VFS: fix dio write returning EIO when try_to_release_page fails
[linux-2.6/mini2440.git] / block / bsg.c
blob0aae8d7ba99c432604995ed3b8b907623032c15e
1 /*
2 * bsg.c - block layer implementation of the sg v4 interface
4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
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.
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>
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>
31 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
32 #define BSG_VERSION "0.4"
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;
50 enum {
51 BSG_F_BLOCK = 1,
54 #define BSG_DEFAULT_CMDS 64
55 #define BSG_MAX_DEVS 32768
57 #undef BSG_DEBUG
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
65 static DEFINE_MUTEX(bsg_mutex);
66 static DEFINE_IDR(bsg_minor_idr);
68 #define BSG_LIST_ARRAY_SIZE 8
69 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
71 static struct class *bsg_class;
72 static int bsg_major;
74 static struct kmem_cache *bsg_cmd_cachep;
77 * our internal command type
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];
90 static void bsg_free_command(struct bsg_command *bc)
92 struct bsg_device *bd = bc->bd;
93 unsigned long flags;
95 kmem_cache_free(bsg_cmd_cachep, bc);
97 spin_lock_irqsave(&bd->lock, flags);
98 bd->queued_cmds--;
99 spin_unlock_irqrestore(&bd->lock, flags);
101 wake_up(&bd->wq_free);
104 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
106 struct bsg_command *bc = ERR_PTR(-EINVAL);
108 spin_lock_irq(&bd->lock);
110 if (bd->queued_cmds >= bd->max_queue)
111 goto out;
113 bd->queued_cmds++;
114 spin_unlock_irq(&bd->lock);
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;
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;
133 static inline struct hlist_head *bsg_dev_idx_hash(int index)
135 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
138 static int bsg_io_schedule(struct bsg_device *bd)
140 DEFINE_WAIT(wait);
141 int ret = 0;
143 spin_lock_irq(&bd->lock);
145 BUG_ON(bd->done_cmds > bd->queued_cmds);
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.
153 if (bd->done_cmds == bd->queued_cmds) {
154 ret = -ENODATA;
155 goto unlock;
158 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
159 ret = -EAGAIN;
160 goto unlock;
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);
168 return ret;
169 unlock:
170 spin_unlock_irq(&bd->lock);
171 return ret;
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)
178 if (hdr->request_len > BLK_MAX_CDB) {
179 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
180 if (!rq->cmd)
181 return -ENOMEM;
184 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
185 hdr->request_len))
186 return -EFAULT;
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;
195 * fill in request structure
197 rq->cmd_len = hdr->request_len;
198 rq->cmd_type = REQ_TYPE_BLOCK_PC;
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;
206 return 0;
210 * Check if sg_io_v4 from user is allowed and valid
212 static int
213 bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
215 int ret = 0;
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;
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;
232 break;
233 default:
234 ret = -EINVAL;
237 *rw = hdr->dout_xfer_len ? WRITE : READ;
238 return ret;
242 * map sg_io_v4 to a request.
