xref: /linux/drivers/block/virtio_blk.c (revision 7503345ac5f5e82fd9a36d6e6b447c016376403a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 //#define DEBUG
3 #include <linux/spinlock.h>
4 #include <linux/slab.h>
5 #include <linux/blkdev.h>
6 #include <linux/hdreg.h>
7 #include <linux/module.h>
8 #include <linux/mutex.h>
9 #include <linux/interrupt.h>
10 #include <linux/virtio.h>
11 #include <linux/virtio_blk.h>
12 #include <linux/scatterlist.h>
13 #include <linux/string_helpers.h>
14 #include <linux/idr.h>
15 #include <linux/blk-mq.h>
16 #include <linux/blk-mq-virtio.h>
17 #include <linux/numa.h>
18 #include <linux/vmalloc.h>
19 #include <uapi/linux/virtio_ring.h>
20 
21 #define PART_BITS 4
22 #define VQ_NAME_LEN 16
23 #define MAX_DISCARD_SEGMENTS 256u
24 
25 /* The maximum number of sg elements that fit into a virtqueue */
26 #define VIRTIO_BLK_MAX_SG_ELEMS 32768
27 
28 #ifdef CONFIG_ARCH_NO_SG_CHAIN
29 #define VIRTIO_BLK_INLINE_SG_CNT	0
30 #else
31 #define VIRTIO_BLK_INLINE_SG_CNT	2
32 #endif
33 
34 static unsigned int num_request_queues;
35 module_param(num_request_queues, uint, 0644);
36 MODULE_PARM_DESC(num_request_queues,
37 		 "Limit the number of request queues to use for blk device. "
38 		 "0 for no limit. "
39 		 "Values > nr_cpu_ids truncated to nr_cpu_ids.");
40 
41 static unsigned int poll_queues;
42 module_param(poll_queues, uint, 0644);
43 MODULE_PARM_DESC(poll_queues, "The number of dedicated virtqueues for polling I/O");
44 
45 static int major;
46 static DEFINE_IDA(vd_index_ida);
47 
48 static struct workqueue_struct *virtblk_wq;
49 
50 struct virtio_blk_vq {
51 	struct virtqueue *vq;
52 	spinlock_t lock;
53 	char name[VQ_NAME_LEN];
54 } ____cacheline_aligned_in_smp;
55 
56 struct virtio_blk {
57 	/*
58 	 * This mutex must be held by anything that may run after
59 	 * virtblk_remove() sets vblk->vdev to NULL.
60 	 *
61 	 * blk-mq, virtqueue processing, and sysfs attribute code paths are
62 	 * shut down before vblk->vdev is set to NULL and therefore do not need
63 	 * to hold this mutex.
64 	 */
65 	struct mutex vdev_mutex;
66 	struct virtio_device *vdev;
67 
68 	/* The disk structure for the kernel. */
69 	struct gendisk *disk;
70 
71 	/* Block layer tags. */
72 	struct blk_mq_tag_set tag_set;
73 
74 	/* Process context for config space updates */
75 	struct work_struct config_work;
76 
77 	/* Ida index - used to track minor number allocations. */
78 	int index;
79 
80 	/* num of vqs */
81 	int num_vqs;
82 	int io_queues[HCTX_MAX_TYPES];
83 	struct virtio_blk_vq *vqs;
84 
85 	/* For zoned device */
86 	unsigned int zone_sectors;
87 };
88 
89 struct virtblk_req {
90 	/* Out header */
91 	struct virtio_blk_outhdr out_hdr;
92 
93 	/* In header */
94 	union {
95 		u8 status;
96 
97 		/*
98 		 * The zone append command has an extended in header.
99 		 * The status field in zone_append_in_hdr must always
100 		 * be the last byte.
101 		 */
102 		struct {
103 			__virtio64 sector;
104 			u8 status;
105 		} zone_append;
106 	} in_hdr;
107 
108 	size_t in_hdr_len;
109 
110 	struct sg_table sg_table;
111 	struct scatterlist sg[];
112 };
113 
virtblk_result(u8 status)114 static inline blk_status_t virtblk_result(u8 status)
115 {
116 	switch (status) {
117 	case VIRTIO_BLK_S_OK:
118 		return BLK_STS_OK;
119 	case VIRTIO_BLK_S_UNSUPP:
120 		return BLK_STS_NOTSUPP;
121 	case VIRTIO_BLK_S_ZONE_OPEN_RESOURCE:
122 		return BLK_STS_ZONE_OPEN_RESOURCE;
123 	case VIRTIO_BLK_S_ZONE_ACTIVE_RESOURCE:
124 		return BLK_STS_ZONE_ACTIVE_RESOURCE;
125 	case VIRTIO_BLK_S_IOERR:
126 	case VIRTIO_BLK_S_ZONE_UNALIGNED_WP:
127 	default:
128 		return BLK_STS_IOERR;
129 	}
130 }
131 
get_virtio_blk_vq(struct blk_mq_hw_ctx * hctx)132 static inline struct virtio_blk_vq *get_virtio_blk_vq(struct blk_mq_hw_ctx *hctx)
133 {
134 	struct virtio_blk *vblk = hctx->queue->queuedata;
135 	struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
136 
137 	return vq;
138 }
139 
virtblk_add_req(struct virtqueue * vq,struct virtblk_req * vbr)140 static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr)
141 {
142 	struct scatterlist out_hdr, in_hdr, *sgs[3];
143 	unsigned int num_out = 0, num_in = 0;
144 
145 	sg_init_one(&out_hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
146 	sgs[num_out++] = &out_hdr;
147 
148 	if (vbr->sg_table.nents) {
149 		if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
150 			sgs[num_out++] = vbr->sg_table.sgl;
151 		else
152 			sgs[num_out + num_in++] = vbr->sg_table.sgl;
153 	}
154 
155 	sg_init_one(&in_hdr, &vbr->in_hdr.status, vbr->in_hdr_len);
156 	sgs[num_out + num_in++] = &in_hdr;
157 
158 	return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
159 }
160 
virtblk_setup_discard_write_zeroes_erase(struct request * req,bool unmap)161 static int virtblk_setup_discard_write_zeroes_erase(struct request *req, bool unmap)
162 {
163 	unsigned short segments = blk_rq_nr_discard_segments(req);
164 	unsigned short n = 0;
165 	struct virtio_blk_discard_write_zeroes *range;
166 	struct bio *bio;
167 	u32 flags = 0;
168 
169 	if (unmap)
170 		flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP;
171 
172 	range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
173 	if (!range)
174 		return -ENOMEM;
175 
176 	/*
177 	 * Single max discard segment means multi-range discard isn't
178 	 * supported, and block layer only runs contiguity merge like
179 	 * normal RW request. So we can't reply on bio for retrieving
180 	 * each range info.
