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1 | //#define DEBUG | |
2 | #include <linux/spinlock.h> | |
3 | #include <linux/slab.h> | |
4 | #include <linux/blkdev.h> | |
5 | #include <linux/hdreg.h> | |
6 | #include <linux/module.h> | |
7 | #include <linux/mutex.h> | |
8 | #include <linux/virtio.h> | |
9 | #include <linux/virtio_blk.h> | |
10 | #include <linux/scatterlist.h> | |
11 | #include <linux/string_helpers.h> | |
12 | #include <scsi/scsi_cmnd.h> | |
13 | #include <linux/idr.h> | |
14 | ||
15 | #define PART_BITS 4 | |
16 | ||
17 | static bool use_bio; | |
18 | module_param(use_bio, bool, S_IRUGO); | |
19 | ||
20 | static int major; | |
21 | static DEFINE_IDA(vd_index_ida); | |
22 | ||
23 | struct workqueue_struct *virtblk_wq; | |
24 | ||
25 | struct virtio_blk | |
26 | { | |
27 | struct virtio_device *vdev; | |
28 | struct virtqueue *vq; | |
29 | wait_queue_head_t queue_wait; | |
30 | ||
31 | /* The disk structure for the kernel. */ | |
32 | struct gendisk *disk; | |
33 | ||
34 | mempool_t *pool; | |
35 | ||
36 | /* Process context for config space updates */ | |
37 | struct work_struct config_work; | |
38 | ||
39 | /* Lock for config space updates */ | |
40 | struct mutex config_lock; | |
41 | ||
42 | /* enable config space updates */ | |
43 | bool config_enable; | |
44 | ||
45 | /* What host tells us, plus 2 for header & tailer. */ | |
46 | unsigned int sg_elems; | |
47 | ||
48 | /* Ida index - used to track minor number allocations. */ | |
49 | int index; | |
50 | ||
51 | /* Scatterlist: can be too big for stack. */ | |
52 | struct scatterlist sg[/*sg_elems*/]; | |
53 | }; | |
54 | ||
55 | struct virtblk_req | |
56 | { | |
57 | struct request *req; | |
58 | struct bio *bio; | |
59 | struct virtio_blk_outhdr out_hdr; | |
60 | struct virtio_scsi_inhdr in_hdr; | |
61 | struct work_struct work; | |
62 | struct virtio_blk *vblk; | |
63 | int flags; | |
64 | u8 status; | |
65 | struct scatterlist sg[]; | |
66 | }; | |
67 | ||
68 | enum { | |
69 | VBLK_IS_FLUSH = 1, | |
70 | VBLK_REQ_FLUSH = 2, | |
71 | VBLK_REQ_DATA = 4, | |
72 | VBLK_REQ_FUA = 8, | |
73 | }; | |
74 | ||
75 | static inline int virtblk_result(struct virtblk_req *vbr) | |
76 | { | |
77 | switch (vbr->status) { | |
78 | case VIRTIO_BLK_S_OK: | |
79 | return 0; | |
80 | case VIRTIO_BLK_S_UNSUPP: | |
81 | return -ENOTTY; | |
82 | default: | |
83 | return -EIO; | |
84 | } | |
85 | } | |
86 | ||
87 | static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk, | |
88 | gfp_t gfp_mask) | |
89 | { | |
90 | struct virtblk_req *vbr; | |
91 | ||
92 | vbr = mempool_alloc(vblk->pool, gfp_mask); | |
93 | if (!vbr) | |
94 | return NULL; | |
95 | ||
96 | vbr->vblk = vblk; | |
97 | if (use_bio) | |
98 | sg_init_table(vbr->sg, vblk->sg_elems); | |
99 | ||
100 | return vbr; | |
101 | } | |
102 | ||
103 | static void virtblk_add_buf_wait(struct virtio_blk *vblk, | |
104 | struct virtblk_req *vbr, | |
105 | unsigned long out, | |
106 | unsigned long in) | |
107 | { | |
108 | DEFINE_WAIT(wait); | |
109 | ||
110 | for (;;) { | |
111 | prepare_to_wait_exclusive(&vblk->queue_wait, &wait, | |
112 | TASK_UNINTERRUPTIBLE); | |
113 | ||
114 | spin_lock_irq(vblk->disk->queue->queue_lock); | |
115 | if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr, | |
116 | GFP_ATOMIC) < 0) { | |
117 | spin_unlock_irq(vblk->disk->queue->queue_lock); | |
118 | io_schedule(); | |
119 | } else { | |
120 | virtqueue_kick(vblk->vq); | |
121 | spin_unlock_irq(vblk->disk->queue->queue_lock); | |
122 | break; | |
123 | } | |
124 | ||
125 | } | |
126 | ||
127 | finish_wait(&vblk->queue_wait, &wait); | |
128 | } | |
129 | ||
130 | static inline void virtblk_add_req(struct virtblk_req *vbr, | |
131 | unsigned int out, unsigned int in) | |
132 | { | |
133 | struct virtio_blk *vblk = vbr->vblk; | |
134 | ||
135 | spin_lock_irq(vblk->disk->queue->queue_lock); | |
136 | if (unlikely(virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr, | |
137 | GFP_ATOMIC) < 0)) { | |
138 | spin_unlock_irq(vblk->disk->queue->queue_lock); | |
139 | virtblk_add_buf_wait(vblk, vbr, out, in); | |
140 | return; | |
141 | } | |
142 | virtqueue_kick(vblk->vq); | |
143 | spin_unlock_irq(vblk->disk->queue->queue_lock); | |
144 | } | |
145 | ||
