blob: f40898dc2d1427990926617792a2bcc89f47e465 [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
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020068static struct kmem_cache *scsi_bidi_sdb_cache;
69
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
210 ret = req->errors;
211 out:
212 blk_put_request(req);
213
214 return ret;
215}
James Bottomley33aa6872005-08-28 11:31:14 -0500216EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500217
James Bottomleyea73a9f2005-08-28 11:33:52 -0500218
219int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
220 int data_direction, void *buffer, unsigned bufflen,
221 struct scsi_sense_hdr *sshdr, int timeout, int retries)
222{
223 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700224 int result;
225
James Bottomleyea73a9f2005-08-28 11:33:52 -0500226 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500227 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500228 if (!sense)
229 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500230 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700231 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Jes Sorensen24669f752006-01-16 10:31:18 -0500232 sense, timeout, retries, 0);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500233 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500234 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500235
236 kfree(sense);
237 return result;
238}
239EXPORT_SYMBOL(scsi_execute_req);
240
Mike Christie6e68af62005-11-11 05:30:27 -0600241struct scsi_io_context {
242 void *data;
243 void (*done)(void *data, char *sense, int result, int resid);
244 char sense[SCSI_SENSE_BUFFERSIZE];
245};
246
Christoph Lametere18b8902006-12-06 20:33:20 -0800247static struct kmem_cache *scsi_io_context_cache;
Mike Christieaa7b5cd2005-11-11 05:31:41 -0600248
Jens Axboee650c302006-01-06 12:38:30 +0100249static void scsi_end_async(struct request *req, int uptodate)
Mike Christie6e68af62005-11-11 05:30:27 -0600250{
251 struct scsi_io_context *sioc = req->end_io_data;
252
253 if (sioc->done)
254 sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
255
Mike Christieaa7b5cd2005-11-11 05:31:41 -0600256 kmem_cache_free(scsi_io_context_cache, sioc);
Mike Christie6e68af62005-11-11 05:30:27 -0600257 __blk_put_request(req->q, req);
258}
259
260static int scsi_merge_bio(struct request *rq, struct bio *bio)
261{
262 struct request_queue *q = rq->q;
263
264 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
265 if (rq_data_dir(rq) == WRITE)
266 bio->bi_rw |= (1 << BIO_RW);
267 blk_queue_bounce(q, &bio);
268
NeilBrown3001ca72007-08-16 13:31:27 +0200269 return blk_rq_append_bio(q, rq, bio);
Mike Christie6e68af62005-11-11 05:30:27 -0600270}
271
NeilBrown6712ecf2007-09-27 12:47:43 +0200272static void scsi_bi_endio(struct bio *bio, int error)
Mike Christie6e68af62005-11-11 05:30:27 -0600273{
Mike Christie6e68af62005-11-11 05:30:27 -0600274 bio_put(bio);
Mike Christie6e68af62005-11-11 05:30:27 -0600275}
276
277/**
278 * scsi_req_map_sg - map a scatterlist into a request
279 * @rq: request to fill
Rob Landleyeb448202007-11-03 13:30:39 -0500280 * @sgl: scatterlist
Mike Christie6e68af62005-11-11 05:30:27 -0600281 * @nsegs: number of elements
282 * @bufflen: len of buffer
283 * @gfp: memory allocation flags
284 *
285 * scsi_req_map_sg maps a scatterlist into a request so that the
286 * request can be sent to the block layer. We do not trust the scatterlist
287 * sent to use, as some ULDs use that struct to only organize the pages.
288 */
289static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
290 int nsegs, unsigned bufflen, gfp_t gfp)
291{
292 struct request_queue *q = rq->q;
Bryan Holtyf5235962006-03-22 06:35:39 -0600293 int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
Mike Christiebd441de2007-03-13 12:52:29 -0500294 unsigned int data_len = bufflen, len, bytes, off;
Jens Axboec6132da2007-10-16 11:08:49 +0200295 struct scatterlist *sg;
Mike Christie6e68af62005-11-11 05:30:27 -0600296 struct page *page;
297 struct bio *bio = NULL;
298 int i, err, nr_vecs = 0;
299
Jens Axboec6132da2007-10-16 11:08:49 +0200300 for_each_sg(sgl, sg, nsegs, i) {
Jens Axboe45711f12007-10-22 21:19:53 +0200301 page = sg_page(sg);
Jens Axboec6132da2007-10-16 11:08:49 +0200302 off = sg->offset;
303 len = sg->length;
Mike Christie6e68af62005-11-11 05:30:27 -0600304
Mike Christiebd441de2007-03-13 12:52:29 -0500305 while (len > 0 && data_len > 0) {
306 /*
307 * sg sends a scatterlist that is larger than
308 * the data_len it wants transferred for certain
309 * IO sizes
310 */
Mike Christie6e68af62005-11-11 05:30:27 -0600311 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
Mike Christiebd441de2007-03-13 12:52:29 -0500312 bytes = min(bytes, data_len);
Mike Christie6e68af62005-11-11 05:30:27 -0600313
314 if (!bio) {
315 nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
316 nr_pages -= nr_vecs;
317
318 bio = bio_alloc(gfp, nr_vecs);
319 if (!bio) {
320 err = -ENOMEM;
321 goto free_bios;
322 }
323 bio->bi_end_io = scsi_bi_endio;
324 }
325
326 if (bio_add_pc_page(q, bio, page, bytes, off) !=
327 bytes) {
328 bio_put(bio);
329 err = -EINVAL;
330 goto free_bios;
331 }
332
333 if (bio->bi_vcnt >= nr_vecs) {
334 err = scsi_merge_bio(rq, bio);
335 if (err) {
NeilBrown6712ecf2007-09-27 12:47:43 +0200336 bio_endio(bio, 0);
Mike Christie6e68af62005-11-11 05:30:27 -0600337 goto free_bios;
338 }
339 bio = NULL;
340 }
341
342 page++;
343 len -= bytes;
Mike Christiebd441de2007-03-13 12:52:29 -0500344 data_len -=bytes;
Mike Christie6e68af62005-11-11 05:30:27 -0600345 off = 0;
346 }
347 }
348
349 rq->buffer = rq->data = NULL;
Mike Christiebd441de2007-03-13 12:52:29 -0500350 rq->data_len = bufflen;
Mike Christie6e68af62005-11-11 05:30:27 -0600351 return 0;
352
353free_bios:
354 while ((bio = rq->bio) != NULL) {
355 rq->bio = bio->bi_next;
356 /*
357 * call endio instead of bio_put incase it was bounced
358 */
NeilBrown6712ecf2007-09-27 12:47:43 +0200359 bio_endio(bio, 0);
Mike Christie6e68af62005-11-11 05:30:27 -0600360 }
361
362 return err;
363}
364
365/**
366 * scsi_execute_async - insert request
367 * @sdev: scsi device
368 * @cmd: scsi command
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600369 * @cmd_len: length of scsi cdb
Rob Landleyeb448202007-11-03 13:30:39 -0500370 * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE
Mike Christie6e68af62005-11-11 05:30:27 -0600371 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
372 * @bufflen: len of buffer
373 * @use_sg: if buffer is a scatterlist this is the number of elements
374 * @timeout: request timeout in seconds
375 * @retries: number of times to retry request
Rob Landleyeb448202007-11-03 13:30:39 -0500376 * @privdata: data passed to done()
377 * @done: callback function when done
378 * @gfp: memory allocation flags
379 */
Mike Christie6e68af62005-11-11 05:30:27 -0600380int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600381 int cmd_len, int data_direction, void *buffer, unsigned bufflen,
Mike Christie6e68af62005-11-11 05:30:27 -0600382 int use_sg, int timeout, int retries, void *privdata,
383 void (*done)(void *, char *, int, int), gfp_t gfp)
384{
385 struct request *req;
386 struct scsi_io_context *sioc;
387 int err = 0;
388 int write = (data_direction == DMA_TO_DEVICE);
389
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800390 sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp);
Mike Christie6e68af62005-11-11 05:30:27 -0600391 if (!sioc)
392 return DRIVER_ERROR << 24;
393
394 req = blk_get_request(sdev->request_queue, write, gfp);
395 if (!req)
396 goto free_sense;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200397 req->cmd_type = REQ_TYPE_BLOCK_PC;
398 req->cmd_flags |= REQ_QUIET;
Mike Christie6e68af62005-11-11 05:30:27 -0600399
400 if (use_sg)
401 err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
402 else if (bufflen)
403 err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
404
405 if (err)
406 goto free_req;
407
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600408 req->cmd_len = cmd_len;
Tejun Heo097b8452006-11-16 01:19:31 -0800409 memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
Mike Christie6e68af62005-11-11 05:30:27 -0600410 memcpy(req->cmd, cmd, req->cmd_len);
411 req->sense = sioc->sense;
412 req->sense_len = 0;
413 req->timeout = timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600414 req->retries = retries;
Mike Christie6e68af62005-11-11 05:30:27 -0600415 req->end_io_data = sioc;
416
417 sioc->data = privdata;
418 sioc->done = done;
419
420 blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
421 return 0;
422
423free_req:
424 blk_put_request(req);
425free_sense:
Arne Redlich6470f2b2006-09-30 15:49:40 +0200426 kmem_cache_free(scsi_io_context_cache, sioc);
Mike Christie6e68af62005-11-11 05:30:27 -0600427 return DRIVER_ERROR << 24;
428}
429EXPORT_SYMBOL_GPL(scsi_execute_async);
430
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431/*
432 * Function: scsi_init_cmd_errh()
433 *
434 * Purpose: Initialize cmd fields related to error handling.
