Version:  2.0.40 2.2.26 2.4.37 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 4.0

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         struct virtio_device *vdev;
 33 
 34         /* The disk structure for the kernel. */
 35         struct gendisk *disk;
 36 
 37         /* Block layer tags. */
 38         struct blk_mq_tag_set tag_set;
 39 
 40         /* Process context for config space updates */
 41         struct work_struct config_work;
 42 
 43         /* What host tells us, plus 2 for header & tailer. */
 44         unsigned int sg_elems;
 45 
 46         /* Ida index - used to track minor number allocations. */
 47         int index;
 48 
 49         /* num of vqs */
 50         int num_vqs;
 51         struct virtio_blk_vq *vqs;
 52 };
 53 
 54 struct virtblk_req {
 55         struct request *req;
 56         struct virtio_blk_outhdr out_hdr;
 57         struct virtio_scsi_inhdr in_hdr;
 58         u8 status;
 59         struct scatterlist sg[];
 60 };
 61 
 62 static inline int virtblk_result(struct virtblk_req *vbr)
 63 {
 64         switch (vbr->status) {
 65         case VIRTIO_BLK_S_OK:
 66                 return 0;
 67         case VIRTIO_BLK_S_UNSUPP:
 68                 return -ENOTTY;
 69         default:
 70                 return -EIO;
 71         }
 72 }
 73 
 74 static int __virtblk_add_req(struct virtqueue *vq,
 75                              struct virtblk_req *vbr,
 76                              struct scatterlist *data_sg,
 77                              bool have_data)
 78 {
 79         struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6];
 80         unsigned int num_out = 0, num_in = 0;
 81         __virtio32 type = vbr->out_hdr.type & ~cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT);
 82 
 83         sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
 84         sgs[num_out++] = &hdr;
 85 
 86         /*
 87          * If this is a packet command we need a couple of additional headers.
 88          * Behind the normal outhdr we put a segment with the scsi command
 89          * block, and before the normal inhdr we put the sense data and the
 90          * inhdr with additional status information.
 91          */
 92         if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
 93                 sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len);
 94                 sgs[num_out++] = &cmd;
 95         }
 96 
 97         if (have_data) {
 98                 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
 99                         sgs[num_out++] = data_sg;
100                 else
101                         sgs[num_out + num_in++] = data_sg;
102         }
103 
104         if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
105                 sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
106                 sgs[num_out + num_in++] = &sense;
107                 sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr));
108                 sgs[num_out + num_in++] = &inhdr;
109         }
110 
111         sg_init_one(&status, &vbr->status, sizeof(vbr->status));
112         sgs[num_out + num_in++] = &status;
113 
114         return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
115 }
116 
117 static inline void virtblk_request_done(struct request *req)
118 {
119         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
120         struct virtio_blk *vblk = req->q->queuedata;
121         int error = virtblk_result(vbr);
122 
123         if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
124                 req->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual);
125                 req->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len);
126                 req->errors = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors);
127         } else if (req->cmd_type == REQ_TYPE_SPECIAL) {
128                 req->errors = (error != 0);
129         }
130 
131         blk_mq_end_request(req, error);
132 }
133 
134 static void virtblk_done(struct virtqueue *vq)
135 {
136         struct virtio_blk *vblk = vq->vdev->priv;
137         bool req_done = false;
138         int qid = vq->index;
139         struct virtblk_req *vbr;
140         unsigned long flags;
141         unsigned int len;
142 
143         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
144         do {
145                 virtqueue_disable_cb(vq);
146                 while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
147                         blk_mq_complete_request(vbr->req);
148                         req_done = true;
149                 }
150                 if (unlikely(virtqueue_is_broken(vq)))
151                         break;
152         } while (!virtqueue_enable_cb(vq));
153 
154         /* In case queue is stopped waiting for more buffers. */
155         if (req_done)
156                 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
157         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
158 }
159 
160 static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
161                            const struct blk_mq_queue_data *bd)
162 {
163         struct virtio_blk *vblk = hctx->queue->queuedata;
164         struct request *req = bd->rq;
