Version:  2.0.40 2.2.26 2.4.37 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 3.17 3.18 3.19

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 #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,
163                            const struct blk_mq_queue_data *bd)
164 {
165         struct virtio_blk *vblk = hctx->queue->queuedata;
166         struct request *req = bd->rq;
167         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
168         unsigned long flags;
169         unsigned int num;
170         int qid = hctx->queue_num;
171         int err;
172         bool notify = false;
173 
174         BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
175 
176         vbr->req = req;
177         if (req->cmd_flags & REQ_FLUSH) {
178                 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH);
179                 vbr->out_hdr.sector = 0;
180                 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
181         } else {
182                 switch (req->cmd_type) {
183                 case REQ_TYPE_FS:
184                         vbr->out_hdr.type = 0;
185                         vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req));
186                         vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
187                         break;
188                 case REQ_TYPE_BLOCK_PC:
189                         vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD);
190                         vbr->out_hdr.sector = 0;
191                         vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
192                         break;
193                 case REQ_TYPE_SPECIAL:
194                         vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
195                         vbr->out_hdr.sector = 0;
196                         vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
197                         break;
198                 default:
199                         /* We don't put anything else in the queue. */
200                         BUG();
201                 }
202         }
203 
204         blk_mq_start_request(req);
205 
206         num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
207         if (num) {
208                 if (rq_data_dir(vbr->req) == WRITE)
209                         vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
210                 else
211                         vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);
212         }
213 
214         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
215         err = __virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
216         if (err) {
217                 virtqueue_kick(vblk->vqs[qid].vq);
218                 blk_mq_stop_hw_queue(hctx);
219                 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
220                 /* Out of mem doesn't actually happen, since we fall back
221                  * to direct descriptors */
222                 if (err == -ENOMEM || err == -ENOSPC)
223                         return BLK_MQ_RQ_QUEUE_BUSY;
224                 return BLK_MQ_RQ_QUEUE_ERROR;
225         }
226 
227         if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
228                 notify = true;
229         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
230 
231         if (notify)
232                 virtqueue_notify(vblk->vqs[qid].vq);
233         return BLK_MQ_RQ_QUEUE_OK;
234 }
235 
236 /* return id (s/n) string for *disk to *id_str
237  */
238 static int virtblk_get_id(struct gendisk *disk, char *id_str)
239 {
240         struct virtio_blk *vblk = disk->private_data;
241         struct request *req;
242         struct bio *bio;
243         int err;
244 
245         bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
246                            GFP_KERNEL);
247         if (IS_ERR(bio))
248                 return PTR_ERR(bio);
249 
250         req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
251         if (IS_ERR(req)) {
252                 bio_put(bio);
253                 return PTR_ERR(req);
254         }
255 
256         req->cmd_type = REQ_TYPE_SPECIAL;
257         err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
258         blk_put_request(req);
259 
260         return err;
261 }
262 
263 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
264                              unsigned int cmd, unsigned long data)
265 {
266         struct gendisk *disk = bdev->bd_disk;
267         struct virtio_blk *vblk = disk->private_data;
268 
269         /*
270          * Only allow the generic SCSI ioctls if the host can support it.
