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virtio_blk: make serial attribute static
[deliverable/linux.git] / drivers / block / virtio_blk.c
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 #include <linux/blk-mq.h>
15 #include <linux/numa.h>
16
17 #define PART_BITS 4
18 #define VQ_NAME_LEN 16
19
20 static int major;
21 static DEFINE_IDA(vd_index_ida);
22
23 static struct workqueue_struct *virtblk_wq;
24
25 struct virtio_blk_vq {
26 struct virtqueue *vq;
27 spinlock_t lock;
28 char name[VQ_NAME_LEN];
29 } ____cacheline_aligned_in_smp;
30
31 struct virtio_blk
32 {
33 struct virtio_device *vdev;
34
35 /* The disk structure for the kernel. */
36 struct gendisk *disk;
37
38 /* Block layer tags. */
39 struct blk_mq_tag_set tag_set;
40
41 /* Process context for config space updates */
42 struct work_struct config_work;
43
44 /* What host tells us, plus 2 for header & tailer. */
45 unsigned int sg_elems;
46
47 /* Ida index - used to track minor number allocations. */
48 int index;
49
50 /* num of vqs */
51 int num_vqs;
52 struct virtio_blk_vq *vqs;
53 };
54
55 struct virtblk_req
56 {
57 struct request *req;
58 struct virtio_blk_outhdr out_hdr;
59 struct virtio_scsi_inhdr in_hdr;
60 u8 status;
61 struct scatterlist sg[];
62 };
63
64 static inline int virtblk_result(struct virtblk_req *vbr)
65 {
66 switch (vbr->status) {
67 case VIRTIO_BLK_S_OK:
68 return 0;
69 case VIRTIO_BLK_S_UNSUPP:
70 return -ENOTTY;
71 default:
72 return -EIO;
73 }
74 }
75
76 static int __virtblk_add_req(struct virtqueue *vq,
77 struct virtblk_req *vbr,
78 struct scatterlist *data_sg,
79 bool have_data)
80 {
81 struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6];
82 unsigned int num_out = 0, num_in = 0;
83 __virtio32 type = vbr->out_hdr.type & ~cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT);
84
85 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
86 sgs[num_out++] = &hdr;
87
88 /*
89 * If this is a packet command we need a couple of additional headers.
90 * Behind the normal outhdr we put a segment with the scsi command
91 * block, and before the normal inhdr we put the sense data and the
92 * inhdr with additional status information.
93 */
94 if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
95 sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len);
96 sgs[num_out++] = &cmd;
97 }
98
99 if (have_data) {
100 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
101 sgs[num_out++] = data_sg;
102 else
103 sgs[num_out + num_in++] = data_sg;
104 }
105
106 if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
107 sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
108 sgs[num_out + num_in++] = &sense;
109 sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr));
110 sgs[num_out + num_in++] = &inhdr;
111 }
112
113 sg_init_one(&status, &vbr->status, sizeof(vbr->status));
114 sgs[num_out + num_in++] = &status;
115
116 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
117 }
118
119 static inline void virtblk_request_done(struct request *req)
120 {
121 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
122 struct virtio_blk *vblk = req->q->queuedata;
123 int error = virtblk_result(vbr);
124
125 if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
126 req->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual);
127 req->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len);
128 req->errors = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors);
129 } else if (req->cmd_type == REQ_TYPE_SPECIAL) {
130 req->errors = (error != 0);
131 }
132
133 blk_mq_end_request(req, error);
134 }
135
136 static void virtblk_done(struct virtqueue *vq)
137 {
138 struct virtio_blk *vblk = vq->vdev->priv;
139 bool req_done = false;
140 int qid = vq->index;
141 struct virtblk_req *vbr;
142 unsigned long flags;
143 unsigned int len;
144
145 spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
146 do {
147 virtqueue_disable_cb(vq);
148 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
149 blk_mq_complete_request(vbr->req);
150 req_done = true;
151 }
152 if (unlikely(virtqueue_is_broken(vq)))
153 break;
154 } while (!virtqueue_enable_cb(vq));
155
