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3d6392cf 1/*
0c6a89ba 2 * bsg.c - block layer implementation of the sg v4 interface
3d6392cf
JA
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 */
3d6392cf
JA
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/file.h>
15#include <linux/blkdev.h>
16#include <linux/poll.h>
17#include <linux/cdev.h>
18#include <linux/percpu.h>
19#include <linux/uio.h>
598443a2 20#include <linux/idr.h>
3d6392cf
JA
21#include <linux/bsg.h>
22
23#include <scsi/scsi.h>
24#include <scsi/scsi_ioctl.h>
25#include <scsi/scsi_cmnd.h>
4e2872d6
FT
26#include <scsi/scsi_device.h>
27#include <scsi/scsi_driver.h>
3d6392cf
JA
28#include <scsi/sg.h>
29
0ed081ce
FT
30#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
31#define BSG_VERSION "0.4"
3d6392cf 32
3d6392cf 33struct bsg_device {
165125e1 34 struct request_queue *queue;
3d6392cf
JA
35 spinlock_t lock;
36 struct list_head busy_list;
37 struct list_head done_list;
38 struct hlist_node dev_list;
39 atomic_t ref_count;
40 int minor;
41 int queued_cmds;
42 int done_cmds;
3d6392cf
JA
43 wait_queue_head_t wq_done;
44 wait_queue_head_t wq_free;
d351af01 45 char name[BUS_ID_SIZE];
3d6392cf
JA
46 int max_queue;
47 unsigned long flags;
48};
49
50enum {
51 BSG_F_BLOCK = 1,
52 BSG_F_WRITE_PERM = 2,
53};
54
5309cb38 55#define BSG_DEFAULT_CMDS 64
292b7f27 56#define BSG_MAX_DEVS 32768
3d6392cf
JA
57
58#undef BSG_DEBUG
59
60#ifdef BSG_DEBUG
61#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __FUNCTION__, ##args)
62#else
63#define dprintk(fmt, args...)
64#endif
65
3d6392cf 66static DEFINE_MUTEX(bsg_mutex);
598443a2 67static DEFINE_IDR(bsg_minor_idr);
3d6392cf 68
25fd1643 69#define BSG_LIST_ARRAY_SIZE 8
25fd1643 70static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
3d6392cf
JA
71
72static struct class *bsg_class;
46f6ef4a 73static int bsg_major;
3d6392cf 74
5309cb38
JA
75static struct kmem_cache *bsg_cmd_cachep;
76
3d6392cf
JA
77/*
78 * our internal command type
79 */
80struct bsg_command {
81 struct bsg_device *bd;
82 struct list_head list;
83 struct request *rq;
84 struct bio *bio;
2c9ecdf4 85 struct bio *bidi_bio;
3d6392cf 86 int err;
70e36ece 87 struct sg_io_v4 hdr;
3d6392cf
JA
88 char sense[SCSI_SENSE_BUFFERSIZE];
89};
90
91static void bsg_free_command(struct bsg_command *bc)
92{
93 struct bsg_device *bd = bc->bd;
3d6392cf
JA
94 unsigned long flags;
95
5309cb38 96 kmem_cache_free(bsg_cmd_cachep, bc);
3d6392cf
JA
97
98 spin_lock_irqsave(&bd->lock, flags);
99 bd->queued_cmds--;
3d6392cf
JA
100 spin_unlock_irqrestore(&bd->lock, flags);
101
102 wake_up(&bd->wq_free);
103}
104
e7d72173 105static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
3d6392cf 106{
e7d72173 107 struct bsg_command *bc = ERR_PTR(-EINVAL);
3d6392cf
JA
108
109 spin_lock_irq(&bd->lock);
110
111 if (bd->queued_cmds >= bd->max_queue)
112 goto out;
113
3d6392cf 114 bd->queued_cmds++;
3d6392cf
JA
115 spin_unlock_irq(&bd->lock);
116
25fd1643 117 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
5309cb38
JA
118 if (unlikely(!bc)) {
119 spin_lock_irq(&bd->lock);
7e75d730 120 bd->queued_cmds--;
e7d72173 121 bc = ERR_PTR(-ENOMEM);
7e75d730 122 goto out;
5309cb38
JA
123 }
124
3d6392cf
JA
125 bc->bd = bd;
126 INIT_LIST_HEAD(&bc->list);
5309cb38 127 dprintk("%s: returning free cmd %p\n", bd->name, bc);
3d6392cf
JA
128 return bc;
129out:
3d6392cf
JA
130 spin_unlock_irq(&bd->lock);
131 return bc;
132}
133
1c1133e1 134static inline struct hlist_head *bsg_dev_idx_hash(int index)
3d6392cf 135{
1c1133e1 136 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
3d6392cf
JA
137}
138
25fd1643 139static int bsg_io_schedule(struct bsg_device *bd)
3d6392cf
JA
140{
141 DEFINE_WAIT(wait);
142 int ret = 0;
143
144 spin_lock_irq(&bd->lock);
145
146 BUG_ON(bd->done_cmds > bd->queued_cmds);
147
148 /*
149 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no
150 * work to do", even though we return -ENOSPC after this same test
151 * during bsg_write() -- there, it means our buffer can't have more
152 * bsg_commands added to it, thus has no space left.
