blob: c56618ae54c326651e237b9984b73e06095c62b6 [file] [log] [blame]
Jens Axboe3d6392c2007-07-09 12:38:05 +02001/*
2 * bsg.c - block layer implementation of the sg v3 interface
3 *
4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License version 2. See the file "COPYING" in the main directory of this
9 * archive for more details.
10 *
11 */
12/*
13 * TODO
14 * - Should this get merged, block/scsi_ioctl.c will be migrated into
15 * this file. To keep maintenance down, it's easier to have them
16 * seperated right now.
17 *
18 */
Jens Axboe3d6392c2007-07-09 12:38:05 +020019#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/file.h>
22#include <linux/blkdev.h>
23#include <linux/poll.h>
24#include <linux/cdev.h>
25#include <linux/percpu.h>
26#include <linux/uio.h>
27#include <linux/bsg.h>
28
29#include <scsi/scsi.h>
30#include <scsi/scsi_ioctl.h>
31#include <scsi/scsi_cmnd.h>
32#include <scsi/sg.h>
33
34static char bsg_version[] = "block layer sg (bsg) 0.4";
35
Jens Axboe3d6392c2007-07-09 12:38:05 +020036struct bsg_device {
37 struct gendisk *disk;
38 request_queue_t *queue;
39 spinlock_t lock;
40 struct list_head busy_list;
41 struct list_head done_list;
42 struct hlist_node dev_list;
43 atomic_t ref_count;
44 int minor;
45 int queued_cmds;
46 int done_cmds;
Jens Axboe3d6392c2007-07-09 12:38:05 +020047 wait_queue_head_t wq_done;
48 wait_queue_head_t wq_free;
49 char name[BDEVNAME_SIZE];
50 int max_queue;
51 unsigned long flags;
52};
53
54enum {
55 BSG_F_BLOCK = 1,
56 BSG_F_WRITE_PERM = 2,
57};
58
Jens Axboe5309cb32007-01-23 16:24:41 +010059#define BSG_DEFAULT_CMDS 64
Jens Axboe3d6392c2007-07-09 12:38:05 +020060
61#undef BSG_DEBUG
62
63#ifdef BSG_DEBUG
64#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __FUNCTION__, ##args)
65#else
66#define dprintk(fmt, args...)
67#endif
68
69#define list_entry_bc(entry) list_entry((entry), struct bsg_command, list)
70
71/*
72 * just for testing
73 */
74#define BSG_MAJOR (240)
75
76static DEFINE_MUTEX(bsg_mutex);
77static int bsg_device_nr;
78
79#define BSG_LIST_SIZE (8)
80#define bsg_list_idx(minor) ((minor) & (BSG_LIST_SIZE - 1))
81static struct hlist_head bsg_device_list[BSG_LIST_SIZE];
82
83static struct class *bsg_class;
84static LIST_HEAD(bsg_class_list);
85
Jens Axboe5309cb32007-01-23 16:24:41 +010086static struct kmem_cache *bsg_cmd_cachep;
87
Jens Axboe3d6392c2007-07-09 12:38:05 +020088/*
89 * our internal command type
90 */
91struct bsg_command {
92 struct bsg_device *bd;
93 struct list_head list;
94 struct request *rq;
95 struct bio *bio;
96 int err;
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +010097 struct sg_io_v4 hdr;
98 struct sg_io_v4 __user *uhdr;
Jens Axboe3d6392c2007-07-09 12:38:05 +020099 char sense[SCSI_SENSE_BUFFERSIZE];
100};
101
102static void bsg_free_command(struct bsg_command *bc)
103{
104 struct bsg_device *bd = bc->bd;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200105 unsigned long flags;
106
Jens Axboe5309cb32007-01-23 16:24:41 +0100107 kmem_cache_free(bsg_cmd_cachep, bc);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200108
109 spin_lock_irqsave(&bd->lock, flags);
110 bd->queued_cmds--;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200111 spin_unlock_irqrestore(&bd->lock, flags);
112
113 wake_up(&bd->wq_free);
114}
115
116static struct bsg_command *__bsg_alloc_command(struct bsg_device *bd)
117{
118 struct bsg_command *bc = NULL;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200119
120 spin_lock_irq(&bd->lock);
121
122 if (bd->queued_cmds >= bd->max_queue)
123 goto out;
124
Jens Axboe3d6392c2007-07-09 12:38:05 +0200125 bd->queued_cmds++;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200126 spin_unlock_irq(&bd->lock);
127
Jens Axboe5309cb32007-01-23 16:24:41 +0100128 bc = kmem_cache_alloc(bsg_cmd_cachep, GFP_USER);
129 if (unlikely(!bc)) {
130 spin_lock_irq(&bd->lock);
131 goto alloc_fail;
132 }
133
Jens Axboe3d6392c2007-07-09 12:38:05 +0200134 memset(bc, 0, sizeof(*bc));
135 bc->bd = bd;
136 INIT_LIST_HEAD(&bc->list);
Jens Axboe5309cb32007-01-23 16:24:41 +0100137 dprintk("%s: returning free cmd %p\n", bd->name, bc);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200138 return bc;
