BLOCK state
2406 * (which must be a legal transition). When the device is in this
2407 * state, all commands are deferred until the scsi lld reenables
2408 * the device with scsi_device_unblock or device_block_tmo fires.
2409 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002410 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411int
2412scsi_internal_device_block(struct scsi_device *sdev)
2413{
Jens Axboe165125e2007-07-24 09:28:11 +02002414 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002415 unsigned long flags;
2416 int err = 0;
2417
2418 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002419 if (err) {
2420 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2421
2422 if (err)
2423 return err;
2424 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002425
2426 /*
2427 * The device has transitioned to SDEV_BLOCK. Stop the
2428 * block layer from calling the midlayer with this device's
2429 * request queue.
2430 */
2431 spin_lock_irqsave(q->queue_lock, flags);
2432 blk_stop_queue(q);
2433 spin_unlock_irqrestore(q->queue_lock, flags);
2434
2435 return 0;
2436}
2437EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2438
2439/**
2440 * scsi_internal_device_unblock - resume a device after a block request
2441 * @sdev: device to resume
2442 *
2443 * Called by scsi lld's or the midlayer to restart the device queue
2444 * for the previously suspended scsi device. Called from interrupt or
2445 * normal process context.
2446 *
2447 * Returns zero if successful or error if not.
2448 *
2449 * Notes:
2450 * This routine transitions the device to the SDEV_RUNNING state
2451 * (which must be a legal transition) allowing the midlayer to
2452 * goose the queue for this device. This routine assumes the
2453 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002454 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455int
2456scsi_internal_device_unblock(struct scsi_device *sdev)
2457{
Jens Axboe165125e2007-07-24 09:28:11 +02002458 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002459 int err;
2460 unsigned long flags;
2461
2462 /*
2463 * Try to transition the scsi device to SDEV_RUNNING
2464 * and goose the device queue if successful.
2465 */
2466 err = scsi_device_set_state(sdev, SDEV_RUNNING);
James Bottomley6f4267e2008-08-22 16:53:31 -05002467 if (err) {
2468 err = scsi_device_set_state(sdev, SDEV_CREATED);
2469
2470 if (err)
2471 return err;
2472 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002473
2474 spin_lock_irqsave(q->queue_lock, flags);
2475 blk_start_queue(q);
2476 spin_unlock_irqrestore(q->queue_lock, flags);
2477
2478 return 0;
2479}
2480EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2481
2482static void
2483device_block(struct scsi_device *sdev, void *data)
2484{
2485 scsi_internal_device_block(sdev);
2486}
2487
2488static int
2489target_block(struct device *dev, void *data)
2490{
2491 if (scsi_is_target_device(dev))
2492 starget_for_each_device(to_scsi_target(dev), NULL,
2493 device_block);
2494 return 0;
2495}
2496
2497void
2498scsi_target_block(struct device *dev)
2499{
2500 if (scsi_is_target_device(dev))
2501 starget_for_each_device(to_scsi_target(dev), NULL,
2502 device_block);
2503 else
2504 device_for_each_child(dev, NULL, target_block);
2505}
2506EXPORT_SYMBOL_GPL(scsi_target_block);
2507
2508static void
2509device_unblock(struct scsi_device *sdev, void *data)
2510{
2511 scsi_internal_device_unblock(sdev);
2512}
2513
2514static int
2515target_unblock(struct device *dev, void *data)
2516{
2517 if (scsi_is_target_device(dev))
2518 starget_for_each_device(to_scsi_target(dev), NULL,
2519 device_unblock);
2520 return 0;
2521}
2522
2523void
2524scsi_target_unblock(struct device *dev)
2525{
2526 if (scsi_is_target_device(dev))
2527 starget_for_each_device(to_scsi_target(dev), NULL,
2528 device_unblock);
2529 else
2530 device_for_each_child(dev, NULL, target_unblock);
2531}
2532EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002533
2534/**
2535 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002536 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002537 * @sg_count: number of segments in sg
2538 * @offset: offset in bytes into sg, on return offset into the mapped area
2539 * @len: bytes to map, on return number of bytes mapped
2540 *
2541 * Returns virtual address of the start of the mapped page
2542 */
Jens Axboec6132da2007-10-16 11:08:49 +02002543void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002544 size_t *offset, size_t *len)
2545{
2546 int i;
2547 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002548 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002549 struct page *page;
2550
Andrew Morton22cfefb2007-02-05 16:39:03 -08002551 WARN_ON(!irqs_disabled());
2552
Jens Axboec6132da2007-10-16 11:08:49 +02002553 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002554 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002555 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002556 if (sg_len > *offset)
2557 break;
2558 }
2559
2560 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002561 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2562 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002563 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002564 WARN_ON(1);
2565 return NULL;
2566 }
2567
2568 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002569 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002570
2571 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002572 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002573 *offset &= ~PAGE_MASK;
2574
2575 /* Bytes in this sg-entry from *offset to the end of the page */
2576 sg_len = PAGE_SIZE - *offset;
2577 if (*len > sg_len)
2578 *len = sg_len;
2579
2580 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2581}
2582EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2583
2584/**
Rob Landleyeb448202007-11-03 13:30:39 -05002585 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002586 * @virt: virtual address to be unmapped
2587 */
2588void scsi_kunmap_atomic_sg(void *virt)
2589{
2590 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2591}
2592EXPORT_SYMBOL(scsi_kunmap_atomic_sg);