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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/smp_lock.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 *)(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 *dxferp = NULL; | |
253 | ||
254 | dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, | |
255 | hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, | |
256 | hdr->din_xfer_len); | |
257 | ||
258 | ret = bsg_validate_sgv4_hdr(q, hdr, &rw); | |
259 | if (ret) | |
260 | return ERR_PTR(ret); | |
261 | ||
262 | /* | |
263 | * map scatter-gather elements separately and string them to request | |
264 | */ | |
265 | rq = blk_get_request(q, rw, GFP_KERNEL); | |
266 | if (!rq) | |
267 | return ERR_PTR(-ENOMEM); | |
268 | ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); | |
269 | if (ret) | |
270 | goto out; | |
271 | ||
272 | if (rw == WRITE && hdr->din_xfer_len) { | |
273 | if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { | |
274 | ret = -EOPNOTSUPP; | |
275 | goto out; | |
276 | } | |
277 | ||
278 | next_rq = blk_get_request(q, READ, GFP_KERNEL); | |
279 | if (!next_rq) { | |
280 | ret = -ENOMEM; | |
281 | goto out; | |
282 | } | |
283 | rq->next_rq = next_rq; | |
284 | next_rq->cmd_type = rq->cmd_type; | |
285 | ||
286 | dxferp = (void*)(unsigned long)hdr->din_xferp; | |
287 | ret = blk_rq_map_user(q, next_rq, NULL, dxferp, | |
288 | hdr->din_xfer_len, GFP_KERNEL); | |
289 | if (ret) | |
290 | goto out; | |
291 | } | |
292 | ||
293 | if (hdr->dout_xfer_len) { | |
294 | dxfer_len = hdr->dout_xfer_len; | |
295 | dxferp = (void*)(unsigned long)hdr->dout_xferp; | |
296 | } else if (hdr->din_xfer_len) { | |
297 | dxfer_len = hdr->din_xfer_len; | |
298 | dxferp = (void*)(unsigned long)hdr->din_xferp; | |
299 | } else | |
300 | dxfer_len = 0; | |
301 | ||
302 | if (dxfer_len) { | |
303 | ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, | |
304 | GFP_KERNEL); | |
305 | if (ret) | |
306 | goto out; | |
307 | } | |
308 | ||
309 | rq->sense = sense; | |
310 | rq->sense_len = 0; | |
311 | ||
312 | return rq; | |
313 | out: | |
314 | if (rq->cmd != rq->__cmd) | |
315 | kfree(rq->cmd); | |
316 | blk_put_request(rq); | |
317 | if (next_rq) { | |
318 | blk_rq_unmap_user(next_rq->bio); | |
319 | blk_put_request(next_rq); | |
320 | } | |
321 | return ERR_PTR(ret); | |
322 | } | |
323 | ||
324 | /* | |
325 | * async completion call-back from the block layer, when scsi/ide/whatever | |
326 | * calls end_that_request_last() on a request | |
327 | */ | |
328 | static void bsg_rq_end_io(struct request *rq, int uptodate) | |
329 | { | |
330 | struct bsg_command *bc = rq->end_io_data; | |
331 | struct bsg_device *bd = bc->bd; | |
332 | unsigned long flags; | |
333 | ||
334 | dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", | |
335 | bd->name, rq, bc, bc->bio, uptodate); | |
336 | ||
337 | bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); | |
338 | ||
339 | spin_lock_irqsave(&bd->lock, flags); | |
340 | list_move_tail(&bc->list, &bd->done_list); | |
341 | bd->done_cmds++; | |
342 | spin_unlock_irqrestore(&bd->lock, flags); | |
343 | ||
344 | wake_up(&bd->wq_done); | |
345 | } | |
346 | ||
347 | /* | |
348 | * do final setup of a 'bc' and submit the matching 'rq' to the block | |