244 static struct request *
245 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, int has_write_perm)
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;
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);
257 ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
258 if (ret)
259 return ERR_PTR(ret);
262 * map scatter-gather elements seperately and string them to request
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;
271 if (rw == WRITE && hdr->din_xfer_len) {
272 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
273 ret = -EOPNOTSUPP;
274 goto out;
277 next_rq = blk_get_request(q, READ, GFP_KERNEL);
278 if (!next_rq) {
279 ret = -ENOMEM;
280 goto out;
282 rq->next_rq = next_rq;
283 next_rq->cmd_type = rq->cmd_type;
285 dxferp = (void*)(unsigned long)hdr->din_xferp;
286 ret = blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len);
287 if (ret)
288 goto out;
291 if (hdr->dout_xfer_len) {
292 dxfer_len = hdr->dout_xfer_len;
293 dxferp = (void*)(unsigned long)hdr->dout_xferp;
294 } else if (hdr->din_xfer_len) {
295 dxfer_len = hdr->din_xfer_len;
296 dxferp = (void*)(unsigned long)hdr->din_xferp;
297 } else
298 dxfer_len = 0;
300 if (dxfer_len) {
301 ret = blk_rq_map_user(q, rq, dxferp, dxfer_len);
302 if (ret)
303 goto out;
305 return rq;
306 out:
307 if (rq->cmd != rq->__cmd)
308 kfree(rq->cmd);
309 blk_put_request(rq);
310 if (next_rq) {
311 blk_rq_unmap_user(next_rq->bio);
312 blk_put_request(next_rq);
314 return ERR_PTR(ret);
318 * async completion call-back from the block layer, when scsi/ide/whatever
319 * calls end_that_request_last() on a request
321 static void bsg_rq_end_io(struct request *rq, int uptodate)
323 struct bsg_command *bc = rq->end_io_data;
324 struct bsg_device *bd = bc->bd;
325 unsigned long flags;
327 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
328 bd->name, rq, bc, bc->bio, uptodate);
330 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
332 spin_lock_irqsave(&bd->lock, flags);
333 list_move_tail(&bc->list, &bd->done_list);
334 bd->done_cmds++;
335 spin_unlock_irqrestore(&bd->lock, flags);
337 wake_up(&bd->wq_done);
341 * do final setup of a 'bc' and submit the matching 'rq' to the block
342 * layer for io
344 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
345 struct bsg_command *bc, struct request *rq)
347 rq->sense = bc->sense;
348 rq->sense_len = 0;
351 * add bc command to busy queue and submit rq for io
353 bc->rq = rq;
354 bc->bio = rq->bio;
355 if (rq->next_rq)
356 bc->bidi_bio = rq->next_rq->bio;
357 bc->hdr.duration = jiffies;
358 spin_lock_irq(&bd->lock);
359 list_add_tail(&bc->list, &bd->busy_list);
360 spin_unlock_irq(&bd->lock);
362 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
364 rq->end_io_data = bc;
365 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io);
368 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
370 struct bsg_command *bc = NULL;
372 spin_lock_irq(&bd->lock);
373 if (bd->done_cmds) {
374 bc = list_first_entry(&bd->done_list, struct bsg_command, list);
375 list_del(&bc->list);
376 bd->done_cmds--;
378 spin_unlock_irq(&bd->lock);
380 return bc;
384 * Get a finished command from the done list
386 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
388 struct bsg_command *bc;
389 int ret;
391 do {
392 bc = bsg_next_done_cmd(bd);
393 if (bc)
394 break;
396 if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
397 bc = ERR_PTR(-EAGAIN);
398 break;
401 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
402 if (ret) {
403 bc = ERR_PTR(-ERESTARTSYS);
404 break;
406 } while (1);
408 dprintk("%s: returning done %p\n", bd->name, bc);
410 return bc;
413 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
414 struct bio *bio, struct bio *bidi_bio)
416 int ret = 0;
418 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors);
420 * fill in all the output members
422 hdr->device_status = status_byte(rq->errors);
423 hdr->transport_status = host_byte(rq->errors);
424 hdr->driver_status = driver_byte(rq->errors);
425 hdr->info = 0;
426 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
427 hdr->info |= SG_INFO_CHECK;
428 hdr->response_len = 0;
430 if (rq->sense_len && hdr->response) {
431 int len = min_t(unsigned int, hdr->max_response_len,
432 rq->sense_len);
434 ret = copy_to_user((void*)(unsigned long)hdr->response,
435 rq->sense, len);
436 if (!ret)
437 hdr->response_len = len;
438 else
439 ret = -EFAULT;
442 if (rq->next_rq) {
443 hdr->dout_resid = rq->data_len;
444 hdr->din_resid = rq->next_rq->data_len;
445 blk_rq_unmap_user(bidi_bio);
446 blk_put_request(rq->next_rq);
447 } else if (rq_data_dir(rq) == READ)
448 hdr->din_resid = rq->data_len;
449 else
450 hdr->dout_resid = rq->data_len;
453 * If the request generated a negative error number, return it
454 * (providing we aren't already returning an error); if it's
455 * just a protocol response (i.e. non negative), that gets
456 * processed above.