156 /* In case queue is stopped waiting for more buffers. */
157 if (req_done)
158 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
159 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
160 }
161
162 static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req,
163 bool last)
164 {
165 struct virtio_blk *vblk = hctx->queue->queuedata;
166 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
167 unsigned long flags;
168 unsigned int num;
169 int qid = hctx->queue_num;
170 int err;
171 bool notify = false;
172
173 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
174
175 vbr->req = req;
176 if (req->cmd_flags & REQ_FLUSH) {
177 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH);
178 vbr->out_hdr.sector = 0;
179 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
180 } else {
181 switch (req->cmd_type) {
182 case REQ_TYPE_FS:
183 vbr->out_hdr.type = 0;
184 vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req));
185 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
186 break;
187 case REQ_TYPE_BLOCK_PC:
188 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD);
189 vbr->out_hdr.sector = 0;
190 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
191 break;
192 case REQ_TYPE_SPECIAL:
193 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
194 vbr->out_hdr.sector = 0;
195 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
196 break;
197 default:
198 /* We don't put anything else in the queue. */
199 BUG();
200 }
201 }
202
203 blk_mq_start_request(req);
204
205 num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
206 if (num) {
207 if (rq_data_dir(vbr->req) == WRITE)
208 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
209 else
210 vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);
211 }
212
213 spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
214 err = __virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
215 if (err) {
216 virtqueue_kick(vblk->vqs[qid].vq);
217 blk_mq_stop_hw_queue(hctx);
218 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
219 /* Out of mem doesn't actually happen, since we fall back
220 * to direct descriptors */
221 if (err == -ENOMEM || err == -ENOSPC)
222 return BLK_MQ_RQ_QUEUE_BUSY;
223 return BLK_MQ_RQ_QUEUE_ERROR;
224 }
225
226 if (last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
227 notify = true;
228 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
229
230 if (notify)
231 virtqueue_notify(vblk->vqs[qid].vq);
232 return BLK_MQ_RQ_QUEUE_OK;
233 }
234
235 /* return id (s/n) string for *disk to *id_str
236 */
237 static int virtblk_get_id(struct gendisk *disk, char *id_str)
238 {
239 struct virtio_blk *vblk = disk->private_data;
240 struct request *req;
241 struct bio *bio;
242 int err;
243
244 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
245 GFP_KERNEL);
246 if (IS_ERR(bio))
247 return PTR_ERR(bio);
248
249 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
250 if (IS_ERR(req)) {
251 bio_put(bio);
252 return PTR_ERR(req);
253 }
254
255 req->cmd_type = REQ_TYPE_SPECIAL;
256 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
257 blk_put_request(req);
258
259 return err;
260 }
261
262 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
263 unsigned int cmd, unsigned long data)
264 {
265 struct gendisk *disk = bdev->bd_disk;
266 struct virtio_blk *vblk = disk->private_data;
267
268 /*
269 * Only allow the generic SCSI ioctls if the host can support it.
270 */
271 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
272 return -ENOTTY;
273
274 return scsi_cmd_blk_ioctl(bdev, mode, cmd,
275 (void __user *)data);
276 }
277
278 /* We provide getgeo only to please some old bootloader/partitioning tools */
279 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
280 {
281 struct virtio_blk *vblk = bd->bd_disk->private_data;
282
283 /* see if the host passed in geometry config */
284 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
285 virtio_cread(vblk->vdev, struct virtio_blk_config,
286 geometry.cylinders, &geo->cylinders);
287 virtio_cread(vblk->vdev, struct virtio_blk_config,
288 geometry.heads, &geo->heads);
289 virtio_cread(vblk->vdev, struct virtio_blk_config,
