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target: Fix kref->refcount underflow in transport_cmd_finish_abort
[linux/fpc-iii.git] / drivers / block / virtio_blk.c
blob3c3b8f601469a1e4ac2bc332feebc0eab321773b
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 u8 sense[SCSI_SENSE_BUFFERSIZE];
60 struct scatterlist sg[];
61 };
62
63 static inline int virtblk_result(struct virtblk_req *vbr)
64 {
65 switch (vbr->status) {
66 case VIRTIO_BLK_S_OK:
67 return 0;
68 case VIRTIO_BLK_S_UNSUPP:
69 return -ENOTTY;
70 default:
71 return -EIO;
72 }
73 }
74
75 static int __virtblk_add_req(struct virtqueue *vq,
76 struct virtblk_req *vbr,
77 struct scatterlist *data_sg,
78 bool have_data)
79 {
80 struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6];
81 unsigned int num_out = 0, num_in = 0;
82 __virtio32 type = vbr->out_hdr.type & ~cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT);
83
84 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
85 sgs[num_out++] = &hdr;
86
87 /*
88 * If this is a packet command we need a couple of additional headers.
89 * Behind the normal outhdr we put a segment with the scsi command
90 * block, and before the normal inhdr we put the sense data and the
91 * inhdr with additional status information.
92 */
93 if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
94 sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len);
95 sgs[num_out++] = &cmd;
96 }
97
98 if (have_data) {
99 if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
100 sgs[num_out++] = data_sg;
101 else
102 sgs[num_out + num_in++] = data_sg;
103 }
104
105 if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
106 memcpy(vbr->sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
107 sg_init_one(&sense, vbr->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_DRV_PRIV) {
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, vbr->req->errors);
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_op(req) == REQ_OP_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_DRV_PRIV:
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_queue *q = vblk->disk->queue;
242 struct request *req;
243 int err;
244
245 req = blk_get_request(q, READ, GFP_KERNEL);
246 if (IS_ERR(req))
247 return PTR_ERR(req);
248 req->cmd_type = REQ_TYPE_DRV_PRIV;
249
250 err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
251 if (err)
252 goto out;
253
254 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
255 out:
256 blk_put_request(req);
257 return err;
258 }
259
260 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
261 unsigned int cmd, unsigned long data)
262 {
263 struct gendisk *disk = bdev->bd_disk;
264 struct virtio_blk *vblk = disk->private_data;
265
266 /*
267 * Only allow the generic SCSI ioctls if the host can support it.
268 */
269 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
270 return -ENOTTY;
271
272 return scsi_cmd_blk_ioctl(bdev, mode, cmd,
273 (void __user *)data);
274 }
275
276 /* We provide getgeo only to please some old bootloader/partitioning tools */
277 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
278 {
279 struct virtio_blk *vblk = bd->bd_disk->private_data;
280
281 /* see if the host passed in geometry config */
282 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
283 virtio_cread(vblk->vdev, struct virtio_blk_config,
284 geometry.cylinders, &geo->cylinders);
285 virtio_cread(vblk->vdev, struct virtio_blk_config,
286 geometry.heads, &geo->heads);
287 virtio_cread(vblk->vdev, struct virtio_blk_config,
288 geometry.sectors, &geo->sectors);
289 } else {
290 /* some standard values, similar to sd */
291 geo->heads = 1 << 6;
292 geo->sectors = 1 << 5;
293 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
294 }
295 return 0;
296 }
297
298 static const struct block_device_operations virtblk_fops = {
