x86: fix virt_addr_valid() with CONFIG_DEBUG_VIRTUAL=y, v2
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / block / bsg.c
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/percpu.h>
19 #include <linux/uio.h>
20 #include <linux/idr.h>
21 #include <linux/bsg.h>
22 #include <linux/smp_lock.h>
23
24 #include <scsi/scsi.h>
25 #include <scsi/scsi_ioctl.h>
26 #include <scsi/scsi_cmnd.h>
27 #include <scsi/scsi_device.h>
28 #include <scsi/scsi_driver.h>
29 #include <scsi/sg.h>
30
31 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
32 #define BSG_VERSION "0.4"
33
34 struct bsg_device {
35 struct request_queue *queue;
36 spinlock_t lock;
37 struct list_head busy_list;
38 struct list_head done_list;
39 struct hlist_node dev_list;
40 atomic_t ref_count;
41 int queued_cmds;
42 int done_cmds;
43 wait_queue_head_t wq_done;
44 wait_queue_head_t wq_free;
45 char name[BUS_ID_SIZE];
46 int max_queue;
47 unsigned long flags;
48 };
49
50 enum {
51 BSG_F_BLOCK = 1,
52 };
53
54 #define BSG_DEFAULT_CMDS 64
55 #define BSG_MAX_DEVS 32768
56
57 #undef BSG_DEBUG
58
59 #ifdef BSG_DEBUG
60 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args)
61 #else
62 #define dprintk(fmt, args...)
63 #endif
64
65 static DEFINE_MUTEX(bsg_mutex);
66 static DEFINE_IDR(bsg_minor_idr);
67
68 #define BSG_LIST_ARRAY_SIZE 8
69 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
70
71 static struct class *bsg_class;
72 static int bsg_major;
73
74 static struct kmem_cache *bsg_cmd_cachep;
75
76 /*
77 * our internal command type
78 */
79 struct bsg_command {
80 struct bsg_device *bd;
81 struct list_head list;
82 struct request *rq;
83 struct bio *bio;
84 struct bio *bidi_bio;
85 int err;
86 struct sg_io_v4 hdr;
87 char sense[SCSI_SENSE_BUFFERSIZE];
88 };
89
90 static void bsg_free_command(struct bsg_command *bc)
91 {
92 struct bsg_device *bd = bc->bd;
93 unsigned long flags;
94
95 kmem_cache_free(bsg_cmd_cachep, bc);
96
97 spin_lock_irqsave(&bd->lock, flags);
98 bd->queued_cmds--;
99 spin_unlock_irqrestore(&bd->lock, flags);
100
101 wake_up(&bd->wq_free);
102 }
103
104 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
105 {
106 struct bsg_command *bc = ERR_PTR(-EINVAL);
107
108 spin_lock_irq(&bd->lock);
109
110 if (bd->queued_cmds >= bd->max_queue)
111 goto out;
112
113 bd->queued_cmds++;
114 spin_unlock_irq(&bd->lock);
115
116 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
117 if (unlikely(!bc)) {
118 spin_lock_irq(&bd->lock);
119 bd->queued_cmds--;
120 bc = ERR_PTR(-ENOMEM);
121 goto out;
122 }
123
124 bc->bd = bd;
125 INIT_LIST_HEAD(&bc->list);
126 dprintk("%s: returning free cmd %p\n", bd->name, bc);
127 return bc;
128 out:
129 spin_unlock_irq(&bd->lock);
130 return bc;
131 }
132
133 static inline struct hlist_head *bsg_dev_idx_hash(int index)
134 {
135 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
136 }
137
138 static int bsg_io_schedule(struct bsg_device *bd)
139 {
140 DEFINE_WAIT(wait);
141 int ret = 0;
142
143 spin_lock_irq(&bd->lock);
144
145 BUG_ON(bd->done_cmds > bd->queued_cmds);
146
147 /*
148 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no
149 * work to do", even though we return -ENOSPC after this same test
150 * during bsg_write() -- there, it means our buffer can't have more
151 * bsg_commands added to it, thus has no space left.