435 *
436 * Arguments: cmd - command that is ready to be queued.
437 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 * Notes: This function has the job of initializing a number of
439 * fields related to error handling. Typically this will
440 * be called once for each command, as required.
441 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200442static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200445 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900446 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 if (cmd->cmd_len == 0)
448 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449}
450
451void scsi_device_unbusy(struct scsi_device *sdev)
452{
453 struct Scsi_Host *shost = sdev->host;
454 unsigned long flags;
455
456 spin_lock_irqsave(shost->host_lock, flags);
457 shost->host_busy--;
James Bottomley939647e2005-09-18 15:05:20 -0500458 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900459 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 scsi_eh_wakeup(shost);
461 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500462 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500464 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465}
466
467/*
468 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
469 * and call blk_run_queue for all the scsi_devices on the target -
470 * including current_sdev first.
471 *
472 * Called with *no* scsi locks held.
473 */
474static void scsi_single_lun_run(struct scsi_device *current_sdev)
475{
476 struct Scsi_Host *shost = current_sdev->host;
477 struct scsi_device *sdev, *tmp;
478 struct scsi_target *starget = scsi_target(current_sdev);
479 unsigned long flags;
480
481 spin_lock_irqsave(shost->host_lock, flags);
482 starget->starget_sdev_user = NULL;
483 spin_unlock_irqrestore(shost->host_lock, flags);
484
485 /*
486 * Call blk_run_queue for all LUNs on the target, starting with
487 * current_sdev. We race with others (to set starget_sdev_user),
488 * but in most cases, we will be first. Ideally, each LU on the
489 * target would get some limited time or requests on the target.
490 */
491 blk_run_queue(current_sdev->request_queue);
492
493 spin_lock_irqsave(shost->host_lock, flags);
494 if (starget->starget_sdev_user)
495 goto out;
496 list_for_each_entry_safe(sdev, tmp, &starget->devices,
497 same_target_siblings) {
498 if (sdev == current_sdev)
499 continue;
500 if (scsi_device_get(sdev))
501 continue;
502
503 spin_unlock_irqrestore(shost->host_lock, flags);
504 blk_run_queue(sdev->request_queue);
505 spin_lock_irqsave(shost->host_lock, flags);
506
507 scsi_device_put(sdev);
508 }
509 out:
510 spin_unlock_irqrestore(shost->host_lock, flags);
511}
512
513/*
514 * Function: scsi_run_queue()
515 *
516 * Purpose: Select a proper request queue to serve next
517 *
518 * Arguments: q - last request's queue
519 *
520 * Returns: Nothing
521 *
522 * Notes: The previous command was completely finished, start
523 * a new one if possible.
524 */
525static void scsi_run_queue(struct request_queue *q)
526{
527 struct scsi_device *sdev = q->queuedata;
528 struct Scsi_Host *shost = sdev->host;
529 unsigned long flags;
530
Tony Battersby25d7c362007-11-12 10:00:44 -0500531 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 scsi_single_lun_run(sdev);
533
534 spin_lock_irqsave(shost->host_lock, flags);
535 while (!list_empty(&shost->starved_list) &&
536 !shost->host_blocked && !shost->host_self_blocked &&
537 !((shost->can_queue > 0) &&
538 (shost->host_busy >= shost->can_queue))) {
539 /*
540 * As long as shost is accepting commands and we have
541 * starved queues, call blk_run_queue. scsi_request_fn
542 * drops the queue_lock and can add us back to the
543 * starved_list.
544 *
545 * host_lock protects the starved_list and starved_entry.
546 * scsi_request_fn must get the host_lock before checking
547 * or modifying starved_list or starved_entry.
548 */
549 sdev = list_entry(shost->starved_list.next,
550 struct scsi_device, starved_entry);
551 list_del_init(&sdev->starved_entry);
552 spin_unlock_irqrestore(shost->host_lock, flags);
553
Andreas Herrmann04846f22006-08-09 17:31:16 +0200554
555 if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) &&
556 !test_and_set_bit(QUEUE_FLAG_REENTER,
557 &sdev->request_queue->queue_flags)) {
558 blk_run_queue(sdev->request_queue);
559 clear_bit(QUEUE_FLAG_REENTER,
560 &sdev->request_queue->queue_flags);
561 } else
562 blk_run_queue(sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
564 spin_lock_irqsave(shost->host_lock, flags);
565 if (unlikely(!list_empty(&sdev->starved_entry)))
566 /*
567 * sdev lost a race, and was put back on the
568 * starved list. This is unlikely but without this
569 * in theory we could loop forever.
570 */
571 break;
572 }
573 spin_unlock_irqrestore(shost->host_lock, flags);
574
575 blk_run_queue(q);
576}
577
578/*
579 * Function: scsi_requeue_command()
580 *
581 * Purpose: Handle post-processing of completed commands.
582 *
583 * Arguments: q - queue to operate on
584 * cmd - command that may need to be requeued.
585 *
586 * Returns: Nothing
587 *
588 * Notes: After command completion, there may be blocks left
589 * over which weren't finished by the previous command
590 * this can be for a number of reasons - the main one is
591 * I/O errors in the middle of the request, in which case
592 * we need to request the blocks that come after the bad
593 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500594 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 */
596static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
597{
James Bottomleye91442b2005-09-09 10:44:16 -0500598 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500599 unsigned long flags;
600
James Bottomleye91442b2005-09-09 10:44:16 -0500601 scsi_unprep_request(req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500602 spin_lock_irqsave(q->queue_lock, flags);
James Bottomleye91442b2005-09-09 10:44:16 -0500603 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500604 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605
606 scsi_run_queue(q);
607}
608
609void scsi_next_command(struct scsi_cmnd *cmd)
610{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800611 struct scsi_device *sdev = cmd->device;
612 struct request_queue *q = sdev->request_queue;
613
614 /* need to hold a reference on the device before we let go of the cmd */
615 get_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616
617 scsi_put_command(cmd);
618 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800619
620 /* ok to remove device now */
621 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622}
623
624void scsi_run_host_queues(struct Scsi_Host *shost)
625{
626 struct scsi_device *sdev;
627
628 shost_for_each_device(sdev, shost)
629 scsi_run_queue(sdev->request_queue);
630}
631
632/*
633 * Function: scsi_end_request()
634 *
635 * Purpose: Post-processing of completed commands (usually invoked at end
636 * of upper level post-processing and scsi_io_completion).
637 *
638 * Arguments: cmd - command that is complete.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500639 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 * bytes - number of bytes of completed I/O
641 * requeue - indicates whether we should requeue leftovers.
642 *
643 * Lock status: Assumed that lock is not held upon entry.
644 *
James Bottomleye91442b2005-09-09 10:44:16 -0500645 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 *
647 * Notes: This is called for block device requests in order to
648 * mark some number of sectors as complete.
649 *
650 * We are guaranteeing that the request queue will be goosed
651 * at some point during this call.
James Bottomleye91442b2005-09-09 10:44:16 -0500652 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500654static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 int bytes, int requeue)
656{
Jens Axboe165125e2007-07-24 09:28:11 +0200657 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659
660 /*
661 * If there are blocks left over at the end, set up the command
662 * to queue the remainder of them.
663 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500664 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 int leftover = (req->hard_nr_sectors << 9);
666
667 if (blk_pc_request(req))
668 leftover = req->data_len;
669
670 /* kill remainder if no retrys */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500671 if (error && blk_noretry_request(req))
672 blk_end_request(req, error, leftover);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500674 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 /*
676 * Bleah. Leftovers again. Stick the
677 * leftovers in the front of the
678 * queue, and goose the queue again.
679 */
680 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500681 cmd = NULL;
682 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 return cmd;
684 }
685 }
686
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 /*
688 * This will goose the queue request function at the end, so we don't
689 * need to worry about launching another command.
690 */
691 scsi_next_command(cmd);
692 return NULL;
693}
694
Jens Axboea8474ce2007-08-07 09:02:51 +0200695static inline unsigned int scsi_sgtable_index(unsigned short nents)
696{
697 unsigned int index;
698
James Bottomleyd3f46f32008-01-15 11:11:46 -0600699 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
700
701 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200702 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600703 else
704 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200705
706 return index;
707}
708
Jens Axboe5ed79592007-11-15 09:13:11 +0100709static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710{
711 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100712
713 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
714 mempool_free(sgl, sgp->pool);
715}
716
717static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
718{
719 struct scsi_host_sg_pool *sgp;
720
721 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
722 return mempool_alloc(sgp->pool, gfp_mask);
723}
724
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200725static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
726 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100727{
728 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200730 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200732 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
733 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100734 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200735 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600736 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737
Jens Axboea8474ce2007-08-07 09:02:51 +0200738 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739}
740
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200741static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200743 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744}
745
746/*
747 * Function: scsi_release_buffers()
748 *
749 * Purpose: Completion processing for block device I/O requests.