299 .ioctl = virtblk_ioctl,
300 .owner = THIS_MODULE,
301 .getgeo = virtblk_getgeo,
302 };
303
304 static int index_to_minor(int index)
305 {
306 return index << PART_BITS;
307 }
308
309 static int minor_to_index(int minor)
310 {
311 return minor >> PART_BITS;
312 }
313
314 static ssize_t virtblk_serial_show(struct device *dev,
315 struct device_attribute *attr, char *buf)
316 {
317 struct gendisk *disk = dev_to_disk(dev);
318 int err;
319
320 /* sysfs gives us a PAGE_SIZE buffer */
321 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
322
323 buf[VIRTIO_BLK_ID_BYTES] = '\0';
324 err = virtblk_get_id(disk, buf);
325 if (!err)
326 return strlen(buf);
327
328 if (err == -EIO) /* Unsupported? Make it empty. */
329 return 0;
330
331 return err;
332 }
333
334 static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
335
336 static void virtblk_config_changed_work(struct work_struct *work)
337 {
338 struct virtio_blk *vblk =
339 container_of(work, struct virtio_blk, config_work);
340 struct virtio_device *vdev = vblk->vdev;
341 struct request_queue *q = vblk->disk->queue;
342 char cap_str_2[10], cap_str_10[10];
343 char *envp[] = { "RESIZE=1", NULL };
344 u64 capacity;
345
346 /* Host must always specify the capacity. */
347 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
348
349 /* If capacity is too big, truncate with warning. */
350 if ((sector_t)capacity != capacity) {
351 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
352 (unsigned long long)capacity);
353 capacity = (sector_t)-1;
354 }
355
356 string_get_size(capacity, queue_logical_block_size(q),
357 STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
358 string_get_size(capacity, queue_logical_block_size(q),
359 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;
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_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
396 if (!vblk->vqs)
397 return -ENOMEM;
398
399 names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
400 callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
401 vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
402 if (!names || !callbacks || !vqs) {
403 err = -ENOMEM;
404 goto out;
405 }
406
407 for (i = 0; i < num_vqs; i++) {
408 callbacks[i] = virtblk_done;
409 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
410 names[i] = vblk->vqs[i].name;
411 }
412
413 /* Discover virtqueues and write information to configuration. */
414 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
415 if (err)
416 goto out;
417
418 for (i = 0; i < num_vqs; i++) {
419 spin_lock_init(&vblk->vqs[i].lock);
420 vblk->vqs[i].vq = vqs[i];
421 }
422 vblk->num_vqs = num_vqs;
423
424 out:
425 kfree(vqs);
426 kfree(callbacks);
427 kfree(names);
428 if (err)
429 kfree(vblk->vqs);
430 return err;
431 }
432
433 /*
434 * Legacy naming scheme used for virtio devices. We are stuck with it for
435 * virtio blk but don't ever use it for any new driver.
436 */
437 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
438 {
439 const int base = 'z' - 'a' + 1;
440 char *begin = buf + strlen(prefix);
441 char *end = buf + buflen;
442 char *p;
443 int unit;
444
445 p = end - 1;
446 *p = '\0';
447 unit = base;
448 do {
449 if (p == begin)
450 return -EINVAL;
451 *--p = 'a' + (index % unit);
452 index = (index / unit) - 1;
453 } while (index >= 0);
454
455 memmove(begin, p, end - p);
456 memcpy(buf, prefix, strlen(prefix));
457
458 return 0;
459 }
460
461 static int virtblk_get_cache_mode(struct virtio_device *vdev)
462 {
463 u8 writeback;
464 int err;
465
466 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
467 struct virtio_blk_config, wce,
468 &writeback);
469
470 /*
471 * If WCE is not configurable and flush is not available,
472 * assume no writeback cache is in use.