152 */
153 if (bd->done_cmds == bd->queued_cmds) {
154 ret = -ENODATA;
155 goto unlock;
156 }
157
158 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
159 ret = -EAGAIN;
160 goto unlock;
161 }
162
163 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE);
164 spin_unlock_irq(&bd->lock);
165 io_schedule();
166 finish_wait(&bd->wq_done, &wait);
167
168 return ret;
169 unlock:
170 spin_unlock_irq(&bd->lock);
171 return ret;
172 }
173
174 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
175 struct sg_io_v4 *hdr, struct bsg_device *bd,
176 int has_write_perm)
177 {
178 if (hdr->request_len > BLK_MAX_CDB) {
179 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
180 if (!rq->cmd)
181 return -ENOMEM;
182 }
183
184 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
185 hdr->request_len))
186 return -EFAULT;
187
188 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
189 if (blk_verify_command(&q->cmd_filter, rq->cmd, has_write_perm))
190 return -EPERM;
191 } else if (!capable(CAP_SYS_RAWIO))
192 return -EPERM;
193
194 /*
195 * fill in request structure
196 */
197 rq->cmd_len = hdr->request_len;
198 rq->cmd_type = REQ_TYPE_BLOCK_PC;
199
200 rq->timeout = (hdr->timeout * HZ) / 1000;
201 if (!rq->timeout)
202 rq->timeout = q->sg_timeout;
203 if (!rq->timeout)
204 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
205
206 return 0;
207 }
208
209 /*
210 * Check if sg_io_v4 from user is allowed and valid
211 */
212 static int
213 bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
214 {
215 int ret = 0;
216
217 if (hdr->guard != 'Q')
218 return -EINVAL;
219 if (hdr->dout_xfer_len > (q->max_sectors << 9) ||
220 hdr->din_xfer_len > (q->max_sectors << 9))
221 return -EIO;
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 */
244 static struct request *
245 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, int has_write_perm)
246 {
247 struct request_queue *q = bd->queue;
248 struct request *rq, *next_rq = NULL;
249 int ret, rw;
250 unsigned int dxfer_len;
251 void *dxferp = NULL;
252
253 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
254 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
255 hdr->din_xfer_len);
256
257 ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
258 if (ret)
259 return ERR_PTR(ret);
260
261 /*
262 * map scatter-gather elements seperately and string them to request
263 */
264 rq = blk_get_request(q, rw, GFP_KERNEL);
265 if (!rq)
266 return ERR_PTR(-ENOMEM);
267 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
268 if (ret)
269 goto out;
270
271 if (rw == WRITE && hdr->din_xfer_len) {
272 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
273 ret = -EOPNOTSUPP;
274 goto out;
275 }
276
277 next_rq = blk_get_request(q, READ, GFP_KERNEL);
278 if (!next_rq) {
279 ret = -ENOMEM;
280 goto out;
281 }
282 rq->next_rq = next_rq;
283 next_rq->cmd_type = rq->cmd_type;
284
285 dxferp = (void*)(unsigned long)hdr->din_xferp;
286 ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
287 hdr->din_xfer_len, GFP_KERNEL);
288 if (ret)
289 goto out;
290 }
291
292 if (hdr->dout_xfer_len) {
293 dxfer_len = hdr->dout_xfer_len;
294 dxferp = (void*)(unsigned long)hdr->dout_xferp;
295 } else if (hdr->din_xfer_len) {
296 dxfer_len = hdr->din_xfer_len;
297 dxferp = (void*)(unsigned long)hdr->din_xferp;
298 } else
299 dxfer_len = 0;
300
301 if (dxfer_len) {
302 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
303 GFP_KERNEL);
304 if (ret)
305 goto out;
306 }
307 return rq;
308 out:
309 if (rq->cmd != rq->__cmd)
310 kfree(rq->cmd);
311 blk_put_request(rq);
312 if (next_rq) {
313 blk_rq_unmap_user(next_rq->bio);
314 blk_put_request(next_rq);
315 }
316 return ERR_PTR(ret);
317 }