271          */
272         if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
273                 return -ENOTTY;
274 
275         return scsi_cmd_blk_ioctl(bdev, mode, cmd,
276                                   (void __user *)data);
277 }
278 
279 /* We provide getgeo only to please some old bootloader/partitioning tools */
280 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
281 {
282         struct virtio_blk *vblk = bd->bd_disk->private_data;
283 
284         /* see if the host passed in geometry config */
285         if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
286                 virtio_cread(vblk->vdev, struct virtio_blk_config,
287                              geometry.cylinders, &geo->cylinders);
288                 virtio_cread(vblk->vdev, struct virtio_blk_config,
289                              geometry.heads, &geo->heads);
290                 virtio_cread(vblk->vdev, struct virtio_blk_config,
291                              geometry.sectors, &geo->sectors);
292         } else {
293                 /* some standard values, similar to sd */
294                 geo->heads = 1 << 6;
295                 geo->sectors = 1 << 5;
296                 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
297         }
298         return 0;
299 }
300 
301 static const struct block_device_operations virtblk_fops = {
302         .ioctl  = virtblk_ioctl,
303         .owner  = THIS_MODULE,
304         .getgeo = virtblk_getgeo,
305 };
306 
307 static int index_to_minor(int index)
308 {
309         return index << PART_BITS;
310 }
311 
312 static int minor_to_index(int minor)
313 {
314         return minor >> PART_BITS;
315 }
316 
317 static ssize_t virtblk_serial_show(struct device *dev,
318                                 struct device_attribute *attr, char *buf)
319 {
320         struct gendisk *disk = dev_to_disk(dev);
321         int err;
322 
323         /* sysfs gives us a PAGE_SIZE buffer */
324         BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
325 
326         buf[VIRTIO_BLK_ID_BYTES] = '\0';
327         err = virtblk_get_id(disk, buf);
328         if (!err)
329                 return strlen(buf);
330 
331         if (err == -EIO) /* Unsupported? Make it empty. */
332                 return 0;
333 
334         return err;
335 }
336 
337 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
338 
339 static void virtblk_config_changed_work(struct work_struct *work)
340 {
341         struct virtio_blk *vblk =
342                 container_of(work, struct virtio_blk, config_work);
343         struct virtio_device *vdev = vblk->vdev;
344         struct request_queue *q = vblk->disk->queue;
345         char cap_str_2[10], cap_str_10[10];
346         char *envp[] = { "RESIZE=1", NULL };
347         u64 capacity, size;
348 
349         /* Host must always specify the capacity. */
350         virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
351 
352         /* If capacity is too big, truncate with warning. */
353         if ((sector_t)capacity != capacity) {
354                 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
355                          (unsigned long long)capacity);
356                 capacity = (sector_t)-1;
357         }
358 
359         size = capacity * queue_logical_block_size(q);
360         string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
361         string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
362 
363         dev_notice(&vdev->dev,
364                   "new size: %llu %d-byte logical blocks (%s/%s)\n",
365                   (unsigned long long)capacity,
366                   queue_logical_block_size(q),
367                   cap_str_10, cap_str_2);
368 
369         set_capacity(vblk->disk, capacity);
370         revalidate_disk(vblk->disk);
371         kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp);
372 }
373 
374 static void virtblk_config_changed(struct virtio_device *vdev)
375 {
376         struct virtio_blk *vblk = vdev->priv;
377 
378         queue_work(virtblk_wq, &vblk->config_work);
379 }
380 
381 static int init_vq(struct virtio_blk *vblk)
382 {
383         int err = 0;
384         int i;
385         vq_callback_t **callbacks;
386         const char **names;
387         struct virtqueue **vqs;
388         unsigned short num_vqs;
389         struct virtio_device *vdev = vblk->vdev;
390 
391         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
392                                    struct virtio_blk_config, num_queues,
393                                    &num_vqs);
394         if (err)
395                 num_vqs = 1;
396 
397         vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL);
398         if (!vblk->vqs) {
399                 err = -ENOMEM;
400                 goto out;
401         }
402 
403         names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL);
404         if (!names)
405                 goto err_names;
406 
407         callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL);
408         if (!callbacks)
409                 goto err_callbacks;
410 
411         vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL);
412         if (!vqs)
413                 goto err_vqs;
414 
415         for (i = 0; i < num_vqs; i++) {
416                 callbacks[i] = virtblk_done;
417                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
418                 names[i] = vblk->vqs[i].name;
419         }
420 
421         /* Discover virtqueues and write information to configuration.  */
422         err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
423         if (err)
424                 goto err_find_vqs;
425 
426         for (i = 0; i < num_vqs; i++) {
427                 spin_lock_init(&vblk->vqs[i].lock);
428                 vblk->vqs[i].vq = vqs[i];
429         }
430         vblk->num_vqs = num_vqs;
431 
432  err_find_vqs:
433         kfree(vqs);
434  err_vqs:
435         kfree(callbacks);
436  err_callbacks:
437         kfree(names);
438  err_names:
439         if (err)
440                 kfree(vblk->vqs);
441  out:
442         return err;
443 }
444 
445 /*
446  * Legacy naming scheme used for virtio devices.  We are stuck with it for
447  * virtio blk but don't ever use it for any new driver.