153 */
154 if (bd->done_cmds == bd->queued_cmds) {
155 ret = -ENODATA;
156 goto unlock;
157 }
158
159 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
160 ret = -EAGAIN;
161 goto unlock;
162 }
163
25fd1643 164 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE);
3d6392cf
JA
165 spin_unlock_irq(&bd->lock);
166 io_schedule();
167 finish_wait(&bd->wq_done, &wait);
168
3d6392cf
JA
169 return ret;
170unlock:
171 spin_unlock_irq(&bd->lock);
172 return ret;
173}
174
165125e1 175static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
70e36ece
FT
176 struct sg_io_v4 *hdr, int has_write_perm)
177{
178 memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
179
180 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
181 hdr->request_len))
182 return -EFAULT;
15d10b61
FT
183
184 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
185 if (blk_verify_command(rq->cmd, has_write_perm))
186 return -EPERM;
187 } else if (!capable(CAP_SYS_RAWIO))
70e36ece
FT
188 return -EPERM;
189
190 /*
191 * fill in request structure
192 */
193 rq->cmd_len = hdr->request_len;
194 rq->cmd_type = REQ_TYPE_BLOCK_PC;
195
196 rq->timeout = (hdr->timeout * HZ) / 1000;
197 if (!rq->timeout)
198 rq->timeout = q->sg_timeout;
199 if (!rq->timeout)
200 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
201
202 return 0;
203}
204
3d6392cf 205/*
70e36ece 206 * Check if sg_io_v4 from user is allowed and valid
3d6392cf
JA
207 */
208static int
165125e1 209bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
3d6392cf 210{
15d10b61
FT
211 int ret = 0;
212
70e36ece 213 if (hdr->guard != 'Q')
3d6392cf 214 return -EINVAL;
70e36ece 215 if (hdr->request_len > BLK_MAX_CDB)
3d6392cf 216 return -EINVAL;
70e36ece
FT
217 if (hdr->dout_xfer_len > (q->max_sectors << 9) ||
218 hdr->din_xfer_len > (q->max_sectors << 9))
3d6392cf
JA
219 return -EIO;
220
15d10b61
FT
221 switch (hdr->protocol) {
222 case BSG_PROTOCOL_SCSI:
223 switch (hdr->subprotocol) {
224 case BSG_SUB_PROTOCOL_SCSI_CMD:
225 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
226 break;
227 default:
228 ret = -EINVAL;
229 }
230 break;
231 default:
232 ret = -EINVAL;
233 }
70e36ece 234
70e36ece 235 *rw = hdr->dout_xfer_len ? WRITE : READ;
15d10b61 236 return ret;
3d6392cf
JA
237}
238
239/*
70e36ece 240 * map sg_io_v4 to a request.
