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1/*
2 * bsg.c - block layer implementation of the sg v4 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#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/jiffies.h>
19#include <linux/percpu.h>
20#include <linux/uio.h>
21#include <linux/idr.h>
22#include <linux/bsg.h>
23#include <linux/slab.h>
24
25#include <scsi/scsi.h>
26#include <scsi/scsi_ioctl.h>
27#include <scsi/scsi_cmnd.h>
28#include <scsi/scsi_device.h>
29#include <scsi/scsi_driver.h>
30#include <scsi/sg.h>
31
32#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
33#define BSG_VERSION "0.4"
34
35struct bsg_device {
36 struct request_queue *queue;
37 spinlock_t lock;
38 struct list_head busy_list;
39 struct list_head done_list;
40 struct hlist_node dev_list;
41 atomic_t ref_count;
42 int queued_cmds;
43 int done_cmds;
44 wait_queue_head_t wq_done;
45 wait_queue_head_t wq_free;
46 char name[20];
47 int max_queue;
48 unsigned long flags;
49};
50
51enum {
52 BSG_F_BLOCK = 1,
53};
54
55#define BSG_DEFAULT_CMDS 64
56#define BSG_MAX_DEVS 32768
57
58#undef BSG_DEBUG
59
60#ifdef BSG_DEBUG
61#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args)
62#else
63#define dprintk(fmt, args...)
64#endif
65
66static DEFINE_MUTEX(bsg_mutex);
67static DEFINE_IDR(bsg_minor_idr);
68
69#define BSG_LIST_ARRAY_SIZE 8
70static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
71
72static struct class *bsg_class;
73static int bsg_major;
74
75static struct kmem_cache *bsg_cmd_cachep;
76
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;
85 struct bio *bidi_bio;
86 int err;
87 struct sg_io_v4 hdr;
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;
94 unsigned long flags;
95
96 kmem_cache_free(bsg_cmd_cachep, bc);
97
98 spin_lock_irqsave(&bd->lock, flags);
99 bd->queued_cmds--;
100 spin_unlock_irqrestore(&bd->lock, flags);
101
102 wake_up(&bd->wq_free);
103}
104
105static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
106{
107 struct bsg_command *bc = ERR_PTR(-EINVAL);
108
109 spin_lock_irq(&bd->lock);
110
111 if (bd->queued_cmds >= bd->max_queue)
112 goto out;
113
114 bd->queued_cmds++;
115 spin_unlock_irq(&bd->lock);
116
117 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
118 if (unlikely(!bc)) {
119 spin_lock_irq(&bd->lock);
120 bd->queued_cmds--;
121 bc = ERR_PTR(-ENOMEM);
122 goto out;
123 }
124
125 bc->bd = bd;
126 INIT_LIST_HEAD(&bc->list);
127 dprintk("%s: returning free cmd %p\n", bd->name, bc);
128 return bc;
129out:
130 spin_unlock_irq(&bd->lock);
131 return bc;
132}
133
134static inline struct hlist_head *bsg_dev_idx_hash(int index)
135{
136 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
137}
138
139static int bsg_io_schedule(struct bsg_device *bd)
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
164 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE);
165 spin_unlock_irq(&bd->lock);
166 io_schedule();
167 finish_wait(&bd->wq_done, &wait);
168
169 return ret;
170unlock:
171 spin_unlock_irq(&bd->lock);
172 return ret;
173}
174
175static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
176 struct sg_io_v4 *hdr, struct bsg_device *bd,
177 fmode_t has_write_perm)
178{
179 if (hdr->request_len > BLK_MAX_CDB) {
180 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
181 if (!rq->cmd)
182 return -ENOMEM;
183 }
184
185 if (copy_from_user(rq->cmd, (void __user *)(unsigned long)hdr->request,
186 hdr->request_len))
187 return -EFAULT;
188
189 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
190 if (blk_verify_command(rq->cmd, has_write_perm))
191 return -EPERM;
192 } else if (!capable(CAP_SYS_RAWIO))
193 return -EPERM;
194
195 /*
196 * fill in request structure
197 */
198 rq->cmd_len = hdr->request_len;
199 rq->cmd_type = REQ_TYPE_BLOCK_PC;
200
201 rq->timeout = msecs_to_jiffies(hdr->timeout);
202 if (!rq->timeout)
203 rq->timeout = q->sg_timeout;
204 if (!rq->timeout)
205 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
206 if (rq->timeout < BLK_MIN_SG_TIMEOUT)
207 rq->timeout = BLK_MIN_SG_TIMEOUT;
208
209 return 0;
210}
211
212/*
213 * Check if sg_io_v4 from user is allowed and valid
214 */
215static int
216bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
217{
218 int ret = 0;
219
220 if (hdr->guard != 'Q')
221 return -EINVAL;
222
223 switch (hdr->protocol) {
224 case BSG_PROTOCOL_SCSI:
225 switch (hdr->subprotocol) {
226 case BSG_SUB_PROTOCOL_SCSI_CMD:
227 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
228 break;
229 default:
230 ret = -EINVAL;
231 }
232 break;
233 default:
234 ret = -EINVAL;
235 }
236
237 *rw = hdr->dout_xfer_len ? WRITE : READ;
238 return ret;
239}
240
241/*
242 * map sg_io_v4 to a request.