448  */
449 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
450 {
451         const int base = 'z' - 'a' + 1;
452         char *begin = buf + strlen(prefix);
453         char *end = buf + buflen;
454         char *p;
455         int unit;
456 
457         p = end - 1;
458         *p = '\0';
459         unit = base;
460         do {
461                 if (p == begin)
462                         return -EINVAL;
463                 *--p = 'a' + (index % unit);
464                 index = (index / unit) - 1;
465         } while (index >= 0);
466 
467         memmove(begin, p, end - p);
468         memcpy(buf, prefix, strlen(prefix));
469 
470         return 0;
471 }
472 
473 static int virtblk_get_cache_mode(struct virtio_device *vdev)
474 {
475         u8 writeback;
476         int err;
477 
478         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
479                                    struct virtio_blk_config, wce,
480                                    &writeback);
481         if (err)
482                 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
483                             virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
484 
485         return writeback;
486 }
487 
488 static void virtblk_update_cache_mode(struct virtio_device *vdev)
489 {
490         u8 writeback = virtblk_get_cache_mode(vdev);
491         struct virtio_blk *vblk = vdev->priv;
492 
493         if (writeback)
494                 blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
495         else
496                 blk_queue_flush(vblk->disk->queue, 0);
497 
498         revalidate_disk(vblk->disk);
499 }
500 
501 static const char *const virtblk_cache_types[] = {
502         "write through", "write back"
503 };
504 
505 static ssize_t
506 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
507                          const char *buf, size_t count)
508 {
509         struct gendisk *disk = dev_to_disk(dev);
510         struct virtio_blk *vblk = disk->private_data;
511         struct virtio_device *vdev = vblk->vdev;
512         int i;
513 
514         BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
515         for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
516                 if (sysfs_streq(buf, virtblk_cache_types[i]))
517                         break;
518 
519         if (i < 0)
520                 return -EINVAL;
521 
522         virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
523         virtblk_update_cache_mode(vdev);
524         return count;
525 }
526 
527 static ssize_t
528 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
529                          char *buf)
530 {
531         struct gendisk *disk = dev_to_disk(dev);
532         struct virtio_blk *vblk = disk->private_data;
533         u8 writeback = virtblk_get_cache_mode(vblk->vdev);
534 
535         BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
536         return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
537 }
538 
539 static const struct device_attribute dev_attr_cache_type_ro =
540         __ATTR(cache_type, S_IRUGO,
541                virtblk_cache_type_show, NULL);
542 static const struct device_attribute dev_attr_cache_type_rw =
543         __ATTR(cache_type, S_IRUGO|S_IWUSR,
544                virtblk_cache_type_show, virtblk_cache_type_store);
545 
546 static int virtblk_init_request(void *data, struct request *rq,
547                 unsigned int hctx_idx, unsigned int request_idx,
548                 unsigned int numa_node)
549 {
550         struct virtio_blk *vblk = data;
551         struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
552 
553         sg_init_table(vbr->sg, vblk->sg_elems);
554         return 0;
555 }
556 
557 static struct blk_mq_ops virtio_mq_ops = {
558         .queue_rq       = virtio_queue_rq,
559         .map_queue      = blk_mq_map_queue,
560         .complete       = virtblk_request_done,
561         .init_request   = virtblk_init_request,
562 };
563 
564 static unsigned int virtblk_queue_depth;
565 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
566 
567 static int virtblk_probe(struct virtio_device *vdev)
568 {
569         struct virtio_blk *vblk;
570         struct request_queue *q;
571         int err, index;
572 
573         u64 cap;
574         u32 v, blk_size, sg_elems, opt_io_size;
575         u16 min_io_size;
576         u8 physical_block_exp, alignment_offset;
577 
578         err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
579                              GFP_KERNEL);
580         if (err < 0)
581                 goto out;
582         index = err;
583 
584         /* We need to know how many segments before we allocate. */
585         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
586                                    struct virtio_blk_config, seg_max,
587                                    &sg_elems);