458 if (!ret && rq->errors < 0)
459 ret = rq->errors;
461 blk_rq_unmap_user(bio);
462 if (rq->cmd != rq->__cmd)
463 kfree(rq->cmd);
464 blk_put_request(rq);
466 return ret;
469 static int bsg_complete_all_commands(struct bsg_device *bd)
471 struct bsg_command *bc;
472 int ret, tret;
474 dprintk("%s: entered\n", bd->name);
477 * wait for all commands to complete
479 ret = 0;
480 do {
481 ret = bsg_io_schedule(bd);
483 * look for -ENODATA specifically -- we'll sometimes get
484 * -ERESTARTSYS when we've taken a signal, but we can't
485 * return until we're done freeing the queue, so ignore
486 * it. The signal will get handled when we're done freeing
487 * the bsg_device.
489 } while (ret != -ENODATA);
492 * discard done commands
494 ret = 0;
495 do {
496 spin_lock_irq(&bd->lock);
497 if (!bd->queued_cmds) {
498 spin_unlock_irq(&bd->lock);
499 break;
501 spin_unlock_irq(&bd->lock);
503 bc = bsg_get_done_cmd(bd);
504 if (IS_ERR(bc))
505 break;
507 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
508 bc->bidi_bio);
509 if (!ret)
510 ret = tret;
512 bsg_free_command(bc);
513 } while (1);
515 return ret;
518 static int
519 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
520 const struct iovec *iov, ssize_t *bytes_read)
522 struct bsg_command *bc;
523 int nr_commands, ret;
525 if (count % sizeof(struct sg_io_v4))
526 return -EINVAL;
528 ret = 0;
529 nr_commands = count / sizeof(struct sg_io_v4);
530 while (nr_commands) {
531 bc = bsg_get_done_cmd(bd);
532 if (IS_ERR(bc)) {
533 ret = PTR_ERR(bc);
534 break;
538 * this is the only case where we need to copy data back
539 * after completing the request. so do that here,
540 * bsg_complete_work() cannot do that for us
542 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
543 bc->bidi_bio);
545 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
546 ret = -EFAULT;
548 bsg_free_command(bc);
550 if (ret)
551 break;
553 buf += sizeof(struct sg_io_v4);
554 *bytes_read += sizeof(struct sg_io_v4);
555 nr_commands--;
558 return ret;
561 static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
563 if (file->f_flags & O_NONBLOCK)
564 clear_bit(BSG_F_BLOCK, &bd->flags);
565 else
566 set_bit(BSG_F_BLOCK, &bd->flags);
570 * Check if the error is a "real" error that we should return.
572 static inline int err_block_err(int ret)
574 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
575 return 1;
577 return 0;
580 static ssize_t
581 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
583 struct bsg_device *bd = file->private_data;
584 int ret;
585 ssize_t bytes_read;
587 dprintk("%s: read %Zd bytes\n", bd->name, count);
589 bsg_set_block(bd, file);
591 bytes_read = 0;
592 ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
593 *ppos = bytes_read;
595 if (!bytes_read || (bytes_read && err_block_err(ret)))
596 bytes_read = ret;
598 return bytes_read;
601 static int __bsg_write(struct bsg_device *bd, const char __user *buf,
602 size_t count, ssize_t *bytes_written, int has_write_perm)
604 struct bsg_command *bc;
605 struct request *rq;
606 int ret, nr_commands;
608 if (count % sizeof(struct sg_io_v4))
609 return -EINVAL;
611 nr_commands = count / sizeof(struct sg_io_v4);
612 rq = NULL;
613 bc = NULL;
614 ret = 0;
615 while (nr_commands) {
616 struct request_queue *q = bd->queue;
618 bc = bsg_alloc_command(bd);
619 if (IS_ERR(bc)) {
620 ret = PTR_ERR(bc);
621 bc = NULL;
622 break;
625 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