243 */
244static struct request *
245bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
246 u8 *sense)
247{
248 struct request_queue *q = bd->queue;
249 struct request *rq, *next_rq = NULL;
250 int ret, rw;
251 unsigned int dxfer_len;
252 void __user *dxferp = NULL;
253 struct bsg_class_device *bcd = &q->bsg_dev;
254
255 /* if the LLD has been removed then the bsg_unregister_queue will
256 * eventually be called and the class_dev was freed, so we can no
257 * longer use this request_queue. Return no such address.
258 */
259 if (!bcd->class_dev)
260 return ERR_PTR(-ENXIO);
261
262 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
263 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
264 hdr->din_xfer_len);
265
266 ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
267 if (ret)
268 return ERR_PTR(ret);
269
270 /*
271 * map scatter-gather elements separately and string them to request
272 */
273 rq = blk_get_request(q, rw, GFP_KERNEL);
274 if (!rq)
275 return ERR_PTR(-ENOMEM);
276 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
277 if (ret)
278 goto out;
279
280 if (rw == WRITE && hdr->din_xfer_len) {
281 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
282 ret = -EOPNOTSUPP;
283 goto out;
284 }
285
286 next_rq = blk_get_request(q, READ, GFP_KERNEL);
287 if (!next_rq) {
288 ret = -ENOMEM;
289 goto out;
290 }
291 rq->next_rq = next_rq;
292 next_rq->cmd_type = rq->cmd_type;
293
294 dxferp = (void __user *)(unsigned long)hdr->din_xferp;
295 ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
296 hdr->din_xfer_len, GFP_KERNEL);
297 if (ret)
298 goto out;
299 }
300
301 if (hdr->dout_xfer_len) {
302 dxfer_len = hdr->dout_xfer_len;
303 dxferp = (void __user *)(unsigned long)hdr->dout_xferp;
304 } else if (hdr->din_xfer_len) {
305 dxfer_len = hdr->din_xfer_len;
306 dxferp = (void __user *)(unsigned long)hdr->din_xferp;
307 } else
308 dxfer_len = 0;
309
310 if (dxfer_len) {
311 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
312 GFP_KERNEL);
313 if (ret)
314 goto out;
315 }
316
317 rq->sense = sense;
318 rq->sense_len = 0;
319
320 return rq;
321out:
322 if (rq->cmd != rq->__cmd)
323 kfree(rq->cmd);
324 blk_put_request(rq);
325 if (next_rq) {
326 blk_rq_unmap_user(next_rq->bio);
327 blk_put_request(next_rq);
328 }
329 return ERR_PTR(ret);
330}
331
332/*
333 * async completion call-back from the block layer, when scsi/ide/whatever
334 * calls end_that_request_last() on a request
335 */
336static void bsg_rq_end_io(struct request *rq, int uptodate)
337{
338 struct bsg_command *bc = rq->end_io_data;
339 struct bsg_device *bd = bc->bd;
340 unsigned long flags;
341
342 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
343 bd->name, rq, bc, bc->bio, uptodate);
344
345 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
346
347 spin_lock_irqsave(&bd->lock, flags);
348 list_move_tail(&bc->list, &bd->done_list);
349 bd->done_cmds++;
350 spin_unlock_irqrestore(&bd->lock, flags);
351
352 wake_up(&bd->wq_done);
353}
354
355/*
356 * do final setup of a 'bc' and submit the matching 'rq' to the block
357 * layer for io
358 */
359static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
360 struct bsg_command *bc, struct request *rq)
361{
362 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL));
363
364 /*
365 * add bc command to busy queue and submit rq for io
366 */
367 bc->rq = rq;
368 bc->bio = rq->bio;
369 if (rq->next_rq)
370 bc->bidi_bio = rq->next_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, NULL, rq, at_head, bsg_rq_end_io);
380}
381
382static 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_first_entry(&bd->done_list, struct bsg_command, list);
389 list_del(&bc->list);
390 bd->done_cmds--;
391 }
392 spin_unlock_irq(&bd->lock);
393
394 return bc;
395}
396
397/*
398 * Get a finished command from the done list
399 */
400static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
401{
402 struct bsg_command *bc;
403 int ret;
404
405 do {
406 bc = bsg_next_done_cmd(bd);
407 if (bc)
408 break;
409
410 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
411 bc = ERR_PTR(-EAGAIN);
412 break;
413 }
414
415 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
416 if (ret) {
417 bc = ERR_PTR(-ERESTARTSYS);
418 break;
419 }
420 } while (1);
421
422 dprintk("%s: returning done %p\n", bd->name, bc);
423
424 return bc;
425}
426
427static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
428 struct bio *bio, struct bio *bidi_bio)
429{
430 int ret = 0;
431
432 dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors);
433 /*
434 * fill in all the output members
435 */
436 hdr->device_status = rq->errors & 0xff;
437 hdr->transport_status = host_byte(rq->errors);
438 hdr->driver_status = driver_byte(rq->errors);
439 hdr->info = 0;
440 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
441 hdr->info |= SG_INFO_CHECK;
442 hdr->response_len = 0;
443
444 if (rq->sense_len && hdr->response) {
445 int len = min_t(unsigned int, hdr->max_response_len,
446 rq->sense_len);
447
448 ret = copy_to_user((void __user *)(unsigned long)hdr->response,
449 rq->sense, len);
450 if (!ret)
451 hdr->response_len = len;
452 else
453 ret = -EFAULT;
454 }
455
456 if (rq->next_rq) {
457 hdr->dout_resid = rq->resid_len;
458 hdr->din_resid = rq->next_rq->resid_len;
459 blk_rq_unmap_user(bidi_bio);
460 blk_put_request(rq->next_rq);
461 } else if (rq_data_dir(rq) == READ)
462 hdr->din_resid = rq->resid_len;
463 else
464 hdr->dout_resid = rq->resid_len;
465
466 /*
467 * If the request generated a negative error number, return it
468 * (providing we aren't already returning an error); if it's
469 * just a protocol response (i.e. non negative), that gets
470 * processed above.