290 geometry.sectors, &geo->sectors);
291 } else {
292 /* some standard values, similar to sd */
293 geo->heads = 1 << 6;
294 geo->sectors = 1 << 5;
295 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
296 }
297 return 0;
298 }
299
300 static const struct block_device_operations virtblk_fops = {
301 .ioctl = virtblk_ioctl,
302 .owner = THIS_MODULE,
303 .getgeo = virtblk_getgeo,
304 };
305
306 static int index_to_minor(int index)
307 {
308 return index << PART_BITS;
309 }
310
311 static int minor_to_index(int minor)
312 {
313 return minor >> PART_BITS;
314 }
315
316 static ssize_t virtblk_serial_show(struct device *dev,
317 struct device_attribute *attr, char *buf)
318 {
319 struct gendisk *disk = dev_to_disk(dev);
320 int err;
321
322 /* sysfs gives us a PAGE_SIZE buffer */
323 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
324
325 buf[VIRTIO_BLK_ID_BYTES] = '\0';
326 err = virtblk_get_id(disk, buf);
327 if (!err)
328 return strlen(buf);
329
330 if (err == -EIO) /* Unsupported? Make it empty. */
331 return 0;
332
333 return err;
334 }
335
336 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
337
338 static void virtblk_config_changed_work(struct work_struct *work)
339 {
340 struct virtio_blk *vblk =
341 container_of(work, struct virtio_blk, config_work);
342 struct virtio_device *vdev = vblk->vdev;
343 struct request_queue *q = vblk->disk->queue;
344 char cap_str_2[10], cap_str_10[10];
345 char *envp[] = { "RESIZE=1", NULL };
346 u64 capacity, size;
347
348 /* Host must always specify the capacity. */
349 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
350
351 /* If capacity is too big, truncate with warning. */
352 if ((sector_t)capacity != capacity) {
353 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
354 (unsigned long long)capacity);
355 capacity = (sector_t)-1;
356 }
357
358 size = capacity * queue_logical_block_size(q);
359 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
360 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
361
362 dev_notice(&vdev->dev,
363 "new size: %llu %d-byte logical blocks (%s/%s)\n",
364 (unsigned long long)capacity,
365 queue_logical_block_size(q),
366 cap_str_10, cap_str_2);
367
368 set_capacity(vblk->disk, capacity);
369 revalidate_disk(vblk->disk);
370 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp);
371 }
372
373 static void virtblk_config_changed(struct virtio_device *vdev)
374 {
375 struct virtio_blk *vblk = vdev->priv;
376
377 queue_work(virtblk_wq, &vblk->config_work);
378 }
379
380 static int init_vq(struct virtio_blk *vblk)
381 {
382 int err = 0;
383 int i;
384 vq_callback_t **callbacks;
385 const char **names;
386 struct virtqueue **vqs;
387 unsigned short num_vqs;
388 struct virtio_device *vdev = vblk->vdev;
389
390 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
391 struct virtio_blk_config, num_queues,
392 &num_vqs);
393 if (err)
394 num_vqs = 1;
395
396 vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL);
397 if (!vblk->vqs) {
398 err = -ENOMEM;
399 goto out;
400 }
401
402 names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL);
403 if (!names)
404 goto err_names;
405
406 callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL);
407 if (!callbacks)
408 goto err_callbacks;
409
410 vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL);
411 if (!vqs)
412 goto err_vqs;
413
414 for (i = 0; i < num_vqs; i++) {
415 callbacks[i] = virtblk_done;
416 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
417 names[i] = vblk->vqs[i].name;
418 }
419
420 /* Discover virtqueues and write information to configuration. */
421 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
422 if (err)
423 goto err_find_vqs;
424
425 for (i = 0; i < num_vqs; i++) {
426 spin_lock_init(&vblk->vqs[i].lock);
427 vblk->vqs[i].vq = vqs[i];
428 }
429 vblk->num_vqs = num_vqs;
430
431 err_find_vqs:
432 kfree(vqs);
433 err_vqs:
434 kfree(callbacks);
435 err_callbacks:
436 kfree(names);
437 err_names:
438 if (err)
439 kfree(vblk->vqs);
440 out:
441 return err;
442 }
443
444 /*
445 * Legacy naming scheme used for virtio devices. We are stuck with it for
446 * virtio blk but don't ever use it for any new driver.