Jens Axboe5309cb32007-01-23 16:24:41 +0100139alloc_fail:
140 bd->queued_cmds--;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200141out:
Jens Axboe3d6392c2007-07-09 12:38:05 +0200142 spin_unlock_irq(&bd->lock);
143 return bc;
144}
145
146static inline void
147bsg_del_done_cmd(struct bsg_device *bd, struct bsg_command *bc)
148{
149 bd->done_cmds--;
150 list_del(&bc->list);
151}
152
153static inline void
154bsg_add_done_cmd(struct bsg_device *bd, struct bsg_command *bc)
155{
156 bd->done_cmds++;
157 list_add_tail(&bc->list, &bd->done_list);
158 wake_up(&bd->wq_done);
159}
160
161static inline int bsg_io_schedule(struct bsg_device *bd, int state)
162{
163 DEFINE_WAIT(wait);
164 int ret = 0;
165
166 spin_lock_irq(&bd->lock);
167
168 BUG_ON(bd->done_cmds > bd->queued_cmds);
169
170 /*
171 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no
172 * work to do", even though we return -ENOSPC after this same test
173 * during bsg_write() -- there, it means our buffer can't have more
174 * bsg_commands added to it, thus has no space left.
175 */
176 if (bd->done_cmds == bd->queued_cmds) {
177 ret = -ENODATA;
178 goto unlock;
179 }
180
181 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
182 ret = -EAGAIN;
183 goto unlock;
184 }
185
186 prepare_to_wait(&bd->wq_done, &wait, state);
187 spin_unlock_irq(&bd->lock);
188 io_schedule();
189 finish_wait(&bd->wq_done, &wait);
190
191 if ((state == TASK_INTERRUPTIBLE) && signal_pending(current))
192 ret = -ERESTARTSYS;
193
194 return ret;
195unlock:
196 spin_unlock_irq(&bd->lock);
197 return ret;
198}
199
200/*
201 * get a new free command, blocking if needed and specified
202 */
203static struct bsg_command *bsg_get_command(struct bsg_device *bd)
204{
205 struct bsg_command *bc;
206 int ret;
207
208 do {
209 bc = __bsg_alloc_command(bd);
210 if (bc)
211 break;
212
213 ret = bsg_io_schedule(bd, TASK_INTERRUPTIBLE);
214 if (ret) {
215 bc = ERR_PTR(ret);
216 break;
217 }
218
219 } while (1);
220
221 return bc;
222}
223
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100224static int blk_fill_sgv4_hdr_rq(request_queue_t *q, struct request *rq,
225 struct sg_io_v4 *hdr, int has_write_perm)
Jens Axboe3d6392c2007-07-09 12:38:05 +0200226{
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100227 memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
228
229 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
230 hdr->request_len))
231 return -EFAULT;
232 if (blk_verify_command(rq->cmd, has_write_perm))
233 return -EPERM;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200234
235 /*
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100236 * fill in request structure
Jens Axboe3d6392c2007-07-09 12:38:05 +0200237 */
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100238 rq->cmd_len = hdr->request_len;
239 rq->cmd_type = REQ_TYPE_BLOCK_PC;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200240
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100241 rq->timeout = (hdr->timeout * HZ) / 1000;
242 if (!rq->timeout)
243 rq->timeout = q->sg_timeout;
244 if (!rq->timeout)
245 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200246
247 return 0;
248}
249
250/*
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100251 * Check if sg_io_v4 from user is allowed and valid
252 */
253static int
254bsg_validate_sgv4_hdr(request_queue_t *q, struct sg_io_v4 *hdr, int *rw)
255{
256 if (hdr->guard != 'Q')
257 return -EINVAL;
258 if (hdr->request_len > BLK_MAX_CDB)
259 return -EINVAL;
260 if (hdr->dout_xfer_len > (q->max_sectors << 9) ||
261 hdr->din_xfer_len > (q->max_sectors << 9))
262 return -EIO;
263
264 /* not supported currently */
265 if (hdr->protocol || hdr->subprotocol)
266 return -EINVAL;
267
268 /*
269 * looks sane, if no data then it should be fine from our POV
270 */
271 if (!hdr->dout_xfer_len && !hdr->din_xfer_len)
272 return 0;
273
274 /* not supported currently */
275 if (hdr->dout_xfer_len && hdr->din_xfer_len)
276 return -EINVAL;
277
278 *rw = hdr->dout_xfer_len ? WRITE : READ;
279
280 return 0;
281}
282
283/*
284 * map sg_io_v4 to a request.
