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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 | #include <linux/slab.h> | |
25 | ||
26 | #include <scsi/scsi.h> | |
27 | #include <scsi/scsi_ioctl.h> | |
28 | #include <scsi/scsi_cmnd.h> | |
29 | #include <scsi/scsi_device.h> | |
30 | #include <scsi/scsi_driver.h> | |
31 | #include <scsi/sg.h> | |
32 | ||
33 | #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" | |
34 | #define BSG_VERSION "0.4" | |
35 | ||
36 | struct bsg_device { | |
37 | struct request_queue *queue; | |
38 | spinlock_t lock; | |
39 | struct list_head busy_list; | |
40 | struct list_head done_list; | |
41 | struct hlist_node dev_list; | |
42 | atomic_t ref_count; | |
43 | int queued_cmds; | |
44 | int done_cmds; | |
45 | wait_queue_head_t wq_done; | |
46 | wait_queue_head_t wq_free; | |
47 | char name[20]; | |
48 | int max_queue; | |
49 | unsigned long flags; | |
50 | }; | |
51 | ||
52 | enum { | |
53 | BSG_F_BLOCK = 1, | |
54 | }; | |
55 | ||
56 | #define BSG_DEFAULT_CMDS 64 | |
57 | #define BSG_MAX_DEVS 32768 | |
58 | ||
59 | #undef BSG_DEBUG | |
60 | ||
61 | #ifdef BSG_DEBUG | |
62 | #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) | |
63 | #else | |
64 | #define dprintk(fmt, args...) | |
65 | #endif | |
66 | ||
67 | static DEFINE_MUTEX(bsg_mutex); | |
68 | static DEFINE_IDR(bsg_minor_idr); | |
69 | ||
70 | #define BSG_LIST_ARRAY_SIZE 8 | |
71 | static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; | |
72 | ||
73 | static struct class *bsg_class; | |
74 | static int bsg_major; | |
75 | ||
76 | static struct kmem_cache *bsg_cmd_cachep; | |
77 | ||
78 | /* | |
79 | * our internal command type | |
80 | */ | |
81 | struct bsg_command { | |
82 | struct bsg_device *bd; | |
83 | struct list_head list; | |
84 | struct request *rq; | |
85 | struct bio *bio; | |
86 | struct bio *bidi_bio; | |
87 | int err; | |
88 | struct sg_io_v4 hdr; | |
89 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
90 | }; | |
91 | ||
92 | static void bsg_free_command(struct bsg_command *bc) | |
93 | { | |
94 | struct bsg_device *bd = bc->bd; | |
95 | unsigned long flags; | |
96 | ||
97 | kmem_cache_free(bsg_cmd_cachep, bc); | |
98 | ||
99 | spin_lock_irqsave(&bd->lock, flags); | |
100 | bd->queued_cmds--; | |
101 | spin_unlock_irqrestore(&bd->lock, flags); | |
102 | ||
103 | wake_up(&bd->wq_free); | |
104 | } | |
105 | ||
106 | static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) | |
107 | { | |
108 | struct bsg_command *bc = ERR_PTR(-EINVAL); | |
109 | ||
110 | spin_lock_irq(&bd->lock); | |
111 | ||
112 | if (bd->queued_cmds >= bd->max_queue) | |
113 | goto out; | |
114 | ||
115 | bd->queued_cmds++; | |
116 | spin_unlock_irq(&bd->lock); | |
117 | ||
118 | bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); | |
119 | if (unlikely(!bc)) { | |
120 | spin_lock_irq(&bd->lock); | |
121 | bd->queued_cmds--; | |
122 | bc = ERR_PTR(-ENOMEM); | |
123 | goto out; | |
124 | } | |
125 | ||
126 | bc->bd = bd; | |
127 | INIT_LIST_HEAD(&bc->list); | |
128 | dprintk("%s: returning free cmd %p\n", bd->name, bc); | |
129 | return bc; | |
130 | out: | |
131 | spin_unlock_irq(&bd->lock); | |
132 | return bc; | |
133 | } | |
134 | ||
135 | static inline struct hlist_head *bsg_dev_idx_hash(int index) | |
136 | { | |
137 | return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; | |
138 | } | |
139 | ||
140 | static int bsg_io_schedule(struct bsg_device *bd) | |
141 | { | |
142 | DEFINE_WAIT(wait); | |
143 | int ret = 0; | |
144 | ||
145 | spin_lock_irq(&bd->lock); | |
146 | ||
147 | BUG_ON(bd->done_cmds > bd->queued_cmds); | |
148 | ||
149 | /* | |
150 | * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no | |
151 | * work to do", even though we return -ENOSPC after this same test | |
152 | * during bsg_write() -- there, it means our buffer can't have more | |
153 | * bsg_commands added to it, thus has no space left. | |
154 | */ | |
155 | if (bd->done_cmds == bd->queued_cmds) { | |
156 | ret = -ENODATA; | |
157 | goto unlock; | |
158 | } | |
159 | ||
160 | if (!test_bit(BSG_F_BLOCK, &bd->flags)) { | |