447 */
448 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
449 {
450 const int base = 'z' - 'a' + 1;
451 char *begin = buf + strlen(prefix);
452 char *end = buf + buflen;
453 char *p;
454 int unit;
455
456 p = end - 1;
457 *p = '\0';
458 unit = base;
459 do {
460 if (p == begin)
461 return -EINVAL;
462 *--p = 'a' + (index % unit);
463 index = (index / unit) - 1;
464 } while (index >= 0);
465
466 memmove(begin, p, end - p);
467 memcpy(buf, prefix, strlen(prefix));
468
469 return 0;
470 }
471
472 static int virtblk_get_cache_mode(struct virtio_device *vdev)
473 {
474 u8 writeback;
475 int err;
476
477 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
478 struct virtio_blk_config, wce,
479 &writeback);
480 if (err)
481 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
482 virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
483
484 return writeback;
485 }
486
487 static void virtblk_update_cache_mode(struct virtio_device *vdev)
488 {
489 u8 writeback = virtblk_get_cache_mode(vdev);
490 struct virtio_blk *vblk = vdev->priv;
491
492 if (writeback)
493 blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
494 else
495 blk_queue_flush(vblk->disk->queue, 0);
496
497 revalidate_disk(vblk->disk);
498 }
499
500 static const char *const virtblk_cache_types[] = {
501 "write through", "write back"
502 };
503
504 static ssize_t
505 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
506 const char *buf, size_t count)
507 {
508 struct gendisk *disk = dev_to_disk(dev);
509 struct virtio_blk *vblk = disk->private_data;
510 struct virtio_device *vdev = vblk->vdev;
511 int i;
512
513 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
514 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
515 if (sysfs_streq(buf, virtblk_cache_types[i]))
516 break;
517
518 if (i < 0)
519 return -EINVAL;
520
521 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
522 virtblk_update_cache_mode(vdev);
523 return count;
524 }
525
526 static ssize_t
527 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
528 char *buf)
529 {
530 struct gendisk *disk = dev_to_disk(dev);
531 struct virtio_blk *vblk = disk->private_data;
532 u8 writeback = virtblk_get_cache_mode(vblk->vdev);
533
534 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
535 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
536 }
537
538 static const struct device_attribute dev_attr_cache_type_ro =
539 __ATTR(cache_type, S_IRUGO,
540 virtblk_cache_type_show, NULL);
541 static const struct device_attribute dev_attr_cache_type_rw =
542 __ATTR(cache_type, S_IRUGO|S_IWUSR,
543 virtblk_cache_type_show, virtblk_cache_type_store);
544
545 static int virtblk_init_request(void *data, struct request *rq,
546 unsigned int hctx_idx, unsigned int request_idx,
547 unsigned int numa_node)
548 {
549 struct virtio_blk *vblk = data;
550 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
551
552 sg_init_table(vbr->sg, vblk->sg_elems);
553 return 0;
554 }
555
556 static struct blk_mq_ops virtio_mq_ops = {
557 .queue_rq = virtio_queue_rq,
558 .map_queue = blk_mq_map_queue,
559 .complete = virtblk_request_done,
560 .init_request = virtblk_init_request,
561 };
562
563 static unsigned int virtblk_queue_depth;
564 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
565
566 static int virtblk_probe(struct virtio_device *vdev)
567 {
568 struct virtio_blk *vblk;
569 struct request_queue *q;
570 int err, index;
571
572 u64 cap;
573 u32 v, blk_size, sg_elems, opt_io_size;
574 u16 min_io_size;
575 u8 physical_block_exp, alignment_offset;
576
577 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
578 GFP_KERNEL);
579 if (err < 0)
580 goto out;
581 index = err;
582
583 /* We need to know how many segments before we allocate. */
584 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
585 struct virtio_blk_config, seg_max,
586 &sg_elems);
587
588 /* We need at least one SG element, whatever they say. */
589 if (err || !sg_elems)
590 sg_elems = 1;
591
592 /* We need an extra sg elements at head and tail. */
593 sg_elems += 2;
594 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
595 if (!vblk) {
596 err = -ENOMEM;
597 goto out_free_index;
598 }
599
600 vblk->vdev = vdev;
601 vblk->sg_elems = sg_elems;
602