3d6392cf
JA
241 */
242static struct request *
70e36ece 243bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
3d6392cf 244{
165125e1 245 struct request_queue *q = bd->queue;
2c9ecdf4 246 struct request *rq, *next_rq = NULL;
25fd1643 247 int ret, rw;
70e36ece
FT
248 unsigned int dxfer_len;
249 void *dxferp = NULL;
3d6392cf 250
70e36ece
FT
251 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
252 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
253 hdr->din_xfer_len);
3d6392cf 254
70e36ece 255 ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
3d6392cf
JA
256 if (ret)
257 return ERR_PTR(ret);
258
259 /*
260 * map scatter-gather elements seperately and string them to request
261 */
262 rq = blk_get_request(q, rw, GFP_KERNEL);
2c9ecdf4
FT
263 if (!rq)
264 return ERR_PTR(-ENOMEM);
70e36ece
FT
265 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, test_bit(BSG_F_WRITE_PERM,
266 &bd->flags));
2c9ecdf4
FT
267 if (ret)
268 goto out;
269
270 if (rw == WRITE && hdr->din_xfer_len) {
271 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
272 ret = -EOPNOTSUPP;
273 goto out;
274 }
275
276 next_rq = blk_get_request(q, READ, GFP_KERNEL);
277 if (!next_rq) {
278 ret = -ENOMEM;
279 goto out;
280 }
281 rq->next_rq = next_rq;
282
283 dxferp = (void*)(unsigned long)hdr->din_xferp;
284 ret = blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len);
285 if (ret)
286 goto out;
3d6392cf
JA
287 }
288
70e36ece
FT
289 if (hdr->dout_xfer_len) {
290 dxfer_len = hdr->dout_xfer_len;
291 dxferp = (void*)(unsigned long)hdr->dout_xferp;
292 } else if (hdr->din_xfer_len) {
293 dxfer_len = hdr->din_xfer_len;
294 dxferp = (void*)(unsigned long)hdr->din_xferp;
295 } else
296 dxfer_len = 0;
297
298 if (dxfer_len) {
299 ret = blk_rq_map_user(q, rq, dxferp, dxfer_len);
2c9ecdf4
FT
300 if (ret)
301 goto out;
3d6392cf 302 }
3d6392cf 303 return rq;
2c9ecdf4
FT
304out:
305 blk_put_request(rq);
306 if (next_rq) {
307 blk_rq_unmap_user(next_rq->bio);
308 blk_put_request(next_rq);
309 }
310 return ERR_PTR(ret);
3d6392cf
JA
311}
312
313/*
314 * async completion call-back from the block layer, when scsi/ide/whatever
315 * calls end_that_request_last() on a request
316 */
317static void bsg_rq_end_io(struct request *rq, int uptodate)
318{
319 struct bsg_command *bc = rq->end_io_data;
320 struct bsg_device *bd = bc->bd;
321 unsigned long flags;
322
5309cb38
JA
323 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
324 bd->name, rq, bc, bc->bio, uptodate);
3d6392cf
JA
325
326 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
327
328 spin_lock_irqsave(&bd->lock, flags);
25fd1643
JA
329 list_move_tail(&bc->list, &bd->done_list);
330 bd->done_cmds++;
3d6392cf 331 spin_unlock_irqrestore(&bd->lock, flags);
25fd1643
JA
332
333 wake_up(&bd->wq_done);
3d6392cf
JA
334}
335
336/*
337 * do final setup of a 'bc' and submit the matching 'rq' to the block
338 * layer for io
339 */
165125e1 340static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
3d6392cf
JA
341 struct bsg_command *bc, struct request *rq)
342{
343 rq->sense = bc->sense;
344 rq->sense_len = 0;
345
346 /*
347 * add bc command to busy queue and submit rq for io
348 */
349 bc->rq = rq;
350 bc->bio = rq->bio;
2c9ecdf4
FT
351 if (rq->next_rq)
352 bc->bidi_bio = rq->next_rq->bio;
3d6392cf
JA
353 bc->hdr.duration = jiffies;
354 spin_lock_irq(&bd->lock);
355 list_add_tail(&bc->list, &bd->busy_list);
356 spin_unlock_irq(&bd->lock);
357
358 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
359
360 rq->end_io_data = bc;
d351af01 361 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io);
3d6392cf
JA
362}
363
25fd1643 364static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
3d6392cf
JA
365{
366 struct bsg_command *bc = NULL;
367
368 spin_lock_irq(&bd->lock);
369 if (bd->done_cmds) {
25fd1643
JA
370 bc = list_entry(bd->done_list.next, struct bsg_command, list);
371 list_del(&bc->list);
372 bd->done_cmds--;
3d6392cf
JA
373 }
374 spin_unlock_irq(&bd->lock);
375
376 return bc;
377}
378
379/*
380 * Get a finished command from the done list
381 */
e7d72173 382static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
3d6392cf
JA
383{
384 struct bsg_command *bc;
385 int ret;
386
387 do {
388 bc = bsg_next_done_cmd(bd);
389 if (bc)
390 break;
391
e7d72173
FT
392 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
393 bc = ERR_PTR(-EAGAIN);
394 break;
395 }
396
397 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
3d6392cf 398 if (ret) {
e7d72173 399 bc = ERR_PTR(-ERESTARTSYS);
3d6392cf
JA
400 break;
401 }
402 } while (1);
403
404 dprintk("%s: returning done %p\n", bd->name, bc);
405
406 return bc;
407}
408
70e36ece 409static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
2c9ecdf4 410 struct bio *bio, struct bio *bidi_bio)
70e36ece
FT
411{
412 int ret = 0;
413
414 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors);
415 /*
416 * fill in all the output members
417 */
418 hdr->device_status = status_byte(rq->errors);
419 hdr->transport_status = host_byte(rq->errors);
420 hdr->driver_status = driver_byte(rq->errors);
421 hdr->info = 0;
422 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
423 hdr->info |= SG_INFO_CHECK;
70e36ece
FT
424 hdr->response_len = 0;
425
426 if (rq->sense_len && hdr->response) {
25fd1643
JA
427 int len = min_t(unsigned int, hdr->max_response_len,
428 rq->sense_len);
70e36ece
FT
429
430 ret = copy_to_user((void*)(unsigned long)hdr->response,
431 rq->sense, len);
432 if (!ret)
433 hdr->response_len = len;
434 else
435 ret = -EFAULT;
436 }
437
2c9ecdf4 438 if (rq->next_rq) {
0c6a89ba
FT
439 hdr->dout_resid = rq->data_len;
440 hdr->din_resid = rq->next_rq->data_len;
2c9ecdf4
FT
441 blk_rq_unmap_user(bidi_bio);
442 blk_put_request(rq->next_rq);
0c6a89ba
FT
443 } else if (rq_data_dir(rq) == READ)
444 hdr->din_resid = rq->data_len;
445 else
446 hdr->dout_resid = rq->data_len;
2c9ecdf4 447
2d507a01
JB
448 /*
449 * If the request generated a negative error number, return it
450 * (providing we aren't already returning an error); if it's
451 * just a protocol response (i.e. non negative), that gets
452 * processed above.