318
319 /*
320 * async completion call-back from the block layer, when scsi/ide/whatever
321 * calls end_that_request_last() on a request
322 */
323 static void bsg_rq_end_io(struct request *rq, int uptodate)
324 {
325 struct bsg_command *bc = rq->end_io_data;
326 struct bsg_device *bd = bc->bd;
327 unsigned long flags;
328
329 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
330 bd->name, rq, bc, bc->bio, uptodate);
331
332 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
333
334 spin_lock_irqsave(&bd->lock, flags);
335 list_move_tail(&bc->list, &bd->done_list);
336 bd->done_cmds++;
337 spin_unlock_irqrestore(&bd->lock, flags);
338
339 wake_up(&bd->wq_done);
340 }
341
342 /*
343 * do final setup of a 'bc' and submit the matching 'rq' to the block
344 * layer for io
345 */
346 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
347 struct bsg_command *bc, struct request *rq)
348 {
349 rq->sense = bc->sense;
350 rq->sense_len = 0;
351
352 /*
353 * add bc command to busy queue and submit rq for io
354 */
355 bc->rq = rq;
356 bc->bio = rq->bio;
357 if (rq->next_rq)
358 bc->bidi_bio = rq->next_rq->bio;
359 bc->hdr.duration = jiffies;
360 spin_lock_irq(&bd->lock);
361 list_add_tail(&bc->list, &bd->busy_list);
362 spin_unlock_irq(&bd->lock);
363
364 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
365
366 rq->end_io_data = bc;
367 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io);
368 }
369
370 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
371 {
372 struct bsg_command *bc = NULL;
373
374 spin_lock_irq(&bd->lock);
375 if (bd->done_cmds) {
376 bc = list_first_entry(&bd->done_list, struct bsg_command, list);
377 list_del(&bc->list);
378 bd->done_cmds--;
379 }
380 spin_unlock_irq(&bd->lock);
381
382 return bc;
383 }
384
385 /*
386 * Get a finished command from the done list
387 */
388 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
389 {
390 struct bsg_command *bc;
391 int ret;
392
393 do {
394 bc = bsg_next_done_cmd(bd);
395 if (bc)
396 break;
397
398 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
399 bc = ERR_PTR(-EAGAIN);
400 break;
401 }
402
403 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
404 if (ret) {
405 bc = ERR_PTR(-ERESTARTSYS);
406 break;
407 }
408 } while (1);
409
410 dprintk("%s: returning done %p\n", bd->name, bc);
411
412 return bc;
413 }
414
415 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
416 struct bio *bio, struct bio *bidi_bio)
417 {
418 int ret = 0;
419
420 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors);
421 /*
422 * fill in all the output members
423 */
424 hdr->device_status = status_byte(rq->errors);
425 hdr->transport_status = host_byte(rq->errors);
426 hdr->driver_status = driver_byte(rq->errors);
427 hdr->info = 0;
428 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
429 hdr->info |= SG_INFO_CHECK;
430 hdr->response_len = 0;
431
432 if (rq->sense_len && hdr->response) {
433 int len = min_t(unsigned int, hdr->max_response_len,
434 rq->sense_len);
435
436 ret = copy_to_user((void*)(unsigned long)hdr->response,
437 rq->sense, len);
438 if (!ret)
439 hdr->response_len = len;
440 else
441 ret = -EFAULT;
442 }
443
444 if (rq->next_rq) {
445 hdr->dout_resid = rq->data_len;
446 hdr->din_resid = rq->next_rq->data_len;
447 blk_rq_unmap_user(bidi_bio);
448 blk_put_request(rq->next_rq);
449 } else if (rq_data_dir(rq) == READ)
450 hdr->din_resid = rq->data_len;
451 else
452 hdr->dout_resid = rq->data_len;
453
454 /*
455 * If the request generated a negative error number, return it
456 * (providing we aren't already returning an error); if it's
457 * just a protocol response (i.e. non negative), that gets
458 * processed above.