588 
589         /* We need at least one SG element, whatever they say. */
590         if (err || !sg_elems)
591                 sg_elems = 1;
592 
593         /* We need an extra sg elements at head and tail. */
594         sg_elems += 2;
595         vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
596         if (!vblk) {
597                 err = -ENOMEM;
598                 goto out_free_index;
599         }
600 
601         vblk->vdev = vdev;
602         vblk->sg_elems = sg_elems;
603 
604         INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
605 
606         err = init_vq(vblk);
607         if (err)
608                 goto out_free_vblk;
609 
610         /* FIXME: How many partitions?  How long is a piece of string? */
611         vblk->disk = alloc_disk(1 << PART_BITS);
612         if (!vblk->disk) {
613                 err = -ENOMEM;
614                 goto out_free_vq;
615         }
616 
617         /* Default queue sizing is to fill the ring. */
618         if (!virtblk_queue_depth) {
619                 virtblk_queue_depth = vblk->vqs[0].vq->num_free;
620                 /* ... but without indirect descs, we use 2 descs per req */
621                 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
622                         virtblk_queue_depth /= 2;
623         }
624 
625         memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
626         vblk->tag_set.ops = &virtio_mq_ops;
627         vblk->tag_set.queue_depth = virtblk_queue_depth;
628         vblk->tag_set.numa_node = NUMA_NO_NODE;
629         vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
630         vblk->tag_set.cmd_size =
631                 sizeof(struct virtblk_req) +
632                 sizeof(struct scatterlist) * sg_elems;
633         vblk->tag_set.driver_data = vblk;
634         vblk->tag_set.nr_hw_queues = vblk->num_vqs;
635 
636         err = blk_mq_alloc_tag_set(&vblk->tag_set);
637         if (err)
638                 goto out_put_disk;
639 
640         q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
641         if (IS_ERR(q)) {
642                 err = -ENOMEM;
643                 goto out_free_tags;
644         }
645 
646         q->queuedata = vblk;
647 
648         virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
649 
650         vblk->disk->major = major;
651         vblk->disk->first_minor = index_to_minor(index);
652         vblk->disk->private_data = vblk;
653         vblk->disk->fops = &virtblk_fops;
654         vblk->disk->driverfs_dev = &vdev->dev;
655         vblk->index = index;
656 
657         /* configure queue flush support */
658         virtblk_update_cache_mode(vdev);
659 
660         /* If disk is read-only in the host, the guest should obey */
661         if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
662                 set_disk_ro(vblk->disk, 1);
663 
664         /* Host must always specify the capacity. */
665         virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
666 
667         /* If capacity is too big, truncate with warning. */
668         if ((sector_t)cap != cap) {
669                 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
670                          (unsigned long long)cap);
671                 cap = (sector_t)-1;
672         }
673         set_capacity(vblk->disk, cap);
674 
675         /* We can handle whatever the host told us to handle. */
676         blk_queue_max_segments(q, vblk->sg_elems-2);
677 
678         /* No need to bounce any requests */
679         blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
680 
681         /* No real sector limit. */
682         blk_queue_max_hw_sectors(q, -1U);
683 
684         /* Host can optionally specify maximum segment size and number of
685          * segments. */
686         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
687                                    struct virtio_blk_config, size_max, &v);
688         if (!err)
689                 blk_queue_max_segment_size(q, v);
690         else
691                 blk_queue_max_segment_size(q, -1U);
692 
693         /* Host can optionally specify the block size of the device */
694         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
695                                    struct virtio_blk_config, blk_size,
696                                    &blk_size);
697         if (!err)
698                 blk_queue_logical_block_size(q, blk_size);
699         else
700                 blk_size = queue_logical_block_size(q);
701 
702         /* Use topology information if available */
703         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
704                                    struct virtio_blk_config, physical_block_exp,
705                                    &physical_block_exp);
706         if (!err && physical_block_exp)
707                 blk_queue_physical_block_size(q,