750 *
751 * Arguments: cmd - command that we are bailing.
752 *
753 * Lock status: Assumed that no lock is held upon entry.
754 *
755 * Returns: Nothing
756 *
757 * Notes: In the event that an upper level driver rejects a
758 * command, we must release resources allocated during
759 * the __init_io() function. Primarily this would involve
760 * the scatter-gather table, and potentially any bounce
761 * buffers.
762 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800763void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200765 if (cmd->sdb.table.nents)
766 scsi_free_sgtable(&cmd->sdb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200768 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200769
770 if (scsi_bidi_cmnd(cmd)) {
771 struct scsi_data_buffer *bidi_sdb =
772 cmd->request->next_rq->special;
773 scsi_free_sgtable(bidi_sdb);
774 kmem_cache_free(scsi_bidi_sdb_cache, bidi_sdb);
775 cmd->request->next_rq->special = NULL;
776 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800778EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779
780/*
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200781 * Bidi commands Must be complete as a whole, both sides at once.
782 * If part of the bytes were written and lld returned
783 * scsi_in()->resid and/or scsi_out()->resid this information will be left
784 * in req->data_len and req->next_rq->data_len. The upper-layer driver can
785 * decide what to do with this information.
786 */
787void scsi_end_bidi_request(struct scsi_cmnd *cmd)
788{
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500789 struct request *req = cmd->request;
790 unsigned int dlen = req->data_len;
791 unsigned int next_dlen = req->next_rq->data_len;
792
793 req->data_len = scsi_out(cmd)->resid;
794 req->next_rq->data_len = scsi_in(cmd)->resid;
795
796 /* The req and req->next_rq have not been completed */
797 BUG_ON(blk_end_bidi_request(req, 0, dlen, next_dlen));
798
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200799 scsi_release_buffers(cmd);
800
801 /*
802 * This will goose the queue request function at the end, so we don't
803 * need to worry about launching another command.
804 */
805 scsi_next_command(cmd);
806}
807
808/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 * Function: scsi_io_completion()
810 *
811 * Purpose: Completion processing for block device I/O requests.
812 *
813 * Arguments: cmd - command that is finished.
814 *
815 * Lock status: Assumed that no lock is held upon entry.
816 *
817 * Returns: Nothing
818 *
819 * Notes: This function is matched in terms of capabilities to
820 * the function that created the scatter-gather list.
821 * In other words, if there are no bounce buffers
822 * (the normal case for most drivers), we don't need
823 * the logic to deal with cleaning up afterwards.
824 *
825 * We must do one of several things here:
826 *
827 * a) Call scsi_end_request. This will finish off the
828 * specified number of sectors. If we are done, the
829 * command block will be released, and the queue
830 * function will be goosed. If we are not done, then
831 * scsi_end_request will directly goose the queue.
832 *
833 * b) We can just use scsi_requeue_command() here. This would
834 * be used if we just wanted to retry, for example.
835 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700836void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837{
838 int result = cmd->result;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200839 int this_count = scsi_bufflen(cmd);
Jens Axboe165125e2007-07-24 09:28:11 +0200840 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 struct request *req = cmd->request;
842 int clear_errors = 1;
843 struct scsi_sense_hdr sshdr;
844 int sense_valid = 0;
845 int sense_deferred = 0;
846
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 if (result) {
848 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
849 if (sense_valid)
850 sense_deferred = scsi_sense_is_deferred(&sshdr);
851 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200852
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
854 req->errors = result;
855 if (result) {
856 clear_errors = 0;
857 if (sense_valid && req->sense) {
858 /*
859 * SG_IO wants current and deferred errors
860 */
861 int len = 8 + cmd->sense_buffer[7];
862
863 if (len > SCSI_SENSE_BUFFERSIZE)
864 len = SCSI_SENSE_BUFFERSIZE;
865 memcpy(req->sense, cmd->sense_buffer, len);
866 req->sense_len = len;
867 }
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400868 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200869 if (scsi_bidi_cmnd(cmd)) {
870 /* will also release_buffers */
871 scsi_end_bidi_request(cmd);
872 return;
873 }
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200874 req->data_len = scsi_get_resid(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 }
876
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200877 BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200878 scsi_release_buffers(cmd);
879
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 * Next deal with any sectors which we were able to correctly
882 * handle.
883 */
James Bottomleyd6b0c532006-07-02 10:06:28 -0500884 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
885 "%d bytes done.\n",
886 req->nr_sectors, good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887
James Bottomleyd6b0c532006-07-02 10:06:28 -0500888 if (clear_errors)
889 req->errors = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890
James Bottomleyd6b0c532006-07-02 10:06:28 -0500891 /* A number of bytes were successfully read. If there
892 * are leftovers and there is some kind of error
893 * (result != 0), retry the rest.
894 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500895 if (scsi_end_request(cmd, 0, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500896 return;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700897
898 /* good_bytes = 0, or (inclusive) there were leftovers and
899 * result = 0, so scsi_end_request couldn't retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 */
901 if (sense_valid && !sense_deferred) {
902 switch (sshdr.sense_key) {
903 case UNIT_ATTENTION:
904 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700905 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 * and quietly refuse further access.
907 */
908 cmd->device->changed = 1;
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500909 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 return;
911 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700912 /* Must have been a power glitch, or a
913 * bus reset. Could not have been a
914 * media change, so we just retry the
915 * request and see what happens.
916 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 scsi_requeue_command(q, cmd);
918 return;
919 }
920 break;
921 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700922 /* If we had an ILLEGAL REQUEST returned, then
923 * we may have performed an unsupported
924 * command. The only thing this should be
925 * would be a ten byte read where only a six
926 * byte read was supported. Also, on a system
927 * where READ CAPACITY failed, we may have
928 * read past the end of the disk.
929 */
Jens Axboe26a68012005-11-29 21:03:34 +0100930 if ((cmd->device->use_10_for_rw &&
931 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 (cmd->cmnd[0] == READ_10 ||
933 cmd->cmnd[0] == WRITE_10)) {
934 cmd->device->use_10_for_rw = 0;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700935 /* This will cause a retry with a
936 * 6-byte command.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 */
938 scsi_requeue_command(q, cmd);
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700939 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940 } else {
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500941 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 return;
943 }
944 break;
945 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700946 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500947 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500949 if (sshdr.asc == 0x04) {
950 switch (sshdr.ascq) {
951 case 0x01: /* becoming ready */
952 case 0x04: /* format in progress */
953 case 0x05: /* rebuild in progress */
954 case 0x06: /* recalculation in progress */
955 case 0x07: /* operation in progress */
956 case 0x08: /* Long write in progress */
957 case 0x09: /* self test in progress */
958 scsi_requeue_command(q, cmd);
959 return;
960 default:
961 break;
962 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 }
James Bottomley311b5812007-09-23 09:08:46 -0500964 if (!(req->cmd_flags & REQ_QUIET))
965 scsi_cmd_print_sense_hdr(cmd,
966 "Device not ready",
967 &sshdr);
968
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500969 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 return;
971 case VOLUME_OVERFLOW:
Jens Axboe4aff5e22006-08-10 08:44:47 +0200972 if (!(req->cmd_flags & REQ_QUIET)) {
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400973 scmd_printk(KERN_INFO, cmd,
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700974 "Volume overflow, CDB: ");
Christoph Hellwig631c2282006-07-08 20:42:15 +0200975 __scsi_print_command(cmd->cmnd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500976 scsi_print_sense("", cmd);
977 }
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700978 /* See SSC3rXX or current. */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500979 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 return;
981 default:
982 break;
983 }
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700984 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 if (host_byte(result) == DID_RESET) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700986 /* Third party bus reset or reset for error recovery
987 * reasons. Just retry the request and see what
988 * happens.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 */
990 scsi_requeue_command(q, cmd);
991 return;
992 }
993 if (result) {
Jens Axboe4aff5e22006-08-10 08:44:47 +0200994 if (!(req->cmd_flags & REQ_QUIET)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500995 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500996 if (driver_byte(result) & DRIVER_SENSE)
997 scsi_print_sense("", cmd);
998 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 }
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -05001000 scsi_end_request(cmd, -EIO, this_count, !result);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001003static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1004 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001006 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007
1008 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001009 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001011 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1012 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -04001014 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015
Christoph Hellwig3b003152006-11-04 20:10:55 +01001016 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017
1018 /*
1019 * Next, walk the list, and fill in the addresses and sizes of
1020 * each segment.