459 */
460 if (!ret && rq->errors < 0)
461 ret = rq->errors;
462
463 blk_rq_unmap_user(bio);
464 if (rq->cmd != rq->__cmd)
465 kfree(rq->cmd);
466 blk_put_request(rq);
467
468 return ret;
469 }
470
471 static int bsg_complete_all_commands(struct bsg_device *bd)
472 {
473 struct bsg_command *bc;
474 int ret, tret;
475
476 dprintk("%s: entered\n", bd->name);
477
478 /*
479 * wait for all commands to complete
480 */
481 ret = 0;
482 do {
483 ret = bsg_io_schedule(bd);
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 spin_lock_irq(&bd->lock);
499 if (!bd->queued_cmds) {
500 spin_unlock_irq(&bd->lock);
501 break;
502 }
503 spin_unlock_irq(&bd->lock);
504
505 bc = bsg_get_done_cmd(bd);
506 if (IS_ERR(bc))
507 break;
508
509 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
510 bc->bidi_bio);
511 if (!ret)
512 ret = tret;
513
514 bsg_free_command(bc);
515 } while (1);
516
517 return ret;
518 }
519
520 static int
521 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
522 const struct iovec *iov, ssize_t *bytes_read)
523 {
524 struct bsg_command *bc;
525 int nr_commands, ret;
526
527 if (count % sizeof(struct sg_io_v4))
528 return -EINVAL;
529
530 ret = 0;
531 nr_commands = count / sizeof(struct sg_io_v4);
532 while (nr_commands) {
533 bc = bsg_get_done_cmd(bd);
534 if (IS_ERR(bc)) {
535 ret = PTR_ERR(bc);
536 break;
537 }
538
539 /*
540 * this is the only case where we need to copy data back
541 * after completing the request. so do that here,
542 * bsg_complete_work() cannot do that for us
543 */
544 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
545 bc->bidi_bio);
546
547 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
548 ret = -EFAULT;
549
550 bsg_free_command(bc);
551
552 if (ret)
553 break;
554
555 buf += sizeof(struct sg_io_v4);
556 *bytes_read += sizeof(struct sg_io_v4);
557 nr_commands--;
558 }
559
560 return ret;
561 }
562
563 static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
564 {
565 if (file->f_flags & O_NONBLOCK)
566 clear_bit(BSG_F_BLOCK, &bd->flags);
567 else
568 set_bit(BSG_F_BLOCK, &bd->flags);
569 }
570
571 /*
572 * Check if the error is a "real" error that we should return.
573 */
574 static inline int err_block_err(int ret)
575 {
576 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
577 return 1;
578
579 return 0;
580 }
581
582 static ssize_t
583 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
584 {
585 struct bsg_device *bd = file->private_data;
586 int ret;
587 ssize_t bytes_read;
588
589 dprintk("%s: read %Zd bytes\n", bd->name, count);
590
591 bsg_set_block(bd, file);
592
593 bytes_read = 0;
594 ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
595 *ppos = bytes_read;
596
597 if (!bytes_read || (bytes_read && err_block_err(ret)))
598 bytes_read = ret;
599
600 return bytes_read;
601 }
602
603 static int __bsg_write(struct bsg_device *bd, const char __user *buf,
604 size_t count, ssize_t *bytes_written, int has_write_perm)
605 {
606 struct bsg_command *bc;
607 struct request *rq;
608 int ret, nr_commands;
609
610 if (count % sizeof(struct sg_io_v4))
611 return -EINVAL;
612
613 nr_commands = count / sizeof(struct sg_io_v4);
614 rq = NULL;
615 bc = NULL;
616 ret = 0;
617 while (nr_commands) {
618 struct request_queue *q = bd->queue;
619
620 bc = bsg_alloc_command(bd);
621 if (IS_ERR(bc)) {
622 ret = PTR_ERR(bc);
623 bc = NULL;
624 break;
625 }
626
627 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
628 ret = -EFAULT;
629 break;
630 }
631
632 /*
633 * get a request, fill in the blanks, and add to request queue
634 */
635 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm);