349 | * layer for io | |
350 | */ | |
351 | static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, | |
352 | struct bsg_command *bc, struct request *rq) | |
353 | { | |
354 | int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); | |
355 | ||
356 | /* | |
357 | * add bc command to busy queue and submit rq for io | |
358 | */ | |
359 | bc->rq = rq; | |
360 | bc->bio = rq->bio; | |
361 | if (rq->next_rq) | |
362 | bc->bidi_bio = rq->next_rq->bio; | |
363 | bc->hdr.duration = jiffies; | |
364 | spin_lock_irq(&bd->lock); | |
365 | list_add_tail(&bc->list, &bd->busy_list); | |
366 | spin_unlock_irq(&bd->lock); | |
367 | ||
368 | dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); | |
369 | ||
370 | rq->end_io_data = bc; | |
371 | blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); | |
372 | } | |
373 | ||
374 | static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) | |
375 | { | |
376 | struct bsg_command *bc = NULL; | |
377 | ||
378 | spin_lock_irq(&bd->lock); | |
379 | if (bd->done_cmds) { | |
380 | bc = list_first_entry(&bd->done_list, struct bsg_command, list); | |
381 | list_del(&bc->list); | |
382 | bd->done_cmds--; | |
383 | } | |
384 | spin_unlock_irq(&bd->lock); | |
385 | ||
386 | return bc; | |
387 | } | |
388 | ||
389 | /* | |
390 | * Get a finished command from the done list | |
391 | */ | |
392 | static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) | |
393 | { | |
394 | struct bsg_command *bc; | |
395 | int ret; | |
396 | ||
397 | do { | |
398 | bc = bsg_next_done_cmd(bd); | |
399 | if (bc) | |
400 | break; | |
401 | ||
402 | if (!test_bit(BSG_F_BLOCK, &bd->flags)) { | |
403 | bc = ERR_PTR(-EAGAIN); | |
404 | break; | |
405 | } | |
406 | ||
407 | ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); | |
408 | if (ret) { | |
409 | bc = ERR_PTR(-ERESTARTSYS); | |
410 | break; | |
411 | } | |
412 | } while (1); | |
413 | ||
414 | dprintk("%s: returning done %p\n", bd->name, bc); | |
415 | ||
416 | return bc; | |
417 | } | |
418 | ||
419 | static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, | |
420 | struct bio *bio, struct bio *bidi_bio) | |
421 | { | |
422 | int ret = 0; | |
423 | ||
424 | dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors); | |
425 | /* | |
426 | * fill in all the output members | |
427 | */ | |
428 | hdr->device_status = status_byte(rq->errors); | |
429 | hdr->transport_status = host_byte(rq->errors); | |
430 | hdr->driver_status = driver_byte(rq->errors); | |
431 | hdr->info = 0; | |
432 | if (hdr->device_status || hdr->transport_status || hdr->driver_status) | |
433 | hdr->info |= SG_INFO_CHECK; | |
434 | hdr->response_len = 0; | |
435 | ||
436 | if (rq->sense_len && hdr->response) { | |
437 | int len = min_t(unsigned int, hdr->max_response_len, | |
438 | rq->sense_len); | |
439 | ||
440 | ret = copy_to_user((void*)(unsigned long)hdr->response, | |
441 | rq->sense, len); | |
442 | if (!ret) | |
443 | hdr->response_len = len; | |
444 | else | |
445 | ret = -EFAULT; | |
446 | } | |
447 | ||
448 | if (rq->next_rq) { | |
449 | hdr->dout_resid = rq->resid_len; | |
450 | hdr->din_resid = rq->next_rq->resid_len; | |
451 | blk_rq_unmap_user(bidi_bio); | |
452 | blk_put_request(rq->next_rq); | |