165         struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
166         unsigned long flags;
167         unsigned int num;
168         int qid = hctx->queue_num;
169         int err;
170         bool notify = false;
171 
172         BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
173 
174         vbr->req = req;
175         if (req->cmd_flags & REQ_FLUSH) {
176                 vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH);
177                 vbr->out_hdr.sector = 0;
178                 vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
179         } else {
180                 switch (req->cmd_type) {
181                 case REQ_TYPE_FS:
182                         vbr->out_hdr.type = 0;
183                         vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req));
184                         vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
185                         break;
186                 case REQ_TYPE_BLOCK_PC:
187                         vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD);
188                         vbr->out_hdr.sector = 0;
189                         vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
190                         break;
191                 case REQ_TYPE_SPECIAL:
192                         vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
193                         vbr->out_hdr.sector = 0;
194                         vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
195                         break;
196                 default:
197                         /* We don't put anything else in the queue. */
198                         BUG();
199                 }
200         }
201 
202         blk_mq_start_request(req);
203 
204         num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
205         if (num) {
206                 if (rq_data_dir(vbr->req) == WRITE)
207                         vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
208                 else
209                         vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);
210         }
211 
212         spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
213         err = __virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
214         if (err) {
215                 virtqueue_kick(vblk->vqs[qid].vq);
216                 blk_mq_stop_hw_queue(hctx);
217                 spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
218                 /* Out of mem doesn't actually happen, since we fall back
219                  * to direct descriptors */
220                 if (err == -ENOMEM || err == -ENOSPC)
221                         return BLK_MQ_RQ_QUEUE_BUSY;
222                 return BLK_MQ_RQ_QUEUE_ERROR;
223         }
224 
225         if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
226                 notify = true;
227         spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
228 
229         if (notify)
230                 virtqueue_notify(vblk->vqs[qid].vq);
231         return BLK_MQ_RQ_QUEUE_OK;
232 }
233 
234 /* return id (s/n) string for *disk to *id_str
235  */
236 static int virtblk_get_id(struct gendisk *disk, char *id_str)
237 {
238         struct virtio_blk *vblk = disk->private_data;
239         struct request *req;
240         struct bio *bio;
241         int err;
242 
243         bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
244                            GFP_KERNEL);
245         if (IS_ERR(bio))
246                 return PTR_ERR(bio);
247 
248         req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
249         if (IS_ERR(req)) {
250                 bio_put(bio);
251                 return PTR_ERR(req);
252         }
253 
254         req->cmd_type = REQ_TYPE_SPECIAL;
255         err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
256         blk_put_request(req);
257 
258         return err;
259 }
260 
261 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
262                              unsigned int cmd, unsigned long data)
263 {
264         struct gendisk *disk = bdev->bd_disk;
265         struct virtio_blk *vblk = disk->private_data;
266 
267         /*
268          * Only allow the generic SCSI ioctls if the host can support it.
269          */
270         if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
271                 return -ENOTTY;
272 
273         return scsi_cmd_blk_ioctl(bdev, mode, cmd,
274                                   (void __user *)data);
275 }
276 
277 /* We provide getgeo only to please some old bootloader/partitioning tools */
278 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
279 {
280         struct virtio_blk *vblk = bd->bd_disk->private_data;
281 
282         /* see if the host passed in geometry config */
283         if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
284                 virtio_cread(vblk->vdev, struct virtio_blk_config,
285                              geometry.cylinders, &geo->cylinders);
286                 virtio_cread(vblk->vdev, struct virtio_blk_config,
287                              geometry.heads, &geo->heads);
288                 virtio_cread(vblk->vdev, struct virtio_blk_config,
289                              geometry.sectors, &geo->sectors);