708                                 blk_size * (1 << physical_block_exp));
709 
710         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
711                                    struct virtio_blk_config, alignment_offset,
712                                    &alignment_offset);
713         if (!err && alignment_offset)
714                 blk_queue_alignment_offset(q, blk_size * alignment_offset);
715 
716         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
717                                    struct virtio_blk_config, min_io_size,
718                                    &min_io_size);
719         if (!err && min_io_size)
720                 blk_queue_io_min(q, blk_size * min_io_size);
721 
722         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
723                                    struct virtio_blk_config, opt_io_size,
724                                    &opt_io_size);
725         if (!err && opt_io_size)
726                 blk_queue_io_opt(q, blk_size * opt_io_size);
727 
728         virtio_device_ready(vdev);
729 
730         add_disk(vblk->disk);
731         err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
732         if (err)
733                 goto out_del_disk;
734 
735         if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
736                 err = device_create_file(disk_to_dev(vblk->disk),
737                                          &dev_attr_cache_type_rw);
738         else
739                 err = device_create_file(disk_to_dev(vblk->disk),
740                                          &dev_attr_cache_type_ro);
741         if (err)
742                 goto out_del_disk;
743         return 0;
744 
745 out_del_disk:
746         del_gendisk(vblk->disk);
747         blk_cleanup_queue(vblk->disk->queue);
748 out_free_tags:
749         blk_mq_free_tag_set(&vblk->tag_set);
750 out_put_disk:
751         put_disk(vblk->disk);
752 out_free_vq:
753         vdev->config->del_vqs(vdev);
754 out_free_vblk:
755         kfree(vblk);
756 out_free_index:
757         ida_simple_remove(&vd_index_ida, index);
758 out:
759         return err;
760 }
761 
762 static void virtblk_remove(struct virtio_device *vdev)
763 {
764         struct virtio_blk *vblk = vdev->priv;
765         int index = vblk->index;
766         int refc;
767 
768         /* Make sure no work handler is accessing the device. */
769         flush_work(&vblk->config_work);
770 
771         del_gendisk(vblk->disk);
772         blk_cleanup_queue(vblk->disk->queue);
773 
774         blk_mq_free_tag_set(&vblk->tag_set);
775 
776         /* Stop all the virtqueues. */
777         vdev->config->reset(vdev);
778 
779         refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
780         put_disk(vblk->disk);
781         vdev->config->del_vqs(vdev);
782         kfree(vblk->vqs);
783         kfree(vblk);
784 
785         /* Only free device id if we don't have any users */
786         if (refc == 1)
787                 ida_simple_remove(&vd_index_ida, index);
788 }
789 
790 #ifdef CONFIG_PM_SLEEP
791 static int virtblk_freeze(struct virtio_device *vdev)
792 {
793         struct virtio_blk *vblk = vdev->priv;
794 
795         /* Ensure we don't receive any more interrupts */
796         vdev->config->reset(vdev);
797 
798         /* Make sure no work handler is accessing the device. */
799         flush_work(&vblk->config_work);
800 
801         blk_mq_stop_hw_queues(vblk->disk->queue);
802 
803         vdev->config->del_vqs(vdev);
804         return 0;
805 }
806 
807 static int virtblk_restore(struct virtio_device *vdev)
808 {
809         struct virtio_blk *vblk = vdev->priv;
810         int ret;
811 
812         ret = init_vq(vdev->priv);
813         if (ret)
814                 return ret;
815 
816         virtio_device_ready(vdev);
817 
818         blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
819         return 0;
820 }
821 #endif
822 
823 static const struct virtio_device_id id_table[] = {
824         { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
825         { 0 },
826 };
827 
828 static unsigned int features_legacy[] = {
829         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
830         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
831         VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
832         VIRTIO_BLK_F_MQ,
833 }
834 ;
835 static unsigned int features[] = {
836         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
837         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
838         VIRTIO_BLK_F_TOPOLOGY,
839         VIRTIO_BLK_F_MQ,
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_virtio_driver(&virtio_blk);
888         unregister_blkdev(major, "virtblk");
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");
897 

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