453 | } else if (rq_data_dir(rq) == READ) | |
454 | hdr->din_resid = rq->resid_len; | |
455 | else | |
456 | hdr->dout_resid = rq->resid_len; | |
457 | ||
458 | /* | |
459 | * If the request generated a negative error number, return it | |
460 | * (providing we aren't already returning an error); if it's | |
461 | * just a protocol response (i.e. non negative), that gets | |
462 | * processed above. | |
463 | */ | |
464 | if (!ret && rq->errors < 0) | |
465 | ret = rq->errors; | |
466 | ||
467 | blk_rq_unmap_user(bio); | |
468 | if (rq->cmd != rq->__cmd) | |
469 | kfree(rq->cmd); | |
470 | blk_put_request(rq); | |
471 | ||
472 | return ret; | |
473 | } | |
474 | ||
475 | static int bsg_complete_all_commands(struct bsg_device *bd) | |
476 | { | |
477 | struct bsg_command *bc; | |
478 | int ret, tret; | |
479 | ||
480 | dprintk("%s: entered\n", bd->name); | |
481 | ||
482 | /* | |
483 | * wait for all commands to complete | |
484 | */ | |
485 | ret = 0; | |
486 | do { | |
487 | ret = bsg_io_schedule(bd); | |
488 | /* | |
489 | * look for -ENODATA specifically -- we'll sometimes get | |
490 | * -ERESTARTSYS when we've taken a signal, but we can't | |
491 | * return until we're done freeing the queue, so ignore | |
492 | * it. The signal will get handled when we're done freeing | |
493 | * the bsg_device. | |
494 | */ | |
495 | } while (ret != -ENODATA); | |
496 | ||
497 | /* | |
498 | * discard done commands | |
499 | */ | |
500 | ret = 0; | |
501 | do { | |
502 | spin_lock_irq(&bd->lock); | |
503 | if (!bd->queued_cmds) { | |
504 | spin_unlock_irq(&bd->lock); | |
505 | break; | |
506 | } | |
507 | spin_unlock_irq(&bd->lock); | |
508 | ||
509 | bc = bsg_get_done_cmd(bd); | |
510 | if (IS_ERR(bc)) | |
511 | break; | |
512 | ||
513 | tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, | |
514 | bc->bidi_bio); | |
515 | if (!ret) | |
516 | ret = tret; | |
517 | ||
518 | bsg_free_command(bc); | |
519 | } while (1); | |
520 | ||
521 | return ret; | |
522 | } | |
523 | ||
524 | static int | |
525 | __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, | |
526 | const struct iovec *iov, ssize_t *bytes_read) | |
527 | { | |
528 | struct bsg_command *bc; | |
529 | int nr_commands, ret; | |
530 | ||
531 | if (count % sizeof(struct sg_io_v4)) | |
532 | return -EINVAL; | |
533 | ||
534 | ret = 0; | |
535 | nr_commands = count / sizeof(struct sg_io_v4); | |
536 | while (nr_commands) { | |
537 | bc = bsg_get_done_cmd(bd); | |
538 | if (IS_ERR(bc)) { | |
539 | ret = PTR_ERR(bc); | |
540 | break; | |
541 | } | |
542 | ||
543 | /* | |
544 | * this is the only case where we need to copy data back | |
545 | * after completing the request. so do that here, | |
546 | * bsg_complete_work() cannot do that for us | |
547 | */ | |
548 | ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, | |
549 | bc->bidi_bio); | |
550 | ||
551 | if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) | |
552 | ret = -EFAULT; | |
553 | ||
554 | bsg_free_command(bc); | |
555 | ||
556 | if (ret) | |
557 | break; | |
558 | ||
559 | buf += sizeof(struct sg_io_v4); | |
560 | *bytes_read += sizeof(struct sg_io_v4); | |
561 | nr_commands--; | |
562 | } | |
563 | ||
564 | return ret; | |
565 | } | |
566 | ||