Jens Axboe3d6392c2007-07-09 12:38:05 +0200285 */
286static struct request *
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100287bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
Jens Axboe3d6392c2007-07-09 12:38:05 +0200288{
289 request_queue_t *q = bd->queue;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200290 struct request *rq;
Jens Axboe2ef70862006-12-20 11:26:11 +0100291 int ret, rw = 0; /* shut up gcc */
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100292 unsigned int dxfer_len;
293 void *dxferp = NULL;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200294
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100295 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
296 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
297 hdr->din_xfer_len);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200298
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100299 ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200300 if (ret)
301 return ERR_PTR(ret);
302
303 /*
304 * map scatter-gather elements seperately and string them to request
305 */
306 rq = blk_get_request(q, rw, GFP_KERNEL);
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100307 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, test_bit(BSG_F_WRITE_PERM,
308 &bd->flags));
Jens Axboe3d6392c2007-07-09 12:38:05 +0200309 if (ret) {
310 blk_put_request(rq);
311 return ERR_PTR(ret);
312 }
313
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100314 if (hdr->dout_xfer_len) {
315 dxfer_len = hdr->dout_xfer_len;
316 dxferp = (void*)(unsigned long)hdr->dout_xferp;
317 } else if (hdr->din_xfer_len) {
318 dxfer_len = hdr->din_xfer_len;
319 dxferp = (void*)(unsigned long)hdr->din_xferp;
320 } else
321 dxfer_len = 0;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200322
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100323 if (dxfer_len) {
324 ret = blk_rq_map_user(q, rq, dxferp, dxfer_len);
325 if (ret) {
326 dprintk("failed map at %d\n", ret);
327 blk_put_request(rq);
328 rq = ERR_PTR(ret);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200329 }
Jens Axboe3d6392c2007-07-09 12:38:05 +0200330 }
331
332 return rq;
333}
334
335/*
336 * async completion call-back from the block layer, when scsi/ide/whatever
337 * calls end_that_request_last() on a request
338 */
339static void bsg_rq_end_io(struct request *rq, int uptodate)
340{
341 struct bsg_command *bc = rq->end_io_data;
342 struct bsg_device *bd = bc->bd;
343 unsigned long flags;
344
Jens Axboe5309cb32007-01-23 16:24:41 +0100345 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
346 bd->name, rq, bc, bc->bio, uptodate);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200347
348 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
349
350 spin_lock_irqsave(&bd->lock, flags);
351 list_del(&bc->list);
352 bsg_add_done_cmd(bd, bc);
353 spin_unlock_irqrestore(&bd->lock, flags);
354}
355
356/*
357 * do final setup of a 'bc' and submit the matching 'rq' to the block
358 * layer for io
359 */
360static void bsg_add_command(struct bsg_device *bd, request_queue_t *q,
361 struct bsg_command *bc, struct request *rq)
362{
363 rq->sense = bc->sense;
364 rq->sense_len = 0;
365
366 /*
367 * add bc command to busy queue and submit rq for io
368 */
369 bc->rq = rq;
