Version:  2.0.40 2.2.26 2.4.37 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 3.16

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

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