567 | static inline void bsg_set_block(struct bsg_device *bd, struct file *file) | |
568 | { | |
569 | if (file->f_flags & O_NONBLOCK) | |
570 | clear_bit(BSG_F_BLOCK, &bd->flags); | |
571 | else | |
572 | set_bit(BSG_F_BLOCK, &bd->flags); | |
573 | } | |
574 | ||
575 | /* | |
576 | * Check if the error is a "real" error that we should return. | |
577 | */ | |
578 | static inline int err_block_err(int ret) | |
579 | { | |
580 | if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) | |
581 | return 1; | |
582 | ||
583 | return 0; | |
584 | } | |
585 | ||
586 | static ssize_t | |
587 | bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
588 | { | |
589 | struct bsg_device *bd = file->private_data; | |
590 | int ret; | |
591 | ssize_t bytes_read; | |
592 | ||
593 | dprintk("%s: read %Zd bytes\n", bd->name, count); | |
594 | ||
595 | bsg_set_block(bd, file); | |
596 | ||
597 | bytes_read = 0; | |
598 | ret = __bsg_read(buf, count, bd, NULL, &bytes_read); | |
599 | *ppos = bytes_read; | |
600 | ||
601 | if (!bytes_read || (bytes_read && err_block_err(ret))) | |
602 | bytes_read = ret; | |
603 | ||
604 | return bytes_read; | |
605 | } | |
606 | ||
607 | static int __bsg_write(struct bsg_device *bd, const char __user *buf, | |
608 | size_t count, ssize_t *bytes_written, | |
609 | fmode_t has_write_perm) | |
610 | { | |
611 | struct bsg_command *bc; | |
612 | struct request *rq; | |
613 | int ret, nr_commands; | |
614 | ||
615 | if (count % sizeof(struct sg_io_v4)) | |
616 | return -EINVAL; | |
617 | ||
618 | nr_commands = count / sizeof(struct sg_io_v4); | |
619 | rq = NULL; | |
620 | bc = NULL; | |
621 | ret = 0; | |
622 | while (nr_commands) { | |
623 | struct request_queue *q = bd->queue; | |
624 | ||
625 | bc = bsg_alloc_command(bd); | |
626 | if (IS_ERR(bc)) { | |
627 | ret = PTR_ERR(bc); | |
628 | bc = NULL; | |
629 | break; | |
630 | } | |
631 | ||
632 | if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { | |
633 | ret = -EFAULT; | |
634 | break; | |
635 | } | |
636 | ||
637 | /* | |
638 | * get a request, fill in the blanks, and add to request queue | |
639 | */ | |
640 | rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense); | |
641 | if (IS_ERR(rq)) { | |
642 | ret = PTR_ERR(rq); | |
643 | rq = NULL; | |
644 | break; | |
645 | } | |
646 | ||
647 | bsg_add_command(bd, q, bc, rq); | |
648 | bc = NULL; | |
649 | rq = NULL; | |
650 | nr_commands--; | |
651 | buf += sizeof(struct sg_io_v4); | |
652 | *bytes_written += sizeof(struct sg_io_v4); | |
653 | } | |
654 | ||
655 | if (bc) | |
656 | bsg_free_command(bc); | |
657 | ||
658 | return ret; | |
659 | } | |
660 | ||
661 | static ssize_t | |
662 | bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
663 | { | |
664 | struct bsg_device *bd = file->private_data; | |
665 | ssize_t bytes_written; | |
666 | int ret; | |
667 | ||
668 | dprintk("%s: write %Zd bytes\n", bd->name, count); | |
669 | ||
670 | bsg_set_block(bd, file); | |
671 | ||
672 | bytes_written = 0; | |
673 | ret = __bsg_write(bd, buf, count, &bytes_written, | |
674 | file->f_mode & FMODE_WRITE); | |
675 | ||
676 | *ppos = bytes_written; | |
677 | ||
678 | /* | |
679 | * return bytes written on non-fatal errors | |
680 | */ | |
681 | if (!bytes_written || (bytes_written && err_block_err(ret))) | |