626 ret = -EFAULT;
627 break;
631 * get a request, fill in the blanks, and add to request queue
633 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm);
634 if (IS_ERR(rq)) {
635 ret = PTR_ERR(rq);
636 rq = NULL;
637 break;
640 bsg_add_command(bd, q, bc, rq);
641 bc = NULL;
642 rq = NULL;
643 nr_commands--;
644 buf += sizeof(struct sg_io_v4);
645 *bytes_written += sizeof(struct sg_io_v4);
648 if (bc)
649 bsg_free_command(bc);
651 return ret;
654 static ssize_t
655 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
657 struct bsg_device *bd = file->private_data;
658 ssize_t bytes_written;
659 int ret;
661 dprintk("%s: write %Zd bytes\n", bd->name, count);
663 bsg_set_block(bd, file);
665 bytes_written = 0;
666 ret = __bsg_write(bd, buf, count, &bytes_written,
667 file->f_mode & FMODE_WRITE);
669 *ppos = bytes_written;
672 * return bytes written on non-fatal errors
674 if (!bytes_written || (bytes_written && err_block_err(ret)))
675 bytes_written = ret;
677 dprintk("%s: returning %Zd\n", bd->name, bytes_written);
678 return bytes_written;
681 static struct bsg_device *bsg_alloc_device(void)
683 struct bsg_device *bd;
685 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
686 if (unlikely(!bd))
687 return NULL;
689 spin_lock_init(&bd->lock);
691 bd->max_queue = BSG_DEFAULT_CMDS;
693 INIT_LIST_HEAD(&bd->busy_list);
694 INIT_LIST_HEAD(&bd->done_list);
695 INIT_HLIST_NODE(&bd->dev_list);
697 init_waitqueue_head(&bd->wq_free);
698 init_waitqueue_head(&bd->wq_done);
699 return bd;
702 static void bsg_kref_release_function(struct kref *kref)
704 struct bsg_class_device *bcd =
705 container_of(kref, struct bsg_class_device, ref);
706 struct device *parent = bcd->parent;
708 if (bcd->release)
709 bcd->release(bcd->parent);
711 put_device(parent);
714 static int bsg_put_device(struct bsg_device *bd)
716 int ret = 0, do_free;
717 struct request_queue *q = bd->queue;
719 mutex_lock(&bsg_mutex);
721 do_free = atomic_dec_and_test(&bd->ref_count);
722 if (!do_free) {
723 mutex_unlock(&bsg_mutex);
724 goto out;
727 hlist_del(&bd->dev_list);
728 mutex_unlock(&bsg_mutex);
730 dprintk("%s: tearing down\n", bd->name);
733 * close can always block
735 set_bit(BSG_F_BLOCK, &bd->flags);
738 * correct error detection baddies here again. it's the responsibility
739 * of the app to properly reap commands before close() if it wants
740 * fool-proof error detection
742 ret = bsg_complete_all_commands(bd);
744 kfree(bd);
745 out:
746 kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
747 if (do_free)
748 blk_put_queue(q);
749 return ret;
752 static struct bsg_device *bsg_add_device(struct inode *inode,
753 struct request_queue *rq,
754 struct file *file)
756 struct bsg_device *bd;
757 int ret;
758 #ifdef BSG_DEBUG
759 unsigned char buf[32];
760 #endif
761 ret = blk_get_queue(rq);
762 if (ret)
763 return ERR_PTR(-ENXIO);
765 bd = bsg_alloc_device();
766 if (!bd) {
767 blk_put_queue(rq);
768 return ERR_PTR(-ENOMEM);
771 bd->queue = rq;
773 bsg_set_block(bd, file);
775 atomic_set(&bd->ref_count, 1);
776 mutex_lock(&bsg_mutex);
777 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
779 strncpy(bd->name, rq->bsg_dev.class_dev->bus_id, sizeof(bd->name) - 1);
780 dprintk("bound to <%s>, max queue %d\n",
781 format_dev_t(buf, inode->i_rdev), bd->max_queue);
783 mutex_unlock(&bsg_mutex);
784 return bd;
787 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
789 struct bsg_device *bd;
790 struct hlist_node *entry;