146 | static int virtblk_bio_send_flush(struct virtblk_req *vbr) | |
147 | { | |
148 | unsigned int out = 0, in = 0; | |
149 | ||
150 | vbr->flags |= VBLK_IS_FLUSH; | |
151 | vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; | |
152 | vbr->out_hdr.sector = 0; | |
153 | vbr->out_hdr.ioprio = 0; | |
154 | sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); | |
155 | sg_set_buf(&vbr->sg[out + in++], &vbr->status, sizeof(vbr->status)); | |
156 | ||
157 | virtblk_add_req(vbr, out, in); | |
158 | ||
159 | return 0; | |
160 | } | |
161 | ||
162 | static int virtblk_bio_send_data(struct virtblk_req *vbr) | |
163 | { | |
164 | struct virtio_blk *vblk = vbr->vblk; | |
165 | unsigned int num, out = 0, in = 0; | |
166 | struct bio *bio = vbr->bio; | |
167 | ||
168 | vbr->flags &= ~VBLK_IS_FLUSH; | |
169 | vbr->out_hdr.type = 0; | |
170 | vbr->out_hdr.sector = bio->bi_sector; | |
171 | vbr->out_hdr.ioprio = bio_prio(bio); | |
172 | ||
173 | sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); | |
174 | ||
175 | num = blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg + out); | |
176 | ||
177 | sg_set_buf(&vbr->sg[num + out + in++], &vbr->status, | |
178 | sizeof(vbr->status)); | |
179 | ||
180 | if (num) { | |
181 | if (bio->bi_rw & REQ_WRITE) { | |
182 | vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; | |
183 | out += num; | |
184 | } else { | |
185 | vbr->out_hdr.type |= VIRTIO_BLK_T_IN; | |
186 | in += num; | |
187 | } | |
188 | } | |
189 | ||
190 | virtblk_add_req(vbr, out, in); | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | static void virtblk_bio_send_data_work(struct work_struct *work) | |
196 | { | |
197 | struct virtblk_req *vbr; | |
198 | ||
199 | vbr = container_of(work, struct virtblk_req, work); | |
200 | ||
201 | virtblk_bio_send_data(vbr); | |
202 | } | |
203 | ||
204 | static void virtblk_bio_send_flush_work(struct work_struct *work) | |
205 | { | |
206 | struct virtblk_req *vbr; | |
207 | ||
208 | vbr = container_of(work, struct virtblk_req, work); | |
209 | ||
210 | virtblk_bio_send_flush(vbr); | |
211 | } | |
212 | ||
213 | static inline void virtblk_request_done(struct virtblk_req *vbr) | |
214 | { | |
215 | struct virtio_blk *vblk = vbr->vblk; | |
216 | struct request *req = vbr->req; | |
217 | int error = virtblk_result(vbr); | |
218 | ||
219 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) { | |
220 | req->resid_len = vbr->in_hdr.residual; | |
221 | req->sense_len = vbr->in_hdr.sense_len; | |
222 | req->errors = vbr->in_hdr.errors; | |
223 | } else if (req->cmd_type == REQ_TYPE_SPECIAL) { | |
224 | req->errors = (error != 0); | |
225 | } | |
226 | ||
227 | __blk_end_request_all(req, error); | |
228 | mempool_free(vbr, vblk->pool); | |
229 | } | |
230 | ||
231 | static inline void virtblk_bio_flush_done(struct virtblk_req *vbr) | |
232 | { | |
233 | struct virtio_blk *vblk = vbr->vblk; | |
234 | ||
235 | if (vbr->flags & VBLK_REQ_DATA) { | |
236 | /* Send out the actual write data */ | |
237 | INIT_WORK(&vbr->work, virtblk_bio_send_data_work); | |
238 | queue_work(virtblk_wq, &vbr->work); | |
239 | } else { | |
240 | bio_endio(vbr->bio, virtblk_result(vbr)); | |
241 | mempool_free(vbr, vblk->pool); | |
242 | } | |
243 | } | |
244 | ||
245 | static inline void virtblk_bio_data_done(struct virtblk_req *vbr) | |
246 | { | |
247 | struct virtio_blk *vblk = vbr->vblk; | |
248 | ||
249 | if (unlikely(vbr->flags & VBLK_REQ_FUA)) { | |
250 | /* Send out a flush before end the bio */ | |
251 | vbr->flags &= ~VBLK_REQ_DATA; | |
252 | INIT_WORK(&vbr->work, virtblk_bio_send_flush_work); | |
253 | queue_work(virtblk_wq, &vbr->work); | |
254 | } else { | |
255 | bio_endio(vbr->bio, virtblk_result(vbr)); | |
256 | mempool_free(vbr, vblk->pool); | |
257 | } | |
258 | } | |
259 | ||
260 | static inline void virtblk_bio_done(struct virtblk_req *vbr) | |
261 | { | |
262 | if (unlikely(vbr->flags & VBLK_IS_FLUSH)) | |
263 | virtblk_bio_flush_done(vbr); | |
264 | else | |
265 | virtblk_bio_data_done(vbr); | |
266 | } | |
267 | ||
268 | static void virtblk_done(struct virtqueue *vq) | |
269 | { | |
270 | struct virtio_blk *vblk = vq->vdev->priv; | |
271 | bool bio_done = false, req_done = false; | |
272 | struct virtblk_req *vbr; | |
