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