161 | ret = -EAGAIN; | |
162 | goto unlock; | |
163 | } | |
164 | ||
165 | prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); | |
166 | spin_unlock_irq(&bd->lock); | |
167 | io_schedule(); | |
168 | finish_wait(&bd->wq_done, &wait); | |
169 | ||
170 | return ret; | |
171 | unlock: | |
172 | spin_unlock_irq(&bd->lock); | |
173 | return ret; | |
174 | } | |
175 | ||
176 | static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, | |
177 | struct sg_io_v4 *hdr, struct bsg_device *bd, | |
178 | fmode_t has_write_perm) | |
179 | { | |
180 | if (hdr->request_len > BLK_MAX_CDB) { | |
181 | rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); | |
182 | if (!rq->cmd) | |
183 | return -ENOMEM; | |
184 | } | |
185 | ||
186 | if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, | |
187 | hdr->request_len)) | |
188 | return -EFAULT; | |
189 | ||
190 | if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { | |
191 | if (blk_verify_command(rq->cmd, has_write_perm)) | |
192 | return -EPERM; | |
193 | } else if (!capable(CAP_SYS_RAWIO)) | |
194 | return -EPERM; | |
195 | ||
196 | /* | |
197 | * fill in request structure | |
198 | */ | |
199 | rq->cmd_len = hdr->request_len; | |
200 | rq->cmd_type = REQ_TYPE_BLOCK_PC; | |
201 | ||
202 | rq->timeout = msecs_to_jiffies(hdr->timeout); | |
203 | if (!rq->timeout) | |
204 | rq->timeout = q->sg_timeout; | |
205 | if (!rq->timeout) | |
206 | rq->timeout = BLK_DEFAULT_SG_TIMEOUT; | |
207 | if (rq->timeout < BLK_MIN_SG_TIMEOUT) | |
208 | rq->timeout = BLK_MIN_SG_TIMEOUT; | |
209 | ||
210 | return 0; | |
211 | } | |
212 | ||
213 | /* | |
214 | * Check if sg_io_v4 from user is allowed and valid | |
215 | */ | |
216 | static int | |
217 | bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) | |
218 | { | |
219 | int ret = 0; | |
220 | ||
221 | if (hdr->guard != 'Q') | |
222 | return -EINVAL; | |
223 | ||
224 | switch (hdr->protocol) { | |
225 | case BSG_PROTOCOL_SCSI: | |
226 | switch (hdr->subprotocol) { | |
227 | case BSG_SUB_PROTOCOL_SCSI_CMD: | |
228 | case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: | |
229 | break; | |
230 | default: | |
231 | ret = -EINVAL; | |
232 | } | |
233 | break; | |
234 | default: | |
235 | ret = -EINVAL; | |
236 | } | |
237 | ||
238 | *rw = hdr->dout_xfer_len ? WRITE : READ; | |
239 | return ret; | |
240 | } | |
241 | ||
242 | /* | |
243 | * map sg_io_v4 to a request. | |
244 | */ | |
245 | static struct request * | |
246 | bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm, | |
247 | u8 *sense) | |
248 | { | |
249 | struct request_queue *q = bd->queue; | |
250 | struct request *rq, *next_rq = NULL; | |
251 | int ret, rw; | |
252 | unsigned int dxfer_len; | |
253 | void *dxferp = NULL; | |
254 | ||
255 | dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, | |
256 | hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, | |
257 | hdr->din_xfer_len); | |
258 | ||
259 | ret = bsg_validate_sgv4_hdr(q, hdr, &rw); | |
260 | if (ret) | |
261 | return ERR_PTR(ret); | |
262 | ||
263 | /* | |
264 | * map scatter-gather elements separately and string them to request | |
265 | */ | |
266 | rq = blk_get_request(q, rw, GFP_KERNEL); | |
267 | if (!rq) | |
268 | return ERR_PTR(-ENOMEM); | |
269 | ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); | |
270 | if (ret) | |
271 | goto out; | |
272 | ||
273 | if (rw == WRITE && hdr->din_xfer_len) { | |
274 | if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { | |
275 | ret = -EOPNOTSUPP; | |
276 | goto out; | |
277 | } | |
278 | ||
279 | next_rq = blk_get_request(q, READ, GFP_KERNEL); | |
280 | if (!next_rq) { | |
281 | ret = -ENOMEM; | |
282 | goto out; | |
283 | } | |
284 | rq->next_rq = next_rq; | |
285 | next_rq->cmd_type = rq->cmd_type; | |
286 | ||
287 | dxferp = (void*)(unsigned long)hdr->din_xferp; | |
288 | ret = blk_rq_map_user(q, next_rq, NULL, dxferp, | |
289 | hdr->din_xfer_len, GFP_KERNEL); | |
290 | if (ret) | |
291 | goto out; | |
292 | } | |
293 | ||
294 | if (hdr->dout_xfer_len) { | |
295 | dxfer_len = hdr->dout_xfer_len; | |