792 mutex_lock(&bsg_mutex);
794 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) {
795 if (bd->queue == q) {
796 atomic_inc(&bd->ref_count);
797 goto found;
800 bd = NULL;
801 found:
802 mutex_unlock(&bsg_mutex);
803 return bd;
806 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
808 struct bsg_device *bd;
809 struct bsg_class_device *bcd;
812 * find the class device
814 mutex_lock(&bsg_mutex);
815 bcd = idr_find(&bsg_minor_idr, iminor(inode));
816 if (bcd)
817 kref_get(&bcd->ref);
818 mutex_unlock(&bsg_mutex);
820 if (!bcd)
821 return ERR_PTR(-ENODEV);
823 bd = __bsg_get_device(iminor(inode), bcd->queue);
824 if (bd)
825 return bd;
827 bd = bsg_add_device(inode, bcd->queue, file);
828 if (IS_ERR(bd))
829 kref_put(&bcd->ref, bsg_kref_release_function);
831 return bd;
834 static int bsg_open(struct inode *inode, struct file *file)
836 struct bsg_device *bd;
838 lock_kernel();
839 bd = bsg_get_device(inode, file);
840 unlock_kernel();
842 if (IS_ERR(bd))
843 return PTR_ERR(bd);
845 file->private_data = bd;
846 return 0;
849 static int bsg_release(struct inode *inode, struct file *file)
851 struct bsg_device *bd = file->private_data;
853 file->private_data = NULL;
854 return bsg_put_device(bd);
857 static unsigned int bsg_poll(struct file *file, poll_table *wait)
859 struct bsg_device *bd = file->private_data;
860 unsigned int mask = 0;
862 poll_wait(file, &bd->wq_done, wait);
863 poll_wait(file, &bd->wq_free, wait);
865 spin_lock_irq(&bd->lock);
866 if (!list_empty(&bd->done_list))
867 mask |= POLLIN | POLLRDNORM;
868 if (bd->queued_cmds >= bd->max_queue)
869 mask |= POLLOUT;
870 spin_unlock_irq(&bd->lock);
872 return mask;
875 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
877 struct bsg_device *bd = file->private_data;
878 int __user *uarg = (int __user *) arg;
879 int ret;
881 switch (cmd) {
883 * our own ioctls
885 case SG_GET_COMMAND_Q:
886 return put_user(bd->max_queue, uarg);
887 case SG_SET_COMMAND_Q: {
888 int queue;
890 if (get_user(queue, uarg))
891 return -EFAULT;
892 if (queue < 1)
893 return -EINVAL;
895 spin_lock_irq(&bd->lock);
896 bd->max_queue = queue;
897 spin_unlock_irq(&bd->lock);
898 return 0;
902 * SCSI/sg ioctls
904 case SG_GET_VERSION_NUM:
905 case SCSI_IOCTL_GET_IDLUN:
906 case SCSI_IOCTL_GET_BUS_NUMBER:
907 case SG_SET_TIMEOUT:
908 case SG_GET_TIMEOUT:
909 case SG_GET_RESERVED_SIZE:
910 case SG_SET_RESERVED_SIZE:
911 case SG_EMULATED_HOST:
912 case SCSI_IOCTL_SEND_COMMAND: {
913 void __user *uarg = (void __user *) arg;
914 return scsi_cmd_ioctl(file, bd->queue, NULL, cmd, uarg);
916 case SG_IO: {
917 struct request *rq;
918 struct bio *bio, *bidi_bio = NULL;
919 struct sg_io_v4 hdr;
921 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
922 return -EFAULT;
924 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE);
925 if (IS_ERR(rq))
926 return PTR_ERR(rq);
928 bio = rq->bio;
929 if (rq->next_rq)
930 bidi_bio = rq->next_rq->bio;
931 blk_execute_rq(bd->queue, NULL, rq, 0);
932 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
934 if (copy_to_user(uarg, &hdr, sizeof(hdr)))
935 return -EFAULT;
937 return ret;
940 * block device ioctls
942 default:
943 #if 0
944 return ioctl_by_bdev(bd->bdev, cmd, arg);
945 #else
946 return -ENOTTY;
947 #endif
951 static const struct file_operations bsg_fops = {
952 .read = bsg_read,
953 .write = bsg_write,
954 .poll = bsg_poll,
955 .open = bsg_open,
956 .release = bsg_release,
957 .unlocked_ioctl = bsg_ioctl,