453 */
454 if (!ret && rq->errors < 0)
455 ret = rq->errors;
456
70e36ece
FT
457 blk_rq_unmap_user(bio);
458 blk_put_request(rq);
459
460 return ret;
461}
462
3d6392cf
JA
463static int bsg_complete_all_commands(struct bsg_device *bd)
464{
465 struct bsg_command *bc;
466 int ret, tret;
467
468 dprintk("%s: entered\n", bd->name);
469
470 set_bit(BSG_F_BLOCK, &bd->flags);
471
472 /*
473 * wait for all commands to complete
474 */
475 ret = 0;
476 do {
25fd1643 477 ret = bsg_io_schedule(bd);
3d6392cf
JA
478 /*
479 * look for -ENODATA specifically -- we'll sometimes get
480 * -ERESTARTSYS when we've taken a signal, but we can't
481 * return until we're done freeing the queue, so ignore
482 * it. The signal will get handled when we're done freeing
483 * the bsg_device.
484 */
485 } while (ret != -ENODATA);
486
487 /*
488 * discard done commands
489 */
490 ret = 0;
491 do {
e7d72173
FT
492 spin_lock_irq(&bd->lock);
493 if (!bd->queued_cmds) {
494 spin_unlock_irq(&bd->lock);
3d6392cf
JA
495 break;
496 }
efba1a31 497 spin_unlock_irq(&bd->lock);
3d6392cf 498
e7d72173
FT
499 bc = bsg_get_done_cmd(bd);
500 if (IS_ERR(bc))
501 break;
502
2c9ecdf4
FT
503 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
504 bc->bidi_bio);
3d6392cf
JA
505 if (!ret)
506 ret = tret;
507
508 bsg_free_command(bc);
509 } while (1);
510
511 return ret;
512}
513
25fd1643 514static int
e7d72173
FT
515__bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
516 const struct iovec *iov, ssize_t *bytes_read)
3d6392cf
JA
517{
518 struct bsg_command *bc;
519 int nr_commands, ret;
520
70e36ece 521 if (count % sizeof(struct sg_io_v4))
3d6392cf
JA
522 return -EINVAL;
523
524 ret = 0;
70e36ece 525 nr_commands = count / sizeof(struct sg_io_v4);
3d6392cf 526 while (nr_commands) {
e7d72173 527 bc = bsg_get_done_cmd(bd);
3d6392cf
JA
528 if (IS_ERR(bc)) {
529 ret = PTR_ERR(bc);
530 break;
531 }
532
533 /*
534 * this is the only case where we need to copy data back
535 * after completing the request. so do that here,
536 * bsg_complete_work() cannot do that for us
537 */
2c9ecdf4
FT
538 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
539 bc->bidi_bio);
3d6392cf 540
25fd1643 541 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
3d6392cf
JA
542 ret = -EFAULT;
543
544 bsg_free_command(bc);
545
546 if (ret)
547 break;
548
70e36ece
FT
549 buf += sizeof(struct sg_io_v4);
550 *bytes_read += sizeof(struct sg_io_v4);
3d6392cf
JA
551 nr_commands--;
552 }
553
554 return ret;
555}
556
557static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
558{
559 if (file->f_flags & O_NONBLOCK)
560 clear_bit(BSG_F_BLOCK, &bd->flags);
561 else
562 set_bit(BSG_F_BLOCK, &bd->flags);
563}
564
565static inline void bsg_set_write_perm(struct bsg_device *bd, struct file *file)
566{
567 if (file->f_mode & FMODE_WRITE)
568 set_bit(BSG_F_WRITE_PERM, &bd->flags);
569 else
570 clear_bit(BSG_F_WRITE_PERM, &bd->flags);
571}
572
25fd1643
JA
573/*
574 * Check if the error is a "real" error that we should return.