273 | unsigned long flags; | |
274 | unsigned int len; | |
275 | ||
276 | spin_lock_irqsave(vblk->disk->queue->queue_lock, flags); | |
277 | do { | |
278 | virtqueue_disable_cb(vq); | |
279 | while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) { | |
280 | if (vbr->bio) { | |
281 | virtblk_bio_done(vbr); | |
282 | bio_done = true; | |
283 | } else { | |
284 | virtblk_request_done(vbr); | |
285 | req_done = true; | |
286 | } | |
287 | } | |
288 | } while (!virtqueue_enable_cb(vq)); | |
289 | /* In case queue is stopped waiting for more buffers. */ | |
290 | if (req_done) | |
291 | blk_start_queue(vblk->disk->queue); | |
292 | spin_unlock_irqrestore(vblk->disk->queue->queue_lock, flags); | |
293 | ||
294 | if (bio_done) | |
295 | wake_up(&vblk->queue_wait); | |
296 | } | |
297 | ||
298 | static bool do_req(struct request_queue *q, struct virtio_blk *vblk, | |
299 | struct request *req) | |
300 | { | |
301 | unsigned long num, out = 0, in = 0; | |
302 | struct virtblk_req *vbr; | |
303 | ||
304 | vbr = virtblk_alloc_req(vblk, GFP_ATOMIC); | |
305 | if (!vbr) | |
306 | /* When another request finishes we'll try again. */ | |
307 | return false; | |
308 | ||
309 | vbr->req = req; | |
310 | vbr->bio = NULL; | |
311 | if (req->cmd_flags & REQ_FLUSH) { | |
312 | vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; | |
313 | vbr->out_hdr.sector = 0; | |
314 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); | |
315 | } else { | |
316 | switch (req->cmd_type) { | |
317 | case REQ_TYPE_FS: | |
318 | vbr->out_hdr.type = 0; | |
319 | vbr->out_hdr.sector = blk_rq_pos(vbr->req); | |
320 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); | |
321 | break; | |
322 | case REQ_TYPE_BLOCK_PC: | |
323 | vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD; | |
324 | vbr->out_hdr.sector = 0; | |
325 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); | |
326 | break; | |
327 | case REQ_TYPE_SPECIAL: | |
328 | vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID; | |
329 | vbr->out_hdr.sector = 0; | |
330 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); | |
331 | break; | |
332 | default: | |
333 | /* We don't put anything else in the queue. */ | |
334 | BUG(); | |
335 | } | |
336 | } | |
337 | ||
338 | sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); | |
339 | ||
340 | /* | |
341 | * If this is a packet command we need a couple of additional headers. | |
342 | * Behind the normal outhdr we put a segment with the scsi command | |
343 | * block, and before the normal inhdr we put the sense data and the | |
344 | * inhdr with additional status information before the normal inhdr. | |
345 | */ | |
346 | if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) | |
347 | sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len); | |
348 | ||
349 | num = blk_rq_map_sg(q, vbr->req, vblk->sg + out); | |
350 | ||
351 | if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) { | |
352 | sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE); | |
353 | sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr, | |
354 | sizeof(vbr->in_hdr)); | |
355 | } | |
356 | ||
357 | sg_set_buf(&vblk->sg[num + out + in++], &vbr->status, | |
358 | sizeof(vbr->status)); | |
359 | ||
360 | if (num) { | |
361 | if (rq_data_dir(vbr->req) == WRITE) { | |
362 | vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; | |
363 | out += num; | |
364 | } else { | |
365 | vbr->out_hdr.type |= VIRTIO_BLK_T_IN; | |
366 | in += num; | |
367 | } | |
368 | } | |
369 | ||
370 | if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr, | |
371 | GFP_ATOMIC) < 0) { | |
372 | mempool_free(vbr, vblk->pool); | |
373 | return false; | |
374 | } | |
375 | ||
376 | return true; | |
377 | } | |
378 | ||
379 | static void virtblk_request(struct request_queue *q) | |
380 | { | |
381 | struct virtio_blk *vblk = q->queuedata; | |
382 | struct request *req; | |
383 | unsigned int issued = 0; | |
384 | ||
385 | while ((req = blk_peek_request(q)) != NULL) { | |
386 | BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); | |
387 | ||
388 | /* If this request fails, stop queue and wait for something to | |
389 | finish to restart it. */ | |
390 | if (!do_req(q, vblk, req)) { | |
391 | blk_stop_queue(q); | |