296 | dxferp = (void*)(unsigned long)hdr->dout_xferp; | |
297 | } else if (hdr->din_xfer_len) { | |
298 | dxfer_len = hdr->din_xfer_len; | |
299 | dxferp = (void*)(unsigned long)hdr->din_xferp; | |
300 | } else | |
301 | dxfer_len = 0; | |
302 | ||
303 | if (dxfer_len) { | |
304 | ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, | |
305 | GFP_KERNEL); | |
306 | if (ret) | |
307 | goto out; | |
308 | } | |
309 | ||
310 | rq->sense = sense; | |
311 | rq->sense_len = 0; | |
312 | ||
313 | return rq; | |
314 | out: | |
315 | if (rq->cmd != rq->__cmd) | |
316 | kfree(rq->cmd); | |
317 | blk_put_request(rq); | |
318 | if (next_rq) { | |
319 | blk_rq_unmap_user(next_rq->bio); | |
320 | blk_put_request(next_rq); | |
321 | } | |
322 | return ERR_PTR(ret); | |
323 | } | |
324 | ||
325 | /* | |
326 | * async completion call-back from the block layer, when scsi/ide/whatever | |
327 | * calls end_that_request_last() on a request | |
328 | */ | |
329 | static void bsg_rq_end_io(struct request *rq, int uptodate) | |
330 | { | |
331 | struct bsg_command *bc = rq->end_io_data; | |
332 | struct bsg_device *bd = bc->bd; | |
333 | unsigned long flags; | |
334 | ||
335 | dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", | |
336 | bd->name, rq, bc, bc->bio, uptodate); | |
337 | ||
338 | bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); | |
339 | ||
340 | spin_lock_irqsave(&bd->lock, flags); | |
341 | list_move_tail(&bc->list, &bd->done_list); | |
342 | bd->done_cmds++; | |
343 | spin_unlock_irqrestore(&bd->lock, flags); | |
344 | ||
345 | wake_up(&bd->wq_done); | |
346 | } | |
347 | ||
348 | /* | |
349 | * do final setup of a 'bc' and submit the matching 'rq' to the block | |
350 | * layer for io | |
351 | */ | |
352 | static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, | |
353 | struct bsg_command *bc, struct request *rq) | |
354 | { | |
355 | int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); | |
356 | ||
357 | /* | |
358 | * add bc command to busy queue and submit rq for io | |
359 | */ | |
360 | bc->rq = rq; | |
361 | bc->bio = rq->bio; | |
362 | if (rq->next_rq) | |
363 | bc->bidi_bio = rq->next_rq->bio; | |
364 | bc->hdr.duration = jiffies; | |
365 | spin_lock_irq(&bd->lock); | |
366 | list_add_tail(&bc->list, &bd->busy_list); | |
367 | spin_unlock_irq(&bd->lock); | |
368 | ||
369 | dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); | |
370 | ||
371 | rq->end_io_data = bc; | |
372 | blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); | |
373 | } | |
374 | ||
375 | static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) | |
376 | { | |
377 | struct bsg_command *bc = NULL; | |
378 | ||
379 | spin_lock_irq(&bd->lock); | |
380 | if (bd->done_cmds) { | |
381 | bc = list_first_entry(&bd->done_list, struct bsg_command, list); | |
382 | list_del(&bc->list); | |
383 | bd->done_cmds--; | |
384 | } | |
385 | spin_unlock_irq(&bd->lock); | |
386 | ||
387 | return bc; | |
388 | } | |
389 | ||
390 | /* | |
391 | * Get a finished command from the done list | |
392 | */ | |
393 | static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) | |
394 | { | |
395 | struct bsg_command *bc; | |
396 | int ret; | |
397 | ||
398 | do { | |
399 | bc = bsg_next_done_cmd(bd); | |
400 | if (bc) | |
401 | break; | |
402 | ||
403 | if (!test_bit(BSG_F_BLOCK, &bd->flags)) { | |
404 | bc = ERR_PTR(-EAGAIN); | |
405 | break; | |
406 | } | |
407 | ||
408 | ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); | |
409 | if (ret) { | |
410 | bc = ERR_PTR(-ERESTARTSYS); | |
411 | break; | |
412 | } | |
413 | } while (1); | |
414 | ||
415 | dprintk("%s: returning done %p\n", bd->name, bc); | |
416 | ||
417 | return bc; | |
418 | } | |
419 | ||
420 | static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, | |
421 | struct bio *bio, struct bio *bidi_bio) | |
422 | { | |
423 | int ret = 0; | |
424 | ||
425 | dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors); | |
426 | /* | |
427 | * fill in all the output members | |
428 | */ | |
429 | hdr->device_status = status_byte(rq->errors); | |