473 */
474 if (err)
475 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
476
477 return writeback;
478 }
479
480 static void virtblk_update_cache_mode(struct virtio_device *vdev)
481 {
482 u8 writeback = virtblk_get_cache_mode(vdev);
483 struct virtio_blk *vblk = vdev->priv;
484
485 blk_queue_write_cache(vblk->disk->queue, writeback, false);
486 revalidate_disk(vblk->disk);
487 }
488
489 static const char *const virtblk_cache_types[] = {
490 "write through", "write back"
491 };
492
493 static ssize_t
494 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
495 const char *buf, size_t count)
496 {
497 struct gendisk *disk = dev_to_disk(dev);
498 struct virtio_blk *vblk = disk->private_data;
499 struct virtio_device *vdev = vblk->vdev;
500 int i;
501
502 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
503 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
504 if (sysfs_streq(buf, virtblk_cache_types[i]))
505 break;
506
507 if (i < 0)
508 return -EINVAL;
509
510 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
511 virtblk_update_cache_mode(vdev);
512 return count;
513 }
514
515 static ssize_t
516 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
517 char *buf)
518 {
519 struct gendisk *disk = dev_to_disk(dev);
520 struct virtio_blk *vblk = disk->private_data;
521 u8 writeback = virtblk_get_cache_mode(vblk->vdev);
522
523 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
524 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
525 }
526
527 static const struct device_attribute dev_attr_cache_type_ro =
528 __ATTR(cache_type, S_IRUGO,
529 virtblk_cache_type_show, NULL);
530 static const struct device_attribute dev_attr_cache_type_rw =
531 __ATTR(cache_type, S_IRUGO|S_IWUSR,
532 virtblk_cache_type_show, virtblk_cache_type_store);
533
534 static int virtblk_init_request(void *data, struct request *rq,
535 unsigned int hctx_idx, unsigned int request_idx,
536 unsigned int numa_node)
537 {
538 struct virtio_blk *vblk = data;
539 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
540
541 sg_init_table(vbr->sg, vblk->sg_elems);
542 return 0;
543 }
544
545 static struct blk_mq_ops virtio_mq_ops = {
546 .queue_rq = virtio_queue_rq,
547 .complete = virtblk_request_done,
548 .init_request = virtblk_init_request,
549 };
550
551 static unsigned int virtblk_queue_depth;
552 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
553
554 static int virtblk_probe(struct virtio_device *vdev)
555 {
556 struct virtio_blk *vblk;
557 struct request_queue *q;
558 int err, index;
559
560 u64 cap;
561 u32 v, blk_size, sg_elems, opt_io_size;
562 u16 min_io_size;
563 u8 physical_block_exp, alignment_offset;
564
565 if (!vdev->config->get) {
566 dev_err(&vdev->dev, "%s failure: config access disabled\n",
567 __func__);
568 return -EINVAL;
569 }
570
571 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
572 GFP_KERNEL);
573 if (err < 0)
574 goto out;
575 index = err;
576
577 /* We need to know how many segments before we allocate. */
578 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
579 struct virtio_blk_config, seg_max,
580 &sg_elems);
581
582 /* We need at least one SG element, whatever they say. */
583 if (err || !sg_elems)
584 sg_elems = 1;
585
586 /* We need an extra sg elements at head and tail. */
587 sg_elems += 2;
588 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
589 if (!vblk) {
590 err = -ENOMEM;
591 goto out_free_index;
592 }
593
594 vblk->vdev = vdev;
595 vblk->sg_elems = sg_elems;
596
597 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
598
599 err = init_vq(vblk);
600 if (err)
601 goto out_free_vblk;
602
603 /* FIXME: How many partitions? How long is a piece of string? */
604 vblk->disk = alloc_disk(1 << PART_BITS);
605 if (!vblk->disk) {
606 err = -ENOMEM;
607 goto out_free_vq;
608 }
609
610 /* Default queue sizing is to fill the ring. */
611 if (!virtblk_queue_depth) {
612 virtblk_queue_depth = vblk->vqs[0].vq->num_free;