682 | bytes_written = ret; | |
683 | ||
684 | dprintk("%s: returning %Zd\n", bd->name, bytes_written); | |
685 | return bytes_written; | |
686 | } | |
687 | ||
688 | static struct bsg_device *bsg_alloc_device(void) | |
689 | { | |
690 | struct bsg_device *bd; | |
691 | ||
692 | bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); | |
693 | if (unlikely(!bd)) | |
694 | return NULL; | |
695 | ||
696 | spin_lock_init(&bd->lock); | |
697 | ||
698 | bd->max_queue = BSG_DEFAULT_CMDS; | |
699 | ||
700 | INIT_LIST_HEAD(&bd->busy_list); | |
701 | INIT_LIST_HEAD(&bd->done_list); | |
702 | INIT_HLIST_NODE(&bd->dev_list); | |
703 | ||
704 | init_waitqueue_head(&bd->wq_free); | |
705 | init_waitqueue_head(&bd->wq_done); | |
706 | return bd; | |
707 | } | |
708 | ||
709 | static void bsg_kref_release_function(struct kref *kref) | |
710 | { | |
711 | struct bsg_class_device *bcd = | |
712 | container_of(kref, struct bsg_class_device, ref); | |
713 | struct device *parent = bcd->parent; | |
714 | ||
715 | if (bcd->release) | |
716 | bcd->release(bcd->parent); | |
717 | ||
718 | put_device(parent); | |
719 | } | |
720 | ||
721 | static int bsg_put_device(struct bsg_device *bd) | |
722 | { | |
723 | int ret = 0, do_free; | |
724 | struct request_queue *q = bd->queue; | |
725 | ||
726 | mutex_lock(&bsg_mutex); | |
727 | ||
728 | do_free = atomic_dec_and_test(&bd->ref_count); | |
729 | if (!do_free) { | |
730 | mutex_unlock(&bsg_mutex); | |
731 | goto out; | |
732 | } | |
733 | ||
734 | hlist_del(&bd->dev_list); | |
735 | mutex_unlock(&bsg_mutex); | |
736 | ||
737 | dprintk("%s: tearing down\n", bd->name); | |
738 | ||
739 | /* | |
740 | * close can always block | |
741 | */ | |
742 | set_bit(BSG_F_BLOCK, &bd->flags); | |
743 | ||
744 | /* | |
745 | * correct error detection baddies here again. it's the responsibility | |
746 | * of the app to properly reap commands before close() if it wants | |
747 | * fool-proof error detection | |
748 | */ | |
749 | ret = bsg_complete_all_commands(bd); | |
750 | ||
751 | kfree(bd); | |
752 | out: | |
753 | kref_put(&q->bsg_dev.ref, bsg_kref_release_function); | |
754 | if (do_free) | |
755 | blk_put_queue(q); | |
756 | return ret; | |
757 | } | |
758 | ||
759 | static struct bsg_device *bsg_add_device(struct inode *inode, | |
760 | struct request_queue *rq, | |
761 | struct file *file) | |
762 | { | |
763 | struct bsg_device *bd; | |
764 | int ret; | |
765 | #ifdef BSG_DEBUG | |
766 | unsigned char buf[32]; | |
767 | #endif | |
768 | ret = blk_get_queue(rq); | |
769 | if (ret) | |
770 | return ERR_PTR(-ENXIO); | |
771 | ||
772 | bd = bsg_alloc_device(); | |
773 | if (!bd) { | |
774 | blk_put_queue(rq); | |
775 | return ERR_PTR(-ENOMEM); | |
776 | } | |
777 | ||
778 | bd->queue = rq; | |
779 | ||
780 | bsg_set_block(bd, file); | |
781 | ||
782 | atomic_set(&bd->ref_count, 1); | |
783 | mutex_lock(&bsg_mutex); | |
784 | hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); | |
785 | ||
786 | strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); | |
787 | dprintk("bound to <%s>, max queue %d\n", | |
788 | format_dev_t(buf, inode->i_rdev), bd->max_queue); | |
789 | ||
790 | mutex_unlock(&bsg_mutex); | |
791 | return bd; | |
792 | } | |
793 | ||