575 */
3d6392cf
JA
576static inline int err_block_err(int ret)
577{
578 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
579 return 1;
580
581 return 0;
582}
583
584static ssize_t
585bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
586{
587 struct bsg_device *bd = file->private_data;
588 int ret;
589 ssize_t bytes_read;
590
9e69fbb5 591 dprintk("%s: read %Zd bytes\n", bd->name, count);
3d6392cf
JA
592
593 bsg_set_block(bd, file);
594 bytes_read = 0;
e7d72173 595 ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
3d6392cf
JA
596 *ppos = bytes_read;
597
598 if (!bytes_read || (bytes_read && err_block_err(ret)))
599 bytes_read = ret;
600
601 return bytes_read;
602}
603
25fd1643
JA
604static int __bsg_write(struct bsg_device *bd, const char __user *buf,
605 size_t count, ssize_t *bytes_written)
3d6392cf
JA
606{
607 struct bsg_command *bc;
608 struct request *rq;
609 int ret, nr_commands;
610
70e36ece 611 if (count % sizeof(struct sg_io_v4))
3d6392cf
JA
612 return -EINVAL;
613
70e36ece 614 nr_commands = count / sizeof(struct sg_io_v4);
3d6392cf
JA
615 rq = NULL;
616 bc = NULL;
617 ret = 0;
618 while (nr_commands) {
165125e1 619 struct request_queue *q = bd->queue;
3d6392cf 620
e7d72173 621 bc = bsg_alloc_command(bd);
3d6392cf
JA
622 if (IS_ERR(bc)) {
623 ret = PTR_ERR(bc);
624 bc = NULL;
625 break;
626 }
627
3d6392cf
JA
628 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
629 ret = -EFAULT;
630 break;
631 }
632
633 /*
634 * get a request, fill in the blanks, and add to request queue
635 */
70e36ece 636 rq = bsg_map_hdr(bd, &bc->hdr);
3d6392cf
JA
637 if (IS_ERR(rq)) {
638 ret = PTR_ERR(rq);
639 rq = NULL;
640 break;
641 }
642
643 bsg_add_command(bd, q, bc, rq);
644 bc = NULL;
645 rq = NULL;
646 nr_commands--;
70e36ece 647 buf += sizeof(struct sg_io_v4);
25fd1643 648 *bytes_written += sizeof(struct sg_io_v4);
3d6392cf
JA
649 }
650
3d6392cf
JA
651 if (bc)
652 bsg_free_command(bc);
653
654 return ret;
655}
656
657static ssize_t
658bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
659{
660 struct bsg_device *bd = file->private_data;
25fd1643 661 ssize_t bytes_written;
3d6392cf
JA
662 int ret;
663
9e69fbb5 664 dprintk("%s: write %Zd bytes\n", bd->name, count);
3d6392cf
JA
665
666 bsg_set_block(bd, file);
667 bsg_set_write_perm(bd, file);
668
25fd1643
JA
669 bytes_written = 0;
670 ret = __bsg_write(bd, buf, count, &bytes_written);
671 *ppos = bytes_written;
3d6392cf
JA
672
673 /*
674 * return bytes written on non-fatal errors
675 */
25fd1643
JA
676 if (!bytes_written || (bytes_written && err_block_err(ret)))
677 bytes_written = ret;
3d6392cf 678
25fd1643
JA
679 dprintk("%s: returning %Zd\n", bd->name, bytes_written);
680 return bytes_written;
3d6392cf
JA
681}
682
3d6392cf
JA
683static struct bsg_device *bsg_alloc_device(void)
684{
3d6392cf 685 struct bsg_device *bd;
3d6392cf
JA
686
687 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
688 if (unlikely(!bd))
689 return NULL;
690
691 spin_lock_init(&bd->lock);
692
5309cb38 693 bd->max_queue = BSG_DEFAULT_CMDS;
3d6392cf
JA
694
695 INIT_LIST_HEAD(&bd->busy_list);
696 INIT_LIST_HEAD(&bd->done_list);
697 INIT_HLIST_NODE(&bd->dev_list);
698
699 init_waitqueue_head(&bd->wq_free);
700 init_waitqueue_head(&bd->wq_done);
701 return bd;
3d6392cf
JA
702}
703
704static int bsg_put_device(struct bsg_device *bd)
705{
706 int ret = 0;
