]>
Commit | Line | Data |
---|---|---|
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 | ||
35 | struct 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 | ||
51 | enum { | |
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 | ||
66 | static DEFINE_MUTEX(bsg_mutex); | |
67 | static DEFINE_IDR(bsg_minor_idr); | |
68 | ||
69 | #define BSG_LIST_ARRAY_SIZE 8 | |
70 | static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; | |
71 | ||
72 | static struct class *bsg_class; | |
73 | static int bsg_major; | |
74 | ||
75 | static struct kmem_cache *bsg_cmd_cachep; | |
76 | ||
77 | /* | |
78 | * our internal command type | |
79 | */ | |
80 | struct 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 | ||
91 | static 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 | ||
105 | static 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; | |
129 | out: | |
130 | spin_unlock_irq(&bd->lock); | |
131 | return bc; | |
132 | } | |
133 | ||
134 | static inline struct hlist_head *bsg_dev_idx_hash(int index) | |
135 | { | |
136 | return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; | |
137 | } | |
138 | ||
139 | static 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; | |
170 | unlock: | |
171 | spin_unlock_irq(&bd->lock); | |
172 | return ret; | |
173 | } | |
174 | ||
175 | static 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 | */ | |
215 | static int | |
216 | bsg_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 | */ | |
244 | static struct request * | |
245 | bsg_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; | |
321 | out: | |
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 | */ | |
336 | static 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 | */ | |
359 | static 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 | ||
382 | static 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 | */ | |
400 | static 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 | ||
427 | static 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 | ||
483 | static 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 | ||
532 | static 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 | ||
575 | static 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 | */ | |
586 | static 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 | ||
594 | static ssize_t | |
595 | bsg_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 | ||
615 | static 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 | ||
669 | static ssize_t | |
670 | bsg_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 | ||
696 | static 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 | ||
717 | static 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 | ||
729 | static 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); | |
760 | out: | |
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 | ||
767 | static 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 | ||
800 | static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) | |
801 | { | |
802 | struct bsg_device *bd; | |
803 | struct hlist_node *entry; | |
804 | ||
805 | mutex_lock(&bsg_mutex); | |
806 | ||
807 | hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { | |
808 | if (bd->queue == q) { | |
809 | atomic_inc(&bd->ref_count); | |
810 | goto found; | |
811 | } | |
812 | } | |
813 | bd = NULL; | |
814 | found: | |
815 | mutex_unlock(&bsg_mutex); | |
816 | return bd; | |
817 | } | |
818 | ||
819 | static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) | |
820 | { | |
821 | struct bsg_device *bd; | |
822 | struct bsg_class_device *bcd; | |
823 | ||
824 | /* | |
825 | * find the class device | |
826 | */ | |
827 | mutex_lock(&bsg_mutex); | |
828 | bcd = idr_find(&bsg_minor_idr, iminor(inode)); | |
829 | if (bcd) | |
830 | kref_get(&bcd->ref); | |
831 | mutex_unlock(&bsg_mutex); | |
832 | ||
833 | if (!bcd) | |
834 | return ERR_PTR(-ENODEV); | |
835 | ||
836 | bd = __bsg_get_device(iminor(inode), bcd->queue); | |
837 | if (bd) | |
838 | return bd; | |
839 | ||
840 | bd = bsg_add_device(inode, bcd->queue, file); | |
841 | if (IS_ERR(bd)) | |
842 | kref_put(&bcd->ref, bsg_kref_release_function); | |
843 | ||