290         } else {
291                 /* some standard values, similar to sd */
292                 geo->heads = 1 << 6;
293                 geo->sectors = 1 << 5;
294                 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
295         }
296         return 0;
297 }
298 
299 static const struct block_device_operations virtblk_fops = {
300         .ioctl  = virtblk_ioctl,
301         .owner  = THIS_MODULE,
302         .getgeo = virtblk_getgeo,
303 };
304 
305 static int index_to_minor(int index)
306 {
307         return index << PART_BITS;
308 }
309 
310 static int minor_to_index(int minor)
311 {
312         return minor >> PART_BITS;
313 }
314 
315 static ssize_t virtblk_serial_show(struct device *dev,
316                                 struct device_attribute *attr, char *buf)
317 {
318         struct gendisk *disk = dev_to_disk(dev);
319         int err;
320 
321         /* sysfs gives us a PAGE_SIZE buffer */
322         BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
323 
324         buf[VIRTIO_BLK_ID_BYTES] = '\0';
325         err = virtblk_get_id(disk, buf);
326         if (!err)
327                 return strlen(buf);
328 
329         if (err == -EIO) /* Unsupported? Make it empty. */
330                 return 0;
331 
332         return err;
333 }
334 
335 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
336 
337 static void virtblk_config_changed_work(struct work_struct *work)
338 {
339         struct virtio_blk *vblk =
340                 container_of(work, struct virtio_blk, config_work);
341         struct virtio_device *vdev = vblk->vdev;
342         struct request_queue *q = vblk->disk->queue;
343         char cap_str_2[10], cap_str_10[10];
344         char *envp[] = { "RESIZE=1", NULL };
345         u64 capacity, size;
346 
347         /* Host must always specify the capacity. */
348         virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
349 
350         /* If capacity is too big, truncate with warning. */
351         if ((sector_t)capacity != capacity) {
352                 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
353                          (unsigned long long)capacity);
354                 capacity = (sector_t)-1;
355         }
356 
357         size = capacity * queue_logical_block_size(q);
358         string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
359         string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
360 
361         dev_notice(&vdev->dev,
362                   "new size: %llu %d-byte logical blocks (%s/%s)\n",
363                   (unsigned long long)capacity,
364                   queue_logical_block_size(q),
365                   cap_str_10, cap_str_2);
366 
367         set_capacity(vblk->disk, capacity);
368         revalidate_disk(vblk->disk);
369         kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp);
370 }
371 
372 static void virtblk_config_changed(struct virtio_device *vdev)
373 {
374         struct virtio_blk *vblk = vdev->priv;
375 
376         queue_work(virtblk_wq, &vblk->config_work);
377 }
378 
379 static int init_vq(struct virtio_blk *vblk)
380 {
381         int err = 0;
382         int i;
383         vq_callback_t **callbacks;
384         const char **names;
385         struct virtqueue **vqs;
386         unsigned short num_vqs;
387         struct virtio_device *vdev = vblk->vdev;
388 
389         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
390                                    struct virtio_blk_config, num_queues,
391                                    &num_vqs);
392         if (err)
393                 num_vqs = 1;
394 
395         vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL);
396         if (!vblk->vqs) {
397                 err = -ENOMEM;
398                 goto out;
399         }
400 
401         names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL);
402         if (!names)
403                 goto err_names;
404 
405         callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL);
406         if (!callbacks)
407                 goto err_callbacks;
408 
409         vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL);
410         if (!vqs)
411                 goto err_vqs;
412 
413         for (i = 0; i < num_vqs; i++) {
414                 callbacks[i] = virtblk_done;
415                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
416                 names[i] = vblk->vqs[i].name;
417         }
418 
419         /* Discover virtqueues and write information to configuration.  */
420         err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
421         if (err)
422                 goto err_find_vqs;
423 
424         for (i = 0; i < num_vqs; i++) {
425                 spin_lock_init(&vblk->vqs[i].lock);
426                 vblk->vqs[i].vq = vqs[i];
427         }
428         vblk->num_vqs = num_vqs;
429 
430  err_find_vqs:
431         kfree(vqs);
432  err_vqs:
433         kfree(callbacks);
434  err_callbacks:
435         kfree(names);
436  err_names:
437         if (err)
438                 kfree(vblk->vqs);
439  out:
440         return err;
441 }
442 
443 /*
444  * Legacy naming scheme used for virtio devices.  We are stuck with it for
445  * virtio blk but don't ever use it for any new driver.