392 | break; | |
393 | } | |
394 | blk_start_request(req); | |
395 | issued++; | |
396 | } | |
397 | ||
398 | if (issued) | |
399 | virtqueue_kick(vblk->vq); | |
400 | } | |
401 | ||
402 | static void virtblk_make_request(struct request_queue *q, struct bio *bio) | |
403 | { | |
404 | struct virtio_blk *vblk = q->queuedata; | |
405 | struct virtblk_req *vbr; | |
406 | ||
407 | BUG_ON(bio->bi_phys_segments + 2 > vblk->sg_elems); | |
408 | ||
409 | vbr = virtblk_alloc_req(vblk, GFP_NOIO); | |
410 | if (!vbr) { | |
411 | bio_endio(bio, -ENOMEM); | |
412 | return; | |
413 | } | |
414 | ||
415 | vbr->bio = bio; | |
416 | vbr->flags = 0; | |
417 | if (bio->bi_rw & REQ_FLUSH) | |
418 | vbr->flags |= VBLK_REQ_FLUSH; | |
419 | if (bio->bi_rw & REQ_FUA) | |
420 | vbr->flags |= VBLK_REQ_FUA; | |
421 | if (bio->bi_size) | |
422 | vbr->flags |= VBLK_REQ_DATA; | |
423 | ||
424 | if (unlikely(vbr->flags & VBLK_REQ_FLUSH)) | |
425 | virtblk_bio_send_flush(vbr); | |
426 | else | |
427 | virtblk_bio_send_data(vbr); | |
428 | } | |
429 | ||
430 | /* return id (s/n) string for *disk to *id_str | |
431 | */ | |
432 | static int virtblk_get_id(struct gendisk *disk, char *id_str) | |
433 | { | |
434 | struct virtio_blk *vblk = disk->private_data; | |
435 | struct request *req; | |
436 | struct bio *bio; | |
437 | int err; | |
438 | ||
439 | bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES, | |
440 | GFP_KERNEL); | |
441 | if (IS_ERR(bio)) | |
442 | return PTR_ERR(bio); | |
443 | ||
444 | req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL); | |
445 | if (IS_ERR(req)) { | |
446 | bio_put(bio); | |
447 | return PTR_ERR(req); | |
448 | } | |
449 | ||
450 | req->cmd_type = REQ_TYPE_SPECIAL; | |
451 | err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); | |
452 | blk_put_request(req); | |
453 | ||
454 | return err; | |
455 | } | |
456 | ||
457 | static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, | |
458 | unsigned int cmd, unsigned long data) | |
459 | { | |
460 | struct gendisk *disk = bdev->bd_disk; | |
461 | struct virtio_blk *vblk = disk->private_data; | |
462 | ||
463 | /* | |
464 | * Only allow the generic SCSI ioctls if the host can support it. | |
465 | */ | |
466 | if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) | |
467 | return -ENOTTY; | |
468 | ||
469 | return scsi_cmd_blk_ioctl(bdev, mode, cmd, | |
470 | (void __user *)data); | |
471 | } | |
472 | ||
473 | /* We provide getgeo only to please some old bootloader/partitioning tools */ | |
474 | static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) | |
475 | { | |
476 | struct virtio_blk *vblk = bd->bd_disk->private_data; | |
477 | struct virtio_blk_geometry vgeo; | |
478 | int err; | |
479 | ||
480 | /* see if the host passed in geometry config */ | |
481 | err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY, | |
482 | offsetof(struct virtio_blk_config, geometry), | |
483 | &vgeo); | |
484 | ||
485 | if (!err) { | |
486 | geo->heads = vgeo.heads; | |
487 | geo->sectors = vgeo.sectors; | |
488 | geo->cylinders = vgeo.cylinders; | |
489 | } else { | |
490 | /* some standard values, similar to sd */ | |
491 | geo->heads = 1 << 6; | |
492 | geo->sectors = 1 << 5; | |
493 | geo->cylinders = get_capacity(bd->bd_disk) >> 11; | |
494 | } | |
495 | return 0; | |
496 | } | |
497 | ||
498 | static const struct block_device_operations virtblk_fops = { | |
499 | .ioctl = virtblk_ioctl, | |
500 | .owner = THIS_MODULE, | |
501 | .getgeo = virtblk_getgeo, | |
502 | }; | |
503 | ||
504 | static int index_to_minor(int index) | |
505 | { | |
506 | return index << PART_BITS; | |
507 | } | |
508 | ||
509 | static int minor_to_index(int minor) | |
510 | { | |
511 | return minor >> PART_BITS; | |
512 | } | |
513 | ||
514 | static ssize_t virtblk_serial_show(struct device *dev, | |
515 | struct device_attribute *attr, char *buf) | |
516 | { | |
517 | struct gendisk *disk = dev_to_disk(dev); | |
518 | int err; | |
519 | ||
520 | /* sysfs gives us a PAGE_SIZE buffer */ | |
521 | BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); | |
522 | ||
523 | buf[VIRTIO_BLK_ID_BYTES] = '\0'; | |
524 | err = virtblk_get_id(disk, buf); | |
525 | if (!err) | |
526 | return strlen(buf); | |
527 | ||