1021 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001022 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1023 BUG_ON(count > sdb->table.nents);
1024 sdb->table.nents = count;
Tejun Heo6b007692008-02-19 11:36:35 +01001025 if (blk_pc_request(req))
1026 sdb->length = req->data_len;
1027 else
1028 sdb->length = req->nr_sectors << 9;
Rusty Russell4a03d902007-11-19 11:28:48 +11001029 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001031
1032/*
1033 * Function: scsi_init_io()
1034 *
1035 * Purpose: SCSI I/O initialize function.
1036 *
1037 * Arguments: cmd - Command descriptor we wish to initialize
1038 *
1039 * Returns: 0 on success
1040 * BLKPREP_DEFER if the failure is retryable
1041 * BLKPREP_KILL if the failure is fatal
1042 */
1043int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1044{
1045 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
1046 if (error)
1047 goto err_exit;
1048
1049 if (blk_bidi_rq(cmd->request)) {
1050 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
1051 scsi_bidi_sdb_cache, GFP_ATOMIC);
1052 if (!bidi_sdb) {
1053 error = BLKPREP_DEFER;
1054 goto err_exit;
1055 }
1056
1057 cmd->request->next_rq->special = bidi_sdb;
1058 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
1059 GFP_ATOMIC);
1060 if (error)
1061 goto err_exit;
1062 }
1063
1064 return BLKPREP_OK ;
1065
1066err_exit:
1067 scsi_release_buffers(cmd);
1068 if (error == BLKPREP_KILL)
1069 scsi_put_command(cmd);
1070 else /* BLKPREP_DEFER */
1071 scsi_unprep_request(cmd->request);
1072
1073 return error;
1074}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001075EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076
Christoph Hellwig3b003152006-11-04 20:10:55 +01001077static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1078 struct request *req)
1079{
1080 struct scsi_cmnd *cmd;
1081
1082 if (!req->special) {
1083 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1084 if (unlikely(!cmd))
1085 return NULL;
1086 req->special = cmd;
1087 } else {
1088 cmd = req->special;
1089 }
1090
1091 /* pull a tag out of the request if we have one */
1092 cmd->tag = req->tag;
1093 cmd->request = req;
1094
1095 return cmd;
1096}
1097
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001098int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001099{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001100 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001101 int ret = scsi_prep_state_check(sdev, req);
1102
1103 if (ret != BLKPREP_OK)
1104 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001105
1106 cmd = scsi_get_cmd_from_req(sdev, req);
1107 if (unlikely(!cmd))
1108 return BLKPREP_DEFER;
1109
1110 /*
1111 * BLOCK_PC requests may transfer data, in which case they must
1112 * a bio attached to them. Or they might contain a SCSI command
1113 * that does not transfer data, in which case they may optionally
1114 * submit a request without an attached bio.
1115 */
1116 if (req->bio) {
1117 int ret;
1118
1119 BUG_ON(!req->nr_phys_segments);
1120
Boaz Harroshbb52d822007-12-13 16:14:27 -08001121 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001122 if (unlikely(ret))
1123 return ret;
1124 } else {
1125 BUG_ON(req->data_len);
1126 BUG_ON(req->data);
1127
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001128 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001129 req->buffer = NULL;
1130 }
James Bottomley7b163182005-12-15 20:17:02 -06001131
Alexey Dobriyan46c43db2006-10-08 15:55:55 +04001132 BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd));
James Bottomley7b163182005-12-15 20:17:02 -06001133 memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd));
1134 cmd->cmd_len = req->cmd_len;
1135 if (!req->data_len)
1136 cmd->sc_data_direction = DMA_NONE;
1137 else if (rq_data_dir(req) == WRITE)
1138 cmd->sc_data_direction = DMA_TO_DEVICE;
1139 else
1140 cmd->sc_data_direction = DMA_FROM_DEVICE;
1141
1142 cmd->transfersize = req->data_len;
1143 cmd->allowed = req->retries;
1144 cmd->timeout_per_command = req->timeout;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001145 return BLKPREP_OK;
1146}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001147EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001148
1149/*
1150 * Setup a REQ_TYPE_FS command. These are simple read/write request
1151 * from filesystems that still need to be translated to SCSI CDBs from
1152 * the ULD.
1153 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001154int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001155{
1156 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001157 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001158
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001159 if (ret != BLKPREP_OK)
1160 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001161 /*
1162 * Filesystem requests must transfer data.
1163 */
1164 BUG_ON(!req->nr_phys_segments);
1165
1166 cmd = scsi_get_cmd_from_req(sdev, req);
1167 if (unlikely(!cmd))
1168 return BLKPREP_DEFER;
1169
Boaz Harroshbb52d822007-12-13 16:14:27 -08001170 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001171}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001172EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001173
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001174int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001176 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177
1178 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001179 * If the device is not in running state we will reject some
1180 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001183 switch (sdev->sdev_state) {
1184 case SDEV_OFFLINE:
1185 /*
1186 * If the device is offline we refuse to process any
1187 * commands. The device must be brought online
1188 * before trying any recovery commands.
1189 */
1190 sdev_printk(KERN_ERR, sdev,
1191 "rejecting I/O to offline device\n");
1192 ret = BLKPREP_KILL;
1193 break;
1194 case SDEV_DEL:
1195 /*
1196 * If the device is fully deleted, we refuse to
1197 * process any commands as well.
1198 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001199 sdev_printk(KERN_ERR, sdev,
1200 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001201 ret = BLKPREP_KILL;
1202 break;
1203 case SDEV_QUIESCE:
1204 case SDEV_BLOCK:
1205 /*
1206 * If the devices is blocked we defer normal commands.
1207 */
1208 if (!(req->cmd_flags & REQ_PREEMPT))
1209 ret = BLKPREP_DEFER;
1210 break;
1211 default:
1212 /*
1213 * For any other not fully online state we only allow
1214 * special commands. In particular any user initiated
1215 * command is not allowed.
1216 */
1217 if (!(req->cmd_flags & REQ_PREEMPT))
1218 ret = BLKPREP_KILL;
1219 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001222 return ret;
1223}
1224EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001226int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1227{
1228 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229
Christoph Hellwig3b003152006-11-04 20:10:55 +01001230 switch (ret) {
1231 case BLKPREP_KILL:
1232 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001233 /* release the command and kill it */
1234 if (req->special) {
1235 struct scsi_cmnd *cmd = req->special;
1236 scsi_release_buffers(cmd);
1237 scsi_put_command(cmd);
1238 req->special = NULL;
1239 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001240 break;
1241 case BLKPREP_DEFER:
1242 /*
1243 * If we defer, the elv_next_request() returns NULL, but the
1244 * queue must be restarted, so we plug here if no returning
1245 * command will automatically do that.
1246 */
1247 if (sdev->device_busy == 0)
1248 blk_plug_device(q);
1249 break;
1250 default:
1251 req->cmd_flags |= REQ_DONTPREP;
1252 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253
Christoph Hellwig3b003152006-11-04 20:10:55 +01001254 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001256EXPORT_SYMBOL(scsi_prep_return);
1257
James Bottomley751bf4d2008-01-02 11:14:30 -06001258int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001259{
1260 struct scsi_device *sdev = q->queuedata;
1261 int ret = BLKPREP_KILL;
1262
1263 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1264 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1265 return scsi_prep_return(q, req, ret);
1266}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267
1268/*
1269 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1270 * return 0.
1271 *
1272 * Called with the queue_lock held.
1273 */
1274static inline int scsi_dev_queue_ready(struct request_queue *q,
1275 struct scsi_device *sdev)
1276{
1277 if (sdev->device_busy >= sdev->queue_depth)
1278 return 0;
1279 if (sdev->device_busy == 0 && sdev->device_blocked) {
1280 /*
1281 * unblock after device_blocked iterates to zero
1282 */
1283 if (--sdev->device_blocked == 0) {
1284 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001285 sdev_printk(KERN_INFO, sdev,
1286 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 } else {
1288 blk_plug_device(q);
1289 return 0;
1290 }
1291 }
1292 if (sdev->device_blocked)
1293 return 0;
1294
1295 return 1;
1296}
1297
1298/*
1299 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1300 * return 0. We must end up running the queue again whenever 0 is
1301 * returned, else IO can hang.
1302 *
1303 * Called with host_lock held.
