Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

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

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