528 | if (err == -EIO) /* Unsupported? Make it empty. */ | |
529 | return 0; | |
530 | ||
531 | return err; | |
532 | } | |
533 | DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); | |
534 | ||
535 | static void virtblk_config_changed_work(struct work_struct *work) | |
536 | { | |
537 | struct virtio_blk *vblk = | |
538 | container_of(work, struct virtio_blk, config_work); | |
539 | struct virtio_device *vdev = vblk->vdev; | |
540 | struct request_queue *q = vblk->disk->queue; | |
541 | char cap_str_2[10], cap_str_10[10]; | |
542 | char *envp[] = { "RESIZE=1", NULL }; | |
543 | u64 capacity, size; | |
544 | ||
545 | mutex_lock(&vblk->config_lock); | |
546 | if (!vblk->config_enable) | |
547 | goto done; | |
548 | ||
549 | /* Host must always specify the capacity. */ | |
550 | vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), | |
551 | &capacity, sizeof(capacity)); | |
552 | ||
553 | /* If capacity is too big, truncate with warning. */ | |
554 | if ((sector_t)capacity != capacity) { | |
555 | dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", | |
556 | (unsigned long long)capacity); | |
557 | capacity = (sector_t)-1; | |
558 | } | |
559 | ||
560 | size = capacity * queue_logical_block_size(q); | |
561 | string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); | |
562 | string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); | |
563 | ||
564 | dev_notice(&vdev->dev, | |
565 | "new size: %llu %d-byte logical blocks (%s/%s)\n", | |
566 | (unsigned long long)capacity, | |
567 | queue_logical_block_size(q), | |
568 | cap_str_10, cap_str_2); | |
569 | ||
570 | set_capacity(vblk->disk, capacity); | |
571 | revalidate_disk(vblk->disk); | |
572 | kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); | |
573 | done: | |
574 | mutex_unlock(&vblk->config_lock); | |
575 | } | |
576 | ||
577 | static void virtblk_config_changed(struct virtio_device *vdev) | |
578 | { | |
579 | struct virtio_blk *vblk = vdev->priv; | |
580 | ||
581 | queue_work(virtblk_wq, &vblk->config_work); | |
582 | } | |
583 | ||
584 | static int init_vq(struct virtio_blk *vblk) | |
585 | { | |
586 | int err = 0; | |
587 | ||
588 | /* We expect one virtqueue, for output. */ | |
589 | vblk->vq = virtio_find_single_vq(vblk->vdev, virtblk_done, "requests"); | |
590 | if (IS_ERR(vblk->vq)) | |
591 | err = PTR_ERR(vblk->vq); | |
592 | ||
593 | return err; | |
594 | } | |
595 | ||
596 | /* | |
597 | * Legacy naming scheme used for virtio devices. We are stuck with it for | |
598 | * virtio blk but don't ever use it for any new driver. | |
599 | */ | |
600 | static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) | |
601 | { | |
602 | const int base = 'z' - 'a' + 1; | |
603 | char *begin = buf + strlen(prefix); | |
604 | char *end = buf + buflen; | |
605 | char *p; | |
606 | int unit; | |
607 | ||
608 | p = end - 1; | |
609 | *p = '\0'; | |
610 | unit = base; | |
611 | do { | |
612 | if (p == begin) | |
613 | return -EINVAL; | |
614 | *--p = 'a' + (index % unit); | |
615 | index = (index / unit) - 1; | |
616 | } while (index >= 0); | |
617 | ||
618 | memmove(begin, p, end - p); | |
619 | memcpy(buf, prefix, strlen(prefix)); | |
620 | ||
621 | return 0; | |
622 | } | |
623 | ||
624 | static int virtblk_get_cache_mode(struct virtio_device *vdev) | |
625 | { | |
626 | u8 writeback; | |
627 | int err; | |
628 | ||
629 | err = virtio_config_val(vdev, VIRTIO_BLK_F_CONFIG_WCE, | |
630 | offsetof(struct virtio_blk_config, wce), | |
631 | &writeback); | |
632 | if (err) | |
633 | writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE); | |
634 | ||
635 | return writeback; | |
636 | } | |
637 | ||
638 | static void virtblk_update_cache_mode(struct virtio_device *vdev) | |
639 | { | |
640 | u8 writeback = virtblk_get_cache_mode(vdev); | |
641 | struct virtio_blk *vblk = vdev->priv; | |
642 | ||
643 | if (writeback) | |
644 | blk_queue_flush(vblk->disk->queue, REQ_FLUSH); | |
645 | else | |
646 | blk_queue_flush(vblk->disk->queue, 0); | |
647 | ||
648 | revalidate_disk(vblk->disk); | |
649 | } | |
650 | ||
651 | static const char *const virtblk_cache_types[] = { | |
652 | "write through", "write back" | |
653 | }; | |
654 | ||
655 | static ssize_t | |
656 | virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, | |