181 	 */
182 	if (queue_max_discard_segments(req->q) == 1) {
183 		range[0].flags = cpu_to_le32(flags);
184 		range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req));
185 		range[0].sector = cpu_to_le64(blk_rq_pos(req));
186 		n = 1;
187 	} else {
188 		__rq_for_each_bio(bio, req) {
189 			u64 sector = bio->bi_iter.bi_sector;
190 			u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT;
191 
192 			range[n].flags = cpu_to_le32(flags);
193 			range[n].num_sectors = cpu_to_le32(num_sectors);
194 			range[n].sector = cpu_to_le64(sector);
195 			n++;
196 		}
197 	}
198 
199 	WARN_ON_ONCE(n != segments);
200 
201 	bvec_set_virt(&req->special_vec, range, sizeof(*range) * segments);
202 	req->rq_flags |= RQF_SPECIAL_PAYLOAD;
203 
204 	return 0;
205 }
206 
virtblk_unmap_data(struct request * req,struct virtblk_req * vbr)207 static void virtblk_unmap_data(struct request *req, struct virtblk_req *vbr)
208 {
209 	if (blk_rq_nr_phys_segments(req))
210 		sg_free_table_chained(&vbr->sg_table,
211 				      VIRTIO_BLK_INLINE_SG_CNT);
212 }
213 
virtblk_map_data(struct blk_mq_hw_ctx * hctx,struct request * req,struct virtblk_req * vbr)214 static int virtblk_map_data(struct blk_mq_hw_ctx *hctx, struct request *req,
215 		struct virtblk_req *vbr)
216 {
217 	int err;
218 
219 	if (!blk_rq_nr_phys_segments(req))
220 		return 0;
221 
222 	vbr->sg_table.sgl = vbr->sg;
223 	err = sg_alloc_table_chained(&vbr->sg_table,
224 				     blk_rq_nr_phys_segments(req),
225 				     vbr->sg_table.sgl,
226 				     VIRTIO_BLK_INLINE_SG_CNT);
227 	if (unlikely(err))
228 		return -ENOMEM;
229 
230 	return blk_rq_map_sg(hctx->queue, req, vbr->sg_table.sgl);
231 }
232 
virtblk_cleanup_cmd(struct request * req)233 static void virtblk_cleanup_cmd(struct request *req)
234 {
235 	if (req->rq_flags & RQF_SPECIAL_PAYLOAD)
236 		kfree(bvec_virt(&req->special_vec));
237 }
238 
virtblk_setup_cmd(struct virtio_device * vdev,struct request * req,struct virtblk_req * vbr)239 static blk_status_t virtblk_setup_cmd(struct virtio_device *vdev,
240 				      struct request *req,
241 				      struct virtblk_req *vbr)
242 {
243 	size_t in_hdr_len = sizeof(vbr->in_hdr.status);
244 	bool unmap = false;
245 	u32 type;
246 	u64 sector = 0;
247 
248 	if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) && op_is_zone_mgmt(req_op(req)))
249 		return BLK_STS_NOTSUPP;
250 
251 	/* Set fields for all request types */
252 	vbr->out_hdr.ioprio = cpu_to_virtio32(vdev, req_get_ioprio(req));
253 
254 	switch (req_op(req)) {
255 	case REQ_OP_READ:
256 		type = VIRTIO_BLK_T_IN;
257 		sector = blk_rq_pos(req);
258 		break;
259 	case REQ_OP_WRITE:
260 		type = VIRTIO_BLK_T_OUT;
261 		sector = blk_rq_pos(req);
262 		break;
263 	case REQ_OP_FLUSH:
264 		type = VIRTIO_BLK_T_FLUSH;
265 		break;
266 	case REQ_OP_DISCARD:
267 		type = VIRTIO_BLK_T_DISCARD;
268 		break;
269 	case REQ_OP_WRITE_ZEROES:
270 		type = VIRTIO_BLK_T_WRITE_ZEROES;
271 		unmap = !(req->cmd_flags & REQ_NOUNMAP);
272 		break;
273 	case REQ_OP_SECURE_ERASE:
274 		type = VIRTIO_BLK_T_SECURE_ERASE;
275 		break;
276 	case REQ_OP_ZONE_OPEN:
277 		type = VIRTIO_BLK_T_ZONE_OPEN;
278 		sector = blk_rq_pos(req);
279 		break;
280 	case REQ_OP_ZONE_CLOSE:
281 		type = VIRTIO_BLK_T_ZONE_CLOSE;
282 		sector = blk_rq_pos(req);
283 		break;
284 	case REQ_OP_ZONE_FINISH:
285 		type = VIRTIO_BLK_T_ZONE_FINISH;
286 		sector = blk_rq_pos(req);
287 		break;
288 	case REQ_OP_ZONE_APPEND:
289 		type = VIRTIO_BLK_T_ZONE_APPEND;
290 		sector = blk_rq_pos(req);
291 		in_hdr_len = sizeof(vbr->in_hdr.zone_append);
292 		break;
293 	case REQ_OP_ZONE_RESET:
294 		type = VIRTIO_BLK_T_ZONE_RESET;
295 		sector = blk_rq_pos(req);
296 		break;
297 	case REQ_OP_ZONE_RESET_ALL:
298 		type = VIRTIO_BLK_T_ZONE_RESET_ALL;
299 		break;
300 	case REQ_OP_DRV_IN:
301 		/*
302 		 * Out header has already been prepared by the caller (virtblk_get_id()
303 		 * or virtblk_submit_zone_report()), nothing to do here.
