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