471 */
472 if (!ret && rq->errors < 0)
473 ret = rq->errors;
474
475 blk_rq_unmap_user(bio);
476 if (rq->cmd != rq->__cmd)
477 kfree(rq->cmd);
478 blk_put_request(rq);
479
480 return ret;
481}
482
483static int bsg_complete_all_commands(struct bsg_device *bd)
484{
485 struct bsg_command *bc;
486 int ret, tret;
487
488 dprintk("%s: entered\n", bd->name);
489
490 /*
491 * wait for all commands to complete
492 */
493 ret = 0;
494 do {
495 ret = bsg_io_schedule(bd);
496 /*
497 * look for -ENODATA specifically -- we'll sometimes get
498 * -ERESTARTSYS when we've taken a signal, but we can't
499 * return until we're done freeing the queue, so ignore
500 * it. The signal will get handled when we're done freeing
501 * the bsg_device.
502 */
503 } while (ret != -ENODATA);
504
505 /*
506 * discard done commands
507 */
508 ret = 0;
509 do {
510 spin_lock_irq(&bd->lock);
511 if (!bd->queued_cmds) {
512 spin_unlock_irq(&bd->lock);
513 break;
514 }
515 spin_unlock_irq(&bd->lock);
516
517 bc = bsg_get_done_cmd(bd);
518 if (IS_ERR(bc))
519 break;
520
521 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
522 bc->bidi_bio);
523 if (!ret)
524 ret = tret;
525
526 bsg_free_command(bc);
527 } while (1);
528
529 return ret;
530}
531
532static int
533__bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
534 const struct iovec *iov, ssize_t *bytes_read)
535{
536 struct bsg_command *bc;
537 int nr_commands, ret;
538
539 if (count % sizeof(struct sg_io_v4))
540 return -EINVAL;
541
542 ret = 0;
543 nr_commands = count / sizeof(struct sg_io_v4);
544 while (nr_commands) {
545 bc = bsg_get_done_cmd(bd);
546 if (IS_ERR(bc)) {
547 ret = PTR_ERR(bc);
548 break;
549 }
550
551 /*
552 * this is the only case where we need to copy data back
553 * after completing the request. so do that here,
554 * bsg_complete_work() cannot do that for us
555 */
556 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
557 bc->bidi_bio);
558
559 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
560 ret = -EFAULT;
561
562 bsg_free_command(bc);
563
564 if (ret)
565 break;
566
567 buf += sizeof(struct sg_io_v4);
568 *bytes_read += sizeof(struct sg_io_v4);
569 nr_commands--;
570 }
571
572 return ret;
573}
574
575static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
576{
577 if (file->f_flags & O_NONBLOCK)
578 clear_bit(BSG_F_BLOCK, &bd->flags);
579 else
580 set_bit(BSG_F_BLOCK, &bd->flags);
581}
582
583/*
584 * Check if the error is a "real" error that we should return.
585 */
586static inline int err_block_err(int ret)
587{
588 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
589 return 1;
590
591 return 0;
592}
593
594static ssize_t
595bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
596{
597 struct bsg_device *bd = file->private_data;
598 int ret;
599 ssize_t bytes_read;
600
601 dprintk("%s: read %Zd bytes\n", bd->name, count);
602
603 bsg_set_block(bd, file);
604
605 bytes_read = 0;
606 ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
607 *ppos = bytes_read;
608
609 if (!bytes_read || err_block_err(ret))
610 bytes_read = ret;
611
612 return bytes_read;
613}
614
615static int __bsg_write(struct bsg_device *bd, const char __user *buf,
616 size_t count, ssize_t *bytes_written,
617 fmode_t has_write_perm)
618{
619 struct bsg_command *bc;
620 struct request *rq;
621 int ret, nr_commands;
622
623 if (count % sizeof(struct sg_io_v4))
624 return -EINVAL;
625
626 nr_commands = count / sizeof(struct sg_io_v4);
627 rq = NULL;
628 bc = NULL;
629 ret = 0;
630 while (nr_commands) {
631 struct request_queue *q = bd->queue;
632
633 bc = bsg_alloc_command(bd);
634 if (IS_ERR(bc)) {
635 ret = PTR_ERR(bc);
636 bc = NULL;
637 break;
638 }
639
640 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
641 ret = -EFAULT;
642 break;
643 }
644
645 /*
646 * get a request, fill in the blanks, and add to request queue
647 */
648 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense);
649 if (IS_ERR(rq)) {
650 ret = PTR_ERR(rq);
651 rq = NULL;
652 break;
653 }
654
655 bsg_add_command(bd, q, bc, rq);
656 bc = NULL;
657 rq = NULL;
658 nr_commands--;
659 buf += sizeof(struct sg_io_v4);
660 *bytes_written += sizeof(struct sg_io_v4);
661 }
662
663 if (bc)
664 bsg_free_command(bc);
665
666 return ret;
667}
668
669static ssize_t
670bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
671{
672 struct bsg_device *bd = file->private_data;
673 ssize_t bytes_written;
674 int ret;
675
676 dprintk("%s: write %Zd bytes\n", bd->name, count);
677
678 bsg_set_block(bd, file);
679
680 bytes_written = 0;
681 ret = __bsg_write(bd, buf, count, &bytes_written,
682 file->f_mode & FMODE_WRITE);
683
684 *ppos = bytes_written;
685
686 /*
687 * return bytes written on non-fatal errors