304 		 */
305 		return 0;
306 	default:
307 		WARN_ON_ONCE(1);
308 		return BLK_STS_IOERR;
309 	}
310 
311 	/* Set fields for non-REQ_OP_DRV_IN request types */
312 	vbr->in_hdr_len = in_hdr_len;
313 	vbr->out_hdr.type = cpu_to_virtio32(vdev, type);
314 	vbr->out_hdr.sector = cpu_to_virtio64(vdev, sector);
315 
316 	if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES ||
317 	    type == VIRTIO_BLK_T_SECURE_ERASE) {
318 		if (virtblk_setup_discard_write_zeroes_erase(req, unmap))
319 			return BLK_STS_RESOURCE;
320 	}
321 
322 	return 0;
323 }
324 
325 /*
326  * The status byte is always the last byte of the virtblk request
327  * in-header. This helper fetches its value for all in-header formats
328  * that are currently defined.
329  */
virtblk_vbr_status(struct virtblk_req * vbr)330 static inline u8 virtblk_vbr_status(struct virtblk_req *vbr)
331 {
332 	return *((u8 *)&vbr->in_hdr + vbr->in_hdr_len - 1);
333 }
334 
virtblk_request_done(struct request * req)335 static inline void virtblk_request_done(struct request *req)
336 {
337 	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
338 	blk_status_t status = virtblk_result(virtblk_vbr_status(vbr));
339 	struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
340 
341 	virtblk_unmap_data(req, vbr);
342 	virtblk_cleanup_cmd(req);
343 
344 	if (req_op(req) == REQ_OP_ZONE_APPEND)
345 		req->__sector = virtio64_to_cpu(vblk->vdev,
346 						vbr->in_hdr.zone_append.sector);
347 
348 	blk_mq_end_request(req, status);
349 }
350 
virtblk_done(struct virtqueue * vq)351 static void virtblk_done(struct virtqueue *vq)
352 {
353 	struct virtio_blk *vblk = vq->vdev->priv;
354 	bool req_done = false;
355 	int qid = vq->index;
356 	struct virtblk_req *vbr;
357 	unsigned long flags;
358 	unsigned int len;
359 
360 	spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
361 	do {
362 		virtqueue_disable_cb(vq);
363 		while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
364 			struct request *req = blk_mq_rq_from_pdu(vbr);
365 
366 			if (likely(!blk_should_fake_timeout(req->q)))
367 				blk_mq_complete_request(req);
368 			req_done = true;
369 		}
370 	} while (!virtqueue_enable_cb(vq));
371 
372 	/* In case queue is stopped waiting for more buffers. */
373 	if (req_done)
374 		blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
375 	spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
376 }
377 
virtio_commit_rqs(struct blk_mq_hw_ctx * hctx)378 static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
379 {
380 	struct virtio_blk *vblk = hctx->queue->queuedata;
381 	struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
382 	bool kick;
383 
384 	spin_lock_irq(&vq->lock);
385 	kick = virtqueue_kick_prepare(vq->vq);
386 	spin_unlock_irq(&vq->lock);
387 
388 	if (kick)
389 		virtqueue_notify(vq->vq);
390 }
391 
virtblk_fail_to_queue(struct request * req,int rc)392 static blk_status_t virtblk_fail_to_queue(struct request *req, int rc)
393 {
394 	virtblk_cleanup_cmd(req);
395 	switch (rc) {
396 	case -ENOSPC:
397 		return BLK_STS_DEV_RESOURCE;
398 	case -ENOMEM:
399 		return BLK_STS_RESOURCE;
400 	default:
401 		return BLK_STS_IOERR;
402 	}
403 }
404 
virtblk_prep_rq(struct blk_mq_hw_ctx * hctx,struct virtio_blk * vblk,struct request * req,struct virtblk_req * vbr)405 static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
406 					struct virtio_blk *vblk,
407 					struct request *req,
408 					struct virtblk_req *vbr)
409 {
410 	blk_status_t status;
411 	int num;
412 
413 	status = virtblk_setup_cmd(vblk->vdev, req, vbr);
414 	if (unlikely(status))
415 		return status;
416 
417 	num = virtblk_map_data(hctx, req, vbr);
418 	if (unlikely(num < 0))
419 		return virtblk_fail_to_queue(req, -ENOMEM);
420 	vbr->sg_table.nents = num;
421 
422 	blk_mq_start_request(req);
423 
424 	return BLK_STS_OK;
425 }
426 
virtio_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)427 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
428 			   const struct blk_mq_queue_data *bd)
429 {
430 	struct virtio_blk *vblk = hctx->queue->queuedata;
431 	struct request *req = bd->rq;
432 	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
433 	unsigned long flags;
434 	int qid = hctx->queue_num;
435 	bool notify = false;
436 	blk_status_t status;
437 	int err;
438 
439 	status = virtblk_prep_rq(hctx, vblk, req, vbr);
440 	if (unlikely(status))
441 		return status;
442 
443 	spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
444 	err = virtblk_add_req(vblk->vqs[qid].vq, vbr);
445 	if (err) {
446 		virtqueue_kick(vblk->vqs[qid].vq);
447 		/* Don't stop the queue if -ENOMEM: we may have failed to
448 		 * bounce the buffer due to global resource outage.