794 | static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) | |
795 | { | |
796 | struct bsg_device *bd; | |
797 | struct hlist_node *entry; | |
798 | ||
799 | mutex_lock(&bsg_mutex); | |
800 | ||
801 | hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { | |
802 | if (bd->queue == q) { | |
803 | atomic_inc(&bd->ref_count); | |
804 | goto found; | |
805 | } | |
806 | } | |
807 | bd = NULL; | |
808 | found: | |
809 | mutex_unlock(&bsg_mutex); | |
810 | return bd; | |
811 | } | |
812 | ||
813 | static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) | |
814 | { | |
815 | struct bsg_device *bd; | |
816 | struct bsg_class_device *bcd; | |
817 | ||
818 | /* | |
819 | * find the class device | |
820 | */ | |
821 | mutex_lock(&bsg_mutex); | |
822 | bcd = idr_find(&bsg_minor_idr, iminor(inode)); | |
823 | if (bcd) | |
824 | kref_get(&bcd->ref); | |
825 | mutex_unlock(&bsg_mutex); | |
826 | ||
827 | if (!bcd) | |
828 | return ERR_PTR(-ENODEV); | |
829 | ||
830 | bd = __bsg_get_device(iminor(inode), bcd->queue); | |
831 | if (bd) | |
832 | return bd; | |
833 | ||
834 | bd = bsg_add_device(inode, bcd->queue, file); | |
835 | if (IS_ERR(bd)) | |
836 | kref_put(&bcd->ref, bsg_kref_release_function); | |
837 | ||
838 | return bd; | |
839 | } | |
840 | ||
841 | static int bsg_open(struct inode *inode, struct file *file) | |
842 | { | |
843 | struct bsg_device *bd; | |
844 | ||
845 | lock_kernel(); | |
846 | bd = bsg_get_device(inode, file); | |
847 | unlock_kernel(); | |
848 | ||
849 | if (IS_ERR(bd)) | |
850 | return PTR_ERR(bd); | |
851 | ||
852 | file->private_data = bd; | |
853 | return 0; | |
854 | } | |
855 | ||
856 | static int bsg_release(struct inode *inode, struct file *file) | |
857 | { | |
858 | struct bsg_device *bd = file->private_data; | |
859 | ||
860 | file->private_data = NULL; | |
861 | return bsg_put_device(bd); | |
862 | } | |
863 | ||
864 | static unsigned int bsg_poll(struct file *file, poll_table *wait) | |
865 | { | |
866 | struct bsg_device *bd = file->private_data; | |
867 | unsigned int mask = 0; | |
868 | ||
869 | poll_wait(file, &bd->wq_done, wait); | |
870 | poll_wait(file, &bd->wq_free, wait); | |
871 | ||
872 | spin_lock_irq(&bd->lock); | |
873 | if (!list_empty(&bd->done_list)) | |
874 | mask |= POLLIN | POLLRDNORM; | |
875 | if (bd->queued_cmds >= bd->max_queue) | |
876 | mask |= POLLOUT; | |
877 | spin_unlock_irq(&bd->lock); | |
878 | ||
879 | return mask; | |
880 | } | |
881 | ||
882 | static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
883 | { | |
884 | struct bsg_device *bd = file->private_data; | |
885 | int __user *uarg = (int __user *) arg; | |
886 | int ret; | |
887 | ||
888 | switch (cmd) { | |
889 | /* | |
890 | * our own ioctls | |
891 | */ | |
892 | case SG_GET_COMMAND_Q: | |
893 | return put_user(bd->max_queue, uarg); | |
894 | case SG_SET_COMMAND_Q: { | |
895 | int queue; | |
896 | ||
897 | if (get_user(queue, uarg)) | |
898 | return -EFAULT; | |
899 | if (queue < 1) | |
900 | return -EINVAL; | |
901 | ||
902 | spin_lock_irq(&bd->lock); | |
903 | bd->max_queue = queue; | |
904 | spin_unlock_irq(&bd->lock); | |
905 | return 0; | |
906 | } | |
907 | ||
908 | /* | |
909 | * SCSI/sg ioctls | |
910 | */ | |
911 | case SG_GET_VERSION_NUM: | |