430 | hdr->transport_status = host_byte(rq->errors); | |
431 | hdr->driver_status = driver_byte(rq->errors); | |
432 | hdr->info = 0; | |
433 | if (hdr->device_status || hdr->transport_status || hdr->driver_status) | |
434 | hdr->info |= SG_INFO_CHECK; | |
435 | hdr->response_len = 0; | |
436 | ||
437 | if (rq->sense_len && hdr->response) { | |
438 | int len = min_t(unsigned int, hdr->max_response_len, | |
439 | rq->sense_len); | |
440 | ||
441 | ret = copy_to_user((void*)(unsigned long)hdr->response, | |
442 | rq->sense, len); | |
443 | if (!ret) | |
444 | hdr->response_len = len; | |
445 | else | |
446 | ret = -EFAULT; | |
447 | } | |
448 | ||
449 | if (rq->next_rq) { | |
450 | hdr->dout_resid = rq->resid_len; | |
451 | hdr->din_resid = rq->next_rq->resid_len; | |
452 | blk_rq_unmap_user(bidi_bio); | |
453 | blk_put_request(rq->next_rq); | |
454 | } else if (rq_data_dir(rq) == READ) | |
455 | hdr->din_resid = rq->resid_len; | |
456 | else | |
457 | hdr->dout_resid = rq->resid_len; | |
458 | ||
459 | /* | |
460 | * If the request generated a negative error number, return it | |
461 | * (providing we aren't already returning an error); if it's | |
462 | * just a protocol response (i.e. non negative), that gets | |
463 | * processed above. | |
464 | */ | |
465 | if (!ret && rq->errors < 0) | |
466 | ret = rq->errors; | |
467 | ||
468 | blk_rq_unmap_user(bio); | |
469 | if (rq->cmd != rq->__cmd) | |
470 | kfree(rq->cmd); | |
471 | blk_put_request(rq); | |
472 | ||
473 | return ret; | |
474 | } | |
475 | ||
476 | static int bsg_complete_all_commands(struct bsg_device *bd) | |
477 | { | |
478 | struct bsg_command *bc; | |
479 | int ret, tret; | |
480 | ||
481 | dprintk("%s: entered\n", bd->name); | |
482 | ||
483 | /* | |
484 | * wait for all commands to complete | |
485 | */ | |
486 | ret = 0; | |
487 | do { | |
488 | ret = bsg_io_schedule(bd); | |
489 | /* | |
490 | * look for -ENODATA specifically -- we'll sometimes get | |
491 | * -ERESTARTSYS when we've taken a signal, but we can't | |
492 | * return until we're done freeing the queue, so ignore | |
493 | * it. The signal will get handled when we're done freeing | |
494 | * the bsg_device. | |
495 | */ | |
496 | } while (ret != -ENODATA); | |
497 | ||
498 | /* | |
499 | * discard done commands | |
500 | */ | |
501 | ret = 0; | |
502 | do { | |
503 | spin_lock_irq(&bd->lock); | |
504 | if (!bd->queued_cmds) { | |
505 | spin_unlock_irq(&bd->lock); | |
506 | break; | |
507 | } | |
508 | spin_unlock_irq(&bd->lock); | |
509 | ||
510 | bc = bsg_get_done_cmd(bd); | |
511 | if (IS_ERR(bc)) | |
512 | break; | |
513 | ||
514 | tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, | |
515 | bc->bidi_bio); | |
516 | if (!ret) | |
517 | ret = tret; | |
518 | ||
519 | bsg_free_command(bc); | |
520 | } while (1); | |
521 | ||
522 | return ret; | |
523 | } | |
524 | ||
525 | static int | |
526 | __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, | |
527 | const struct iovec *iov, ssize_t *bytes_read) | |
528 | { | |
529 | struct bsg_command *bc; | |
530 | int nr_commands, ret; | |
531 | ||
532 | if (count % sizeof(struct sg_io_v4)) | |
533 | return -EINVAL; | |
534 | ||
535 | ret = 0; | |
536 | nr_commands = count / sizeof(struct sg_io_v4); | |
537 | while (nr_commands) { | |
538 | bc = bsg_get_done_cmd(bd); | |
539 | if (IS_ERR(bc)) { | |
540 | ret = PTR_ERR(bc); | |
541 | break; | |
542 | } | |
543 | ||
544 | /* | |
545 | * this is the only case where we need to copy data back | |
546 | * after completing the request. so do that here, | |
547 | * bsg_complete_work() cannot do that for us | |
548 | */ | |
549 | ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, | |
550 | bc->bidi_bio); | |
551 | ||
552 | if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) | |
553 | ret = -EFAULT; | |
554 | ||
555 | bsg_free_command(bc); | |
556 | ||
557 | if (ret) | |
558 | break; | |
559 | ||
560 | buf += sizeof(struct sg_io_v4); | |
561 | *bytes_read += sizeof(struct sg_io_v4); | |
562 | nr_commands--; | |
563 | } | |
564 | ||
565 | return ret; | |
566 | } | |