370 bc->bio = rq->bio;
371 bc->hdr.duration = jiffies;
372 spin_lock_irq(&bd->lock);
373 list_add_tail(&bc->list, &bd->busy_list);
374 spin_unlock_irq(&bd->lock);
375
376 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
377
378 rq->end_io_data = bc;
379 blk_execute_rq_nowait(q, bd->disk, rq, 1, bsg_rq_end_io);
380}
381
382static inline struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
383{
384 struct bsg_command *bc = NULL;
385
386 spin_lock_irq(&bd->lock);
387 if (bd->done_cmds) {
388 bc = list_entry_bc(bd->done_list.next);
389 bsg_del_done_cmd(bd, bc);
390 }
391 spin_unlock_irq(&bd->lock);
392
393 return bc;
394}
395
396/*
397 * Get a finished command from the done list
398 */
399static struct bsg_command *__bsg_get_done_cmd(struct bsg_device *bd, int state)
400{
401 struct bsg_command *bc;
402 int ret;
403
404 do {
405 bc = bsg_next_done_cmd(bd);
406 if (bc)
407 break;
408
409 ret = bsg_io_schedule(bd, state);
410 if (ret) {
411 bc = ERR_PTR(ret);
412 break;
413 }
414 } while (1);
415
416 dprintk("%s: returning done %p\n", bd->name, bc);
417
418 return bc;
419}
420
421static struct bsg_command *
422bsg_get_done_cmd(struct bsg_device *bd, const struct iovec *iov)
423{
424 return __bsg_get_done_cmd(bd, TASK_INTERRUPTIBLE);
425}
426
427static struct bsg_command *
428bsg_get_done_cmd_nosignals(struct bsg_device *bd)
429{
430 return __bsg_get_done_cmd(bd, TASK_UNINTERRUPTIBLE);
431}
432
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100433static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
434 struct bio *bio)
435{
436 int ret = 0;
437
438 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors);
439 /*
440 * fill in all the output members
441 */
442 hdr->device_status = status_byte(rq->errors);
443 hdr->transport_status = host_byte(rq->errors);
444 hdr->driver_status = driver_byte(rq->errors);
445 hdr->info = 0;
446 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
447 hdr->info |= SG_INFO_CHECK;
448 hdr->din_resid = rq->data_len;
449 hdr->response_len = 0;
450
451 if (rq->sense_len && hdr->response) {
452 int len = min((unsigned int) hdr->max_response_len,
453 rq->sense_len);
454
455 ret = copy_to_user((void*)(unsigned long)hdr->response,
456 rq->sense, len);
457 if (!ret)
458 hdr->response_len = len;
459 else
460 ret = -EFAULT;
461 }
462
463 blk_rq_unmap_user(bio);
464 blk_put_request(rq);
465
466 return ret;
467}
468
Jens Axboe3d6392c2007-07-09 12:38:05 +0200469static int bsg_complete_all_commands(struct bsg_device *bd)
470{
471 struct bsg_command *bc;
472 int ret, tret;
473
474 dprintk("%s: entered\n", bd->name);
475
476 set_bit(BSG_F_BLOCK, &bd->flags);
477
478 /*
479 * wait for all commands to complete
480 */
481 ret = 0;
482 do {
483 ret = bsg_io_schedule(bd, TASK_UNINTERRUPTIBLE);
484 /*
485 * look for -ENODATA specifically -- we'll sometimes get
486 * -ERESTARTSYS when we've taken a signal, but we can't
487 * return until we're done freeing the queue, so ignore
488 * it. The signal will get handled when we're done freeing
489 * the bsg_device.
490 */
491 } while (ret != -ENODATA);
492
493 /*
494 * discard done commands
495 */
496 ret = 0;
497 do {
498 bc = bsg_get_done_cmd_nosignals(bd);
499
500 /*
501 * we _must_ complete before restarting, because
502 * bsg_release can't handle this failing.