449 		 */
450 		if (err == -ENOSPC)
451 			blk_mq_stop_hw_queue(hctx);
452 		spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
453 		virtblk_unmap_data(req, vbr);
454 		return virtblk_fail_to_queue(req, err);
455 	}
456 
457 	if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
458 		notify = true;
459 	spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
460 
461 	if (notify)
462 		virtqueue_notify(vblk->vqs[qid].vq);
463 	return BLK_STS_OK;
464 }
465 
virtblk_prep_rq_batch(struct request * req)466 static bool virtblk_prep_rq_batch(struct request *req)
467 {
468 	struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
469 	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
470 
471 	return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK;
472 }
473 
virtblk_add_req_batch(struct virtio_blk_vq * vq,struct rq_list * rqlist)474 static void virtblk_add_req_batch(struct virtio_blk_vq *vq,
475 		struct rq_list *rqlist)
476 {
477 	struct request *req;
478 	unsigned long flags;
479 	bool kick;
480 
481 	spin_lock_irqsave(&vq->lock, flags);
482 
483 	while ((req = rq_list_pop(rqlist))) {
484 		struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
485 		int err;
486 
487 		err = virtblk_add_req(vq->vq, vbr);
488 		if (err) {
489 			virtblk_unmap_data(req, vbr);
490 			virtblk_cleanup_cmd(req);
491 			blk_mq_requeue_request(req, true);
492 		}
493 	}
494 
495 	kick = virtqueue_kick_prepare(vq->vq);
496 	spin_unlock_irqrestore(&vq->lock, flags);
497 
498 	if (kick)
499 		virtqueue_notify(vq->vq);
500 }
501 
virtio_queue_rqs(struct rq_list * rqlist)502 static void virtio_queue_rqs(struct rq_list *rqlist)
503 {
504 	struct rq_list submit_list = { };
505 	struct rq_list requeue_list = { };
506 	struct virtio_blk_vq *vq = NULL;
507 	struct request *req;
508 
509 	while ((req = rq_list_pop(rqlist))) {
510 		struct virtio_blk_vq *this_vq = get_virtio_blk_vq(req->mq_hctx);
511 
512 		if (vq && vq != this_vq)
513 			virtblk_add_req_batch(vq, &submit_list);
514 		vq = this_vq;
515 
516 		if (virtblk_prep_rq_batch(req))
517 			rq_list_add_tail(&submit_list, req);
518 		else
519 			rq_list_add_tail(&requeue_list, req);
520 	}
521 
522 	if (vq)
523 		virtblk_add_req_batch(vq, &submit_list);
524 	*rqlist = requeue_list;
525 }
526 
527 #ifdef CONFIG_BLK_DEV_ZONED
virtblk_alloc_report_buffer(struct virtio_blk * vblk,unsigned int nr_zones,size_t * buflen)528 static void *virtblk_alloc_report_buffer(struct virtio_blk *vblk,
529 					  unsigned int nr_zones,
530 					  size_t *buflen)
531 {
532 	struct request_queue *q = vblk->disk->queue;
533 	size_t bufsize;
534 	void *buf;
535 
536 	nr_zones = min_t(unsigned int, nr_zones,
537 			 get_capacity(vblk->disk) >> ilog2(vblk->zone_sectors));
538 
539 	bufsize = sizeof(struct virtio_blk_zone_report) +
540 		nr_zones * sizeof(struct virtio_blk_zone_descriptor);
541 	bufsize = min_t(size_t, bufsize,
542 			queue_max_hw_sectors(q) << SECTOR_SHIFT);
543 	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
544 
545 	while (bufsize >= sizeof(struct virtio_blk_zone_report)) {
546 		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
547 		if (buf) {
548 			*buflen = bufsize;
549 			return buf;
550 		}
551 		bufsize >>= 1;
552 	}
553 
554 	return NULL;
555 }
556 
virtblk_submit_zone_report(struct virtio_blk * vblk,char * report_buf,size_t report_len,sector_t sector)557 static int virtblk_submit_zone_report(struct virtio_blk *vblk,
558 				       char *report_buf, size_t report_len,
559 				       sector_t sector)
560 {
561 	struct request_queue *q = vblk->disk->queue;
562 	struct request *req;
563 	struct virtblk_req *vbr;
564 	int err;
565 
566 	req = blk_mq_alloc_request(q, REQ_OP_DRV_IN, 0);
567 	if (IS_ERR(req))
568 		return PTR_ERR(req);
569 
570 	vbr = blk_mq_rq_to_pdu(req);
571 	vbr->in_hdr_len = sizeof(vbr->in_hdr.status);
572 	vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_ZONE_REPORT);
573 	vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, sector);
574 
575 	err = blk_rq_map_kern(q, req, report_buf, report_len, GFP_KERNEL);
576 	if (err)
577 		goto out;
578 
579 	blk_execute_rq(req, false);
580 	err = blk_status_to_errno(virtblk_result(vbr->in_hdr.status));
581 out:
582 	blk_mq_free_request(req);
583 	return err;
584 }
585 
virtblk_parse_zone(struct virtio_blk * vblk,struct virtio_blk_zone_descriptor * entry,unsigned int idx,report_zones_cb cb,void * data)586 static int virtblk_parse_zone(struct virtio_blk *vblk,
587 			       struct virtio_blk_zone_descriptor *entry,
588 			       unsigned int idx, report_zones_cb cb, void *data)
589 {
590 	struct blk_zone zone = { };
591 
592 	zone.start = virtio64_to_cpu(vblk->vdev, entry->z_start);
593 	if (zone.start + vblk->zone_sectors <= get_capacity(vblk->disk))
594 		zone.len = vblk->zone_sectors;
595 	else
596 		zone.len = get_capacity(vblk->disk) - zone.start;
597 	zone.capacity = virtio64_to_cpu(vblk->vdev, entry->z_cap);
598 	zone.wp = virtio64_to_cpu(vblk->vdev, entry->z_wp);
599 
600 	switch (entry->z_type) {
601 	case VIRTIO_BLK_ZT_SWR:
602 		zone.type = BLK_ZONE_TYPE_SEQWRITE_REQ;
603 		break;
604 	case VIRTIO_BLK_ZT_SWP:
605 		zone.type = BLK_ZONE_TYPE_SEQWRITE_PREF;
606 		break;
607 	case VIRTIO_BLK_ZT_CONV:
608 		zone.type = BLK_ZONE_TYPE_CONVENTIONAL;
609 		break;
610 	default:
611 		dev_err(&vblk->vdev->dev, "zone %llu: invalid type %#x\n",
612 			zone.start, entry->z_type);
613 		return -EIO;
614 	}
615 
616 	switch (entry->z_state) {
617 	case VIRTIO_BLK_ZS_EMPTY:
618 		zone.cond = BLK_ZONE_COND_EMPTY;
619 		break;
620 	case VIRTIO_BLK_ZS_CLOSED:
621 		zone.cond = BLK_ZONE_COND_CLOSED;
622 		break;
623 	case VIRTIO_BLK_ZS_FULL:
624 		zone.cond = BLK_ZONE_COND_FULL;
625 		zone.wp = zone.start + zone.len;
626 		break;
627 	case VIRTIO_BLK_ZS_EOPEN:
628 		zone.cond = BLK_ZONE_COND_EXP_OPEN;
629 		break;
630 	case VIRTIO_BLK_ZS_IOPEN:
631 		zone.cond = BLK_ZONE_COND_IMP_OPEN;
632 		break;
633 	case VIRTIO_BLK_ZS_NOT_WP:
634 		zone.cond = BLK_ZONE_COND_NOT_WP;
635 		break;
636 	case VIRTIO_BLK_ZS_RDONLY:
637 		zone.cond = BLK_ZONE_COND_READONLY;
638 		zone.wp = ULONG_MAX;
639 		break;
640 	case VIRTIO_BLK_ZS_OFFLINE:
641 		zone.cond = BLK_ZONE_COND_OFFLINE;
642 		zone.wp = ULONG_MAX;
643 		break;
644 	default:
645 		dev_err(&vblk->vdev->dev, "zone %llu: invalid condition %#x\n",
646 			zone.start, entry->z_state);
647 		return -EIO;
648 	}
649 
650 	/*
651 	 * The callback below checks the validity of the reported
652 	 * entry data, no need to further validate it here.