688 */
689 if (!bytes_written || err_block_err(ret))
690 bytes_written = ret;
691
692 dprintk("%s: returning %Zd\n", bd->name, bytes_written);
693 return bytes_written;
694}
695
696static struct bsg_device *bsg_alloc_device(void)
697{
698 struct bsg_device *bd;
699
700 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
701 if (unlikely(!bd))
702 return NULL;
703
704 spin_lock_init(&bd->lock);
705
706 bd->max_queue = BSG_DEFAULT_CMDS;
707
708 INIT_LIST_HEAD(&bd->busy_list);
709 INIT_LIST_HEAD(&bd->done_list);
710 INIT_HLIST_NODE(&bd->dev_list);
711
712 init_waitqueue_head(&bd->wq_free);
713 init_waitqueue_head(&bd->wq_done);
714 return bd;
715}
716
717static void bsg_kref_release_function(struct kref *kref)
718{
719 struct bsg_class_device *bcd =
720 container_of(kref, struct bsg_class_device, ref);
721 struct device *parent = bcd->parent;
722
723 if (bcd->release)
724 bcd->release(bcd->parent);
725
726 put_device(parent);
727}
728
729static int bsg_put_device(struct bsg_device *bd)
730{
731 int ret = 0, do_free;
732 struct request_queue *q = bd->queue;
733
734 mutex_lock(&bsg_mutex);
735
736 do_free = atomic_dec_and_test(&bd->ref_count);
737 if (!do_free) {
738 mutex_unlock(&bsg_mutex);
739 goto out;
740 }
741
742 hlist_del(&bd->dev_list);
743 mutex_unlock(&bsg_mutex);
744
745 dprintk("%s: tearing down\n", bd->name);
746
747 /*
748 * close can always block
749 */
750 set_bit(BSG_F_BLOCK, &bd->flags);
751
752 /*
753 * correct error detection baddies here again. it's the responsibility
754 * of the app to properly reap commands before close() if it wants
755 * fool-proof error detection
756 */
757 ret = bsg_complete_all_commands(bd);
758
759 kfree(bd);
760out:
761 kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
762 if (do_free)
763 blk_put_queue(q);
764 return ret;
765}
766
767static struct bsg_device *bsg_add_device(struct inode *inode,
768 struct request_queue *rq,
769 struct file *file)
770{
771 struct bsg_device *bd;
772#ifdef BSG_DEBUG
773 unsigned char buf[32];
774#endif
775 if (!blk_get_queue(rq))
776 return ERR_PTR(-ENXIO);
777
778 bd = bsg_alloc_device();
779 if (!bd) {
780 blk_put_queue(rq);
781 return ERR_PTR(-ENOMEM);
782 }
783
784 bd->queue = rq;
785
786 bsg_set_block(bd, file);
787
788 atomic_set(&bd->ref_count, 1);
789 mutex_lock(&bsg_mutex);
790 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
791
792 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
793 dprintk("bound to <%s>, max queue %d\n",
794 format_dev_t(buf, inode->i_rdev), bd->max_queue);
795
796 mutex_unlock(&bsg_mutex);
797 return bd;
798}
799
800static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
801{
802 struct bsg_device *bd;
803
804 mutex_lock(&bsg_mutex);
805
806 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
807 if (bd->queue == q) {
808 atomic_inc(&bd->ref_count);
809 goto found;
810 }
811 }
812 bd = NULL;
813found:
814 mutex_unlock(&bsg_mutex);
815 return bd;
816}
817
818static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
819{
820 struct bsg_device *bd;
821 struct bsg_class_device *bcd;
822
823 /*
824 * find the class device
825 */
826 mutex_lock(&bsg_mutex);
827 bcd = idr_find(&bsg_minor_idr, iminor(inode));
828 if (bcd)
829 kref_get(&bcd->ref);
830 mutex_unlock(&bsg_mutex);
831
832 if (!bcd)
833 return ERR_PTR(-ENODEV);
834
835 bd = __bsg_get_device(iminor(inode), bcd->queue);
836 if (bd)
837 return bd;
838
839 bd = bsg_add_device(inode, bcd->queue, file);
840 if (IS_ERR(bd))
841 kref_put(&bcd->ref, bsg_kref_release_function);
842
843 return bd;
844}
845
846static int bsg_open(struct inode *inode, struct file *file)
847{
848 struct bsg_device *bd;
849
850 bd = bsg_get_device(inode, file);
851
852 if (IS_ERR(bd))
853 return PTR_ERR(bd);
854
855 file->private_data = bd;
856 return 0;
857}
858
859static int bsg_release(struct inode *inode, struct file *file)
860{
861 struct bsg_device *bd = file->private_data;
862
863 file->private_data = NULL;
864 return bsg_put_device(bd);
865}
866
867static unsigned int bsg_poll(struct file *file, poll_table *wait)
868{
869 struct bsg_device *bd = file->private_data;
870 unsigned int mask = 0;
871
872 poll_wait(file, &bd->wq_done, wait);
873 poll_wait(file, &bd->wq_free, wait);
874
875 spin_lock_irq(&bd->lock);
876 if (!list_empty(&bd->done_list))
877 mask |= POLLIN | POLLRDNORM;
878 if (bd->queued_cmds < bd->max_queue)
879 mask |= POLLOUT;
880 spin_unlock_irq(&bd->lock);
881
882 return mask;
883}
884
885static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
886{
887 struct bsg_device *bd = file->private_data;
888 int __user *uarg = (int __user *) arg;
889 int ret;
890
891 switch (cmd) {
892 /*
893 * our own ioctls