503 */
504 if (PTR_ERR(bc) == -ERESTARTSYS)
505 continue;
506 if (IS_ERR(bc)) {
507 ret = PTR_ERR(bc);
508 break;
509 }
510
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100511 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200512 if (!ret)
513 ret = tret;
514
515 bsg_free_command(bc);
516 } while (1);
517
518 return ret;
519}
520
521typedef struct bsg_command *(*bsg_command_callback)(struct bsg_device *bd, const struct iovec *iov);
522
523static ssize_t
524__bsg_read(char __user *buf, size_t count, bsg_command_callback get_bc,
525 struct bsg_device *bd, const struct iovec *iov, ssize_t *bytes_read)
526{
527 struct bsg_command *bc;
528 int nr_commands, ret;
529
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100530 if (count % sizeof(struct sg_io_v4))
Jens Axboe3d6392c2007-07-09 12:38:05 +0200531 return -EINVAL;
532
533 ret = 0;
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100534 nr_commands = count / sizeof(struct sg_io_v4);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200535 while (nr_commands) {
536 bc = get_bc(bd, iov);
537 if (IS_ERR(bc)) {
538 ret = PTR_ERR(bc);
539 break;
540 }
541
542 /*
543 * this is the only case where we need to copy data back
544 * after completing the request. so do that here,
545 * bsg_complete_work() cannot do that for us
546 */
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100547 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200548
549 if (copy_to_user(buf, (char *) &bc->hdr, sizeof(bc->hdr)))
550 ret = -EFAULT;
551
552 bsg_free_command(bc);
553
554 if (ret)
555 break;
556
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100557 buf += sizeof(struct sg_io_v4);
558 *bytes_read += sizeof(struct sg_io_v4);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200559 nr_commands--;
560 }
561
562 return ret;
563}
564
565static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
566{
567 if (file->f_flags & O_NONBLOCK)
568 clear_bit(BSG_F_BLOCK, &bd->flags);
569 else
570 set_bit(BSG_F_BLOCK, &bd->flags);
571}
572
573static inline void bsg_set_write_perm(struct bsg_device *bd, struct file *file)
574{
575 if (file->f_mode & FMODE_WRITE)
576 set_bit(BSG_F_WRITE_PERM, &bd->flags);
577 else
578 clear_bit(BSG_F_WRITE_PERM, &bd->flags);
579}
580
581static inline int err_block_err(int ret)
582{
583 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
584 return 1;
585
586 return 0;
587}
588
589static ssize_t
590bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
591{
592 struct bsg_device *bd = file->private_data;
593 int ret;
594 ssize_t bytes_read;
595
FUJITA Tomonori9e69fbb2006-12-20 11:18:22 +0100596 dprintk("%s: read %Zd bytes\n", bd->name, count);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200597
598 bsg_set_block(bd, file);
599 bytes_read = 0;
600 ret = __bsg_read(buf, count, bsg_get_done_cmd,
601 bd, NULL, &bytes_read);
602 *ppos = bytes_read;
603
604 if (!bytes_read || (bytes_read && err_block_err(ret)))
605 bytes_read = ret;
606
607 return bytes_read;
608}
609
610static ssize_t __bsg_write(struct bsg_device *bd, const char __user *buf,
611 size_t count, ssize_t *bytes_read)
612{
613 struct bsg_command *bc;
614 struct request *rq;
615 int ret, nr_commands;
616
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100617 if (count % sizeof(struct sg_io_v4))
Jens Axboe3d6392c2007-07-09 12:38:05 +0200618 return -EINVAL;
619
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100620 nr_commands = count / sizeof(struct sg_io_v4);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200621 rq = NULL;
622 bc = NULL;
623 ret = 0;
624 while (nr_commands) {
625 request_queue_t *q = bd->queue;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200626
627 bc = bsg_get_command(bd);