653 	 */
654 	return cb(&zone, idx, data);
655 }
656 
virtblk_report_zones(struct gendisk * disk,sector_t sector,unsigned int nr_zones,report_zones_cb cb,void * data)657 static int virtblk_report_zones(struct gendisk *disk, sector_t sector,
658 				 unsigned int nr_zones, report_zones_cb cb,
659 				 void *data)
660 {
661 	struct virtio_blk *vblk = disk->private_data;
662 	struct virtio_blk_zone_report *report;
663 	unsigned long long nz, i;
664 	size_t buflen;
665 	unsigned int zone_idx = 0;
666 	int ret;
667 
668 	if (WARN_ON_ONCE(!vblk->zone_sectors))
669 		return -EOPNOTSUPP;
670 
671 	report = virtblk_alloc_report_buffer(vblk, nr_zones, &buflen);
672 	if (!report)
673 		return -ENOMEM;
674 
675 	mutex_lock(&vblk->vdev_mutex);
676 
677 	if (!vblk->vdev) {
678 		ret = -ENXIO;
679 		goto fail_report;
680 	}
681 
682 	while (zone_idx < nr_zones && sector < get_capacity(vblk->disk)) {
683 		memset(report, 0, buflen);
684 
685 		ret = virtblk_submit_zone_report(vblk, (char *)report,
686 						 buflen, sector);
687 		if (ret)
688 			goto fail_report;
689 
690 		nz = min_t(u64, virtio64_to_cpu(vblk->vdev, report->nr_zones),
691 			   nr_zones);
692 		if (!nz)
693 			break;
694 
695 		for (i = 0; i < nz && zone_idx < nr_zones; i++) {
696 			ret = virtblk_parse_zone(vblk, &report->zones[i],
697 						 zone_idx, cb, data);
698 			if (ret)
699 				goto fail_report;
700 
701 			sector = virtio64_to_cpu(vblk->vdev,
702 						 report->zones[i].z_start) +
703 				 vblk->zone_sectors;
704 			zone_idx++;
705 		}
706 	}
707 
708 	if (zone_idx > 0)
709 		ret = zone_idx;
710 	else
711 		ret = -EINVAL;
712 fail_report:
713 	mutex_unlock(&vblk->vdev_mutex);
714 	kvfree(report);
715 	return ret;
716 }
717 
virtblk_read_zoned_limits(struct virtio_blk * vblk,struct queue_limits * lim)718 static int virtblk_read_zoned_limits(struct virtio_blk *vblk,
719 		struct queue_limits *lim)
720 {
721 	struct virtio_device *vdev = vblk->vdev;
722 	u32 v, wg;
723 
724 	dev_dbg(&vdev->dev, "probing host-managed zoned device\n");
725 
726 	lim->features |= BLK_FEAT_ZONED;
727 
728 	virtio_cread(vdev, struct virtio_blk_config,
729 		     zoned.max_open_zones, &v);
730 	lim->max_open_zones = v;
731 	dev_dbg(&vdev->dev, "max open zones = %u\n", v);
732 
733 	virtio_cread(vdev, struct virtio_blk_config,
734 		     zoned.max_active_zones, &v);
735 	lim->max_active_zones = v;
736 	dev_dbg(&vdev->dev, "max active zones = %u\n", v);
737 
738 	virtio_cread(vdev, struct virtio_blk_config,
739 		     zoned.write_granularity, &wg);
740 	if (!wg) {
741 		dev_warn(&vdev->dev, "zero write granularity reported\n");
742 		return -ENODEV;
743 	}
744 	lim->physical_block_size = wg;
745 	lim->io_min = wg;
746 
747 	dev_dbg(&vdev->dev, "write granularity = %u\n", wg);
748 
749 	/*
750 	 * virtio ZBD specification doesn't require zones to be a power of
751 	 * two sectors in size, but the code in this driver expects that.