567 | ||
568 | static inline void bsg_set_block(struct bsg_device *bd, struct file *file) | |
569 | { | |
570 | if (file->f_flags & O_NONBLOCK) | |
571 | clear_bit(BSG_F_BLOCK, &bd->flags); | |
572 | else | |
573 | set_bit(BSG_F_BLOCK, &bd->flags); | |
574 | } | |
575 | ||
576 | /* | |
577 | * Check if the error is a "real" error that we should return. | |
578 | */ | |
579 | static inline int err_block_err(int ret) | |
580 | { | |
581 | if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) | |
582 | return 1; | |
583 | ||
584 | return 0; | |
585 | } | |
586 | ||
587 | static ssize_t | |
588 | bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
589 | { | |
590 | struct bsg_device *bd = file->private_data; | |
591 | int ret; | |
592 | ssize_t bytes_read; | |
593 | ||
594 | dprintk("%s: read %Zd bytes\n", bd->name, count); | |
595 | ||
596 | bsg_set_block(bd, file); | |
597 | ||
598 | bytes_read = 0; | |
599 | ret = __bsg_read(buf, count, bd, NULL, &bytes_read); | |
600 | *ppos = bytes_read; | |
601 | ||
602 | if (!bytes_read || (bytes_read && err_block_err(ret))) | |
603 | bytes_read = ret; | |
604 | ||
605 | return bytes_read; | |
606 | } | |
607 | ||
608 | static int __bsg_write(struct bsg_device *bd, const char __user *buf, | |
609 | size_t count, ssize_t *bytes_written, | |
610 | fmode_t has_write_perm) | |
611 | { | |
612 | struct bsg_command *bc; | |
613 | struct request *rq; | |
614 | int ret, nr_commands; | |
615 | ||
616 | if (count % sizeof(struct sg_io_v4)) | |
617 | return -EINVAL; | |
618 | ||
619 | nr_commands = count / sizeof(struct sg_io_v4); | |
620 | rq = NULL; | |
621 | bc = NULL; | |
622 | ret = 0; | |
623 | while (nr_commands) { | |
624 | struct request_queue *q = bd->queue; | |
625 | ||
626 | bc = bsg_alloc_command(bd); | |
627 | if (IS_ERR(bc)) { | |
628 | ret = PTR_ERR(bc); | |
629 | bc = NULL; | |
630 | break; | |
631 | } | |
632 | ||
633 | if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { | |
634 | ret = -EFAULT; | |
635 | break; | |
636 | } | |
637 | ||
638 | /* | |
639 | * get a request, fill in the blanks, and add to request queue | |
640 | */ | |
641 | rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense); | |
642 | if (IS_ERR(rq)) { | |
643 | ret = PTR_ERR(rq); | |
644 | rq = NULL; | |
645 | break; | |
646 | } | |
647 | ||
648 | bsg_add_command(bd, q, bc, rq); | |
649 | bc = NULL; | |
650 | rq = NULL; | |
651 | nr_commands--; | |
652 | buf += sizeof(struct sg_io_v4); | |
653 | *bytes_written += sizeof(struct sg_io_v4); | |
654 | } | |
655 | ||
656 | if (bc) | |
657 | bsg_free_command(bc); | |
658 | ||
659 | return ret; | |
660 | } | |
661 | ||
662 | static ssize_t | |
663 | bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
664 | { | |
665 | struct bsg_device *bd = file->private_data; | |
666 | ssize_t bytes_written; | |
667 | int ret; | |
668 | ||
669 | dprintk("%s: write %Zd bytes\n", bd->name, count); | |
670 | ||
671 | bsg_set_block(bd, file); | |
672 | ||
673 | bytes_written = 0; | |
674 | ret = __bsg_write(bd, buf, count, &bytes_written, | |
675 | file->f_mode & FMODE_WRITE); | |
676 | ||
677 | *ppos = bytes_written; | |
678 | ||
679 | /* | |
680 | * return bytes written on non-fatal errors | |
681 | */ | |
682 | if (!bytes_written || (bytes_written && err_block_err(ret))) | |
683 | bytes_written = ret; | |
684 | ||
685 | dprintk("%s: returning %Zd\n", bd->name, bytes_written); | |
686 | return bytes_written; | |
687 | } | |
688 | ||
689 | static struct bsg_device *bsg_alloc_device(void) | |
690 | { | |
691 | struct bsg_device *bd; | |
692 | ||
693 | bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); | |
694 | if (unlikely(!bd)) | |
695 | return NULL; | |
696 | ||
697 | spin_lock_init(&bd->lock); | |
698 | ||
699 | bd->max_queue = BSG_DEFAULT_CMDS; | |
700 | ||
701 | INIT_LIST_HEAD(&bd->busy_list); | |
702 | INIT_LIST_HEAD(&bd->done_list); | |
703 | INIT_HLIST_NODE(&bd->dev_list); | |
704 | ||
705 | init_waitqueue_head(&bd->wq_free); | |
706 | init_waitqueue_head(&bd->wq_done); | |
707 | return bd; | |
708 | } | |
709 | ||