912 | case SCSI_IOCTL_GET_IDLUN: | |
913 | case SCSI_IOCTL_GET_BUS_NUMBER: | |
914 | case SG_SET_TIMEOUT: | |
915 | case SG_GET_TIMEOUT: | |
916 | case SG_GET_RESERVED_SIZE: | |
917 | case SG_SET_RESERVED_SIZE: | |
918 | case SG_EMULATED_HOST: | |
919 | case SCSI_IOCTL_SEND_COMMAND: { | |
920 | void __user *uarg = (void __user *) arg; | |
921 | return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); | |
922 | } | |
923 | case SG_IO: { | |
924 | struct request *rq; | |
925 | struct bio *bio, *bidi_bio = NULL; | |
926 | struct sg_io_v4 hdr; | |
927 | int at_head; | |
928 | u8 sense[SCSI_SENSE_BUFFERSIZE]; | |
929 | ||
930 | if (copy_from_user(&hdr, uarg, sizeof(hdr))) | |
931 | return -EFAULT; | |
932 | ||
933 | rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); | |
934 | if (IS_ERR(rq)) | |
935 | return PTR_ERR(rq); | |
936 | ||
937 | bio = rq->bio; | |
938 | if (rq->next_rq) | |
939 | bidi_bio = rq->next_rq->bio; | |
940 | ||
941 | at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); | |
942 | blk_execute_rq(bd->queue, NULL, rq, at_head); | |
943 | ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); | |
944 | ||
945 | if (copy_to_user(uarg, &hdr, sizeof(hdr))) | |
946 | return -EFAULT; | |
947 | ||
948 | return ret; | |
949 | } | |
950 | /* | |
951 | * block device ioctls | |
952 | */ | |
953 | default: | |
954 | #if 0 | |
955 | return ioctl_by_bdev(bd->bdev, cmd, arg); | |
956 | #else | |
957 | return -ENOTTY; | |
958 | #endif | |
959 | } | |
960 | } | |
961 | ||
962 | static const struct file_operations bsg_fops = { | |
963 | .read = bsg_read, | |
964 | .write = bsg_write, | |
965 | .poll = bsg_poll, | |
966 | .open = bsg_open, | |
967 | .release = bsg_release, | |
968 | .unlocked_ioctl = bsg_ioctl, | |
969 | .owner = THIS_MODULE, | |
970 | }; | |
971 | ||
972 | void bsg_unregister_queue(struct request_queue *q) | |
973 | { | |
974 | struct bsg_class_device *bcd = &q->bsg_dev; | |
975 | ||
976 | if (!bcd->class_dev) | |
977 | return; | |
978 | ||
979 | mutex_lock(&bsg_mutex); | |
980 | idr_remove(&bsg_minor_idr, bcd->minor); | |
981 | sysfs_remove_link(&q->kobj, "bsg"); | |
982 | device_unregister(bcd->class_dev); | |
983 | bcd->class_dev = NULL; | |
984 | kref_put(&bcd->ref, bsg_kref_release_function); | |
985 | mutex_unlock(&bsg_mutex); | |
986 | } | |
987 | EXPORT_SYMBOL_GPL(bsg_unregister_queue); | |
988 | ||
989 | int bsg_register_queue(struct request_queue *q, struct device *parent, | |
990 | const char *name, void (*release)(struct device *)) | |
991 | { | |
992 | struct bsg_class_device *bcd; | |
993 | dev_t dev; | |
994 | int ret, minor; | |
995 | struct device *class_dev = NULL; | |
996 | const char *devname; | |
997 | ||
998 | if (name) | |
999 | devname = name; | |
1000 | else | |
1001 | devname = dev_name(parent); | |
1002 | ||
1003 | /* | |
1004 | * we need a proper transport to send commands, not a stacked device | |
1005 | */ | |
1006 | if (!q->request_fn) | |
1007 | return 0; | |
1008 | ||
1009 | bcd = &q->bsg_dev; | |
1010 | memset(bcd, 0, sizeof(*bcd)); | |
1011 | ||
1012 | mutex_lock(&bsg_mutex); | |
1013 | ||
1014 | ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); | |
1015 | if (!ret) { | |
1016 | ret = -ENOMEM; | |
1017 | goto unlock; | |
1018 | } | |
1019 | ||