446  */
447 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
448 {
449         const int base = 'z' - 'a' + 1;
450         char *begin = buf + strlen(prefix);
451         char *end = buf + buflen;
452         char *p;
453         int unit;
454 
455         p = end - 1;
456         *p = '\0';
457         unit = base;
458         do {
459                 if (p == begin)
460                         return -EINVAL;
461                 *--p = 'a' + (index % unit);
462                 index = (index / unit) - 1;
463         } while (index >= 0);
464 
465         memmove(begin, p, end - p);
466         memcpy(buf, prefix, strlen(prefix));
467 
468         return 0;
469 }
470 
471 static int virtblk_get_cache_mode(struct virtio_device *vdev)
472 {
473         u8 writeback;
474         int err;
475 
476         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
477                                    struct virtio_blk_config, wce,
478                                    &writeback);
479         if (err)
480                 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
481                             virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
482 
483         return writeback;
484 }
485 
486 static void virtblk_update_cache_mode(struct virtio_device *vdev)
487 {
488         u8 writeback = virtblk_get_cache_mode(vdev);
489         struct virtio_blk *vblk = vdev->priv;
490 
491         if (writeback)
492                 blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
493         else
494                 blk_queue_flush(vblk->disk->queue, 0);
495 
496         revalidate_disk(vblk->disk);
497 }
498 
499 static const char *const virtblk_cache_types[] = {
500         "write through", "write back"
501 };
502 
503 static ssize_t
504 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
505                          const char *buf, size_t count)
506 {
507         struct gendisk *disk = dev_to_disk(dev);
508         struct virtio_blk *vblk = disk->private_data;
509         struct virtio_device *vdev = vblk->vdev;
510         int i;
511 
512         BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
513         for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
514                 if (sysfs_streq(buf, virtblk_cache_types[i]))
515                         break;
516 
517         if (i < 0)
518                 return -EINVAL;
519 
520         virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
521         virtblk_update_cache_mode(vdev);
522         return count;
523 }
524 
525 static ssize_t
526 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
527                          char *buf)
528 {
529         struct gendisk *disk = dev_to_disk(dev);
530         struct virtio_blk *vblk = disk->private_data;
531         u8 writeback = virtblk_get_cache_mode(vblk->vdev);
532 
533         BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
534         return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
535 }
536 
537 static const struct device_attribute dev_attr_cache_type_ro =
538         __ATTR(cache_type, S_IRUGO,
539                virtblk_cache_type_show, NULL);
540 static const struct device_attribute dev_attr_cache_type_rw =
541         __ATTR(cache_type, S_IRUGO|S_IWUSR,
542                virtblk_cache_type_show, virtblk_cache_type_store);
543 
544 static int virtblk_init_request(void *data, struct request *rq,
545                 unsigned int hctx_idx, unsigned int request_idx,
546                 unsigned int numa_node)
547 {
548         struct virtio_blk *vblk = data;
549         struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
550 
551         sg_init_table(vbr->sg, vblk->sg_elems);
552         return 0;
553 }
554 
555 static struct blk_mq_ops virtio_mq_ops = {
556         .queue_rq       = virtio_queue_rq,
557         .map_queue      = blk_mq_map_queue,
558         .complete       = virtblk_request_done,
559         .init_request   = virtblk_init_request,
560 };
561 
562 static unsigned int virtblk_queue_depth;
563 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
564 
565 static int virtblk_probe(struct virtio_device *vdev)
566 {
567         struct virtio_blk *vblk;
568         struct request_queue *q;
569         int err, index;
570 
571         u64 cap;
572         u32 v, blk_size, sg_elems, opt_io_size;
573         u16 min_io_size;
574         u8 physical_block_exp, alignment_offset;
575 
576         if (!vdev->config->get) {
577                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
578                         __func__);
579                 return -EINVAL;
580         }
581 
582         err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
583                              GFP_KERNEL);
584         if (err < 0)
585                 goto out;
586         index = err;
587 
588         /* We need to know how many segments before we allocate. */
589         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
590                                    struct virtio_blk_config, seg_max,
591                                    &sg_elems);
592 
593         /* We need at least one SG element, whatever they say. */
594         if (err || !sg_elems)
595                 sg_elems = 1;
596 
597         /* We need an extra sg elements at head and tail. */
598         sg_elems += 2;
599         vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
600         if (!vblk) {
601                 err = -ENOMEM;
602                 goto out_free_index;
603         }
604 