1304 */
1305static inline int scsi_host_queue_ready(struct request_queue *q,
1306 struct Scsi_Host *shost,
1307 struct scsi_device *sdev)
1308{
James Bottomley939647e2005-09-18 15:05:20 -05001309 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 return 0;
1311 if (shost->host_busy == 0 && shost->host_blocked) {
1312 /*
1313 * unblock after host_blocked iterates to zero
1314 */
1315 if (--shost->host_blocked == 0) {
1316 SCSI_LOG_MLQUEUE(3,
1317 printk("scsi%d unblocking host at zero depth\n",
1318 shost->host_no));
1319 } else {
1320 blk_plug_device(q);
1321 return 0;
1322 }
1323 }
1324 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
1325 shost->host_blocked || shost->host_self_blocked) {
1326 if (list_empty(&sdev->starved_entry))
1327 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1328 return 0;
1329 }
1330
1331 /* We're OK to process the command, so we can't be starved */
1332 if (!list_empty(&sdev->starved_entry))
1333 list_del_init(&sdev->starved_entry);
1334
1335 return 1;
1336}
1337
1338/*
James Bottomleye91442b2005-09-09 10:44:16 -05001339 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 */
Jens Axboe165125e2007-07-24 09:28:11 +02001341static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342{
James Bottomleye91442b2005-09-09 10:44:16 -05001343 struct scsi_cmnd *cmd = req->special;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001344 struct scsi_device *sdev = cmd->device;
1345 struct Scsi_Host *shost = sdev->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346
James Bottomley788ce432005-09-09 13:40:23 -05001347 blkdev_dequeue_request(req);
1348
James Bottomleye91442b2005-09-09 10:44:16 -05001349 if (unlikely(cmd == NULL)) {
1350 printk(KERN_CRIT "impossible request in %s.\n",
1351 __FUNCTION__);
1352 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 }
James Bottomleye91442b2005-09-09 10:44:16 -05001354
1355 scsi_init_cmd_errh(cmd);
1356 cmd->result = DID_NO_CONNECT << 16;
1357 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001358
1359 /*
1360 * SCSI request completion path will do scsi_device_unbusy(),
1361 * bump busy counts. To bump the counters, we need to dance
1362 * with the locks as normal issue path does.
1363 */
1364 sdev->device_busy++;
1365 spin_unlock(sdev->request_queue->queue_lock);
1366 spin_lock(shost->host_lock);
1367 shost->host_busy++;
1368 spin_unlock(shost->host_lock);
1369 spin_lock(sdev->request_queue->queue_lock);
1370
James Bottomleye91442b2005-09-09 10:44:16 -05001371 __scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372}
1373
Jens Axboe1aea6432006-01-09 16:03:03 +01001374static void scsi_softirq_done(struct request *rq)
1375{
1376 struct scsi_cmnd *cmd = rq->completion_data;
Brian King8884efa2006-02-24 17:10:04 -06001377 unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
Jens Axboe1aea6432006-01-09 16:03:03 +01001378 int disposition;
1379
1380 INIT_LIST_HEAD(&cmd->eh_entry);
1381
1382 disposition = scsi_decide_disposition(cmd);
1383 if (disposition != SUCCESS &&
1384 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1385 sdev_printk(KERN_ERR, cmd->device,
1386 "timing out command, waited %lus\n",
1387 wait_for/HZ);
1388 disposition = SUCCESS;
1389 }
1390
1391 scsi_log_completion(cmd, disposition);
1392
1393 switch (disposition) {
1394 case SUCCESS:
1395 scsi_finish_command(cmd);
1396 break;
1397 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001398 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001399 break;
1400 case ADD_TO_MLQUEUE:
1401 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1402 break;
1403 default:
1404 if (!scsi_eh_scmd_add(cmd, 0))
1405 scsi_finish_command(cmd);
1406 }
1407}
1408
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409/*
1410 * Function: scsi_request_fn()
1411 *
1412 * Purpose: Main strategy routine for SCSI.
1413 *
1414 * Arguments: q - Pointer to actual queue.
1415 *
1416 * Returns: Nothing
1417 *
1418 * Lock status: IO request lock assumed to be held when called.
1419 */
1420static void scsi_request_fn(struct request_queue *q)
1421{
1422 struct scsi_device *sdev = q->queuedata;
1423 struct Scsi_Host *shost;
1424 struct scsi_cmnd *cmd;
1425 struct request *req;
1426
1427 if (!sdev) {
1428 printk("scsi: killing requests for dead queue\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001429 while ((req = elv_next_request(q)) != NULL)
1430 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 return;
1432 }
1433
1434 if(!get_device(&sdev->sdev_gendev))
1435 /* We must be tearing the block queue down already */
1436 return;
1437
1438 /*
1439 * To start with, we keep looping until the queue is empty, or until
1440 * the host is no longer able to accept any more requests.
1441 */
1442 shost = sdev->host;
1443 while (!blk_queue_plugged(q)) {
1444 int rtn;
1445 /*
1446 * get next queueable request. We do this early to make sure
1447 * that the request is fully prepared even if we cannot
1448 * accept it.
1449 */
1450 req = elv_next_request(q);
1451 if (!req || !scsi_dev_queue_ready(q, sdev))
1452 break;
1453
1454 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001455 sdev_printk(KERN_ERR, sdev,
1456 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001457 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 continue;
1459 }
1460
1461
1462 /*
1463 * Remove the request from the request list.
1464 */
1465 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1466 blkdev_dequeue_request(req);
1467 sdev->device_busy++;
1468
1469 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001470 cmd = req->special;
1471 if (unlikely(cmd == NULL)) {
1472 printk(KERN_CRIT "impossible request in %s.\n"
1473 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001474 "linux-scsi@vger.kernel.org\n",
James Bottomleye91442b2005-09-09 10:44:16 -05001475 __FUNCTION__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001476 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001477 BUG();
1478 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 spin_lock(shost->host_lock);
1480
1481 if (!scsi_host_queue_ready(q, shost, sdev))
1482 goto not_ready;
Tony Battersby25d7c362007-11-12 10:00:44 -05001483 if (scsi_target(sdev)->single_lun) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 if (scsi_target(sdev)->starget_sdev_user &&
1485 scsi_target(sdev)->starget_sdev_user != sdev)
1486 goto not_ready;
1487 scsi_target(sdev)->starget_sdev_user = sdev;
1488 }
1489 shost->host_busy++;
1490
1491 /*
1492 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1493 * take the lock again.
1494 */
1495 spin_unlock_irq(shost->host_lock);
1496
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 /*
1498 * Finally, initialize any error handling parameters, and set up
1499 * the timers for timeouts.
1500 */
1501 scsi_init_cmd_errh(cmd);
1502
1503 /*
1504 * Dispatch the command to the low-level driver.
1505 */
1506 rtn = scsi_dispatch_cmd(cmd);
1507 spin_lock_irq(q->queue_lock);
1508 if(rtn) {
1509 /* we're refusing the command; because of
1510 * the way locks get dropped, we need to
1511 * check here if plugging is required */
1512 if(sdev->device_busy == 0)
1513 blk_plug_device(q);
1514
1515 break;
1516 }
1517 }
1518
1519 goto out;
1520
1521 not_ready:
1522 spin_unlock_irq(shost->host_lock);
1523
1524 /*
1525 * lock q, handle tag, requeue req, and decrement device_busy. We
1526 * must return with queue_lock held.
1527 *
1528 * Decrementing device_busy without checking it is OK, as all such
1529 * cases (host limits or settings) should run the queue at some
1530 * later time.
1531 */
1532 spin_lock_irq(q->queue_lock);
1533 blk_requeue_request(q, req);
1534 sdev->device_busy--;
1535 if(sdev->device_busy == 0)
1536 blk_plug_device(q);
1537 out:
1538 /* must be careful here...if we trigger the ->remove() function
1539 * we cannot be holding the q lock */
1540 spin_unlock_irq(q->queue_lock);
1541 put_device(&sdev->sdev_gendev);
1542 spin_lock_irq(q->queue_lock);
1543}
1544
1545u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1546{
1547 struct device *host_dev;
1548 u64 bounce_limit = 0xffffffff;
1549
1550 if (shost->unchecked_isa_dma)
1551 return BLK_BOUNCE_ISA;
1552 /*
1553 * Platforms with virtual-DMA translation
1554 * hardware have no practical limit.
1555 */
1556 if (!PCI_DMA_BUS_IS_PHYS)
1557 return BLK_BOUNCE_ANY;
1558
1559 host_dev = scsi_get_device(shost);
1560 if (host_dev && host_dev->dma_mask)
1561 bounce_limit = *host_dev->dma_mask;
1562
1563 return bounce_limit;
1564}
1565EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1566
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001567struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1568 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 struct request_queue *q;
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001571 struct device *dev = shost->shost_gendev.parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001573 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 if (!q)
1575 return NULL;
1576
Jens Axboea8474ce2007-08-07 09:02:51 +02001577 /*
1578 * this limit is imposed by hardware restrictions
1579 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580 blk_queue_max_hw_segments(q, shost->sg_tablesize);
James Bottomleyd3f46f32008-01-15 11:11:46 -06001581 blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
Jens Axboea8474ce2007-08-07 09:02:51 +02001582
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 blk_queue_max_sectors(q, shost->max_sectors);
1584 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1585 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001586 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001588 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1589
Linus Torvalds1da177e2005-04-16 15:20:36 -07001590 if (!shost->use_clustering)
1591 clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
James Bottomley465ff312008-01-01 10:00:10 -06001592
1593 /*
1594 * set a reasonable default alignment on word boundaries: the
1595 * host and device may alter it using
1596 * blk_queue_update_dma_alignment() later.