752 	 */
753 	virtio_cread(vdev, struct virtio_blk_config, zoned.zone_sectors,
754 		     &vblk->zone_sectors);
755 	if (vblk->zone_sectors == 0 || !is_power_of_2(vblk->zone_sectors)) {
756 		dev_err(&vdev->dev,
757 			"zoned device with non power of two zone size %u\n",
758 			vblk->zone_sectors);
759 		return -ENODEV;
760 	}
761 	lim->chunk_sectors = vblk->zone_sectors;
762 	dev_dbg(&vdev->dev, "zone sectors = %u\n", vblk->zone_sectors);
763 
764 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
765 		dev_warn(&vblk->vdev->dev,
766 			 "ignoring negotiated F_DISCARD for zoned device\n");
767 		lim->max_hw_discard_sectors = 0;
768 	}
769 
770 	virtio_cread(vdev, struct virtio_blk_config,
771 		     zoned.max_append_sectors, &v);
772 	if (!v) {
773 		dev_warn(&vdev->dev, "zero max_append_sectors reported\n");
774 		return -ENODEV;
775 	}
776 	if ((v << SECTOR_SHIFT) < wg) {
777 		dev_err(&vdev->dev,
778 			"write granularity %u exceeds max_append_sectors %u limit\n",
779 			wg, v);
780 		return -ENODEV;
781 	}
782 	lim->max_hw_zone_append_sectors = v;
783 	dev_dbg(&vdev->dev, "max append sectors = %u\n", v);
784 
785 	return 0;
786 }
787 #else
788 /*
789  * Zoned block device support is not configured in this kernel, host-managed
790  * zoned devices can't be supported.
791  */
792 #define virtblk_report_zones       NULL
virtblk_read_zoned_limits(struct virtio_blk * vblk,struct queue_limits * lim)793 static inline int virtblk_read_zoned_limits(struct virtio_blk *vblk,
794 		struct queue_limits *lim)
795 {
796 	dev_err(&vblk->vdev->dev,
797 		"virtio_blk: zoned devices are not supported");
798 	return -EOPNOTSUPP;
799 }
800 #endif /* CONFIG_BLK_DEV_ZONED */
801 
802 /* return id (s/n) string for *disk to *id_str
803  */
virtblk_get_id(struct gendisk * disk,char * id_str)804 static int virtblk_get_id(struct gendisk *disk, char *id_str)
805 {
806 	struct virtio_blk *vblk = disk->private_data;
807 	struct request_queue *q = vblk->disk->queue;
808 	struct request *req;
809 	struct virtblk_req *vbr;
810 	int err;
811 
812 	req = blk_mq_alloc_request(q, REQ_OP_DRV_IN, 0);
813 	if (IS_ERR(req))
814 		return PTR_ERR(req);
815 
816 	vbr = blk_mq_rq_to_pdu(req);
817 	vbr->in_hdr_len = sizeof(vbr->in_hdr.status);
818 	vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
819 	vbr->out_hdr.sector = 0;
820 
821 	err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
822 	if (err)
823 		goto out;
824 
825 	blk_execute_rq(req, false);
826 	err = blk_status_to_errno(virtblk_result(vbr->in_hdr.status));
827 out:
828 	blk_mq_free_request(req);
829 	return err;
830 }
831 
832 /* We provide getgeo only to please some old bootloader/partitioning tools */
virtblk_getgeo(struct block_device * bd,struct hd_geometry * geo)833 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
834 {
835 	struct virtio_blk *vblk = bd->bd_disk->private_data;
836 	int ret = 0;
837 
838 	mutex_lock(&vblk->vdev_mutex);
839 
840 	if (!vblk->vdev) {
841 		ret = -ENXIO;
842 		goto out;
843 	}
844 
845 	/* see if the host passed in geometry config */
846 	if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
847 		virtio_cread(vblk->vdev, struct virtio_blk_config,
848 			     geometry.cylinders, &geo->cylinders);
849 		virtio_cread(vblk->vdev, struct virtio_blk_config,
850 			     geometry.heads, &geo->heads);
851 		virtio_cread(vblk->vdev, struct virtio_blk_config,
852 			     geometry.sectors, &geo->sectors);
853 	} else {
854 		/* some standard values, similar to sd */
855 		geo->heads = 1 << 6;
856 		geo->sectors = 1 << 5;
857 		geo->cylinders = get_capacity(bd->bd_disk) >> 11;
858 	}
859 out:
860 	mutex_unlock(&vblk->vdev_mutex);
861 	return ret;
862 }
863 
virtblk_free_disk(struct gendisk * disk)864 static void virtblk_free_disk(struct gendisk *disk)
865 {
866 	struct virtio_blk *vblk = disk->private_data;
867 
868 	ida_free(&vd_index_ida, vblk->index);
869 	mutex_destroy(&vblk->vdev_mutex);
870 	kfree(vblk);
871 }
872 
873 static const struct block_device_operations virtblk_fops = {
874 	.owner  	= THIS_MODULE,
875 	.getgeo		= virtblk_getgeo,
876 	.free_disk	= virtblk_free_disk,
877 	.report_zones	= virtblk_report_zones,
878 };
879 
index_to_minor(int index)880 static int index_to_minor(int index)
881 {
882 	return index << PART_BITS;
883 }
884 
minor_to_index(int minor)885 static int minor_to_index(int minor)
886 {
887 	return minor >> PART_BITS;
888 }
889 
serial_show(struct device * dev,struct device_attribute * attr,char * buf)890 static ssize_t serial_show(struct device *dev,
891 			   struct device_attribute *attr, char *buf)
892 {
893 	struct gendisk *disk = dev_to_disk(dev);
894 	int err;
895 
896 	/* sysfs gives us a PAGE_SIZE buffer */
897 	BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
898 
899 	buf[VIRTIO_BLK_ID_BYTES] = '\0';
900 	err = virtblk_get_id(disk, buf);
901 	if (!err)
902 		return strlen(buf);
903 
904 	if (err == -EIO) /* Unsupported? Make it empty. */
905 		return 0;
906 
907 	return err;
908 }
909 
910 static DEVICE_ATTR_RO(serial);
911 
912 /* The queue's logical block size must be set before calling this */