657 | const char *buf, size_t count) | |
658 | { | |
659 | struct gendisk *disk = dev_to_disk(dev); | |
660 | struct virtio_blk *vblk = disk->private_data; | |
661 | struct virtio_device *vdev = vblk->vdev; | |
662 | int i; | |
663 | u8 writeback; | |
664 | ||
665 | BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); | |
666 | for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) | |
667 | if (sysfs_streq(buf, virtblk_cache_types[i])) | |
668 | break; | |
669 | ||
670 | if (i < 0) | |
671 | return -EINVAL; | |
672 | ||
673 | writeback = i; | |
674 | vdev->config->set(vdev, | |
675 | offsetof(struct virtio_blk_config, wce), | |
676 | &writeback, sizeof(writeback)); | |
677 | ||
678 | virtblk_update_cache_mode(vdev); | |
679 | return count; | |
680 | } | |
681 | ||
682 | static ssize_t | |
683 | virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, | |
684 | char *buf) | |
685 | { | |
686 | struct gendisk *disk = dev_to_disk(dev); | |
687 | struct virtio_blk *vblk = disk->private_data; | |
688 | u8 writeback = virtblk_get_cache_mode(vblk->vdev); | |
689 | ||
690 | BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); | |
691 | return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); | |
692 | } | |
693 | ||
694 | static const struct device_attribute dev_attr_cache_type_ro = | |
695 | __ATTR(cache_type, S_IRUGO, | |
696 | virtblk_cache_type_show, NULL); | |
697 | static const struct device_attribute dev_attr_cache_type_rw = | |
698 | __ATTR(cache_type, S_IRUGO|S_IWUSR, | |
699 | virtblk_cache_type_show, virtblk_cache_type_store); | |
700 | ||
701 | static int virtblk_probe(struct virtio_device *vdev) | |
702 | { | |
703 | struct virtio_blk *vblk; | |
704 | struct request_queue *q; | |
705 | int err, index; | |
706 | int pool_size; | |
707 | ||
708 | u64 cap; | |
709 | u32 v, blk_size, sg_elems, opt_io_size; | |
710 | u16 min_io_size; | |
711 | u8 physical_block_exp, alignment_offset; | |
712 | ||
713 | err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), | |
714 | GFP_KERNEL); | |
715 | if (err < 0) | |
716 | goto out; | |
717 | index = err; | |
718 | ||
719 | /* We need to know how many segments before we allocate. */ | |
720 | err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX, | |
721 | offsetof(struct virtio_blk_config, seg_max), | |
722 | &sg_elems); | |
723 | ||
724 | /* We need at least one SG element, whatever they say. */ | |
725 | if (err || !sg_elems) | |
726 | sg_elems = 1; | |
727 | ||
728 | /* We need an extra sg elements at head and tail. */ | |
729 | sg_elems += 2; | |
730 | vdev->priv = vblk = kmalloc(sizeof(*vblk) + | |
731 | sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL); | |
732 | if (!vblk) { | |
733 | err = -ENOMEM; | |
734 | goto out_free_index; | |
735 | } | |
736 | ||
737 | init_waitqueue_head(&vblk->queue_wait); | |
738 | vblk->vdev = vdev; | |
739 | vblk->sg_elems = sg_elems; | |
740 | sg_init_table(vblk->sg, vblk->sg_elems); | |
741 | mutex_init(&vblk->config_lock); | |
742 | ||
743 | INIT_WORK(&vblk->config_work, virtblk_config_changed_work); | |
744 | vblk->config_enable = true; | |
745 | ||
746 | err = init_vq(vblk); | |
747 | if (err) | |
748 | goto out_free_vblk; | |
749 | ||
750 | pool_size = sizeof(struct virtblk_req); | |
751 | if (use_bio) | |
752 | pool_size += sizeof(struct scatterlist) * sg_elems; | |
753 | vblk->pool = mempool_create_kmalloc_pool(1, pool_size); | |
754 | if (!vblk->pool) { | |
755 | err = -ENOMEM; | |
756 | goto out_free_vq; | |
757 | } | |
758 | ||
759 | /* FIXME: How many partitions? How long is a piece of string? */ | |
760 | vblk->disk = alloc_disk(1 << PART_BITS); | |
761 | if (!vblk->disk) { | |
762 | err = -ENOMEM; | |
763 | goto out_mempool; | |
764 | } | |
765 | ||
766 | q = vblk->disk->queue = blk_init_queue(virtblk_request, NULL); | |
767 | if (!q) { | |
768 | err = -ENOMEM; | |
769 | goto out_put_disk; | |
770 | } | |
771 | ||
772 | if (use_bio) | |
773 | blk_queue_make_request(q, virtblk_make_request); | |
774 | q->queuedata = vblk; | |
775 | ||
776 | virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); | |
777 | ||
778 | vblk->disk->major = major; | |
779 | vblk->disk->first_minor = index_to_minor(index); | |
780 | vblk->disk->private_data = vblk; | |