1597 */
1598 blk_queue_dma_alignment(q, 0x03);
1599
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600 return q;
1601}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001602EXPORT_SYMBOL(__scsi_alloc_queue);
1603
1604struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1605{
1606 struct request_queue *q;
1607
1608 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1609 if (!q)
1610 return NULL;
1611
1612 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001613 blk_queue_softirq_done(q, scsi_softirq_done);
1614 return q;
1615}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616
1617void scsi_free_queue(struct request_queue *q)
1618{
1619 blk_cleanup_queue(q);
1620}
1621
1622/*
1623 * Function: scsi_block_requests()
1624 *
1625 * Purpose: Utility function used by low-level drivers to prevent further
1626 * commands from being queued to the device.
1627 *
1628 * Arguments: shost - Host in question
1629 *
1630 * Returns: Nothing
1631 *
1632 * Lock status: No locks are assumed held.
1633 *
1634 * Notes: There is no timer nor any other means by which the requests
1635 * get unblocked other than the low-level driver calling
1636 * scsi_unblock_requests().
1637 */
1638void scsi_block_requests(struct Scsi_Host *shost)
1639{
1640 shost->host_self_blocked = 1;
1641}
1642EXPORT_SYMBOL(scsi_block_requests);
1643
1644/*
1645 * Function: scsi_unblock_requests()
1646 *
1647 * Purpose: Utility function used by low-level drivers to allow further
1648 * commands from being queued to the device.
1649 *
1650 * Arguments: shost - Host in question
1651 *
1652 * Returns: Nothing
1653 *
1654 * Lock status: No locks are assumed held.
1655 *
1656 * Notes: There is no timer nor any other means by which the requests
1657 * get unblocked other than the low-level driver calling
1658 * scsi_unblock_requests().
1659 *
1660 * This is done as an API function so that changes to the
1661 * internals of the scsi mid-layer won't require wholesale
1662 * changes to drivers that use this feature.
1663 */
1664void scsi_unblock_requests(struct Scsi_Host *shost)
1665{
1666 shost->host_self_blocked = 0;
1667 scsi_run_host_queues(shost);
1668}
1669EXPORT_SYMBOL(scsi_unblock_requests);
1670
1671int __init scsi_init_queue(void)
1672{
1673 int i;
1674
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001675 scsi_io_context_cache = kmem_cache_create("scsi_io_context",
1676 sizeof(struct scsi_io_context),
Paul Mundt20c2df82007-07-20 10:11:58 +09001677 0, 0, NULL);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001678 if (!scsi_io_context_cache) {
1679 printk(KERN_ERR "SCSI: can't init scsi io context cache\n");
1680 return -ENOMEM;
1681 }
1682
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001683 scsi_bidi_sdb_cache = kmem_cache_create("scsi_bidi_sdb",
1684 sizeof(struct scsi_data_buffer),
1685 0, 0, NULL);
1686 if (!scsi_bidi_sdb_cache) {
1687 printk(KERN_ERR "SCSI: can't init scsi bidi sdb cache\n");
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001688 goto cleanup_io_context;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001689 }
1690
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1692 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1693 int size = sgp->size * sizeof(struct scatterlist);
1694
1695 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001696 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 if (!sgp->slab) {
1698 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1699 sgp->name);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001700 goto cleanup_bidi_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 }
1702
Matthew Dobson93d23412006-03-26 01:37:50 -08001703 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1704 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705 if (!sgp->pool) {
1706 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1707 sgp->name);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001708 goto cleanup_bidi_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709 }
1710 }
1711
1712 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001713
1714cleanup_bidi_sdb:
1715 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1716 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1717 if (sgp->pool)
1718 mempool_destroy(sgp->pool);
1719 if (sgp->slab)
1720 kmem_cache_destroy(sgp->slab);
1721 }
1722 kmem_cache_destroy(scsi_bidi_sdb_cache);
1723cleanup_io_context:
1724 kmem_cache_destroy(scsi_io_context_cache);
1725
1726 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727}
1728
1729void scsi_exit_queue(void)
1730{
1731 int i;
1732
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001733 kmem_cache_destroy(scsi_io_context_cache);
FUJITA Tomonorib172b6e2008-01-25 23:25:13 +09001734 kmem_cache_destroy(scsi_bidi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001735
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1737 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1738 mempool_destroy(sgp->pool);
1739 kmem_cache_destroy(sgp->slab);
1740 }
1741}
James Bottomley5baba832006-03-18 14:10:35 -06001742
1743/**
1744 * scsi_mode_select - issue a mode select
1745 * @sdev: SCSI device to be queried
1746 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1747 * @sp: Save page bit (0 == don't save, 1 == save)
1748 * @modepage: mode page being requested
1749 * @buffer: request buffer (may not be smaller than eight bytes)
1750 * @len: length of request buffer.
1751 * @timeout: command timeout
1752 * @retries: number of retries before failing
1753 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001754 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001755 * must be SCSI_SENSE_BUFFERSIZE big.
1756 *
1757 * Returns zero if successful; negative error number or scsi
1758 * status on error
1759 *
1760 */
1761int
1762scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1763 unsigned char *buffer, int len, int timeout, int retries,
1764 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1765{
1766 unsigned char cmd[10];
1767 unsigned char *real_buffer;
1768 int ret;
1769
1770 memset(cmd, 0, sizeof(cmd));
1771 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1772
1773 if (sdev->use_10_for_ms) {
1774 if (len > 65535)
1775 return -EINVAL;
1776 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1777 if (!real_buffer)
1778 return -ENOMEM;
1779 memcpy(real_buffer + 8, buffer, len);
1780 len += 8;
1781 real_buffer[0] = 0;
1782 real_buffer[1] = 0;
1783 real_buffer[2] = data->medium_type;
1784 real_buffer[3] = data->device_specific;
1785 real_buffer[4] = data->longlba ? 0x01 : 0;
1786 real_buffer[5] = 0;
1787 real_buffer[6] = data->block_descriptor_length >> 8;
1788 real_buffer[7] = data->block_descriptor_length;
1789
1790 cmd[0] = MODE_SELECT_10;
1791 cmd[7] = len >> 8;
1792 cmd[8] = len;
1793 } else {
1794 if (len > 255 || data->block_descriptor_length > 255 ||
1795 data->longlba)
1796 return -EINVAL;
1797
1798 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1799 if (!real_buffer)
1800 return -ENOMEM;
1801 memcpy(real_buffer + 4, buffer, len);
1802 len += 4;
1803 real_buffer[0] = 0;
1804 real_buffer[1] = data->medium_type;
1805 real_buffer[2] = data->device_specific;
1806 real_buffer[3] = data->block_descriptor_length;
1807
1808
1809 cmd[0] = MODE_SELECT;
1810 cmd[4] = len;
1811 }
1812
1813 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1814 sshdr, timeout, retries);
1815 kfree(real_buffer);
1816 return ret;
1817}
1818EXPORT_SYMBOL_GPL(scsi_mode_select);
1819
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820/**
Rob Landleyeb448202007-11-03 13:30:39 -05001821 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001822 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823 * @dbd: set if mode sense will allow block descriptors to be returned
1824 * @modepage: mode page being requested
1825 * @buffer: request buffer (may not be smaller than eight bytes)
1826 * @len: length of request buffer.
1827 * @timeout: command timeout
1828 * @retries: number of retries before failing
1829 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001830 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001831 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832 *
1833 * Returns zero if unsuccessful, or the header offset (either 4
1834 * or 8 depending on whether a six or ten byte command was
1835 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001836 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837int
James Bottomley1cf72692005-08-28 11:27:01 -05001838scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001839 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001840 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1841{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842 unsigned char cmd[12];
1843 int use_10_for_ms;
1844 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001845 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001846 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847
1848 memset(data, 0, sizeof(*data));
1849 memset(&cmd[0], 0, 12);
1850 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1851 cmd[2] = modepage;
1852
James Bottomleyea73a9f2005-08-28 11:33:52 -05001853 /* caller might not be interested in sense, but we need it */
1854 if (!sshdr)
1855 sshdr = &my_sshdr;
1856
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001858 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859
1860 if (use_10_for_ms) {
1861 if (len < 8)
1862 len = 8;
1863
1864 cmd[0] = MODE_SENSE_10;
1865 cmd[8] = len;
1866 header_length = 8;
1867 } else {
1868 if (len < 4)
1869 len = 4;
1870
1871 cmd[0] = MODE_SENSE;
1872 cmd[4] = len;
1873 header_length = 4;
1874 }
1875
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876 memset(buffer, 0, len);
1877
James Bottomley1cf72692005-08-28 11:27:01 -05001878 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
James Bottomleyea73a9f2005-08-28 11:33:52 -05001879 sshdr, timeout, retries);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880
1881 /* This code looks awful: what it's doing is making sure an
1882 * ILLEGAL REQUEST sense return identifies the actual command
1883 * byte as the problem. MODE_SENSE commands can return
1884 * ILLEGAL REQUEST if the code page isn't supported */
1885
James Bottomley1cf72692005-08-28 11:27:01 -05001886 if (use_10_for_ms && !scsi_status_is_good(result) &&
1887 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001888 if (scsi_sense_valid(sshdr)) {
1889 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1890 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 /*
1892 * Invalid command operation code
1893 */
James Bottomley1cf72692005-08-28 11:27:01 -05001894 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 goto retry;
1896 }
1897 }
1898 }
1899
James Bottomley1cf72692005-08-28 11:27:01 -05001900 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001901 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1902 (modepage == 6 || modepage == 8))) {
1903 /* Initio breakage? */
1904 header_length = 0;
1905 data->length = 13;
1906 data->medium_type = 0;
1907 data->device_specific = 0;
1908 data->longlba = 0;
1909 data->block_descriptor_length = 0;
1910 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911 data->length = buffer[0]*256 + buffer[1] + 2;
1912 data->medium_type = buffer[2];
1913 data->device_specific = buffer[3];
1914 data->longlba = buffer[4] & 0x01;
1915 data->block_descriptor_length = buffer[6]*256
1916 + buffer[7];
1917 } else {
1918 data->length = buffer[0] + 1;
1919 data->medium_type = buffer[1];
1920 data->device_specific = buffer[2];
1921 data->block_descriptor_length = buffer[3];
1922 }
Al Viro6d73c852006-02-23 02:03:16 +01001923 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 }
1925
James Bottomley1cf72692005-08-28 11:27:01 -05001926 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927}
1928EXPORT_SYMBOL(scsi_mode_sense);
1929
James Bottomley001aac22007-12-02 19:10:40 +02001930/**
1931 * scsi_test_unit_ready - test if unit is ready
1932 * @sdev: scsi device to change the state of.