707
708 mutex_lock(&bsg_mutex);
709
710 if (!atomic_dec_and_test(&bd->ref_count))
711 goto out;
712
713 dprintk("%s: tearing down\n", bd->name);
714
715 /*
716 * close can always block
717 */
718 set_bit(BSG_F_BLOCK, &bd->flags);
719
720 /*
721 * correct error detection baddies here again. it's the responsibility
722 * of the app to properly reap commands before close() if it wants
723 * fool-proof error detection
724 */
725 ret = bsg_complete_all_commands(bd);
726
727 blk_put_queue(bd->queue);
728 hlist_del(&bd->dev_list);
5309cb38 729 kfree(bd);
3d6392cf
JA
730out:
731 mutex_unlock(&bsg_mutex);
732 return ret;
733}
734
735static struct bsg_device *bsg_add_device(struct inode *inode,
d351af01 736 struct request_queue *rq,
3d6392cf
JA
737 struct file *file)
738{
25fd1643 739 struct bsg_device *bd;
3d6392cf
JA
740#ifdef BSG_DEBUG
741 unsigned char buf[32];
742#endif
743
744 bd = bsg_alloc_device();
745 if (!bd)
746 return ERR_PTR(-ENOMEM);
747
d351af01
FT
748 bd->queue = rq;
749 kobject_get(&rq->kobj);
3d6392cf
JA
750 bsg_set_block(bd, file);
751
752 atomic_set(&bd->ref_count, 1);
753 bd->minor = iminor(inode);
754 mutex_lock(&bsg_mutex);
1c1133e1 755 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(bd->minor));
3d6392cf 756
d351af01 757 strncpy(bd->name, rq->bsg_dev.class_dev->class_id, sizeof(bd->name) - 1);
3d6392cf 758 dprintk("bound to <%s>, max queue %d\n",
9e69fbb5 759 format_dev_t(buf, inode->i_rdev), bd->max_queue);
3d6392cf
JA
760
761 mutex_unlock(&bsg_mutex);
762 return bd;
763}
764
765static struct bsg_device *__bsg_get_device(int minor)
766{
3d6392cf
JA
767 struct bsg_device *bd = NULL;
768 struct hlist_node *entry;
769
770 mutex_lock(&bsg_mutex);
771
1c1133e1 772 hlist_for_each(entry, bsg_dev_idx_hash(minor)) {
3d6392cf
JA
773 bd = hlist_entry(entry, struct bsg_device, dev_list);
774 if (bd->minor == minor) {
775 atomic_inc(&bd->ref_count);
776 break;
777 }
778
779 bd = NULL;
780 }
781
782 mutex_unlock(&bsg_mutex);
783 return bd;
784}
785
786static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
787{
598443a2
FT
788 struct bsg_device *bd;
789 struct bsg_class_device *bcd;
3d6392cf 790
598443a2 791 bd = __bsg_get_device(iminor(inode));
3d6392cf
JA
792 if (bd)
793 return bd;
794
795 /*
796 * find the class device
797 */
3d6392cf 798 mutex_lock(&bsg_mutex);
598443a2 799 bcd = idr_find(&bsg_minor_idr, iminor(inode));
3d6392cf
JA
800 mutex_unlock(&bsg_mutex);
801
802 if (!bcd)
803 return ERR_PTR(-ENODEV);
804
d351af01 805 return bsg_add_device(inode, bcd->queue, file);
3d6392cf
JA
806}
807
808static int bsg_open(struct inode *inode, struct file *file)
809{
810 struct bsg_device *bd = bsg_get_device(inode, file);
811
812 if (IS_ERR(bd))
813 return PTR_ERR(bd);
814
815 file->private_data = bd;
816 return 0;
817}
818
819static int bsg_release(struct inode *inode, struct file *file)
820{
821 struct bsg_device *bd = file->private_data;
822
823 file->private_data = NULL;
824 return bsg_put_device(bd);
825}
826
827static unsigned int bsg_poll(struct file *file, poll_table *wait)
828{
829 struct bsg_device *bd = file->private_data;
830 unsigned int mask = 0;
831
832 poll_wait(file, &bd->wq_done, wait);
833 poll_wait(file, &bd->wq_free, wait);
834
835 spin_lock_irq(&bd->lock);
836 if (!list_empty(&bd->done_list))
837 mask |= POLLIN | POLLRDNORM;
838 if (bd->queued_cmds >= bd->max_queue)