894 */
895 case SG_GET_COMMAND_Q:
896 return put_user(bd->max_queue, uarg);
897 case SG_SET_COMMAND_Q: {
898 int queue;
899
900 if (get_user(queue, uarg))
901 return -EFAULT;
902 if (queue < 1)
903 return -EINVAL;
904
905 spin_lock_irq(&bd->lock);
906 bd->max_queue = queue;
907 spin_unlock_irq(&bd->lock);
908 return 0;
909 }
910
911 /*
912 * SCSI/sg ioctls
913 */
914 case SG_GET_VERSION_NUM:
915 case SCSI_IOCTL_GET_IDLUN:
916 case SCSI_IOCTL_GET_BUS_NUMBER:
917 case SG_SET_TIMEOUT:
918 case SG_GET_TIMEOUT:
919 case SG_GET_RESERVED_SIZE:
920 case SG_SET_RESERVED_SIZE:
921 case SG_EMULATED_HOST:
922 case SCSI_IOCTL_SEND_COMMAND: {
923 void __user *uarg = (void __user *) arg;
924 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
925 }
926 case SG_IO: {
927 struct request *rq;
928 struct bio *bio, *bidi_bio = NULL;
929 struct sg_io_v4 hdr;
930 int at_head;
931 u8 sense[SCSI_SENSE_BUFFERSIZE];
932
933 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
934 return -EFAULT;
935
936 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
937 if (IS_ERR(rq))
938 return PTR_ERR(rq);
939
940 bio = rq->bio;
941 if (rq->next_rq)
942 bidi_bio = rq->next_rq->bio;
943
944 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
945 blk_execute_rq(bd->queue, NULL, rq, at_head);
946 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
947
948 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
949 return -EFAULT;
950
951 return ret;
952 }
953 /*
954 * block device ioctls
955 */
956 default:
957#if 0
958 return ioctl_by_bdev(bd->bdev, cmd, arg);
959#else
960 return -ENOTTY;
961#endif
962 }
963}
964
965static const struct file_operations bsg_fops = {
966 .read = bsg_read,
967 .write = bsg_write,
968 .poll = bsg_poll,
969 .open = bsg_open,
970 .release = bsg_release,
971 .unlocked_ioctl = bsg_ioctl,
972 .owner = THIS_MODULE,
973 .llseek = default_llseek,
974};
975
976void bsg_unregister_queue(struct request_queue *q)
977{
978 struct bsg_class_device *bcd = &q->bsg_dev;
979
980 if (!bcd->class_dev)
981 return;
982
983 mutex_lock(&bsg_mutex);
984 idr_remove(&bsg_minor_idr, bcd->minor);
985 if (q->kobj.sd)
986 sysfs_remove_link(&q->kobj, "bsg");
987 device_unregister(bcd->class_dev);
988 bcd->class_dev = NULL;
989 kref_put(&bcd->ref, bsg_kref_release_function);
990 mutex_unlock(&bsg_mutex);
991}
992EXPORT_SYMBOL_GPL(bsg_unregister_queue);
993
994int bsg_register_queue(struct request_queue *q, struct device *parent,
995 const char *name, void (*release)(struct device *))
996{
997 struct bsg_class_device *bcd;
998 dev_t dev;
999 int ret;
1000 struct device *class_dev = NULL;
1001 const char *devname;
1002
1003 if (name)
1004 devname = name;
1005 else
1006 devname = dev_name(parent);
1007
1008 /*
1009 * we need a proper transport to send commands, not a stacked device
1010 */
1011 if (!q->request_fn)
1012 return 0;
1013
1014 bcd = &q->bsg_dev;
1015 memset(bcd, 0, sizeof(*bcd));
1016
1017 mutex_lock(&bsg_mutex);
1018
1019 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
1020 if (ret < 0) {
1021 if (ret == -ENOSPC) {
1022 printk(KERN_ERR "bsg: too many bsg devices\n");
1023 ret = -EINVAL;
1024 }
1025 goto unlock;
1026 }
1027
1028 bcd->minor = ret;
1029 bcd->queue = q;
1030 bcd->parent = get_device(parent);
1031 bcd->release = release;
1032 kref_init(&bcd->ref);
1033 dev = MKDEV(bsg_major, bcd->minor);
1034 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
1035 if (IS_ERR(class_dev)) {
1036 ret = PTR_ERR(class_dev);
1037 goto put_dev;
1038 }
1039 bcd->class_dev = class_dev;
1040
1041 if (q->kobj.sd) {
1042 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
1043 if (ret)
1044 goto unregister_class_dev;
1045 }
1046
1047 mutex_unlock(&bsg_mutex);
1048 return 0;
1049
1050unregister_class_dev:
1051 device_unregister(class_dev);
1052put_dev:
1053 put_device(parent);
1054 idr_remove(&bsg_minor_idr, bcd->minor);
1055unlock:
1056 mutex_unlock(&bsg_mutex);
1057 return ret;
1058}
1059EXPORT_SYMBOL_GPL(bsg_register_queue);
1060
1061static struct cdev bsg_cdev;
1062
1063static char *bsg_devnode(struct device *dev, umode_t *mode)
1064{
1065 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
1066}
1067
1068static int __init bsg_init(void)
1069{
1070 int ret, i;
1071 dev_t devid;
1072
1073 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
1074 sizeof(struct bsg_command), 0, 0, NULL);
1075 if (!bsg_cmd_cachep) {
1076 printk(KERN_ERR "bsg: failed creating slab cache\n");
1077 return -ENOMEM;
1078 }
1079
1080 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
1081 INIT_HLIST_HEAD(&bsg_device_list[i]);
1082
1083 bsg_class = class_create(THIS_MODULE, "bsg");
1084 if (IS_ERR(bsg_class)) {
1085 ret = PTR_ERR(bsg_class);