781 | vblk->disk->fops = &virtblk_fops; | |
782 | vblk->disk->driverfs_dev = &vdev->dev; | |
783 | vblk->index = index; | |
784 | ||
785 | /* configure queue flush support */ | |
786 | virtblk_update_cache_mode(vdev); | |
787 | ||
788 | /* If disk is read-only in the host, the guest should obey */ | |
789 | if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) | |
790 | set_disk_ro(vblk->disk, 1); | |
791 | ||
792 | /* Host must always specify the capacity. */ | |
793 | vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), | |
794 | &cap, sizeof(cap)); | |
795 | ||
796 | /* If capacity is too big, truncate with warning. */ | |
797 | if ((sector_t)cap != cap) { | |
798 | dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", | |
799 | (unsigned long long)cap); | |
800 | cap = (sector_t)-1; | |
801 | } | |
802 | set_capacity(vblk->disk, cap); | |
803 | ||
804 | /* We can handle whatever the host told us to handle. */ | |
805 | blk_queue_max_segments(q, vblk->sg_elems-2); | |
806 | ||
807 | /* No need to bounce any requests */ | |
808 | blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); | |
809 | ||
810 | /* No real sector limit. */ | |
811 | blk_queue_max_hw_sectors(q, -1U); | |
812 | ||
813 | /* Host can optionally specify maximum segment size and number of | |
814 | * segments. */ | |
815 | err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX, | |
816 | offsetof(struct virtio_blk_config, size_max), | |
817 | &v); | |
818 | if (!err) | |
819 | blk_queue_max_segment_size(q, v); | |
820 | else | |
821 | blk_queue_max_segment_size(q, -1U); | |
822 | ||
823 | /* Host can optionally specify the block size of the device */ | |
824 | err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE, | |
825 | offsetof(struct virtio_blk_config, blk_size), | |
826 | &blk_size); | |
827 | if (!err) | |
828 | blk_queue_logical_block_size(q, blk_size); | |
829 | else | |
830 | blk_size = queue_logical_block_size(q); | |
831 | ||
832 | /* Use topology information if available */ | |
833 | err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, | |
834 | offsetof(struct virtio_blk_config, physical_block_exp), | |
835 | &physical_block_exp); | |
836 | if (!err && physical_block_exp) | |
837 | blk_queue_physical_block_size(q, | |
838 | blk_size * (1 << physical_block_exp)); | |
839 | ||
840 | err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, | |
841 | offsetof(struct virtio_blk_config, alignment_offset), | |
842 | &alignment_offset); | |
843 | if (!err && alignment_offset) | |
844 | blk_queue_alignment_offset(q, blk_size * alignment_offset); | |
845 | ||
846 | err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, | |
847 | offsetof(struct virtio_blk_config, min_io_size), | |
848 | &min_io_size); | |
849 | if (!err && min_io_size) | |
850 | blk_queue_io_min(q, blk_size * min_io_size); | |
851 | ||
852 | err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, | |
853 | offsetof(struct virtio_blk_config, opt_io_size), | |
854 | &opt_io_size); | |
855 | if (!err && opt_io_size) | |
856 | blk_queue_io_opt(q, blk_size * opt_io_size); | |
857 | ||
858 | add_disk(vblk->disk); | |
859 | err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); | |
860 | if (err) | |
861 | goto out_del_disk; | |
862 | ||
863 | if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) | |
864 | err = device_create_file(disk_to_dev(vblk->disk), | |
865 | &dev_attr_cache_type_rw); | |
866 | else | |
867 | err = device_create_file(disk_to_dev(vblk->disk), | |
868 | &dev_attr_cache_type_ro); | |
869 | if (err) | |
870 | goto out_del_disk; | |
871 | return 0; | |
872 | ||
873 | out_del_disk: | |
874 | del_gendisk(vblk->disk); | |
875 | blk_cleanup_queue(vblk->disk->queue); | |
876 | out_put_disk: | |
877 | put_disk(vblk->disk); | |
878 | out_mempool: | |
879 | mempool_destroy(vblk->pool); | |
880 | out_free_vq: | |
881 | vdev->config->del_vqs(vdev); | |
882 | out_free_vblk: | |
883 | kfree(vblk); | |
884 | out_free_index: | |
885 | ida_simple_remove(&vd_index_ida, index); | |
886 | out: | |
887 | return err; | |
888 | } | |
889 | ||
890 | static void virtblk_remove(struct virtio_device *vdev) | |
891 | { | |
892 | struct virtio_blk *vblk = vdev->priv; | |