839 mask |= POLLOUT;
840 spin_unlock_irq(&bd->lock);
841
842 return mask;
843}
844
25fd1643 845static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3d6392cf
JA
846{
847 struct bsg_device *bd = file->private_data;
848 int __user *uarg = (int __user *) arg;
2d507a01 849 int ret;
3d6392cf 850
3d6392cf
JA
851 switch (cmd) {
852 /*
853 * our own ioctls
854 */
855 case SG_GET_COMMAND_Q:
856 return put_user(bd->max_queue, uarg);
5309cb38 857 case SG_SET_COMMAND_Q: {
3d6392cf
JA
858 int queue;
859
860 if (get_user(queue, uarg))
861 return -EFAULT;
5309cb38 862 if (queue < 1)
3d6392cf
JA
863 return -EINVAL;
864
5309cb38 865 spin_lock_irq(&bd->lock);
3d6392cf 866 bd->max_queue = queue;
5309cb38 867 spin_unlock_irq(&bd->lock);
3d6392cf
JA
868 return 0;
869 }
870
871 /*
872 * SCSI/sg ioctls
873 */
874 case SG_GET_VERSION_NUM:
875 case SCSI_IOCTL_GET_IDLUN:
876 case SCSI_IOCTL_GET_BUS_NUMBER:
877 case SG_SET_TIMEOUT:
878 case SG_GET_TIMEOUT:
879 case SG_GET_RESERVED_SIZE:
880 case SG_SET_RESERVED_SIZE:
881 case SG_EMULATED_HOST:
3d6392cf
JA
882 case SCSI_IOCTL_SEND_COMMAND: {
883 void __user *uarg = (void __user *) arg;
d351af01 884 return scsi_cmd_ioctl(file, bd->queue, NULL, cmd, uarg);
3d6392cf 885 }
10e8855b
FT
886 case SG_IO: {
887 struct request *rq;
2c9ecdf4 888 struct bio *bio, *bidi_bio = NULL;
10e8855b
FT
889 struct sg_io_v4 hdr;
890
891 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
892 return -EFAULT;
893
894 rq = bsg_map_hdr(bd, &hdr);
895 if (IS_ERR(rq))
896 return PTR_ERR(rq);
897
898 bio = rq->bio;
2c9ecdf4
FT
899 if (rq->next_rq)
900 bidi_bio = rq->next_rq->bio;
d351af01 901 blk_execute_rq(bd->queue, NULL, rq, 0);
2d507a01 902 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
10e8855b
FT
903
904 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
905 return -EFAULT;
b711afa6 906
2d507a01 907 return ret;
10e8855b 908 }
3d6392cf
JA
909 /*
910 * block device ioctls
911 */
912 default:
913#if 0
914 return ioctl_by_bdev(bd->bdev, cmd, arg);
915#else
916 return -ENOTTY;
917#endif
918 }
919}
920
7344be05 921static const struct file_operations bsg_fops = {
3d6392cf
JA
922 .read = bsg_read,
923 .write = bsg_write,
924 .poll = bsg_poll,
925 .open = bsg_open,
926 .release = bsg_release,
25fd1643 927 .unlocked_ioctl = bsg_ioctl,
3d6392cf
JA
928 .owner = THIS_MODULE,
929};
930
d351af01 931void bsg_unregister_queue(struct request_queue *q)
3d6392cf 932{
d351af01 933 struct bsg_class_device *bcd = &q->bsg_dev;
3d6392cf 934
df468820
FT
935 if (!bcd->class_dev)
936 return;
3d6392cf
JA
937
938 mutex_lock(&bsg_mutex);
598443a2 939 idr_remove(&bsg_minor_idr, bcd->minor);
d351af01 940 sysfs_remove_link(&q->kobj, "bsg");
39dca558
JB
941 class_device_unregister(bcd->class_dev);
942 put_device(bcd->dev);
3d6392cf 943 bcd->class_dev = NULL;
39dca558 944 bcd->dev = NULL;
3d6392cf
JA
945 mutex_unlock(&bsg_mutex);
946}
4cf0723a 947EXPORT_SYMBOL_GPL(bsg_unregister_queue);
3d6392cf 948
39dca558
JB
949int bsg_register_queue(struct request_queue *q, struct device *gdev,
950 const char *name)
3d6392cf 951{
598443a2 952 struct bsg_class_device *bcd;
3d6392cf 953 dev_t dev;
598443a2 954 int ret, minor;
4e2872d6 955 struct class_device *class_dev = NULL;
39dca558
JB
956 const char *devname;
957
958 if (name)
959 devname = name;
960 else
961 devname = gdev->bus_id;
3d6392cf
JA
962