1086 goto destroy_kmemcache;
1087 }
1088 bsg_class->devnode = bsg_devnode;
1089
1090 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
1091 if (ret)
1092 goto destroy_bsg_class;
1093
1094 bsg_major = MAJOR(devid);
1095
1096 cdev_init(&bsg_cdev, &bsg_fops);
1097 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1098 if (ret)
1099 goto unregister_chrdev;
1100
1101 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
1102 " loaded (major %d)\n", bsg_major);
1103 return 0;
1104unregister_chrdev:
1105 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1106destroy_bsg_class:
1107 class_destroy(bsg_class);
1108destroy_kmemcache:
1109 kmem_cache_destroy(bsg_cmd_cachep);
1110 return ret;
1111}
1112
1113MODULE_AUTHOR("Jens Axboe");
1114MODULE_DESCRIPTION(BSG_DESCRIPTION);
1115MODULE_LICENSE("GPL");
1116
1117device_initcall(bsg_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * bsg.c - block layer implementation of the sg v4 interface
4 */
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/file.h>
8#include <linux/blkdev.h>
9#include <linux/cdev.h>
10#include <linux/jiffies.h>
11#include <linux/percpu.h>
12#include <linux/idr.h>
13#include <linux/bsg.h>
14#include <linux/slab.h>
15
16#include <scsi/scsi.h>
17#include <scsi/scsi_ioctl.h>
18#include <scsi/scsi_cmnd.h>
19#include <scsi/scsi_device.h>
20#include <scsi/scsi_driver.h>
21#include <scsi/sg.h>
22
23#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
24#define BSG_VERSION "0.4"
25
26#define bsg_dbg(bd, fmt, ...) \
27 pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
28
29struct bsg_device {
30 struct request_queue *queue;
31 spinlock_t lock;
32 struct hlist_node dev_list;
33 refcount_t ref_count;
34 char name[20];
35 int max_queue;
36};
37
38#define BSG_DEFAULT_CMDS 64
39#define BSG_MAX_DEVS 32768
40
41static DEFINE_MUTEX(bsg_mutex);
42static DEFINE_IDR(bsg_minor_idr);
43
44#define BSG_LIST_ARRAY_SIZE 8
45static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
46
47static struct class *bsg_class;
48static int bsg_major;
49
50static inline struct hlist_head *bsg_dev_idx_hash(int index)
51{
52 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
53}
54
55#define uptr64(val) ((void __user *)(uintptr_t)(val))
56
57static int bsg_scsi_check_proto(struct sg_io_v4 *hdr)
58{
59 if (hdr->protocol != BSG_PROTOCOL_SCSI ||
60 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
61 return -EINVAL;
62 return 0;
63}
64
65static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
66 fmode_t mode)
67{
68 struct scsi_request *sreq = scsi_req(rq);
69
70 if (hdr->dout_xfer_len && hdr->din_xfer_len) {
71 pr_warn_once("BIDI support in bsg has been removed.\n");
72 return -EOPNOTSUPP;
73 }
74
75 sreq->cmd_len = hdr->request_len;
76 if (sreq->cmd_len > BLK_MAX_CDB) {
77 sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
78 if (!sreq->cmd)
79 return -ENOMEM;
80 }
81
82 if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
83 return -EFAULT;
84 if (blk_verify_command(sreq->cmd, mode))
85 return -EPERM;
86 return 0;
87}
88
89static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
90{
91 struct scsi_request *sreq = scsi_req(rq);
92 int ret = 0;
93
94 /*
95 * fill in all the output members
96 */
97 hdr->device_status = sreq->result & 0xff;
98 hdr->transport_status = host_byte(sreq->result);
99 hdr->driver_status = driver_byte(sreq->result);
100 hdr->info = 0;
101 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
102 hdr->info |= SG_INFO_CHECK;
103 hdr->response_len = 0;
104
105 if (sreq->sense_len && hdr->response) {
106 int len = min_t(unsigned int, hdr->max_response_len,
107 sreq->sense_len);
108
109 if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
110 ret = -EFAULT;
111 else
112 hdr->response_len = len;
113 }
114
115 if (rq_data_dir(rq) == READ)
116 hdr->din_resid = sreq->resid_len;
117 else
118 hdr->dout_resid = sreq->resid_len;
119
120 return ret;
121}
122
123static void bsg_scsi_free_rq(struct request *rq)
124{
125 scsi_req_free_cmd(scsi_req(rq));
126}
127
128static const struct bsg_ops bsg_scsi_ops = {
129 .check_proto = bsg_scsi_check_proto,
130 .fill_hdr = bsg_scsi_fill_hdr,
131 .complete_rq = bsg_scsi_complete_rq,
132 .free_rq = bsg_scsi_free_rq,
133};
134
135static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
136{
137 struct request *rq;
138 struct bio *bio;
139 struct sg_io_v4 hdr;
140 int ret;
141
142 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
143 return -EFAULT;
144
145 if (!q->bsg_dev.class_dev)
146 return -ENXIO;
147
148 if (hdr.guard != 'Q')
149 return -EINVAL;
150 ret = q->bsg_dev.ops->check_proto(&hdr);
151 if (ret)
152 return ret;
153
154 rq = blk_get_request(q, hdr.dout_xfer_len ?