844 | return bd; | |
845 | } | |
846 | ||
847 | static int bsg_open(struct inode *inode, struct file *file) | |
848 | { | |
849 | struct bsg_device *bd; | |
850 | ||
851 | bd = bsg_get_device(inode, file); | |
852 | ||
853 | if (IS_ERR(bd)) | |
854 | return PTR_ERR(bd); | |
855 | ||
856 | file->private_data = bd; | |
857 | return 0; | |
858 | } | |
859 | ||
860 | static int bsg_release(struct inode *inode, struct file *file) | |
861 | { | |
862 | struct bsg_device *bd = file->private_data; | |
863 | ||
864 | file->private_data = NULL; | |
865 | return bsg_put_device(bd); | |
866 | } | |
867 | ||
868 | static unsigned int bsg_poll(struct file *file, poll_table *wait) | |
869 | { | |
870 | struct bsg_device *bd = file->private_data; | |
871 | unsigned int mask = 0; | |
872 | ||
873 | poll_wait(file, &bd->wq_done, wait); | |
874 | poll_wait(file, &bd->wq_free, wait); | |
875 | ||
876 | spin_lock_irq(&bd->lock); | |
877 | if (!list_empty(&bd->done_list)) | |
878 | mask |= POLLIN | POLLRDNORM; | |
879 | if (bd->queued_cmds < bd->max_queue) | |
880 | mask |= POLLOUT; | |
881 | spin_unlock_irq(&bd->lock); | |
882 | ||
883 | return mask; | |
884 | } | |
885 | ||
886 | static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
887 | { | |
888 | struct bsg_device *bd = file->private_data; | |
889 | int __user *uarg = (int __user *) arg; | |
890 | int ret; | |
891 | ||
892 | switch (cmd) { | |
893 | /* | |
894 | * our own ioctls | |
895 | */ | |
896 | case SG_GET_COMMAND_Q: | |
897 | return put_user(bd->max_queue, uarg); | |
898 | case SG_SET_COMMAND_Q: { | |
899 | int queue; | |
900 | ||
901 | if (get_user(queue, uarg)) | |
902 | return -EFAULT; | |
903 | if (queue < 1) | |
904 | return -EINVAL; | |
905 | ||
906 | spin_lock_irq(&bd->lock); | |
907 | bd->max_queue = queue; | |
908 | spin_unlock_irq(&bd->lock); | |
909 | return 0; | |
910 | } | |
911 | ||
912 | /* | |
913 | * SCSI/sg ioctls | |
914 | */ | |
915 | case SG_GET_VERSION_NUM: | |
916 | case SCSI_IOCTL_GET_IDLUN: | |
917 | case SCSI_IOCTL_GET_BUS_NUMBER: | |
918 | case SG_SET_TIMEOUT: | |
919 | case SG_GET_TIMEOUT: | |
920 | case SG_GET_RESERVED_SIZE: | |
921 | case SG_SET_RESERVED_SIZE: | |
922 | case SG_EMULATED_HOST: | |
923 | case SCSI_IOCTL_SEND_COMMAND: { | |
924 | void __user *uarg = (void __user *) arg; | |
925 | return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); | |
926 | } | |
927 | case SG_IO: { | |
928 | struct request *rq; | |
929 | struct bio *bio, *bidi_bio = NULL; | |
930 | struct sg_io_v4 hdr; | |
931 | int at_head; | |
932 | u8 sense[SCSI_SENSE_BUFFERSIZE]; | |
933 | ||
934 | if (copy_from_user(&hdr, uarg, sizeof(hdr))) | |
935 | return -EFAULT; | |
936 | ||
937 | rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); | |
938 | if (IS_ERR(rq)) | |
939 | return PTR_ERR(rq); | |
940 | ||
941 | bio = rq->bio; | |
942 | if (rq->next_rq) | |
943 | bidi_bio = rq->next_rq->bio; | |
944 | ||
945 | at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); | |
946 | blk_execute_rq(bd->queue, NULL, rq, at_head); | |
947 | ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); | |
948 | ||
949 | if (copy_to_user(uarg, &hdr, sizeof(hdr))) | |
950 | return -EFAULT; | |
951 | ||
952 | return ret; | |
953 | } | |
954 | /* | |
955 | * block device ioctls | |
956 | */ | |
957 | default: | |
958 | #if 0 | |
959 | return ioctl_by_bdev(bd->bdev, cmd, arg); | |
960 | #else | |
961 | return -ENOTTY; | |
962 | #endif | |
963 | } | |
964 | } | |
965 | ||
966 | static const struct file_operations bsg_fops = { | |
967 | .read = bsg_read, | |
968 | .write = bsg_write, | |
969 | .poll = bsg_poll, | |
970 | .open = bsg_open, | |
971 | .release = bsg_release, | |
972 | .unlocked_ioctl = bsg_ioctl, | |
973 | .owner = THIS_MODULE, | |
974 | .llseek = default_llseek, | |
975 | }; | |
976 | ||
977 | void bsg_unregister_queue(struct request_queue *q) | |
978 | { | |
979 | struct bsg_class_device *bcd = &q->bsg_dev; | |
980 | ||
981 | if (!bcd->class_dev) | |
982 | return; | |
983 | ||
984 | mutex_lock(&bsg_mutex); | |
985 | idr_remove(&bsg_minor_idr, bcd->minor); | |
986 | if (q->kobj.sd) | |
987 | sysfs_remove_link(&q->kobj, "bsg"); | |