628 if (!bc)
629 break;
630 if (IS_ERR(bc)) {
631 ret = PTR_ERR(bc);
632 bc = NULL;
633 break;
634 }
635
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100636 bc->uhdr = (struct sg_io_v4 __user *) buf;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200637 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
638 ret = -EFAULT;
639 break;
640 }
641
642 /*
643 * get a request, fill in the blanks, and add to request queue
644 */
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100645 rq = bsg_map_hdr(bd, &bc->hdr);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200646 if (IS_ERR(rq)) {
647 ret = PTR_ERR(rq);
648 rq = NULL;
649 break;
650 }
651
652 bsg_add_command(bd, q, bc, rq);
653 bc = NULL;
654 rq = NULL;
655 nr_commands--;
FUJITA Tomonori70e36ec2006-12-20 11:20:15 +0100656 buf += sizeof(struct sg_io_v4);
657 *bytes_read += sizeof(struct sg_io_v4);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200658 }
659
Jens Axboe3d6392c2007-07-09 12:38:05 +0200660 if (bc)
661 bsg_free_command(bc);
662
663 return ret;
664}
665
666static ssize_t
667bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
668{
669 struct bsg_device *bd = file->private_data;
670 ssize_t bytes_read;
671 int ret;
672
FUJITA Tomonori9e69fbb2006-12-20 11:18:22 +0100673 dprintk("%s: write %Zd bytes\n", bd->name, count);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200674
675 bsg_set_block(bd, file);
676 bsg_set_write_perm(bd, file);
677
678 bytes_read = 0;
679 ret = __bsg_write(bd, buf, count, &bytes_read);
680 *ppos = bytes_read;
681
682 /*
683 * return bytes written on non-fatal errors
684 */
685 if (!bytes_read || (bytes_read && err_block_err(ret)))
686 bytes_read = ret;
687
FUJITA Tomonori9e69fbb2006-12-20 11:18:22 +0100688 dprintk("%s: returning %Zd\n", bd->name, bytes_read);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200689 return bytes_read;
690}
691
Jens Axboe3d6392c2007-07-09 12:38:05 +0200692static struct bsg_device *bsg_alloc_device(void)
693{
Jens Axboe3d6392c2007-07-09 12:38:05 +0200694 struct bsg_device *bd;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200695
696 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
697 if (unlikely(!bd))
698 return NULL;
699
700 spin_lock_init(&bd->lock);
701
Jens Axboe5309cb32007-01-23 16:24:41 +0100702 bd->max_queue = BSG_DEFAULT_CMDS;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200703
704 INIT_LIST_HEAD(&bd->busy_list);
705 INIT_LIST_HEAD(&bd->done_list);
706 INIT_HLIST_NODE(&bd->dev_list);
707
708 init_waitqueue_head(&bd->wq_free);
709 init_waitqueue_head(&bd->wq_done);
710 return bd;
Jens Axboe3d6392c2007-07-09 12:38:05 +0200711}
712
713static int bsg_put_device(struct bsg_device *bd)
714{
715 int ret = 0;
716
717 mutex_lock(&bsg_mutex);
718
719 if (!atomic_dec_and_test(&bd->ref_count))
720 goto out;
721
722 dprintk("%s: tearing down\n", bd->name);
723
724 /*
725 * close can always block
726 */
727 set_bit(BSG_F_BLOCK, &bd->flags);
728
729 /*
730 * correct error detection baddies here again. it's the responsibility
731 * of the app to properly reap commands before close() if it wants
732 * fool-proof error detection
733 */
734 ret = bsg_complete_all_commands(bd);
735
736 blk_put_queue(bd->queue);
737 hlist_del(&bd->dev_list);
Jens Axboe5309cb32007-01-23 16:24:41 +0100738 kfree(bd);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200739out:
740 mutex_unlock(&bsg_mutex);
741 return ret;
742}
743
744static struct bsg_device *bsg_add_device(struct inode *inode,
745 struct gendisk *disk,
746 struct file *file)
747{
748 struct bsg_device *bd = NULL;
749#ifdef BSG_DEBUG
750 unsigned char buf[32];
751#endif
752
753 bd = bsg_alloc_device();
754 if (!bd)
755 return ERR_PTR(-ENOMEM);
756