710 | static void bsg_kref_release_function(struct kref *kref) | |
711 | { | |
712 | struct bsg_class_device *bcd = | |
713 | container_of(kref, struct bsg_class_device, ref); | |
714 | struct device *parent = bcd->parent; | |
715 | ||
716 | if (bcd->release) | |
717 | bcd->release(bcd->parent); | |
718 | ||
719 | put_device(parent); | |
720 | } | |
721 | ||
722 | static int bsg_put_device(struct bsg_device *bd) | |
723 | { | |
724 | int ret = 0, do_free; | |
725 | struct request_queue *q = bd->queue; | |
726 | ||
727 | mutex_lock(&bsg_mutex); | |
728 | ||
729 | do_free = atomic_dec_and_test(&bd->ref_count); | |
730 | if (!do_free) { | |
731 | mutex_unlock(&bsg_mutex); | |
732 | goto out; | |
733 | } | |
734 | ||
735 | hlist_del(&bd->dev_list); | |
736 | mutex_unlock(&bsg_mutex); | |
737 | ||
738 | dprintk("%s: tearing down\n", bd->name); | |
739 | ||
740 | /* | |
741 | * close can always block | |
742 | */ | |
743 | set_bit(BSG_F_BLOCK, &bd->flags); | |
744 | ||
745 | /* | |
746 | * correct error detection baddies here again. it's the responsibility | |
747 | * of the app to properly reap commands before close() if it wants | |
748 | * fool-proof error detection | |
749 | */ | |
750 | ret = bsg_complete_all_commands(bd); | |
751 | ||
752 | kfree(bd); | |
753 | out: | |
754 | kref_put(&q->bsg_dev.ref, bsg_kref_release_function); | |
755 | if (do_free) | |
756 | blk_put_queue(q); | |
757 | return ret; | |
758 | } | |
759 | ||
760 | static struct bsg_device *bsg_add_device(struct inode *inode, | |
761 | struct request_queue *rq, | |
762 | struct file *file) | |
763 | { | |
764 | struct bsg_device *bd; | |
765 | int ret; | |
766 | #ifdef BSG_DEBUG | |
767 | unsigned char buf[32]; | |
768 | #endif | |
769 | ret = blk_get_queue(rq); | |
770 | if (ret) | |
771 | return ERR_PTR(-ENXIO); | |
772 | ||
773 | bd = bsg_alloc_device(); | |
774 | if (!bd) { | |
775 | blk_put_queue(rq); | |
776 | return ERR_PTR(-ENOMEM); | |
777 | } | |
778 | ||
779 | bd->queue = rq; | |
780 | ||
781 | bsg_set_block(bd, file); | |
782 | ||
783 | atomic_set(&bd->ref_count, 1); | |
784 | mutex_lock(&bsg_mutex); | |
785 | hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); | |
786 | ||
787 | strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); | |
788 | dprintk("bound to <%s>, max queue %d\n", | |
789 | format_dev_t(buf, inode->i_rdev), bd->max_queue); | |
790 | ||
791 | mutex_unlock(&bsg_mutex); | |
792 | return bd; | |
793 | } | |
794 | ||
795 | static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) | |
796 | { | |
797 | struct bsg_device *bd; | |
798 | struct hlist_node *entry; | |
799 | ||
800 | mutex_lock(&bsg_mutex); | |
801 | ||
802 | hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { | |
803 | if (bd->queue == q) { | |
804 | atomic_inc(&bd->ref_count); | |
805 | goto found; | |
806 | } | |
807 | } | |
808 | bd = NULL; | |
809 | found: | |
810 | mutex_unlock(&bsg_mutex); | |
811 | return bd; | |
812 | } | |
813 | ||
814 | static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) | |
815 | { | |
816 | struct bsg_device *bd; | |
817 | struct bsg_class_device *bcd; | |
818 | ||
819 | /* | |
820 | * find the class device | |
821 | */ | |
822 | mutex_lock(&bsg_mutex); | |
823 | bcd = idr_find(&bsg_minor_idr, iminor(inode)); | |
824 | if (bcd) | |
825 | kref_get(&bcd->ref); | |
826 | mutex_unlock(&bsg_mutex); | |
827 | ||
828 | if (!bcd) | |
829 | return ERR_PTR(-ENODEV); | |
830 | ||
831 | bd = __bsg_get_device(iminor(inode), bcd->queue); | |
832 | if (bd) | |
833 | return bd; | |
834 | ||
835 | bd = bsg_add_device(inode, bcd->queue, file); | |
836 | if (IS_ERR(bd)) | |
837 | kref_put(&bcd->ref, bsg_kref_release_function); | |
838 | ||
839 | return bd; | |
840 | } | |
841 | ||
842 | static int bsg_open(struct inode *inode, struct file *file) | |
843 | { | |
844 | struct bsg_device *bd; | |
845 | ||
846 | lock_kernel(); | |
847 | bd = bsg_get_device(inode, file); | |
848 | unlock_kernel(); | |
849 | ||
850 | if (IS_ERR(bd)) | |
851 | return PTR_ERR(bd); | |
852 | ||
853 | file->private_data = bd; | |
854 | return 0; | |