1933 * @timeout: command timeout
1934 * @retries: number of retries before failing
1935 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1936 * returning sense. Make sure that this is cleared before passing
1937 * in.
1938 *
1939 * Returns zero if unsuccessful or an error if TUR failed. For
1940 * removable media, a return of NOT_READY or UNIT_ATTENTION is
1941 * translated to success, with the ->changed flag updated.
1942 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943int
James Bottomley001aac22007-12-02 19:10:40 +02001944scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
1945 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947 char cmd[] = {
1948 TEST_UNIT_READY, 0, 0, 0, 0, 0,
1949 };
James Bottomley001aac22007-12-02 19:10:40 +02001950 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951 int result;
James Bottomley001aac22007-12-02 19:10:40 +02001952
1953 if (!sshdr_external)
1954 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
1955 else
1956 sshdr = sshdr_external;
1957
1958 /* try to eat the UNIT_ATTENTION if there are enough retries */
1959 do {
1960 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
1961 timeout, retries);
1962 } while ((driver_byte(result) & DRIVER_SENSE) &&
1963 sshdr && sshdr->sense_key == UNIT_ATTENTION &&
1964 --retries);
1965
1966 if (!sshdr)
1967 /* could not allocate sense buffer, so can't process it */
1968 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001969
James Bottomley1cf72692005-08-28 11:27:01 -05001970 if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001971
James Bottomley001aac22007-12-02 19:10:40 +02001972 if ((scsi_sense_valid(sshdr)) &&
1973 ((sshdr->sense_key == UNIT_ATTENTION) ||
1974 (sshdr->sense_key == NOT_READY))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 sdev->changed = 1;
James Bottomley1cf72692005-08-28 11:27:01 -05001976 result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 }
1978 }
James Bottomley001aac22007-12-02 19:10:40 +02001979 if (!sshdr_external)
1980 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981 return result;
1982}
1983EXPORT_SYMBOL(scsi_test_unit_ready);
1984
1985/**
Rob Landleyeb448202007-11-03 13:30:39 -05001986 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987 * @sdev: scsi device to change the state of.
1988 * @state: state to change to.
1989 *
1990 * Returns zero if unsuccessful or an error if the requested
1991 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05001992 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001993int
1994scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
1995{
1996 enum scsi_device_state oldstate = sdev->sdev_state;
1997
1998 if (state == oldstate)
1999 return 0;
2000
2001 switch (state) {
2002 case SDEV_CREATED:
2003 /* There are no legal states that come back to
2004 * created. This is the manually initialised start
2005 * state */
2006 goto illegal;
2007
2008 case SDEV_RUNNING:
2009 switch (oldstate) {
2010 case SDEV_CREATED:
2011 case SDEV_OFFLINE:
2012 case SDEV_QUIESCE:
2013 case SDEV_BLOCK:
2014 break;
2015 default:
2016 goto illegal;
2017 }
2018 break;
2019
2020 case SDEV_QUIESCE:
2021 switch (oldstate) {
2022 case SDEV_RUNNING:
2023 case SDEV_OFFLINE:
2024 break;
2025 default:
2026 goto illegal;
2027 }
2028 break;
2029
2030 case SDEV_OFFLINE:
2031 switch (oldstate) {
2032 case SDEV_CREATED:
2033 case SDEV_RUNNING:
2034 case SDEV_QUIESCE:
2035 case SDEV_BLOCK:
2036 break;
2037 default:
2038 goto illegal;
2039 }
2040 break;
2041
2042 case SDEV_BLOCK:
2043 switch (oldstate) {
2044 case SDEV_CREATED:
2045 case SDEV_RUNNING:
2046 break;
2047 default:
2048 goto illegal;
2049 }
2050 break;
2051
2052 case SDEV_CANCEL:
2053 switch (oldstate) {
2054 case SDEV_CREATED:
2055 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002056 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002057 case SDEV_OFFLINE:
2058 case SDEV_BLOCK:
2059 break;
2060 default:
2061 goto illegal;
2062 }
2063 break;
2064
2065 case SDEV_DEL:
2066 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002067 case SDEV_CREATED:
2068 case SDEV_RUNNING:
2069 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 case SDEV_CANCEL:
2071 break;
2072 default:
2073 goto illegal;
2074 }
2075 break;
2076
2077 }
2078 sdev->sdev_state = state;
2079 return 0;
2080
2081 illegal:
2082 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002083 sdev_printk(KERN_ERR, sdev,
2084 "Illegal state transition %s->%s\n",
2085 scsi_device_state_name(oldstate),
2086 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002087 );
2088 return -EINVAL;
2089}
2090EXPORT_SYMBOL(scsi_device_set_state);
2091
2092/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002093 * sdev_evt_emit - emit a single SCSI device uevent
2094 * @sdev: associated SCSI device
2095 * @evt: event to emit
2096 *
2097 * Send a single uevent (scsi_event) to the associated scsi_device.
2098 */
2099static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2100{
2101 int idx = 0;
2102 char *envp[3];
2103
2104 switch (evt->evt_type) {
2105 case SDEV_EVT_MEDIA_CHANGE:
2106 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2107 break;
2108
2109 default:
2110 /* do nothing */
2111 break;
2112 }
2113
2114 envp[idx++] = NULL;
2115
2116 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2117}
2118
2119/**
2120 * sdev_evt_thread - send a uevent for each scsi event
2121 * @work: work struct for scsi_device
2122 *
2123 * Dispatch queued events to their associated scsi_device kobjects
2124 * as uevents.
2125 */
2126void scsi_evt_thread(struct work_struct *work)
2127{
2128 struct scsi_device *sdev;
2129 LIST_HEAD(event_list);
2130
2131 sdev = container_of(work, struct scsi_device, event_work);
2132
2133 while (1) {
2134 struct scsi_event *evt;
2135 struct list_head *this, *tmp;
2136 unsigned long flags;
2137
2138 spin_lock_irqsave(&sdev->list_lock, flags);
2139 list_splice_init(&sdev->event_list, &event_list);
2140 spin_unlock_irqrestore(&sdev->list_lock, flags);
2141
2142 if (list_empty(&event_list))
2143 break;
2144
2145 list_for_each_safe(this, tmp, &event_list) {
2146 evt = list_entry(this, struct scsi_event, node);
2147 list_del(&evt->node);
2148 scsi_evt_emit(sdev, evt);
2149 kfree(evt);
2150 }
2151 }
2152}
2153
2154/**
2155 * sdev_evt_send - send asserted event to uevent thread
2156 * @sdev: scsi_device event occurred on
2157 * @evt: event to send
2158 *
2159 * Assert scsi device event asynchronously.
2160 */
2161void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2162{
2163 unsigned long flags;
2164
Kay Sievers4d1566e2008-03-19 13:04:47 +01002165#if 0
2166 /* FIXME: currently this check eliminates all media change events
2167 * for polled devices. Need to update to discriminate between AN
2168 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002169 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2170 kfree(evt);
2171 return;
2172 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002173#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002174
2175 spin_lock_irqsave(&sdev->list_lock, flags);
2176 list_add_tail(&evt->node, &sdev->event_list);
2177 schedule_work(&sdev->event_work);
2178 spin_unlock_irqrestore(&sdev->list_lock, flags);
2179}
2180EXPORT_SYMBOL_GPL(sdev_evt_send);
2181
2182/**
2183 * sdev_evt_alloc - allocate a new scsi event
2184 * @evt_type: type of event to allocate
2185 * @gfpflags: GFP flags for allocation
2186 *
2187 * Allocates and returns a new scsi_event.