636 if (IS_ERR(rq)) {
637 ret = PTR_ERR(rq);
638 rq = NULL;
639 break;
640 }
641
642 bsg_add_command(bd, q, bc, rq);
643 bc = NULL;
644 rq = NULL;
645 nr_commands--;
646 buf += sizeof(struct sg_io_v4);
647 *bytes_written += sizeof(struct sg_io_v4);
648 }
649
650 if (bc)
651 bsg_free_command(bc);
652
653 return ret;
654 }
655
656 static ssize_t
657 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
658 {
659 struct bsg_device *bd = file->private_data;
660 ssize_t bytes_written;
661 int ret;
662
663 dprintk("%s: write %Zd bytes\n", bd->name, count);
664
665 bsg_set_block(bd, file);
666
667 bytes_written = 0;
668 ret = __bsg_write(bd, buf, count, &bytes_written,
669 file->f_mode & FMODE_WRITE);
670
671 *ppos = bytes_written;
672
673 /*
674 * return bytes written on non-fatal errors
675 */
676 if (!bytes_written || (bytes_written && err_block_err(ret)))
677 bytes_written = ret;
678
679 dprintk("%s: returning %Zd\n", bd->name, bytes_written);
680 return bytes_written;
681 }
682
683 static struct bsg_device *bsg_alloc_device(void)
684 {
685 struct bsg_device *bd;
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
693 bd->max_queue = BSG_DEFAULT_CMDS;
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;
702 }
703
704 static void bsg_kref_release_function(struct kref *kref)
705 {
706 struct bsg_class_device *bcd =
707 container_of(kref, struct bsg_class_device, ref);
708 struct device *parent = bcd->parent;
709
710 if (bcd->release)
711 bcd->release(bcd->parent);
712
713 put_device(parent);
714 }
715
716 static int bsg_put_device(struct bsg_device *bd)
717 {
718 int ret = 0, do_free;
719 struct request_queue *q = bd->queue;
720
721 mutex_lock(&bsg_mutex);
722
723 do_free = atomic_dec_and_test(&bd->ref_count);
724 if (!do_free) {
725 mutex_unlock(&bsg_mutex);
726 goto out;
727 }
728
729 hlist_del(&bd->dev_list);
730 mutex_unlock(&bsg_mutex);
731
732 dprintk("%s: tearing down\n", bd->name);
733
734 /*
735 * close can always block
736 */
737 set_bit(BSG_F_BLOCK, &bd->flags);
738
739 /*
740 * correct error detection baddies here again. it's the responsibility
741 * of the app to properly reap commands before close() if it wants
742 * fool-proof error detection
743 */
744 ret = bsg_complete_all_commands(bd);
745
746 kfree(bd);
747 out:
748 kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
749 if (do_free)
750 blk_put_queue(q);
751 return ret;
752 }
753
754 static struct bsg_device *bsg_add_device(struct inode *inode,
755 struct request_queue *rq,
756 struct file *file)
757 {
758 struct bsg_device *bd;
759 int ret;
760 #ifdef BSG_DEBUG
761 unsigned char buf[32];
762 #endif
763 ret = blk_get_queue(rq);
764 if (ret)
765 return ERR_PTR(-ENXIO);
766
767 bd = bsg_alloc_device();
768 if (!bd) {
769 blk_put_queue(rq);
770 return ERR_PTR(-ENOMEM);
771 }
772
773 bd->queue = rq;
774
775 bsg_set_block(bd, file);
776
777 atomic_set(&bd->ref_count, 1);
778 mutex_lock(&bsg_mutex);
779 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
780
781 strncpy(bd->name, rq->bsg_dev.class_dev->bus_id, sizeof(bd->name) - 1);
782 dprintk("bound to <%s>, max queue %d\n",
783 format_dev_t(buf, inode->i_rdev), bd->max_queue);
784
785 mutex_unlock(&bsg_mutex);
786 return bd;
787 }
788
789 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
790 {
791 struct bsg_device *bd;
792 struct hlist_node *entry;
793
794 mutex_lock(&bsg_mutex);
795
796 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) {
797 if (bd->queue == q) {
798 atomic_inc(&bd->ref_count);
799 goto found;
800 }
801 }
802 bd = NULL;
803 found:
804 mutex_unlock(&bsg_mutex);