605         vblk->vdev = vdev;
606         vblk->sg_elems = sg_elems;
607 
608         INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
609 
610         err = init_vq(vblk);
611         if (err)
612                 goto out_free_vblk;
613 
614         /* FIXME: How many partitions?  How long is a piece of string? */
615         vblk->disk = alloc_disk(1 << PART_BITS);
616         if (!vblk->disk) {
617                 err = -ENOMEM;
618                 goto out_free_vq;
619         }
620 
621         /* Default queue sizing is to fill the ring. */
622         if (!virtblk_queue_depth) {
623                 virtblk_queue_depth = vblk->vqs[0].vq->num_free;
624                 /* ... but without indirect descs, we use 2 descs per req */
625                 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
626                         virtblk_queue_depth /= 2;
627         }
628 
629         memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
630         vblk->tag_set.ops = &virtio_mq_ops;
631         vblk->tag_set.queue_depth = virtblk_queue_depth;
632         vblk->tag_set.numa_node = NUMA_NO_NODE;
633         vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
634         vblk->tag_set.cmd_size =
635                 sizeof(struct virtblk_req) +
636                 sizeof(struct scatterlist) * sg_elems;
637         vblk->tag_set.driver_data = vblk;
638         vblk->tag_set.nr_hw_queues = vblk->num_vqs;
639 
640         err = blk_mq_alloc_tag_set(&vblk->tag_set);
641         if (err)
642                 goto out_put_disk;
643 
644         q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
645         if (IS_ERR(q)) {
646                 err = -ENOMEM;
647                 goto out_free_tags;
648         }
649 
650         q->queuedata = vblk;
651 
652         virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
653 
654         vblk->disk->major = major;
655         vblk->disk->first_minor = index_to_minor(index);
656         vblk->disk->private_data = vblk;
657         vblk->disk->fops = &virtblk_fops;
658         vblk->disk->driverfs_dev = &vdev->dev;
659         vblk->index = index;
660 
661         /* configure queue flush support */
662         virtblk_update_cache_mode(vdev);
663 
664         /* If disk is read-only in the host, the guest should obey */
665         if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
666                 set_disk_ro(vblk->disk, 1);
667 
668         /* Host must always specify the capacity. */
669         virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
670 
671         /* If capacity is too big, truncate with warning. */
672         if ((sector_t)cap != cap) {
673                 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
674                          (unsigned long long)cap);
675                 cap = (sector_t)-1;
676         }
677         set_capacity(vblk->disk, cap);
678 
679         /* We can handle whatever the host told us to handle. */
680         blk_queue_max_segments(q, vblk->sg_elems-2);
681 
682         /* No need to bounce any requests */
683         blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
684 
685         /* No real sector limit. */
686         blk_queue_max_hw_sectors(q, -1U);
687 
688         /* Host can optionally specify maximum segment size and number of
689          * segments. */
690         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
691                                    struct virtio_blk_config, size_max, &v);
692         if (!err)
693                 blk_queue_max_segment_size(q, v);
694         else
695                 blk_queue_max_segment_size(q, -1U);
696 
697         /* Host can optionally specify the block size of the device */
698         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
699                                    struct virtio_blk_config, blk_size,
700                                    &blk_size);
701         if (!err)
702                 blk_queue_logical_block_size(q, blk_size);
703         else
704                 blk_size = queue_logical_block_size(q);
705 
706         /* Use topology information if available */
707         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
708                                    struct virtio_blk_config, physical_block_exp,
709                                    &physical_block_exp);
710         if (!err && physical_block_exp)
711                 blk_queue_physical_block_size(q,
712                                 blk_size * (1 << physical_block_exp));
713 
714         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
715                                    struct virtio_blk_config, alignment_offset,
716                                    &alignment_offset);
717         if (!err && alignment_offset)
718                 blk_queue_alignment_offset(q, blk_size * alignment_offset);
719 
720         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
721                                    struct virtio_blk_config, min_io_size,
722                                    &min_io_size);
723         if (!err && min_io_size)
724                 blk_queue_io_min(q, blk_size * min_io_size);
725 
726         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
727                                    struct virtio_blk_config, opt_io_size,
728                                    &opt_io_size);
729         if (!err && opt_io_size)
730                 blk_queue_io_opt(q, blk_size * opt_io_size);
731 
732         virtio_device_ready(vdev);
733 