603 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
604
605 err = init_vq(vblk);
606 if (err)
607 goto out_free_vblk;
608
609 /* FIXME: How many partitions? How long is a piece of string? */
610 vblk->disk = alloc_disk(1 << PART_BITS);
611 if (!vblk->disk) {
612 err = -ENOMEM;
613 goto out_free_vq;
614 }
615
616 /* Default queue sizing is to fill the ring. */
617 if (!virtblk_queue_depth) {
618 virtblk_queue_depth = vblk->vqs[0].vq->num_free;
619 /* ... but without indirect descs, we use 2 descs per req */
620 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
621 virtblk_queue_depth /= 2;
622 }
623
624 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
625 vblk->tag_set.ops = &virtio_mq_ops;
626 vblk->tag_set.queue_depth = virtblk_queue_depth;
627 vblk->tag_set.numa_node = NUMA_NO_NODE;
628 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
629 vblk->tag_set.cmd_size =
630 sizeof(struct virtblk_req) +
631 sizeof(struct scatterlist) * sg_elems;
632 vblk->tag_set.driver_data = vblk;
633 vblk->tag_set.nr_hw_queues = vblk->num_vqs;
634
635 err = blk_mq_alloc_tag_set(&vblk->tag_set);
636 if (err)
637 goto out_put_disk;
638
639 q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
640 if (!q) {
641 err = -ENOMEM;
642 goto out_free_tags;
643 }
644
645 q->queuedata = vblk;
646
647 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
648
649 vblk->disk->major = major;
650 vblk->disk->first_minor = index_to_minor(index);
651 vblk->disk->private_data = vblk;
652 vblk->disk->fops = &virtblk_fops;
653 vblk->disk->driverfs_dev = &vdev->dev;
654 vblk->index = index;
655
656 /* configure queue flush support */
657 virtblk_update_cache_mode(vdev);
658
659 /* If disk is read-only in the host, the guest should obey */
660 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
661 set_disk_ro(vblk->disk, 1);
662
663 /* Host must always specify the capacity. */
664 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
665
666 /* If capacity is too big, truncate with warning. */
667 if ((sector_t)cap != cap) {
668 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
669 (unsigned long long)cap);
670 cap = (sector_t)-1;
671 }
672 set_capacity(vblk->disk, cap);
673
674 /* We can handle whatever the host told us to handle. */
675 blk_queue_max_segments(q, vblk->sg_elems-2);
676
677 /* No need to bounce any requests */
678 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
679
680 /* No real sector limit. */
681 blk_queue_max_hw_sectors(q, -1U);
682
683 /* Host can optionally specify maximum segment size and number of
684 * segments. */
685 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
686 struct virtio_blk_config, size_max, &v);
687 if (!err)
688 blk_queue_max_segment_size(q, v);
689 else
690 blk_queue_max_segment_size(q, -1U);
691
692 /* Host can optionally specify the block size of the device */
693 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
694 struct virtio_blk_config, blk_size,
695 &blk_size);
696 if (!err)
697 blk_queue_logical_block_size(q, blk_size);
698 else
699 blk_size = queue_logical_block_size(q);
700
701 /* Use topology information if available */
702 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
703 struct virtio_blk_config, physical_block_exp,
704 &physical_block_exp);
705 if (!err && physical_block_exp)
706 blk_queue_physical_block_size(q,
707 blk_size * (1 << physical_block_exp));
708
709 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
710 struct virtio_blk_config, alignment_offset,
711 &alignment_offset);
712 if (!err && alignment_offset)
713 blk_queue_alignment_offset(q, blk_size * alignment_offset);
714
715 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
716 struct virtio_blk_config, min_io_size,
717 &min_io_size);
718 if (!err && min_io_size)
719 blk_queue_io_min(q, blk_size * min_io_size);
720
721 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
722 struct virtio_blk_config, opt_io_size,
723 &opt_io_size);
724 if (!err && opt_io_size)
725 blk_queue_io_opt(q, blk_size * opt_io_size);
726
727 virtio_device_ready(vdev);
728
729 add_disk(vblk->disk);
730 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
731 if (err)
732 goto out_del_disk;
733
734 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