963 /*
964 * we need a proper transport to send commands, not a stacked device
965 */
966 if (!q->request_fn)
967 return 0;
968
d351af01 969 bcd = &q->bsg_dev;
3d6392cf 970 memset(bcd, 0, sizeof(*bcd));
3d6392cf
JA
971
972 mutex_lock(&bsg_mutex);
292b7f27 973
598443a2
FT
974 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL);
975 if (!ret) {
976 ret = -ENOMEM;
977 goto unlock;
292b7f27
FT
978 }
979
598443a2
FT
980 ret = idr_get_new(&bsg_minor_idr, bcd, &minor);
981 if (ret < 0)
982 goto unlock;
292b7f27 983
598443a2
FT
984 if (minor >= BSG_MAX_DEVS) {
985 printk(KERN_ERR "bsg: too many bsg devices\n");
986 ret = -EINVAL;
987 goto remove_idr;
988 }
989
990 bcd->minor = minor;
d351af01 991 bcd->queue = q;
39dca558 992 bcd->dev = get_device(gdev);
46f6ef4a 993 dev = MKDEV(bsg_major, bcd->minor);
39dca558
JB
994 class_dev = class_device_create(bsg_class, NULL, dev, gdev, "%s",
995 devname);
4e2872d6
FT
996 if (IS_ERR(class_dev)) {
997 ret = PTR_ERR(class_dev);
598443a2 998 goto put_dev;
4e2872d6
FT
999 }
1000 bcd->class_dev = class_dev;
1001
abce891a 1002 if (q->kobj.sd) {
4e2872d6
FT
1003 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
1004 if (ret)
598443a2 1005 goto unregister_class_dev;
4e2872d6
FT
1006 }
1007
3d6392cf
JA
1008 mutex_unlock(&bsg_mutex);
1009 return 0;
6826ee4f 1010
598443a2 1011unregister_class_dev:
6826ee4f 1012 class_device_unregister(class_dev);
598443a2 1013put_dev:
39dca558 1014 put_device(gdev);
598443a2
FT
1015remove_idr:
1016 idr_remove(&bsg_minor_idr, minor);
1017unlock:
264a0472 1018 mutex_unlock(&bsg_mutex);
4e2872d6
FT
1019 return ret;
1020}
4cf0723a 1021EXPORT_SYMBOL_GPL(bsg_register_queue);
4e2872d6 1022
7e7654a9 1023static struct cdev bsg_cdev;
292b7f27 1024
3d6392cf
JA
1025static int __init bsg_init(void)
1026{
1027 int ret, i;
46f6ef4a 1028 dev_t devid;
3d6392cf 1029
5309cb38 1030 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
20c2df83 1031 sizeof(struct bsg_command), 0, 0, NULL);
5309cb38
JA
1032 if (!bsg_cmd_cachep) {
1033 printk(KERN_ERR "bsg: failed creating slab cache\n");
1034 return -ENOMEM;
1035 }
1036
25fd1643 1037 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
3d6392cf
JA
1038 INIT_HLIST_HEAD(&bsg_device_list[i]);
1039
1040 bsg_class = class_create(THIS_MODULE, "bsg");
5309cb38 1041 if (IS_ERR(bsg_class)) {
9b9f770c
FT
1042 ret = PTR_ERR(bsg_class);
1043 goto destroy_kmemcache;
5309cb38 1044 }
3d6392cf 1045
46f6ef4a 1046 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
9b9f770c
FT
1047 if (ret)
1048 goto destroy_bsg_class;
292b7f27 1049
46f6ef4a
JA
1050 bsg_major = MAJOR(devid);
1051
292b7f27 1052 cdev_init(&bsg_cdev, &bsg_fops);
46f6ef4a 1053 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
9b9f770c
FT
1054 if (ret)
1055 goto unregister_chrdev;
3d6392cf 1056
5d3a8cd3 1057 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
0ed081ce 1058 " loaded (major %d)\n", bsg_major);
3d6392cf 1059 return 0;
9b9f770c
FT
1060unregister_chrdev:
1061 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1062destroy_bsg_class:
1063 class_destroy(bsg_class);
1064destroy_kmemcache:
1065 kmem_cache_destroy(bsg_cmd_cachep);
1066 return ret;
3d6392cf
JA
1067}
1068
1069MODULE_AUTHOR("Jens Axboe");
0ed081ce 1070MODULE_DESCRIPTION(BSG_DESCRIPTION);
3d6392cf
JA
1071MODULE_LICENSE("GPL");
1072
4e2872d6 1073device_initcall(bsg_init);