1020 | ret = idr_get_new(&bsg_minor_idr, bcd, &minor); | |
1021 | if (ret < 0) | |
1022 | goto unlock; | |
1023 | ||
1024 | if (minor >= BSG_MAX_DEVS) { | |
1025 | printk(KERN_ERR "bsg: too many bsg devices\n"); | |
1026 | ret = -EINVAL; | |
1027 | goto remove_idr; | |
1028 | } | |
1029 | ||
1030 | bcd->minor = minor; | |
1031 | bcd->queue = q; | |
1032 | bcd->parent = get_device(parent); | |
1033 | bcd->release = release; | |
1034 | kref_init(&bcd->ref); | |
1035 | dev = MKDEV(bsg_major, bcd->minor); | |
1036 | class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); | |
1037 | if (IS_ERR(class_dev)) { | |
1038 | ret = PTR_ERR(class_dev); | |
1039 | goto put_dev; | |
1040 | } | |
1041 | bcd->class_dev = class_dev; | |
1042 | ||
1043 | if (q->kobj.sd) { | |
1044 | ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); | |
1045 | if (ret) | |
1046 | goto unregister_class_dev; | |
1047 | } | |
1048 | ||
1049 | mutex_unlock(&bsg_mutex); | |
1050 | return 0; | |
1051 | ||
1052 | unregister_class_dev: | |
1053 | device_unregister(class_dev); | |
1054 | put_dev: | |
1055 | put_device(parent); | |
1056 | remove_idr: | |
1057 | idr_remove(&bsg_minor_idr, minor); | |
1058 | unlock: | |
1059 | mutex_unlock(&bsg_mutex); | |
1060 | return ret; | |
1061 | } | |
1062 | EXPORT_SYMBOL_GPL(bsg_register_queue); | |
1063 | ||
1064 | static struct cdev bsg_cdev; | |
1065 | ||
1066 | static char *bsg_devnode(struct device *dev, mode_t *mode) | |
1067 | { | |
1068 | return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); | |
1069 | } | |
1070 | ||
1071 | static int __init bsg_init(void) | |
1072 | { | |
1073 | int ret, i; | |
1074 | dev_t devid; | |
1075 | ||
1076 | bsg_cmd_cachep = kmem_cache_create("bsg_cmd", | |
1077 | sizeof(struct bsg_command), 0, 0, NULL); | |
1078 | if (!bsg_cmd_cachep) { | |
1079 | printk(KERN_ERR "bsg: failed creating slab cache\n"); | |
1080 | return -ENOMEM; | |
1081 | } | |
1082 | ||
1083 | for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) | |
1084 | INIT_HLIST_HEAD(&bsg_device_list[i]); | |
1085 | ||
1086 | bsg_class = class_create(THIS_MODULE, "bsg"); | |
1087 | if (IS_ERR(bsg_class)) { | |
1088 | ret = PTR_ERR(bsg_class); | |
1089 | goto destroy_kmemcache; | |
1090 | } | |
1091 | bsg_class->devnode = bsg_devnode; | |
1092 | ||
1093 | ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); | |
1094 | if (ret) | |
1095 | goto destroy_bsg_class; | |
1096 | ||
1097 | bsg_major = MAJOR(devid); | |
1098 | ||
1099 | cdev_init(&bsg_cdev, &bsg_fops); | |
1100 | ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); | |
1101 | if (ret) | |
1102 | goto unregister_chrdev; | |
1103 | ||
1104 | printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION | |
1105 | " loaded (major %d)\n", bsg_major); | |
1106 | return 0; | |
1107 | unregister_chrdev: | |
1108 | unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); | |
1109 | destroy_bsg_class: | |
1110 | class_destroy(bsg_class); | |
1111 | destroy_kmemcache: | |
1112 | kmem_cache_destroy(bsg_cmd_cachep); | |
1113 | return ret; | |
1114 | } | |
1115 | ||
1116 | MODULE_AUTHOR("Jens Axboe"); | |
1117 | MODULE_DESCRIPTION(BSG_DESCRIPTION); | |
1118 | MODULE_LICENSE("GPL"); | |
1119 | ||
1120 | device_initcall(bsg_init); |