155 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
156 if (IS_ERR(rq))
157 return PTR_ERR(rq);
158
159 ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);
160 if (ret)
161 return ret;
162
163 rq->timeout = msecs_to_jiffies(hdr.timeout);
164 if (!rq->timeout)
165 rq->timeout = q->sg_timeout;
166 if (!rq->timeout)
167 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
168 if (rq->timeout < BLK_MIN_SG_TIMEOUT)
169 rq->timeout = BLK_MIN_SG_TIMEOUT;
170
171 if (hdr.dout_xfer_len) {
172 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),
173 hdr.dout_xfer_len, GFP_KERNEL);
174 } else if (hdr.din_xfer_len) {
175 ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.din_xferp),
176 hdr.din_xfer_len, GFP_KERNEL);
177 }
178
179 if (ret)
180 goto out_free_rq;
181
182 bio = rq->bio;
183
184 blk_execute_rq(q, NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
185 ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);
186 blk_rq_unmap_user(bio);
187
188out_free_rq:
189 rq->q->bsg_dev.ops->free_rq(rq);
190 blk_put_request(rq);
191 if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
192 return -EFAULT;
193 return ret;
194}
195
196static struct bsg_device *bsg_alloc_device(void)
197{
198 struct bsg_device *bd;
199
200 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
201 if (unlikely(!bd))
202 return NULL;
203
204 spin_lock_init(&bd->lock);
205 bd->max_queue = BSG_DEFAULT_CMDS;
206 INIT_HLIST_NODE(&bd->dev_list);
207 return bd;
208}
209
210static int bsg_put_device(struct bsg_device *bd)
211{
212 struct request_queue *q = bd->queue;
213
214 mutex_lock(&bsg_mutex);
215
216 if (!refcount_dec_and_test(&bd->ref_count)) {
217 mutex_unlock(&bsg_mutex);
218 return 0;
219 }
220
221 hlist_del(&bd->dev_list);
222 mutex_unlock(&bsg_mutex);
223
224 bsg_dbg(bd, "tearing down\n");
225
226 /*
227 * close can always block
228 */
229 kfree(bd);
230 blk_put_queue(q);
231 return 0;
232}
233
234static struct bsg_device *bsg_add_device(struct inode *inode,
235 struct request_queue *rq,
236 struct file *file)
237{
238 struct bsg_device *bd;
239 unsigned char buf[32];
240
241 lockdep_assert_held(&bsg_mutex);
242
243 if (!blk_get_queue(rq))
244 return ERR_PTR(-ENXIO);
245
246 bd = bsg_alloc_device();
247 if (!bd) {
248 blk_put_queue(rq);
249 return ERR_PTR(-ENOMEM);
250 }
251
252 bd->queue = rq;
253
254 refcount_set(&bd->ref_count, 1);
255 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
256
257 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
258 bsg_dbg(bd, "bound to <%s>, max queue %d\n",
259 format_dev_t(buf, inode->i_rdev), bd->max_queue);
260
261 return bd;
262}
263
264static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
265{
266 struct bsg_device *bd;
267
268 lockdep_assert_held(&bsg_mutex);
269
270 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
271 if (bd->queue == q) {
272 refcount_inc(&bd->ref_count);
273 goto found;
274 }
275 }
276 bd = NULL;
277found:
278 return bd;
279}
280
281static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
282{
283 struct bsg_device *bd;
284 struct bsg_class_device *bcd;
285
286 /*
287 * find the class device
288 */
289 mutex_lock(&bsg_mutex);
290 bcd = idr_find(&bsg_minor_idr, iminor(inode));
291
292 if (!bcd) {
293 bd = ERR_PTR(-ENODEV);
294 goto out_unlock;
295 }
296
297 bd = __bsg_get_device(iminor(inode), bcd->queue);
298 if (!bd)
299 bd = bsg_add_device(inode, bcd->queue, file);
300
301out_unlock:
302 mutex_unlock(&bsg_mutex);
303 return bd;
304}
305
306static int bsg_open(struct inode *inode, struct file *file)
307{
308 struct bsg_device *bd;
309
310 bd = bsg_get_device(inode, file);
311
312 if (IS_ERR(bd))
313 return PTR_ERR(bd);
314
315 file->private_data = bd;
316 return 0;
317}
318
319static int bsg_release(struct inode *inode, struct file *file)
320{
321 struct bsg_device *bd = file->private_data;
322
323 file->private_data = NULL;
324 return bsg_put_device(bd);
325}
326
327static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
328{
329 return put_user(bd->max_queue, uarg);
330}
331
332static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
333{
334 int queue;
335
336 if (get_user(queue, uarg))
337 return -EFAULT;
338 if (queue < 1)
339 return -EINVAL;
340
341 spin_lock_irq(&bd->lock);
342 bd->max_queue = queue;
343 spin_unlock_irq(&bd->lock);
344 return 0;
345}
346