613 /* ... but without indirect descs, we use 2 descs per req */
614 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
615 virtblk_queue_depth /= 2;
616 }
617
618 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
619 vblk->tag_set.ops = &virtio_mq_ops;
620 vblk->tag_set.queue_depth = virtblk_queue_depth;
621 vblk->tag_set.numa_node = NUMA_NO_NODE;
622 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
623 vblk->tag_set.cmd_size =
624 sizeof(struct virtblk_req) +
625 sizeof(struct scatterlist) * sg_elems;
626 vblk->tag_set.driver_data = vblk;
627 vblk->tag_set.nr_hw_queues = vblk->num_vqs;
628
629 err = blk_mq_alloc_tag_set(&vblk->tag_set);
630 if (err)
631 goto out_put_disk;
632
633 q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
634 if (IS_ERR(q)) {
635 err = -ENOMEM;
636 goto out_free_tags;
637 }
638
639 q->queuedata = vblk;
640
641 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
642
643 vblk->disk->major = major;
644 vblk->disk->first_minor = index_to_minor(index);
645 vblk->disk->private_data = vblk;
646 vblk->disk->fops = &virtblk_fops;
647 vblk->disk->flags |= GENHD_FL_EXT_DEVT;
648 vblk->index = index;
649
650 /* configure queue flush support */
651 virtblk_update_cache_mode(vdev);
652
653 /* If disk is read-only in the host, the guest should obey */
654 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
655 set_disk_ro(vblk->disk, 1);
656
657 /* Host must always specify the capacity. */
658 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
659
660 /* If capacity is too big, truncate with warning. */
661 if ((sector_t)cap != cap) {
662 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
663 (unsigned long long)cap);
664 cap = (sector_t)-1;
665 }
666 set_capacity(vblk->disk, cap);
667
668 /* We can handle whatever the host told us to handle. */
669 blk_queue_max_segments(q, vblk->sg_elems-2);
670
671 /* No need to bounce any requests */
672 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
673
674 /* No real sector limit. */
675 blk_queue_max_hw_sectors(q, -1U);
676
677 /* Host can optionally specify maximum segment size and number of
678 * segments. */
679 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
680 struct virtio_blk_config, size_max, &v);
681 if (!err)
682 blk_queue_max_segment_size(q, v);
683 else
684 blk_queue_max_segment_size(q, -1U);
685
686 /* Host can optionally specify the block size of the device */
687 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
688 struct virtio_blk_config, blk_size,
689 &blk_size);
690 if (!err)
691 blk_queue_logical_block_size(q, blk_size);
692 else
693 blk_size = queue_logical_block_size(q);
694
695 /* Use topology information if available */
696 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
697 struct virtio_blk_config, physical_block_exp,
698 &physical_block_exp);
699 if (!err && physical_block_exp)
700 blk_queue_physical_block_size(q,
701 blk_size * (1 << physical_block_exp));
702
703 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
704 struct virtio_blk_config, alignment_offset,
705 &alignment_offset);
706 if (!err && alignment_offset)
707 blk_queue_alignment_offset(q, blk_size * alignment_offset);
708
709 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
710 struct virtio_blk_config, min_io_size,
711 &min_io_size);
712 if (!err && min_io_size)
713 blk_queue_io_min(q, blk_size * min_io_size);
714
715 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
716 struct virtio_blk_config, opt_io_size,
717 &opt_io_size);
718 if (!err && opt_io_size)
719 blk_queue_io_opt(q, blk_size * opt_io_size);
720
721 virtio_device_ready(vdev);
722
723 device_add_disk(&vdev->dev, vblk->disk);
724 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
725 if (err)
726 goto out_del_disk;
727
728 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
729 err = device_create_file(disk_to_dev(vblk->disk),
730 &dev_attr_cache_type_rw);
731 else
732 err = device_create_file(disk_to_dev(vblk->disk),
733 &dev_attr_cache_type_ro);