805 return bd;
806 }
807
808 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
809 {
810 struct bsg_device *bd;
811 struct bsg_class_device *bcd;
812
813 /*
814 * find the class device
815 */
816 mutex_lock(&bsg_mutex);
817 bcd = idr_find(&bsg_minor_idr, iminor(inode));
818 if (bcd)
819 kref_get(&bcd->ref);
820 mutex_unlock(&bsg_mutex);
821
822 if (!bcd)
823 return ERR_PTR(-ENODEV);
824
825 bd = __bsg_get_device(iminor(inode), bcd->queue);
826 if (bd)
827 return bd;
828
829 bd = bsg_add_device(inode, bcd->queue, file);
830 if (IS_ERR(bd))
831 kref_put(&bcd->ref, bsg_kref_release_function);
832
833 return bd;
834 }
835
836 static int bsg_open(struct inode *inode, struct file *file)
837 {
838 struct bsg_device *bd;
839
840 lock_kernel();
841 bd = bsg_get_device(inode, file);
842 unlock_kernel();
843
844 if (IS_ERR(bd))
845 return PTR_ERR(bd);
846
847 file->private_data = bd;
848 return 0;
849 }
850
851 static int bsg_release(struct inode *inode, struct file *file)
852 {
853 struct bsg_device *bd = file->private_data;
854
855 file->private_data = NULL;
856 return bsg_put_device(bd);
857 }
858
859 static unsigned int bsg_poll(struct file *file, poll_table *wait)
860 {
861 struct bsg_device *bd = file->private_data;
862 unsigned int mask = 0;
863
864 poll_wait(file, &bd->wq_done, wait);
865 poll_wait(file, &bd->wq_free, wait);
866
867 spin_lock_irq(&bd->lock);
868 if (!list_empty(&bd->done_list))
869 mask |= POLLIN | POLLRDNORM;
870 if (bd->queued_cmds >= bd->max_queue)
871 mask |= POLLOUT;
872 spin_unlock_irq(&bd->lock);
873
874 return mask;
875 }
876
877 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
878 {
879 struct bsg_device *bd = file->private_data;
880 int __user *uarg = (int __user *) arg;
881 int ret;
882
883 switch (cmd) {
884 /*
885 * our own ioctls
886 */
887 case SG_GET_COMMAND_Q:
888 return put_user(bd->max_queue, uarg);
889 case SG_SET_COMMAND_Q: {
890 int queue;
891
892 if (get_user(queue, uarg))
893 return -EFAULT;
894 if (queue < 1)
895 return -EINVAL;
896
897 spin_lock_irq(&bd->lock);
898 bd->max_queue = queue;
899 spin_unlock_irq(&bd->lock);
900 return 0;
901 }
902
903 /*
904 * SCSI/sg ioctls
905 */
906 case SG_GET_VERSION_NUM:
907 case SCSI_IOCTL_GET_IDLUN:
908 case SCSI_IOCTL_GET_BUS_NUMBER:
909 case SG_SET_TIMEOUT:
910 case SG_GET_TIMEOUT:
911 case SG_GET_RESERVED_SIZE:
912 case SG_SET_RESERVED_SIZE:
913 case SG_EMULATED_HOST:
914 case SCSI_IOCTL_SEND_COMMAND: {
915 void __user *uarg = (void __user *) arg;
916 return scsi_cmd_ioctl(file, bd->queue, NULL, cmd, uarg);
917 }
918 case SG_IO: {
919 struct request *rq;
920 struct bio *bio, *bidi_bio = NULL;
921 struct sg_io_v4 hdr;
922
923 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
924 return -EFAULT;
925
926 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE);
927 if (IS_ERR(rq))
928 return PTR_ERR(rq);
929
930 bio = rq->bio;
931 if (rq->next_rq)
932 bidi_bio = rq->next_rq->bio;
933 blk_execute_rq(bd->queue, NULL, rq, 0);
934 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
935
936 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
937 return -EFAULT;
938
939 return ret;
940 }
941 /*
942 * block device ioctls
943 */
944 default:
945 #if 0
946 return ioctl_by_bdev(bd->bdev, cmd, arg);
947 #else
948 return -ENOTTY;
949 #endif
950 }
951 }
952
953 static const struct file_operations bsg_fops = {
954 .read = bsg_read,
955 .write = bsg_write,
956 .poll = bsg_poll,
957 .open = bsg_open,
958 .release = bsg_release,
959 .unlocked_ioctl = bsg_ioctl,
960 .owner = THIS_MODULE,
961 };
962
963 void bsg_unregister_queue(struct request_queue *q)
964 {