893 | int index = vblk->index; | |
894 | int refc; | |
895 | ||
896 | /* Prevent config work handler from accessing the device. */ | |
897 | mutex_lock(&vblk->config_lock); | |
898 | vblk->config_enable = false; | |
899 | mutex_unlock(&vblk->config_lock); | |
900 | ||
901 | del_gendisk(vblk->disk); | |
902 | blk_cleanup_queue(vblk->disk->queue); | |
903 | ||
904 | /* Stop all the virtqueues. */ | |
905 | vdev->config->reset(vdev); | |
906 | ||
907 | flush_work(&vblk->config_work); | |
908 | ||
909 | refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); | |
910 | put_disk(vblk->disk); | |
911 | mempool_destroy(vblk->pool); | |
912 | vdev->config->del_vqs(vdev); | |
913 | kfree(vblk); | |
914 | ||
915 | /* Only free device id if we don't have any users */ | |
916 | if (refc == 1) | |
917 | ida_simple_remove(&vd_index_ida, index); | |
918 | } | |
919 | ||
920 | #ifdef CONFIG_PM | |
921 | static int virtblk_freeze(struct virtio_device *vdev) | |
922 | { | |
923 | struct virtio_blk *vblk = vdev->priv; | |
924 | ||
925 | /* Ensure we don't receive any more interrupts */ | |
926 | vdev->config->reset(vdev); | |
927 | ||
928 | /* Prevent config work handler from accessing the device. */ | |
929 | mutex_lock(&vblk->config_lock); | |
930 | vblk->config_enable = false; | |
931 | mutex_unlock(&vblk->config_lock); | |
932 | ||
933 | flush_work(&vblk->config_work); | |
934 | ||
935 | spin_lock_irq(vblk->disk->queue->queue_lock); | |
936 | blk_stop_queue(vblk->disk->queue); | |
937 | spin_unlock_irq(vblk->disk->queue->queue_lock); | |
938 | blk_sync_queue(vblk->disk->queue); | |
939 | ||
940 | vdev->config->del_vqs(vdev); | |
941 | return 0; | |
942 | } | |
943 | ||
944 | static int virtblk_restore(struct virtio_device *vdev) | |
945 | { | |
946 | struct virtio_blk *vblk = vdev->priv; | |
947 | int ret; | |
948 | ||
949 | vblk->config_enable = true; | |
950 | ret = init_vq(vdev->priv); | |
951 | if (!ret) { | |
952 | spin_lock_irq(vblk->disk->queue->queue_lock); | |
953 | blk_start_queue(vblk->disk->queue); | |
954 | spin_unlock_irq(vblk->disk->queue->queue_lock); | |
955 | } | |
956 | return ret; | |
957 | } | |
958 | #endif | |
959 | ||
960 | static const struct virtio_device_id id_table[] = { | |
961 | { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, | |
962 | { 0 }, | |
963 | }; | |
964 | ||
965 | static unsigned int features[] = { | |
966 | VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, | |
967 | VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, | |
968 | VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE | |
969 | }; | |
970 | ||
971 | static struct virtio_driver virtio_blk = { | |
972 | .feature_table = features, | |
973 | .feature_table_size = ARRAY_SIZE(features), | |
974 | .driver.name = KBUILD_MODNAME, | |
975 | .driver.owner = THIS_MODULE, | |
976 | .id_table = id_table, | |
977 | .probe = virtblk_probe, | |
978 | .remove = virtblk_remove, | |
979 | .config_changed = virtblk_config_changed, | |
980 | #ifdef CONFIG_PM | |
981 | .freeze = virtblk_freeze, | |
982 | .restore = virtblk_restore, | |
983 | #endif | |
984 | }; | |
985 | ||
986 | static int __init init(void) | |
987 | { | |
988 | int error; | |
989 | ||
990 | virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); | |
991 | if (!virtblk_wq) | |
992 | return -ENOMEM; | |
993 | ||
994 | major = register_blkdev(0, "virtblk"); | |
995 | if (major < 0) { | |
996 | error = major; | |
997 | goto out_destroy_workqueue; | |
998 | } | |
999 | ||
1000 | error = register_virtio_driver(&virtio_blk); | |
1001 | if (error) | |
1002 | goto out_unregister_blkdev; | |
1003 | return 0; | |
1004 | ||
1005 | out_unregister_blkdev: | |
1006 | unregister_blkdev(major, "virtblk"); | |
1007 | out_destroy_workqueue: | |
1008 | destroy_workqueue(virtblk_wq); | |
1009 | return error; | |
1010 | } | |
1011 | ||
1012 | static void __exit fini(void) | |
1013 | { | |
1014 | unregister_blkdev(major, "virtblk"); | |
1015 | unregister_virtio_driver(&virtio_blk); | |
1016 | destroy_workqueue(virtblk_wq); | |
1017 | } | |
1018 | module_init(init); | |
1019 | module_exit(fini); | |
1020 | ||
1021 | MODULE_DEVICE_TABLE(virtio, id_table); | |
1022 | MODULE_DESCRIPTION("Virtio block driver"); | |
1023 | MODULE_LICENSE("GPL"); |