855 | } | |
856 | ||
857 | static int bsg_release(struct inode *inode, struct file *file) | |
858 | { | |
859 | struct bsg_device *bd = file->private_data; | |
860 | ||
861 | file->private_data = NULL; | |
862 | return bsg_put_device(bd); | |
863 | } | |
864 | ||
865 | static unsigned int bsg_poll(struct file *file, poll_table *wait) | |
866 | { | |
867 | struct bsg_device *bd = file->private_data; | |
868 | unsigned int mask = 0; | |
869 | ||
870 | poll_wait(file, &bd->wq_done, wait); | |
871 | poll_wait(file, &bd->wq_free, wait); | |
872 | ||
873 | spin_lock_irq(&bd->lock); | |
874 | if (!list_empty(&bd->done_list)) | |
875 | mask |= POLLIN | POLLRDNORM; | |
876 | if (bd->queued_cmds >= bd->max_queue) | |
877 | mask |= POLLOUT; | |
878 | spin_unlock_irq(&bd->lock); | |
879 | ||
880 | return mask; | |
881 | } | |
882 | ||
883 | static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
884 | { | |
885 | struct bsg_device *bd = file->private_data; | |
886 | int __user *uarg = (int __user *) arg; | |
887 | int ret; | |
888 | ||
889 | switch (cmd) { | |
890 | /* | |
891 | * our own ioctls | |
892 | */ | |
893 | case SG_GET_COMMAND_Q: | |
894 | return put_user(bd->max_queue, uarg); | |
895 | case SG_SET_COMMAND_Q: { | |
896 | int queue; | |
897 | ||
898 | if (get_user(queue, uarg)) | |
899 | return -EFAULT; | |
900 | if (queue < 1) | |
901 | return -EINVAL; | |
902 | ||
903 | spin_lock_irq(&bd->lock); | |
904 | bd->max_queue = queue; | |
905 | spin_unlock_irq(&bd->lock); | |
906 | return 0; | |
907 | } | |
908 | ||
909 | /* | |
910 | * SCSI/sg ioctls | |
911 | */ | |
912 | case SG_GET_VERSION_NUM: | |
913 | case SCSI_IOCTL_GET_IDLUN: | |
914 | case SCSI_IOCTL_GET_BUS_NUMBER: | |
915 | case SG_SET_TIMEOUT: | |
916 | case SG_GET_TIMEOUT: | |
917 | case SG_GET_RESERVED_SIZE: | |
918 | case SG_SET_RESERVED_SIZE: | |
919 | case SG_EMULATED_HOST: | |
920 | case SCSI_IOCTL_SEND_COMMAND: { | |
921 | void __user *uarg = (void __user *) arg; | |
922 | return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); | |
923 | } | |
924 | case SG_IO: { | |
925 | struct request *rq; | |
926 | struct bio *bio, *bidi_bio = NULL; | |
927 | struct sg_io_v4 hdr; | |
928 | int at_head; | |
929 | u8 sense[SCSI_SENSE_BUFFERSIZE]; | |
930 | ||
931 | if (copy_from_user(&hdr, uarg, sizeof(hdr))) | |
932 | return -EFAULT; | |
933 | ||
934 | rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense); | |
935 | if (IS_ERR(rq)) | |
936 | return PTR_ERR(rq); | |
937 | ||
938 | bio = rq->bio; | |
939 | if (rq->next_rq) | |
940 | bidi_bio = rq->next_rq->bio; | |
941 | ||
942 | at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); | |
943 | blk_execute_rq(bd->queue, NULL, rq, at_head); | |
944 | ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); | |
945 | ||
946 | if (copy_to_user(uarg, &hdr, sizeof(hdr))) | |
947 | return -EFAULT; | |
948 | ||
949 | return ret; | |
950 | } | |
951 | /* | |
952 | * block device ioctls | |
953 | */ | |
954 | default: | |
955 | #if 0 | |
956 | return ioctl_by_bdev(bd->bdev, cmd, arg); | |
957 | #else | |
958 | return -ENOTTY; | |
959 | #endif | |
960 | } | |
961 | } | |
962 | ||
963 | static const struct file_operations bsg_fops = { | |
964 | .read = bsg_read, | |
965 | .write = bsg_write, | |
966 | .poll = bsg_poll, | |
967 | .open = bsg_open, | |
968 | .release = bsg_release, | |
969 | .unlocked_ioctl = bsg_ioctl, | |
970 | .owner = THIS_MODULE, | |
971 | }; | |
972 | ||
973 | void bsg_unregister_queue(struct request_queue *q) | |
974 | { | |
975 | struct bsg_class_device *bcd = &q->bsg_dev; | |
976 | ||
977 | if (!bcd->class_dev) | |
978 | return; | |
979 | ||
980 | mutex_lock(&bsg_mutex); | |
981 | idr_remove(&bsg_minor_idr, bcd->minor); | |
982 | sysfs_remove_link(&q->kobj, "bsg"); | |
983 | device_unregister(bcd->class_dev); | |
984 | bcd->class_dev = NULL; | |
985 | kref_put(&bcd->ref, bsg_kref_release_function); | |
986 | mutex_unlock(&bsg_mutex); | |
987 | } | |
988 | EXPORT_SYMBOL_GPL(bsg_unregister_queue); | |
989 | ||
990 | int bsg_register_queue(struct request_queue *q, struct device *parent, | |