734         add_disk(vblk->disk);
735         err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
736         if (err)
737                 goto out_del_disk;
738 
739         if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
740                 err = device_create_file(disk_to_dev(vblk->disk),
741                                          &dev_attr_cache_type_rw);
742         else
743                 err = device_create_file(disk_to_dev(vblk->disk),
744                                          &dev_attr_cache_type_ro);
745         if (err)
746                 goto out_del_disk;
747         return 0;
748 
749 out_del_disk:
750         del_gendisk(vblk->disk);
751         blk_cleanup_queue(vblk->disk->queue);
752 out_free_tags:
753         blk_mq_free_tag_set(&vblk->tag_set);
754 out_put_disk:
755         put_disk(vblk->disk);
756 out_free_vq:
757         vdev->config->del_vqs(vdev);
758 out_free_vblk:
759         kfree(vblk);
760 out_free_index:
761         ida_simple_remove(&vd_index_ida, index);
762 out:
763         return err;
764 }
765 
766 static void virtblk_remove(struct virtio_device *vdev)
767 {
768         struct virtio_blk *vblk = vdev->priv;
769         int index = vblk->index;
770         int refc;
771 
772         /* Make sure no work handler is accessing the device. */
773         flush_work(&vblk->config_work);
774 
775         del_gendisk(vblk->disk);
776         blk_cleanup_queue(vblk->disk->queue);
777 
778         blk_mq_free_tag_set(&vblk->tag_set);
779 
780         /* Stop all the virtqueues. */
781         vdev->config->reset(vdev);
782 
783         refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
784         put_disk(vblk->disk);
785         vdev->config->del_vqs(vdev);
786         kfree(vblk->vqs);
787         kfree(vblk);
788 
789         /* Only free device id if we don't have any users */
790         if (refc == 1)
791                 ida_simple_remove(&vd_index_ida, index);
792 }
793 
794 #ifdef CONFIG_PM_SLEEP
795 static int virtblk_freeze(struct virtio_device *vdev)
796 {
797         struct virtio_blk *vblk = vdev->priv;
798 
799         /* Ensure we don't receive any more interrupts */
800         vdev->config->reset(vdev);
801 
802         /* Make sure no work handler is accessing the device. */
803         flush_work(&vblk->config_work);
804 
805         blk_mq_stop_hw_queues(vblk->disk->queue);
806 
807         vdev->config->del_vqs(vdev);
808         return 0;
809 }
810 
811 static int virtblk_restore(struct virtio_device *vdev)
812 {
813         struct virtio_blk *vblk = vdev->priv;
814         int ret;
815 
816         ret = init_vq(vdev->priv);
817         if (ret)
818                 return ret;
819 
820         virtio_device_ready(vdev);
821 
822         blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
823         return 0;
824 }
825 #endif
826 
827 static const struct virtio_device_id id_table[] = {
828         { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
829         { 0 },
830 };
831 
832 static unsigned int features_legacy[] = {
833         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
834         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
835         VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
836         VIRTIO_BLK_F_MQ,
837 }
838 ;
839 static unsigned int features[] = {
840         VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
841         VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
842         VIRTIO_BLK_F_TOPOLOGY,
843         VIRTIO_BLK_F_MQ,
844 };
845 
846 static struct virtio_driver virtio_blk = {
847         .feature_table                  = features,
848         .feature_table_size             = ARRAY_SIZE(features),
849         .feature_table_legacy           = features_legacy,
850         .feature_table_size_legacy      = ARRAY_SIZE(features_legacy),
851         .driver.name                    = KBUILD_MODNAME,
852         .driver.owner                   = THIS_MODULE,
853         .id_table                       = id_table,
854         .probe                          = virtblk_probe,
855         .remove                         = virtblk_remove,
856         .config_changed                 = virtblk_config_changed,
857 #ifdef CONFIG_PM_SLEEP
858         .freeze                         = virtblk_freeze,
859         .restore                        = virtblk_restore,
860 #endif
861 };
862 
863 static int __init init(void)
864 {
865         int error;
866 
867         virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
868         if (!virtblk_wq)
869                 return -ENOMEM;
870 
871         major = register_blkdev(0, "virtblk");
872         if (major < 0) {
873                 error = major;
874                 goto out_destroy_workqueue;
875         }
876 
877         error = register_virtio_driver(&virtio_blk);
878         if (error)
879                 goto out_unregister_blkdev;
880         return 0;
881 
882 out_unregister_blkdev:
883         unregister_blkdev(major, "virtblk");
884 out_destroy_workqueue:
885         destroy_workqueue(virtblk_wq);
886         return error;
887 }
888 
889 static void __exit fini(void)
890 {
891         unregister_virtio_driver(&virtio_blk);
892         unregister_blkdev(major, "virtblk");
893         destroy_workqueue(virtblk_wq);
894 }
895 module_init(init);
896 module_exit(fini);
897 
898 MODULE_DEVICE_TABLE(virtio, id_table);
899 MODULE_DESCRIPTION("Virtio block driver");
900 MODULE_LICENSE("GPL");
901 

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