2188 */
2189struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2190 gfp_t gfpflags)
2191{
2192 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2193 if (!evt)
2194 return NULL;
2195
2196 evt->evt_type = evt_type;
2197 INIT_LIST_HEAD(&evt->node);
2198
2199 /* evt_type-specific initialization, if any */
2200 switch (evt_type) {
2201 case SDEV_EVT_MEDIA_CHANGE:
2202 default:
2203 /* do nothing */
2204 break;
2205 }
2206
2207 return evt;
2208}
2209EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2210
2211/**
2212 * sdev_evt_send_simple - send asserted event to uevent thread
2213 * @sdev: scsi_device event occurred on
2214 * @evt_type: type of event to send
2215 * @gfpflags: GFP flags for allocation
2216 *
2217 * Assert scsi device event asynchronously, given an event type.
2218 */
2219void sdev_evt_send_simple(struct scsi_device *sdev,
2220 enum scsi_device_event evt_type, gfp_t gfpflags)
2221{
2222 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2223 if (!evt) {
2224 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2225 evt_type);
2226 return;
2227 }
2228
2229 sdev_evt_send(sdev, evt);
2230}
2231EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2232
2233/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 * scsi_device_quiesce - Block user issued commands.
2235 * @sdev: scsi device to quiesce.
2236 *
2237 * This works by trying to transition to the SDEV_QUIESCE state
2238 * (which must be a legal transition). When the device is in this
2239 * state, only special requests will be accepted, all others will
2240 * be deferred. Since special requests may also be requeued requests,
2241 * a successful return doesn't guarantee the device will be
2242 * totally quiescent.
2243 *
2244 * Must be called with user context, may sleep.
2245 *
2246 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002247 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248int
2249scsi_device_quiesce(struct scsi_device *sdev)
2250{
2251 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2252 if (err)
2253 return err;
2254
2255 scsi_run_queue(sdev->request_queue);
2256 while (sdev->device_busy) {
2257 msleep_interruptible(200);
2258 scsi_run_queue(sdev->request_queue);
2259 }
2260 return 0;
2261}
2262EXPORT_SYMBOL(scsi_device_quiesce);
2263
2264/**
2265 * scsi_device_resume - Restart user issued commands to a quiesced device.
2266 * @sdev: scsi device to resume.
2267 *
2268 * Moves the device from quiesced back to running and restarts the
2269 * queues.
2270 *
2271 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002272 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273void
2274scsi_device_resume(struct scsi_device *sdev)
2275{
2276 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2277 return;
2278 scsi_run_queue(sdev->request_queue);
2279}
2280EXPORT_SYMBOL(scsi_device_resume);
2281
2282static void
2283device_quiesce_fn(struct scsi_device *sdev, void *data)
2284{
2285 scsi_device_quiesce(sdev);
2286}
2287
2288void
2289scsi_target_quiesce(struct scsi_target *starget)
2290{
2291 starget_for_each_device(starget, NULL, device_quiesce_fn);
2292}
2293EXPORT_SYMBOL(scsi_target_quiesce);
2294
2295static void
2296device_resume_fn(struct scsi_device *sdev, void *data)
2297{
2298 scsi_device_resume(sdev);
2299}
2300
2301void
2302scsi_target_resume(struct scsi_target *starget)
2303{
2304 starget_for_each_device(starget, NULL, device_resume_fn);
2305}
2306EXPORT_SYMBOL(scsi_target_resume);
2307
2308/**
Rob Landleyeb448202007-11-03 13:30:39 -05002309 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310 * @sdev: device to block
2311 *
2312 * Block request made by scsi lld's to temporarily stop all
2313 * scsi commands on the specified device. Called from interrupt
2314 * or normal process context.
2315 *
2316 * Returns zero if successful or error if not
2317 *
2318 * Notes:
2319 * This routine transitions the device to the SDEV_BLOCK state
2320 * (which must be a legal transition). When the device is in this
2321 * state, all commands are deferred until the scsi lld reenables
2322 * the device with scsi_device_unblock or device_block_tmo fires.
2323 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002324 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002325int
2326scsi_internal_device_block(struct scsi_device *sdev)
2327{
Jens Axboe165125e2007-07-24 09:28:11 +02002328 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002329 unsigned long flags;
2330 int err = 0;
2331
2332 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2333 if (err)
2334 return err;
2335
2336 /*
2337 * The device has transitioned to SDEV_BLOCK. Stop the
2338 * block layer from calling the midlayer with this device's
2339 * request queue.
2340 */
2341 spin_lock_irqsave(q->queue_lock, flags);
2342 blk_stop_queue(q);
2343 spin_unlock_irqrestore(q->queue_lock, flags);
2344
2345 return 0;
2346}
2347EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2348
2349/**
2350 * scsi_internal_device_unblock - resume a device after a block request
2351 * @sdev: device to resume
2352 *
2353 * Called by scsi lld's or the midlayer to restart the device queue
2354 * for the previously suspended scsi device. Called from interrupt or
2355 * normal process context.
2356 *
2357 * Returns zero if successful or error if not.
2358 *
2359 * Notes:
2360 * This routine transitions the device to the SDEV_RUNNING state
2361 * (which must be a legal transition) allowing the midlayer to
2362 * goose the queue for this device. This routine assumes the
2363 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002364 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365int
2366scsi_internal_device_unblock(struct scsi_device *sdev)
2367{
Jens Axboe165125e2007-07-24 09:28:11 +02002368 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 int err;
2370 unsigned long flags;
2371
2372 /*
2373 * Try to transition the scsi device to SDEV_RUNNING
2374 * and goose the device queue if successful.
2375 */
2376 err = scsi_device_set_state(sdev, SDEV_RUNNING);
2377 if (err)
2378 return err;
2379
2380 spin_lock_irqsave(q->queue_lock, flags);
2381 blk_start_queue(q);
2382 spin_unlock_irqrestore(q->queue_lock, flags);
2383
2384 return 0;
2385}
2386EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2387
2388static void
2389device_block(struct scsi_device *sdev, void *data)
2390{
2391 scsi_internal_device_block(sdev);
2392}
2393
2394static int
2395target_block(struct device *dev, void *data)
2396{
2397 if (scsi_is_target_device(dev))
2398 starget_for_each_device(to_scsi_target(dev), NULL,
2399 device_block);
2400 return 0;
2401}
2402
2403void
2404scsi_target_block(struct device *dev)
2405{
2406 if (scsi_is_target_device(dev))
2407 starget_for_each_device(to_scsi_target(dev), NULL,
2408 device_block);
2409 else
2410 device_for_each_child(dev, NULL, target_block);
2411}
2412EXPORT_SYMBOL_GPL(scsi_target_block);
2413
2414static void
2415device_unblock(struct scsi_device *sdev, void *data)
2416{
2417 scsi_internal_device_unblock(sdev);
2418}
2419
2420static int
2421target_unblock(struct device *dev, void *data)
2422{
2423 if (scsi_is_target_device(dev))
2424 starget_for_each_device(to_scsi_target(dev), NULL,
2425 device_unblock);
2426 return 0;
2427}
2428
2429void
2430scsi_target_unblock(struct device *dev)
2431{
2432 if (scsi_is_target_device(dev))
2433 starget_for_each_device(to_scsi_target(dev), NULL,
2434 device_unblock);
2435 else
2436 device_for_each_child(dev, NULL, target_unblock);
2437}
2438EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002439
2440/**
2441 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002442 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002443 * @sg_count: number of segments in sg
2444 * @offset: offset in bytes into sg, on return offset into the mapped area
2445 * @len: bytes to map, on return number of bytes mapped
2446 *
2447 * Returns virtual address of the start of the mapped page
2448 */
Jens Axboec6132da2007-10-16 11:08:49 +02002449void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002450 size_t *offset, size_t *len)
2451{
2452 int i;
2453 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002454 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002455 struct page *page;
2456
Andrew Morton22cfefb2007-02-05 16:39:03 -08002457 WARN_ON(!irqs_disabled());
2458
Jens Axboec6132da2007-10-16 11:08:49 +02002459 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002460 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002461 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002462 if (sg_len > *offset)
2463 break;
2464 }
2465
2466 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002467 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2468 "elements %d\n",
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002469 __FUNCTION__, sg_len, *offset, sg_count);
2470 WARN_ON(1);
2471 return NULL;
2472 }
2473
2474 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002475 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002476
2477 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002478 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002479 *offset &= ~PAGE_MASK;
2480
2481 /* Bytes in this sg-entry from *offset to the end of the page */
2482 sg_len = PAGE_SIZE - *offset;
2483 if (*len > sg_len)
2484 *len = sg_len;
2485
2486 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2487}
2488EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2489
2490/**
Rob Landleyeb448202007-11-03 13:30:39 -05002491 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002492 * @virt: virtual address to be unmapped
2493 */
2494void scsi_kunmap_atomic_sg(void *virt)
2495{
2496 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2497}
2498EXPORT_SYMBOL(scsi_kunmap_atomic_sg);