991 | const char *name, void (*release)(struct device *)) | |
992 | { | |
993 | struct bsg_class_device *bcd; | |
994 | dev_t dev; | |
995 | int ret, minor; | |
996 | struct device *class_dev = NULL; | |
997 | const char *devname; | |
998 | ||
999 | if (name) | |
1000 | devname = name; | |
1001 | else | |
1002 | devname = dev_name(parent); | |
1003 | ||
1004 | /* | |
1005 | * we need a proper transport to send commands, not a stacked device | |
1006 | */ | |
1007 | if (!q->request_fn) | |
1008 | return 0; | |
1009 | ||
1010 | bcd = &q->bsg_dev; | |
1011 | memset(bcd, 0, sizeof(*bcd)); | |
1012 | ||
1013 | mutex_lock(&bsg_mutex); | |
1014 | ||
1015 | ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); | |
1016 | if (!ret) { | |
1017 | ret = -ENOMEM; | |
1018 | goto unlock; | |
1019 | } | |
1020 | ||
1021 | ret = idr_get_new(&bsg_minor_idr, bcd, &minor); | |
1022 | if (ret < 0) | |
1023 | goto unlock; | |
1024 | ||
1025 | if (minor >= BSG_MAX_DEVS) { | |
1026 | printk(KERN_ERR "bsg: too many bsg devices\n"); | |
1027 | ret = -EINVAL; | |
1028 | goto remove_idr; | |
1029 | } | |
1030 | ||
1031 | bcd->minor = minor; | |
1032 | bcd->queue = q; | |
1033 | bcd->parent = get_device(parent); | |
1034 | bcd->release = release; | |
1035 | kref_init(&bcd->ref); | |
1036 | dev = MKDEV(bsg_major, bcd->minor); | |
1037 | class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); | |
1038 | if (IS_ERR(class_dev)) { | |
1039 | ret = PTR_ERR(class_dev); | |
1040 | goto put_dev; | |
1041 | } | |
1042 | bcd->class_dev = class_dev; | |
1043 | ||
1044 | if (q->kobj.sd) { | |
1045 | ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); | |
1046 | if (ret) | |
1047 | goto unregister_class_dev; | |
1048 | } | |
1049 | ||
1050 | mutex_unlock(&bsg_mutex); | |
1051 | return 0; | |
1052 | ||
1053 | unregister_class_dev: | |
1054 | device_unregister(class_dev); | |
1055 | put_dev: | |
1056 | put_device(parent); | |
1057 | remove_idr: | |
1058 | idr_remove(&bsg_minor_idr, minor); | |
1059 | unlock: | |
1060 | mutex_unlock(&bsg_mutex); | |
1061 | return ret; | |
1062 | } | |
1063 | EXPORT_SYMBOL_GPL(bsg_register_queue); | |
1064 | ||
1065 | static struct cdev bsg_cdev; | |
1066 | ||
1067 | static char *bsg_devnode(struct device *dev, mode_t *mode) | |
1068 | { | |
1069 | return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); | |
1070 | } | |
1071 | ||
1072 | static int __init bsg_init(void) | |
1073 | { | |
1074 | int ret, i; | |
1075 | dev_t devid; | |
1076 | ||
1077 | bsg_cmd_cachep = kmem_cache_create("bsg_cmd", | |
1078 | sizeof(struct bsg_command), 0, 0, NULL); | |
1079 | if (!bsg_cmd_cachep) { | |
1080 | printk(KERN_ERR "bsg: failed creating slab cache\n"); | |
1081 | return -ENOMEM; | |
1082 | } | |
1083 | ||
1084 | for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) | |
1085 | INIT_HLIST_HEAD(&bsg_device_list[i]); | |
1086 | ||
1087 | bsg_class = class_create(THIS_MODULE, "bsg"); | |
1088 | if (IS_ERR(bsg_class)) { | |
1089 | ret = PTR_ERR(bsg_class); | |
1090 | goto destroy_kmemcache; | |
1091 | } | |
1092 | bsg_class->devnode = bsg_devnode; | |
1093 | ||
1094 | ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); | |
1095 | if (ret) | |
1096 | goto destroy_bsg_class; | |
1097 | ||
1098 | bsg_major = MAJOR(devid); | |
1099 | ||
1100 | cdev_init(&bsg_cdev, &bsg_fops); | |
1101 | ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); | |
1102 | if (ret) | |
1103 | goto unregister_chrdev; | |
1104 | ||
1105 | printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION | |
1106 | " loaded (major %d)\n", bsg_major); | |
1107 | return 0; | |
1108 | unregister_chrdev: | |
1109 | unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); | |
1110 | destroy_bsg_class: | |
1111 | class_destroy(bsg_class); | |
1112 | destroy_kmemcache: | |
1113 | kmem_cache_destroy(bsg_cmd_cachep); | |
1114 | return ret; | |
1115 | } | |
1116 | ||
1117 | MODULE_AUTHOR("Jens Axboe"); | |
1118 | MODULE_DESCRIPTION(BSG_DESCRIPTION); | |
1119 | MODULE_LICENSE("GPL"); | |
1120 | ||
1121 | device_initcall(bsg_init); |