757 bd->disk = disk;
758 bd->queue = disk->queue;
759 kobject_get(&disk->queue->kobj);
760 bsg_set_block(bd, file);
761
762 atomic_set(&bd->ref_count, 1);
763 bd->minor = iminor(inode);
764 mutex_lock(&bsg_mutex);
765 hlist_add_head(&bd->dev_list,&bsg_device_list[bsg_list_idx(bd->minor)]);
766
767 strncpy(bd->name, disk->disk_name, sizeof(bd->name) - 1);
768 dprintk("bound to <%s>, max queue %d\n",
FUJITA Tomonori9e69fbb2006-12-20 11:18:22 +0100769 format_dev_t(buf, inode->i_rdev), bd->max_queue);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200770
771 mutex_unlock(&bsg_mutex);
772 return bd;
773}
774
775static struct bsg_device *__bsg_get_device(int minor)
776{
777 struct hlist_head *list = &bsg_device_list[bsg_list_idx(minor)];
778 struct bsg_device *bd = NULL;
779 struct hlist_node *entry;
780
781 mutex_lock(&bsg_mutex);
782
783 hlist_for_each(entry, list) {
784 bd = hlist_entry(entry, struct bsg_device, dev_list);
785 if (bd->minor == minor) {
786 atomic_inc(&bd->ref_count);
787 break;
788 }
789
790 bd = NULL;
791 }
792
793 mutex_unlock(&bsg_mutex);
794 return bd;
795}
796
797static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
798{
799 struct bsg_device *bd = __bsg_get_device(iminor(inode));
800 struct bsg_class_device *bcd, *__bcd;
801
802 if (bd)
803 return bd;
804
805 /*
806 * find the class device
807 */
808 bcd = NULL;
809 mutex_lock(&bsg_mutex);
810 list_for_each_entry(__bcd, &bsg_class_list, list) {
811 if (__bcd->minor == iminor(inode)) {
812 bcd = __bcd;
813 break;
814 }
815 }
816 mutex_unlock(&bsg_mutex);
817
818 if (!bcd)
819 return ERR_PTR(-ENODEV);
820
821 return bsg_add_device(inode, bcd->disk, file);
822}
823
824static int bsg_open(struct inode *inode, struct file *file)
825{
826 struct bsg_device *bd = bsg_get_device(inode, file);
827
828 if (IS_ERR(bd))
829 return PTR_ERR(bd);
830
831 file->private_data = bd;
832 return 0;
833}
834
835static int bsg_release(struct inode *inode, struct file *file)
836{
837 struct bsg_device *bd = file->private_data;
838
839 file->private_data = NULL;
840 return bsg_put_device(bd);
841}
842
843static unsigned int bsg_poll(struct file *file, poll_table *wait)
844{
845 struct bsg_device *bd = file->private_data;
846 unsigned int mask = 0;
847
848 poll_wait(file, &bd->wq_done, wait);
849 poll_wait(file, &bd->wq_free, wait);
850
851 spin_lock_irq(&bd->lock);
852 if (!list_empty(&bd->done_list))
853 mask |= POLLIN | POLLRDNORM;
854 if (bd->queued_cmds >= bd->max_queue)
855 mask |= POLLOUT;
856 spin_unlock_irq(&bd->lock);
857
858 return mask;
859}
860
861static int
862bsg_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
863 unsigned long arg)
864{
865 struct bsg_device *bd = file->private_data;
866 int __user *uarg = (int __user *) arg;
867
868 if (!bd)
869 return -ENXIO;
870
871 switch (cmd) {
872 /*
873 * our own ioctls
874 */
875 case SG_GET_COMMAND_Q:
876 return put_user(bd->max_queue, uarg);
Jens Axboe5309cb32007-01-23 16:24:41 +0100877 case SG_SET_COMMAND_Q: {
Jens Axboe3d6392c2007-07-09 12:38:05 +0200878 int queue;
879
880 if (get_user(queue, uarg))
881 return -EFAULT;
Jens Axboe5309cb32007-01-23 16:24:41 +0100882 if (queue < 1)
Jens Axboe3d6392c2007-07-09 12:38:05 +0200883 return -EINVAL;
884
Jens Axboe5309cb32007-01-23 16:24:41 +0100885 spin_lock_irq(&bd->lock);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200886 bd->max_queue = queue;
Jens Axboe5309cb32007-01-23 16:24:41 +0100887 spin_unlock_irq(&bd->lock);
Jens Axboe3d6392c2007-07-09 12:38:05 +0200888 return 0;
889 }
890
891 /*
892 * SCSI/sg ioctls
893 */
894 case SG_GET_VERSION_NUM:
895 case SCSI_IOCTL_GET_IDLUN:
896 case SCSI_IOCTL_GET_BUS_NUMBER:
897 case SG_SET_TIMEOUT:
898 case SG_GET_TIMEOUT:
899 case SG_GET_RESERVED_SIZE:
900 case SG_SET_RESERVED_SIZE:
901 case SG_EMULATED_HOST:
Jens Axboe3d6392c2007-07-09 12:38:05 +0200902 case SCSI_IOCTL_SEND_COMMAND: {
903 void __user *uarg = (void __user *) arg;
904 return scsi_cmd_ioctl(file, bd->disk, cmd, uarg);
905 }
FUJITA Tomonori10e88552006-12-20 11:20:57 +0100906 case SG_IO: {
907 struct request *rq;
908 struct bio *bio;
909 struct sg_io_v4 hdr;
910
911 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
912 return -EFAULT;
913
914 rq = bsg_map_hdr(bd, &hdr);
915 if (IS_ERR(rq))
916 return PTR_ERR(rq);
917
918 bio = rq->bio;
919 blk_execute_rq(bd->queue, bd->disk, rq, 0);
920 blk_complete_sgv4_hdr_rq(rq, &hdr, bio);
921
922 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
923 return -EFAULT;
Jens Axboeb711afa2006-12-20 11:25:23 +0100924
925 return 0;
FUJITA Tomonori10e88552006-12-20 11:20:57 +0100926 }
Jens Axboe3d6392c2007-07-09 12:38:05 +0200927 /*
928 * block device ioctls
929 */
930 default:
931#if 0
932 return ioctl_by_bdev(bd->bdev, cmd, arg);
933#else
934 return -ENOTTY;
935#endif
936 }
937}
938
939static struct file_operations bsg_fops = {
940 .read = bsg_read,
941 .write = bsg_write,
942 .poll = bsg_poll,
943 .open = bsg_open,
944 .release = bsg_release,
945 .ioctl = bsg_ioctl,
946 .owner = THIS_MODULE,
947};
948
949void bsg_unregister_disk(struct gendisk *disk)
950{
951 struct bsg_class_device *bcd = &disk->bsg_dev;
952
953 if (!bcd->class_dev)
954 return;
955
956 mutex_lock(&bsg_mutex);
957 sysfs_remove_link(&bcd->disk->queue->kobj, "bsg");
958 class_device_destroy(bsg_class, MKDEV(BSG_MAJOR, bcd->minor));
959 bcd->class_dev = NULL;
960 list_del_init(&bcd->list);
961 mutex_unlock(&bsg_mutex);
962}
963
964int bsg_register_disk(struct gendisk *disk)
965{
966 request_queue_t *q = disk->queue;
967 struct bsg_class_device *bcd;
968 dev_t dev;
969
970 /*
971 * we need a proper transport to send commands, not a stacked device
972 */
973 if (!q->request_fn)
974 return 0;
975
976 bcd = &disk->bsg_dev;
977 memset(bcd, 0, sizeof(*bcd));
978 INIT_LIST_HEAD(&bcd->list);
979
980 mutex_lock(&bsg_mutex);
981 dev = MKDEV(BSG_MAJOR, bsg_device_nr);
982 bcd->minor = bsg_device_nr;
983 bsg_device_nr++;
984 bcd->disk = disk;
985 bcd->class_dev = class_device_create(bsg_class, NULL, dev, bcd->dev, "%s", disk->disk_name);
986 list_add_tail(&bcd->list, &bsg_class_list);
987 sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
988 mutex_unlock(&bsg_mutex);
989 return 0;
990}
991
992static int __init bsg_init(void)
993{
994 int ret, i;
995
Jens Axboe5309cb32007-01-23 16:24:41 +0100996 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
997 sizeof(struct bsg_command), 0, 0, NULL, NULL);
998 if (!bsg_cmd_cachep) {
999 printk(KERN_ERR "bsg: failed creating slab cache\n");
1000 return -ENOMEM;
1001 }
1002
Jens Axboe3d6392c2007-07-09 12:38:05 +02001003 for (i = 0; i < BSG_LIST_SIZE; i++)
1004 INIT_HLIST_HEAD(&bsg_device_list[i]);
1005
1006 bsg_class = class_create(THIS_MODULE, "bsg");
Jens Axboe5309cb32007-01-23 16:24:41 +01001007 if (IS_ERR(bsg_class)) {
1008 kmem_cache_destroy(bsg_cmd_cachep);
Jens Axboe3d6392c2007-07-09 12:38:05 +02001009 return PTR_ERR(bsg_class);
Jens Axboe5309cb32007-01-23 16:24:41 +01001010 }
Jens Axboe3d6392c2007-07-09 12:38:05 +02001011
1012 ret = register_chrdev(BSG_MAJOR, "bsg", &bsg_fops);
1013 if (ret) {
Jens Axboe5309cb32007-01-23 16:24:41 +01001014 kmem_cache_destroy(bsg_cmd_cachep);
Jens Axboe3d6392c2007-07-09 12:38:05 +02001015 class_destroy(bsg_class);
1016 return ret;
1017 }
1018
1019 printk(KERN_INFO "%s loaded\n", bsg_version);
1020 return 0;
1021}
1022
1023MODULE_AUTHOR("Jens Axboe");
1024MODULE_DESCRIPTION("Block layer SGSI generic (sg) driver");
1025MODULE_LICENSE("GPL");
1026
1027subsys_initcall(bsg_init);