virtblk_update_capacity(struct virtio_blk * vblk,bool resize)913 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
914 {
915 	struct virtio_device *vdev = vblk->vdev;
916 	struct request_queue *q = vblk->disk->queue;
917 	char cap_str_2[10], cap_str_10[10];
918 	unsigned long long nblocks;
919 	u64 capacity;
920 
921 	/* Host must always specify the capacity. */
922 	virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
923 
924 	nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
925 
926 	string_get_size(nblocks, queue_logical_block_size(q),
927 			STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
928 	string_get_size(nblocks, queue_logical_block_size(q),
929 			STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
930 
931 	dev_notice(&vdev->dev,
932 		   "[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
933 		   vblk->disk->disk_name,
934 		   resize ? "new size: " : "",
935 		   nblocks,
936 		   queue_logical_block_size(q),
937 		   cap_str_10,
938 		   cap_str_2);
939 
940 	set_capacity_and_notify(vblk->disk, capacity);
941 }
942 
virtblk_config_changed_work(struct work_struct * work)943 static void virtblk_config_changed_work(struct work_struct *work)
944 {
945 	struct virtio_blk *vblk =
946 		container_of(work, struct virtio_blk, config_work);
947 
948 	virtblk_update_capacity(vblk, true);
949 }
950 
virtblk_config_changed(struct virtio_device * vdev)951 static void virtblk_config_changed(struct virtio_device *vdev)
952 {
953 	struct virtio_blk *vblk = vdev->priv;
954 
955 	queue_work(virtblk_wq, &vblk->config_work);
956 }
957 
init_vq(struct virtio_blk * vblk)958 static int init_vq(struct virtio_blk *vblk)
959 {
960 	int err;
961 	unsigned short i;
962 	struct virtqueue_info *vqs_info;
963 	struct virtqueue **vqs;
964 	unsigned short num_vqs;
965 	unsigned short num_poll_vqs;
966 	struct virtio_device *vdev = vblk->vdev;
967 	struct irq_affinity desc = { 0, };
968 
969 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
970 				   struct virtio_blk_config, num_queues,
971 				   &num_vqs);
972 	if (err)
973 		num_vqs = 1;
974 
975 	if (!err && !num_vqs) {
976 		dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
977 		return -EINVAL;
978 	}
979 
980 	num_vqs = min_t(unsigned int,
981 			min_not_zero(num_request_queues, nr_cpu_ids),
982 			num_vqs);
983 
984 	num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
985 
986 	vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs;
987 	vblk->io_queues[HCTX_TYPE_READ] = 0;
988 	vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
989 
990 	dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
991 				vblk->io_queues[HCTX_TYPE_DEFAULT],
992 				vblk->io_queues[HCTX_TYPE_READ],
993 				vblk->io_queues[HCTX_TYPE_POLL]);
994 
995 	vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
996 	if (!vblk->vqs)
997 		return -ENOMEM;
998 
999 	vqs_info = kcalloc(num_vqs, sizeof(*vqs_info), GFP_KERNEL);
1000 	vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
1001 	if (!vqs_info || !vqs) {
1002 		err = -ENOMEM;
1003 		goto out;
1004 	}
1005 
1006 	for (i = 0; i < num_vqs - num_poll_vqs; i++) {
1007 		vqs_info[i].callback = virtblk_done;
1008 		snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%u", i);
1009 		vqs_info[i].name = vblk->vqs[i].name;
1010 	}
1011 
1012 	for (; i < num_vqs; i++) {
1013 		snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%u", i);
1014 		vqs_info[i].name = vblk->vqs[i].name;
1015 	}
1016 
1017 	/* Discover virtqueues and write information to configuration.  */
1018 	err = virtio_find_vqs(vdev, num_vqs, vqs, vqs_info, &desc);
1019 	if (err)
1020 		goto out;
1021 
1022 	for (i = 0; i < num_vqs; i++) {
1023 		spin_lock_init(&vblk->vqs[i].lock);
1024 		vblk->vqs[i].vq = vqs[i];
1025 	}
1026 	vblk->num_vqs = num_vqs;
1027 
1028 out:
1029 	kfree(vqs);
1030 	kfree(vqs_info);
1031 	if (err)
1032 		kfree(vblk->vqs);
1033 	return err;
1034 }
1035 
1036 /*
1037  * Legacy naming scheme used for virtio devices.  We are stuck with it for
1038  * virtio blk but don't ever use it for any new driver.
1039  */
virtblk_name_format(char * prefix,int index,char * buf,int buflen)1040 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
1041 {
1042 	const int base = 'z' - 'a' + 1;
1043 	char *begin = buf + strlen(prefix);
1044 	char *end = buf + buflen;
1045 	char *p;
1046 	int unit;
1047 
1048 	p = end - 1;
1049 	*p = '\0';
1050 	unit = base;
1051 	do {
1052 		if (p == begin)
1053 			return -EINVAL;
1054 		*--p = 'a' + (index % unit);
1055 		index = (index / unit) - 1;
1056 	} while (index >= 0);
1057 
1058 	memmove(begin, p, end - p);
1059 	memcpy(buf, prefix, strlen(prefix));
1060 
1061 	return 0;
1062 }
1063 
virtblk_get_cache_mode(struct virtio_device * vdev)1064 static int virtblk_get_cache_mode(struct virtio_device *vdev)
1065 {
1066 	u8 writeback;
1067 	int err;
1068 
1069 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
1070 				   struct virtio_blk_config, wce,
1071 				   &writeback);
1072 
1073 	/*
1074 	 * If WCE is not configurable and flush is not available,
1075 	 * assume no writeback cache is in use.