347static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
348{
349 struct bsg_device *bd = file->private_data;
350 void __user *uarg = (void __user *) arg;
351
352 switch (cmd) {
353 /*
354 * Our own ioctls
355 */
356 case SG_GET_COMMAND_Q:
357 return bsg_get_command_q(bd, uarg);
358 case SG_SET_COMMAND_Q:
359 return bsg_set_command_q(bd, uarg);
360
361 /*
362 * SCSI/sg ioctls
363 */
364 case SG_GET_VERSION_NUM:
365 case SCSI_IOCTL_GET_IDLUN:
366 case SCSI_IOCTL_GET_BUS_NUMBER:
367 case SG_SET_TIMEOUT:
368 case SG_GET_TIMEOUT:
369 case SG_GET_RESERVED_SIZE:
370 case SG_SET_RESERVED_SIZE:
371 case SG_EMULATED_HOST:
372 case SCSI_IOCTL_SEND_COMMAND:
373 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
374 case SG_IO:
375 return bsg_sg_io(bd->queue, file->f_mode, uarg);
376 default:
377 return -ENOTTY;
378 }
379}
380
381static const struct file_operations bsg_fops = {
382 .open = bsg_open,
383 .release = bsg_release,
384 .unlocked_ioctl = bsg_ioctl,
385 .compat_ioctl = compat_ptr_ioctl,
386 .owner = THIS_MODULE,
387 .llseek = default_llseek,
388};
389
390void bsg_unregister_queue(struct request_queue *q)
391{
392 struct bsg_class_device *bcd = &q->bsg_dev;
393
394 if (!bcd->class_dev)
395 return;
396
397 mutex_lock(&bsg_mutex);
398 idr_remove(&bsg_minor_idr, bcd->minor);
399 if (q->kobj.sd)
400 sysfs_remove_link(&q->kobj, "bsg");
401 device_unregister(bcd->class_dev);
402 bcd->class_dev = NULL;
403 mutex_unlock(&bsg_mutex);
404}
405EXPORT_SYMBOL_GPL(bsg_unregister_queue);
406
407int bsg_register_queue(struct request_queue *q, struct device *parent,
408 const char *name, const struct bsg_ops *ops)
409{
410 struct bsg_class_device *bcd;
411 dev_t dev;
412 int ret;
413 struct device *class_dev = NULL;
414
415 /*
416 * we need a proper transport to send commands, not a stacked device
417 */
418 if (!queue_is_mq(q))
419 return 0;
420
421 bcd = &q->bsg_dev;
422 memset(bcd, 0, sizeof(*bcd));
423
424 mutex_lock(&bsg_mutex);
425
426 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
427 if (ret < 0) {
428 if (ret == -ENOSPC) {
429 printk(KERN_ERR "bsg: too many bsg devices\n");
430 ret = -EINVAL;
431 }
432 goto unlock;
433 }
434
435 bcd->minor = ret;
436 bcd->queue = q;
437 bcd->ops = ops;
438 dev = MKDEV(bsg_major, bcd->minor);
439 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name);
440 if (IS_ERR(class_dev)) {
441 ret = PTR_ERR(class_dev);
442 goto idr_remove;
443 }
444 bcd->class_dev = class_dev;
445
446 if (q->kobj.sd) {
447 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
448 if (ret)
449 goto unregister_class_dev;
450 }
451
452 mutex_unlock(&bsg_mutex);
453 return 0;
454
455unregister_class_dev:
456 device_unregister(class_dev);
457idr_remove:
458 idr_remove(&bsg_minor_idr, bcd->minor);
459unlock:
460 mutex_unlock(&bsg_mutex);
461 return ret;
462}
463
464int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
465{
466 if (!blk_queue_scsi_passthrough(q)) {
467 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
468 return -EINVAL;
469 }
470
471 return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops);
472}
473EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);
474
475static struct cdev bsg_cdev;
476
477static char *bsg_devnode(struct device *dev, umode_t *mode)
478{
479 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
480}
481
482static int __init bsg_init(void)
483{
484 int ret, i;
485 dev_t devid;
486
487 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
488 INIT_HLIST_HEAD(&bsg_device_list[i]);
489
490 bsg_class = class_create(THIS_MODULE, "bsg");
491 if (IS_ERR(bsg_class))
492 return PTR_ERR(bsg_class);
493 bsg_class->devnode = bsg_devnode;
494
495 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
496 if (ret)
497 goto destroy_bsg_class;
498
499 bsg_major = MAJOR(devid);
500
501 cdev_init(&bsg_cdev, &bsg_fops);
502 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
503 if (ret)
504 goto unregister_chrdev;
505
506 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
507 " loaded (major %d)\n", bsg_major);
508 return 0;
509unregister_chrdev:
510 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
511destroy_bsg_class:
512 class_destroy(bsg_class);
513 return ret;
514}
515
516MODULE_AUTHOR("Jens Axboe");
517MODULE_DESCRIPTION(BSG_DESCRIPTION);
518MODULE_LICENSE("GPL");
519
520device_initcall(bsg_init);