988 | device_unregister(bcd->class_dev); | |
989 | bcd->class_dev = NULL; | |
990 | kref_put(&bcd->ref, bsg_kref_release_function); | |
991 | mutex_unlock(&bsg_mutex); | |
992 | } | |
993 | EXPORT_SYMBOL_GPL(bsg_unregister_queue); | |
994 | ||
995 | int bsg_register_queue(struct request_queue *q, struct device *parent, | |
996 | const char *name, void (*release)(struct device *)) | |
997 | { | |
998 | struct bsg_class_device *bcd; | |
999 | dev_t dev; | |
1000 | int ret; | |
1001 | struct device *class_dev = NULL; | |
1002 | const char *devname; | |
1003 | ||
1004 | if (name) | |
1005 | devname = name; | |
1006 | else | |
1007 | devname = dev_name(parent); | |
1008 | ||
1009 | /* | |
1010 | * we need a proper transport to send commands, not a stacked device | |
1011 | */ | |
1012 | if (!q->request_fn) | |
1013 | return 0; | |
1014 | ||
1015 | bcd = &q->bsg_dev; | |
1016 | memset(bcd, 0, sizeof(*bcd)); | |
1017 | ||
1018 | mutex_lock(&bsg_mutex); | |
1019 | ||
1020 | ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); | |
1021 | if (ret < 0) { | |
1022 | if (ret == -ENOSPC) { | |
1023 | printk(KERN_ERR "bsg: too many bsg devices\n"); | |
1024 | ret = -EINVAL; | |
1025 | } | |
1026 | goto unlock; | |
1027 | } | |
1028 | ||
1029 | bcd->minor = ret; | |
1030 | bcd->queue = q; | |
1031 | bcd->parent = get_device(parent); | |
1032 | bcd->release = release; | |
1033 | kref_init(&bcd->ref); | |
1034 | dev = MKDEV(bsg_major, bcd->minor); | |
1035 | class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); | |
1036 | if (IS_ERR(class_dev)) { | |
1037 | ret = PTR_ERR(class_dev); | |
1038 | goto put_dev; | |
1039 | } | |
1040 | bcd->class_dev = class_dev; | |
1041 | ||
1042 | if (q->kobj.sd) { | |
1043 | ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); | |
1044 | if (ret) | |
1045 | goto unregister_class_dev; | |
1046 | } | |
1047 | ||
1048 | mutex_unlock(&bsg_mutex); | |
1049 | return 0; | |
1050 | ||
1051 | unregister_class_dev: | |
1052 | device_unregister(class_dev); | |
1053 | put_dev: | |
1054 | put_device(parent); | |
1055 | idr_remove(&bsg_minor_idr, bcd->minor); | |
1056 | unlock: | |
1057 | mutex_unlock(&bsg_mutex); | |
1058 | return ret; | |
1059 | } | |
1060 | EXPORT_SYMBOL_GPL(bsg_register_queue); | |
1061 | ||
1062 | static struct cdev bsg_cdev; | |
1063 | ||
1064 | static char *bsg_devnode(struct device *dev, umode_t *mode) | |
1065 | { | |
1066 | return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); | |
1067 | } | |
1068 | ||
1069 | static int __init bsg_init(void) | |
1070 | { | |
1071 | int ret, i; | |
1072 | dev_t devid; | |
1073 | ||
1074 | bsg_cmd_cachep = kmem_cache_create("bsg_cmd", | |
1075 | sizeof(struct bsg_command), 0, 0, NULL); | |
1076 | if (!bsg_cmd_cachep) { | |
1077 | printk(KERN_ERR "bsg: failed creating slab cache\n"); | |
1078 | return -ENOMEM; | |
1079 | } | |
1080 | ||
1081 | for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) | |
1082 | INIT_HLIST_HEAD(&bsg_device_list[i]); | |
1083 | ||
1084 | bsg_class = class_create(THIS_MODULE, "bsg"); | |
1085 | if (IS_ERR(bsg_class)) { | |
1086 | ret = PTR_ERR(bsg_class); | |
1087 | goto destroy_kmemcache; | |
1088 | } | |
1089 | bsg_class->devnode = bsg_devnode; | |
1090 | ||
1091 | ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); | |
1092 | if (ret) | |
1093 | goto destroy_bsg_class; | |
1094 | ||
1095 | bsg_major = MAJOR(devid); | |
1096 | ||
1097 | cdev_init(&bsg_cdev, &bsg_fops); | |
1098 | ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); | |
1099 | if (ret) | |
1100 | goto unregister_chrdev; | |
1101 | ||
1102 | printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION | |
1103 | " loaded (major %d)\n", bsg_major); | |
1104 | return 0; | |
1105 | unregister_chrdev: | |
1106 | unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); | |
1107 | destroy_bsg_class: | |
1108 | class_destroy(bsg_class); | |
1109 | destroy_kmemcache: | |
1110 | kmem_cache_destroy(bsg_cmd_cachep); | |
1111 | return ret; | |
1112 | } | |
1113 | ||
1114 | MODULE_AUTHOR("Jens Axboe"); | |
1115 | MODULE_DESCRIPTION(BSG_DESCRIPTION); | |
1116 | MODULE_LICENSE("GPL"); | |
1117 | ||
1118 | device_initcall(bsg_init); |