958 .owner = THIS_MODULE,
961 void bsg_unregister_queue(struct request_queue *q)
963 struct bsg_class_device *bcd = &q->bsg_dev;
965 if (!bcd->class_dev)
966 return;
968 mutex_lock(&bsg_mutex);
969 idr_remove(&bsg_minor_idr, bcd->minor);
970 sysfs_remove_link(&q->kobj, "bsg");
971 device_unregister(bcd->class_dev);
972 bcd->class_dev = NULL;
973 kref_put(&bcd->ref, bsg_kref_release_function);
974 mutex_unlock(&bsg_mutex);
976 EXPORT_SYMBOL_GPL(bsg_unregister_queue);
978 int bsg_register_queue(struct request_queue *q, struct device *parent,
979 const char *name, void (*release)(struct device *))
981 struct bsg_class_device *bcd;
982 dev_t dev;
983 int ret, minor;
984 struct device *class_dev = NULL;
985 const char *devname;
987 if (name)
988 devname = name;
989 else
990 devname = parent->bus_id;
993 * we need a proper transport to send commands, not a stacked device
995 if (!q->request_fn)
996 return 0;
998 bcd = &q->bsg_dev;
999 memset(bcd, 0, sizeof(*bcd));
1001 mutex_lock(&bsg_mutex);
1003 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL);
1004 if (!ret) {
1005 ret = -ENOMEM;
1006 goto unlock;
1009 ret = idr_get_new(&bsg_minor_idr, bcd, &minor);
1010 if (ret < 0)
1011 goto unlock;
1013 if (minor >= BSG_MAX_DEVS) {
1014 printk(KERN_ERR "bsg: too many bsg devices\n");
1015 ret = -EINVAL;
1016 goto remove_idr;
1019 bcd->minor = minor;
1020 bcd->queue = q;
1021 bcd->parent = get_device(parent);
1022 bcd->release = release;
1023 kref_init(&bcd->ref);
1024 dev = MKDEV(bsg_major, bcd->minor);
1025 class_dev = device_create_drvdata(bsg_class, parent, dev, NULL,
1026 "%s", devname);
1027 if (IS_ERR(class_dev)) {
1028 ret = PTR_ERR(class_dev);
1029 goto put_dev;
1031 bcd->class_dev = class_dev;
1033 if (q->kobj.sd) {
1034 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
1035 if (ret)
1036 goto unregister_class_dev;
1039 mutex_unlock(&bsg_mutex);
1040 return 0;
1042 unregister_class_dev:
1043 device_unregister(class_dev);
1044 put_dev:
1045 put_device(parent);
1046 remove_idr:
1047 idr_remove(&bsg_minor_idr, minor);
1048 unlock:
1049 mutex_unlock(&bsg_mutex);
1050 return ret;
1052 EXPORT_SYMBOL_GPL(bsg_register_queue);
1054 static struct cdev bsg_cdev;
1056 static int __init bsg_init(void)
1058 int ret, i;
1059 dev_t devid;
1061 bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
1062 sizeof(struct bsg_command), 0, 0, NULL);
1063 if (!bsg_cmd_cachep) {
1064 printk(KERN_ERR "bsg: failed creating slab cache\n");
1065 return -ENOMEM;
1068 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
1069 INIT_HLIST_HEAD(&bsg_device_list[i]);
1071 bsg_class = class_create(THIS_MODULE, "bsg");
1072 if (IS_ERR(bsg_class)) {
1073 ret = PTR_ERR(bsg_class);
1074 goto destroy_kmemcache;
1077 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
1078 if (ret)
1079 goto destroy_bsg_class;
1081 bsg_major = MAJOR(devid);
1083 cdev_init(&bsg_cdev, &bsg_fops);
1084 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1085 if (ret)
1086 goto unregister_chrdev;
1088 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
1089 " loaded (major %d)\n", bsg_major);
1090 return 0;
1091 unregister_chrdev:
1092 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
1093 destroy_bsg_class:
1094 class_destroy(bsg_class);
1095 destroy_kmemcache:
1096 kmem_cache_destroy(bsg_cmd_cachep);
1097 return ret;
1100 MODULE_AUTHOR("Jens Axboe");
1101 MODULE_DESCRIPTION(BSG_DESCRIPTION);
1102 MODULE_LICENSE("GPL");
1104 device_initcall(bsg_init);