734 if (err)
735 goto out_del_disk;
736 return 0;
737
738 out_del_disk:
739 del_gendisk(vblk->disk);
740 blk_cleanup_queue(vblk->disk->queue);
741 out_free_tags:
742 blk_mq_free_tag_set(&vblk->tag_set);
743 out_put_disk:
744 put_disk(vblk->disk);
745 out_free_vq:
746 vdev->config->del_vqs(vdev);
747 out_free_vblk:
748 kfree(vblk);
749 out_free_index:
750 ida_simple_remove(&vd_index_ida, index);
751 out:
752 return err;
753 }
754
755 static void virtblk_remove(struct virtio_device *vdev)
756 {
757 struct virtio_blk *vblk = vdev->priv;
758 int index = vblk->index;
759 int refc;
760
761 /* Make sure no work handler is accessing the device. */
762 flush_work(&vblk->config_work);
763
764 del_gendisk(vblk->disk);
765 blk_cleanup_queue(vblk->disk->queue);
766
767 blk_mq_free_tag_set(&vblk->tag_set);
768
769 /* Stop all the virtqueues. */
770 vdev->config->reset(vdev);
771
772 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
773 put_disk(vblk->disk);
774 vdev->config->del_vqs(vdev);
775 kfree(vblk->vqs);
776 kfree(vblk);
777
778 /* Only free device id if we don't have any users */
779 if (refc == 1)
780 ida_simple_remove(&vd_index_ida, index);
781 }
782
783 #ifdef CONFIG_PM_SLEEP
784 static int virtblk_freeze(struct virtio_device *vdev)
785 {
786 struct virtio_blk *vblk = vdev->priv;
787
788 /* Ensure we don't receive any more interrupts */
789 vdev->config->reset(vdev);
790
791 /* Make sure no work handler is accessing the device. */
792 flush_work(&vblk->config_work);
793
794 blk_mq_stop_hw_queues(vblk->disk->queue);
795
796 vdev->config->del_vqs(vdev);
797 return 0;
798 }
799
800 static int virtblk_restore(struct virtio_device *vdev)
801 {
802 struct virtio_blk *vblk = vdev->priv;
803 int ret;
804
805 ret = init_vq(vdev->priv);
806 if (ret)
807 return ret;
808
809 virtio_device_ready(vdev);
810
811 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
812 return 0;
813 }
814 #endif
815
816 static const struct virtio_device_id id_table[] = {
817 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
818 { 0 },
819 };
820
821 static unsigned int features_legacy[] = {
822 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
823 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
824 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
825 VIRTIO_BLK_F_MQ,
826 }
827 ;
828 static unsigned int features[] = {
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,
831 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
832 VIRTIO_BLK_F_MQ,
833 };
834
835 static struct virtio_driver virtio_blk = {
836 .feature_table = features,
837 .feature_table_size = ARRAY_SIZE(features),
838 .feature_table_legacy = features_legacy,
839 .feature_table_size_legacy = ARRAY_SIZE(features_legacy),
840 .driver.name = KBUILD_MODNAME,
841 .driver.owner = THIS_MODULE,
842 .id_table = id_table,
843 .probe = virtblk_probe,
844 .remove = virtblk_remove,
845 .config_changed = virtblk_config_changed,
846 #ifdef CONFIG_PM_SLEEP
847 .freeze = virtblk_freeze,
848 .restore = virtblk_restore,
849 #endif
850 };
851
852 static int __init init(void)
853 {
854 int error;
855
856 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
857 if (!virtblk_wq)
858 return -ENOMEM;
859
860 major = register_blkdev(0, "virtblk");
861 if (major < 0) {
862 error = major;
863 goto out_destroy_workqueue;
864 }
865
866 error = register_virtio_driver(&virtio_blk);
867 if (error)
868 goto out_unregister_blkdev;
869 return 0;
870
871 out_unregister_blkdev:
872 unregister_blkdev(major, "virtblk");
873 out_destroy_workqueue:
874 destroy_workqueue(virtblk_wq);
875 return error;
876 }
877
878 static void __exit fini(void)
879 {
880 unregister_virtio_driver(&virtio_blk);
881 unregister_blkdev(major, "virtblk");
882 destroy_workqueue(virtblk_wq);
883 }
884 module_init(init);
885 module_exit(fini);
886
887 MODULE_DEVICE_TABLE(virtio, id_table);
888 MODULE_DESCRIPTION("Virtio block driver");
889 MODULE_LICENSE("GPL");
Linux with added FPC-III support