735 err = device_create_file(disk_to_dev(vblk->disk),
736 &dev_attr_cache_type_rw);
737 else
738 err = device_create_file(disk_to_dev(vblk->disk),
739 &dev_attr_cache_type_ro);
740 if (err)
741 goto out_del_disk;
742 return 0;
743
744 out_del_disk:
745 del_gendisk(vblk->disk);
746 blk_cleanup_queue(vblk->disk->queue);
747 out_free_tags:
748 blk_mq_free_tag_set(&vblk->tag_set);
749 out_put_disk:
750 put_disk(vblk->disk);
751 out_free_vq:
752 vdev->config->del_vqs(vdev);
753 out_free_vblk:
754 kfree(vblk);
755 out_free_index:
756 ida_simple_remove(&vd_index_ida, index);
757 out:
758 return err;
759 }
760
761 static void virtblk_remove(struct virtio_device *vdev)
762 {
763 struct virtio_blk *vblk = vdev->priv;
764 int index = vblk->index;
765 int refc;
766
767 /* Make sure no work handler is accessing the device. */
768 flush_work(&vblk->config_work);
769
770 del_gendisk(vblk->disk);
771 blk_cleanup_queue(vblk->disk->queue);
772
773 blk_mq_free_tag_set(&vblk->tag_set);
774
775 /* Stop all the virtqueues. */
776 vdev->config->reset(vdev);
777
778 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
779 put_disk(vblk->disk);
780 vdev->config->del_vqs(vdev);
781 kfree(vblk->vqs);
782 kfree(vblk);
783
784 /* Only free device id if we don't have any users */
785 if (refc == 1)
786 ida_simple_remove(&vd_index_ida, index);
787 }
788
789 #ifdef CONFIG_PM_SLEEP
790 static int virtblk_freeze(struct virtio_device *vdev)
791 {
792 struct virtio_blk *vblk = vdev->priv;
793
794 /* Ensure we don't receive any more interrupts */
795 vdev->config->reset(vdev);
796
797 /* Make sure no work handler is accessing the device. */
798 flush_work(&vblk->config_work);
799
800 blk_mq_stop_hw_queues(vblk->disk->queue);
801
802 vdev->config->del_vqs(vdev);
803 return 0;
804 }
805
806 static int virtblk_restore(struct virtio_device *vdev)
807 {
808 struct virtio_blk *vblk = vdev->priv;
809 int ret;
810
811 ret = init_vq(vdev->priv);
812 if (ret)
813 return ret;
814
815 virtio_device_ready(vdev);
816
817 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
818 return 0;
819 }
820 #endif
821
822 static const struct virtio_device_id id_table[] = {
823 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
824 { 0 },
825 };
826
827 static unsigned int features_legacy[] = {
828 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
829 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
830 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
831 VIRTIO_BLK_F_MQ,
832 }
833 ;
834 static unsigned int features[] = {
835 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
836 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
837 VIRTIO_BLK_F_TOPOLOGY,
838 VIRTIO_BLK_F_MQ,
839 VIRTIO_F_VERSION_1,
840 };
841
842 static struct virtio_driver virtio_blk = {
843 .feature_table = features,
844 .feature_table_size = ARRAY_SIZE(features),
845 .feature_table_legacy = features_legacy,
846 .feature_table_size_legacy = ARRAY_SIZE(features_legacy),
847 .driver.name = KBUILD_MODNAME,
848 .driver.owner = THIS_MODULE,
849 .id_table = id_table,
850 .probe = virtblk_probe,
851 .remove = virtblk_remove,
852 .config_changed = virtblk_config_changed,
853 #ifdef CONFIG_PM_SLEEP
854 .freeze = virtblk_freeze,
855 .restore = virtblk_restore,
856 #endif
857 };
858
859 static int __init init(void)
860 {
861 int error;
862
863 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
864 if (!virtblk_wq)
865 return -ENOMEM;
866
867 major = register_blkdev(0, "virtblk");
868 if (major < 0) {
869 error = major;
870 goto out_destroy_workqueue;
871 }
872
873 error = register_virtio_driver(&virtio_blk);
874 if (error)
875 goto out_unregister_blkdev;
876 return 0;
877
878 out_unregister_blkdev:
879 unregister_blkdev(major, "virtblk");
880 out_destroy_workqueue:
881 destroy_workqueue(virtblk_wq);
882 return error;
883 }
884
885 static void __exit fini(void)
886 {
887 unregister_blkdev(major, "virtblk");
888 unregister_virtio_driver(&virtio_blk);
889 destroy_workqueue(virtblk_wq);
890 }
891 module_init(init);
892 module_exit(fini);
893
894 MODULE_DEVICE_TABLE(virtio, id_table);
895 MODULE_DESCRIPTION("Virtio block driver");
896 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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