965 struct bsg_class_device *bcd = &q->bsg_dev;
966
967 if (!bcd->class_dev)
968 return;
969
970 mutex_lock(&bsg_mutex);
971 idr_remove(&bsg_minor_idr, bcd->minor);
972 sysfs_remove_link(&q->kobj, "bsg");
973 device_unregister(bcd->class_dev);
974 bcd->class_dev = NULL;
975 kref_put(&bcd->ref, bsg_kref_release_function);
976 mutex_unlock(&bsg_mutex);
977 }
978 EXPORT_SYMBOL_GPL(bsg_unregister_queue);
979
980 int bsg_register_queue(struct request_queue *q, struct device *parent,
981 const char *name, void (*release)(struct device *))
982 {
983 struct bsg_class_device *bcd;
984 dev_t dev;
985 int ret, minor;
986 struct device *class_dev = NULL;
987 const char *devname;
988
989 if (name)
990 devname = name;
991 else
992 devname = parent->bus_id;
993
994 /*
995 * we need a proper transport to send commands, not a stacked device
996 */
997 if (!q->request_fn)
998 return 0;
999
1000 bcd = &q->bsg_dev;
1001 memset(bcd, 0, sizeof(*bcd));
1002
1003 mutex_lock(&bsg_mutex);
1004
1005 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL);
1006 if (!ret) {
1007 ret = -ENOMEM;
1008 goto unlock;
1009 }
1010
1011 ret = idr_get_new(&bsg_minor_idr, bcd, &minor);
1012 if (ret < 0)
1013 goto unlock;
1014
1015 if (minor >= BSG_MAX_DEVS) {
1016 printk(KERN_ERR "bsg: too many bsg devices\n");
1017 ret = -EINVAL;
1018 goto remove_idr;
1019 }
1020
1021 bcd->minor = minor;
1022 bcd->queue = q;
1023 bcd->parent = get_device(parent);
1024 bcd->release = release;
1025 kref_init(&bcd->ref);
1026 dev = MKDEV(bsg_major, bcd->minor);
1027 class_dev = device_create_drvdata(bsg_class, parent, dev, NULL,
1028 "%s", devname);
1029 if (IS_ERR(class_dev)) {
1030 ret = PTR_ERR(class_dev);
1031 goto put_dev;
1032 }
1033 bcd->class_dev = class_dev;
1034
1035 if (q->kobj.sd) {
1036 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
1037 if (ret)
1038 goto unregister_class_dev;
1039 }
1040
1041 mutex_unlock(&bsg_mutex);
1042 return 0;
1043
1044 unregister_class_dev:
1045 device_unregister(class_dev);
1046 put_dev:
1047 put_device(parent);
1048 remove_idr:
1049 idr_remove(&bsg_minor_idr, minor);
1050 unlock:
1051 mutex_unlock(&bsg_mutex);
1052 return ret;
1053 }
1054 EXPORT_SYMBOL_GPL(bsg_register_queue);
1055
1056 static struct cdev bsg_cdev;
1057
1058 static int __init bsg_init(void)
1059 {
1060 int ret, i;
1061 dev_t devid;
1062
1063 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
1064 sizeof(struct bsg_command), 0, 0, NULL);
1065 if (!bsg_cmd_cachep) {
1066 printk(KERN_ERR "bsg: failed creating slab cache\n");
1067 return -ENOMEM;
1068 }
1069
1070 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
1071 INIT_HLIST_HEAD(&bsg_device_list[i]);
1072
1073 bsg_class = class_create(THIS_MODULE, "bsg");
1074 if (IS_ERR(bsg_class)) {
1075 ret = PTR_ERR(bsg_class);
1076 goto destroy_kmemcache;
1077 }
1078
1079 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
1080 if (ret)
1081 goto destroy_bsg_class;
1082
1083 bsg_major = MAJOR(devid);
1084
1085 cdev_init(&bsg_cdev, &bsg_fops);
1086 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1087 if (ret)
1088 goto unregister_chrdev;
1089
1090 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
1091 " loaded (major %d)\n", bsg_major);
1092 return 0;
1093 unregister_chrdev:
1094 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1095 destroy_bsg_class:
1096 class_destroy(bsg_class);
1097 destroy_kmemcache:
1098 kmem_cache_destroy(bsg_cmd_cachep);
1099 return ret;
1100 }
1101
1102 MODULE_AUTHOR("Jens Axboe");
1103 MODULE_DESCRIPTION(BSG_DESCRIPTION);
1104 MODULE_LICENSE("GPL");
1105
1106 device_initcall(bsg_init);