1076 	 */
1077 	if (err)
1078 		writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
1079 
1080 	return writeback;
1081 }
1082 
1083 static const char *const virtblk_cache_types[] = {
1084 	"write through", "write back"
1085 };
1086 
1087 static ssize_t
cache_type_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1088 cache_type_store(struct device *dev, struct device_attribute *attr,
1089 		 const char *buf, size_t count)
1090 {
1091 	struct gendisk *disk = dev_to_disk(dev);
1092 	struct virtio_blk *vblk = disk->private_data;
1093 	struct virtio_device *vdev = vblk->vdev;
1094 	struct queue_limits lim;
1095 	int i;
1096 
1097 	BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
1098 	i = sysfs_match_string(virtblk_cache_types, buf);
1099 	if (i < 0)
1100 		return i;
1101 
1102 	virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
1103 
1104 	lim = queue_limits_start_update(disk->queue);
1105 	if (virtblk_get_cache_mode(vdev))
1106 		lim.features |= BLK_FEAT_WRITE_CACHE;
1107 	else
1108 		lim.features &= ~BLK_FEAT_WRITE_CACHE;
1109 	blk_mq_freeze_queue(disk->queue);
1110 	i = queue_limits_commit_update(disk->queue, &lim);
1111 	blk_mq_unfreeze_queue(disk->queue);
1112 	if (i)
1113 		return i;
1114 	return count;
1115 }
1116 
1117 static ssize_t
cache_type_show(struct device * dev,struct device_attribute * attr,char * buf)1118 cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
1119 {
1120 	struct gendisk *disk = dev_to_disk(dev);
1121 	struct virtio_blk *vblk = disk->private_data;
1122 	u8 writeback = virtblk_get_cache_mode(vblk->vdev);
1123 
1124 	BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
1125 	return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);
1126 }
1127 
1128 static DEVICE_ATTR_RW(cache_type);
1129 
1130 static struct attribute *virtblk_attrs[] = {
1131 	&dev_attr_serial.attr,
1132 	&dev_attr_cache_type.attr,
1133 	NULL,
1134 };
1135 
virtblk_attrs_are_visible(struct kobject * kobj,struct attribute * a,int n)1136 static umode_t virtblk_attrs_are_visible(struct kobject *kobj,
1137 		struct attribute *a, int n)
1138 {
1139 	struct device *dev = kobj_to_dev(kobj);
1140 	struct gendisk *disk = dev_to_disk(dev);
1141 	struct virtio_blk *vblk = disk->private_data;
1142 	struct virtio_device *vdev = vblk->vdev;
1143 
1144 	if (a == &dev_attr_cache_type.attr &&
1145 	    !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
1146 		return S_IRUGO;
1147 
1148 	return a->mode;
1149 }
1150 
1151 static const struct attribute_group virtblk_attr_group = {
1152 	.attrs = virtblk_attrs,
1153 	.is_visible = virtblk_attrs_are_visible,
1154 };
1155 
1156 static const struct attribute_group *virtblk_attr_groups[] = {
1157 	&virtblk_attr_group,
1158 	NULL,
1159 };
1160 
virtblk_map_queues(struct blk_mq_tag_set * set)1161 static void virtblk_map_queues(struct blk_mq_tag_set *set)
1162 {
1163 	struct virtio_blk *vblk = set->driver_data;
1164 	int i, qoff;
1165 
1166 	for (i = 0, qoff = 0; i < set->nr_maps; i++) {
1167 		struct blk_mq_queue_map *map = &set->map[i];
1168 
1169 		map->nr_queues = vblk->io_queues[i];
1170 		map->queue_offset = qoff;
1171 		qoff += map->nr_queues;
1172 
1173 		if (map->nr_queues == 0)
1174 			continue;
1175 
1176 		/*
1177 		 * Regular queues have interrupts and hence CPU affinity is
1178 		 * defined by the core virtio code, but polling queues have
1179 		 * no interrupts so we let the block layer assign CPU affinity.
1180 		 */
1181 		if (i == HCTX_TYPE_POLL)
1182 			blk_mq_map_queues(&set->map[i]);
1183 		else
1184 			blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);
1185 	}
1186 }
1187 
virtblk_complete_batch(struct io_comp_batch * iob)1188 static void virtblk_complete_batch(struct io_comp_batch *iob)
1189 {
1190 	struct request *req;
1191 
1192 	rq_list_for_each(&iob->req_list, req) {
1193 		virtblk_unmap_data(req, blk_mq_rq_to_pdu(req));
1194 		virtblk_cleanup_cmd(req);
1195 	}
1196 	blk_mq_end_request_batch(iob);
1197 }
1198 
virtblk_poll(struct blk_mq_hw_ctx * hctx,struct io_comp_batch * iob)1199 static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1200 {
1201 	struct virtio_blk *vblk = hctx->queue->queuedata;
1202 	struct virtio_blk_vq *vq = get_virtio_blk_vq(hctx);
1203 	struct virtblk_req *vbr;
1204 	unsigned long flags;
1205 	unsigned int len;
1206 	int found = 0;
1207 
1208 	spin_lock_irqsave(&vq->lock, flags);
1209 
1210 	while ((vbr = virtqueue_get_buf(vq->vq, &len)) != NULL) {
1211 		struct request *req = blk_mq_rq_from_pdu(vbr);
1212 
1213 		found++;
1214 		if (!blk_mq_complete_request_remote(req) &&
1215 		    !blk_mq_add_to_batch(req, iob, virtblk_vbr_status(vbr),
1216 						virtblk_complete_batch))
1217 			virtblk_request_done(req);
1218 	}
1219 
1220 	if (found)
1221 		blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
1222 
1223 	spin_unlock_irqrestore(&vq->lock, flags);
1224 
1225 	return found;
1226 }
1227 
1228 static const struct blk_mq_ops virtio_mq_ops = {
1229 	.queue_rq	= virtio_queue_rq,
1230 	.queue_rqs	= virtio_queue_rqs,
1231 	.commit_rqs	= virtio_commit_rqs,
1232 	.complete	= virtblk_request_done,
1233 	.map_queues	= virtblk_map_queues,
1234 	.poll		= virtblk_poll,
1235 };
1236 
1237 static unsigned int virtblk_queue_depth;
1238 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
1239 
virtblk_read_limits(struct virtio_blk * vblk,struct queue_limits * lim)1240 static int virtblk_read_limits(struct virtio_blk *vblk,
1241 		struct queue_limits *lim)
1242 {
1243 	struct virtio_device *vdev = vblk->vdev;
1244 	u32 v, max_size, sg_elems, opt_io_size;
1245 	u32 max_discard_segs = 0;
1246 	u32 discard_granularity = 0;
1247 	u16 min_io_size;
1248 	u8 physical_block_exp, alignment_offset;
1249 	size_t max_dma_size;
1250 	int err;
1251 
1252 	/* We need to know how many segments before we allocate. */
1253 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
1254 				   struct virtio_blk_config, seg_max,
1255 				   &sg_elems);
1256 
1257 	/* We need at least one SG element, whatever they say. */
1258 	if (err || !sg_elems)
1259 		sg_elems = 1;
1260 
1261 	/* Prevent integer overflows and honor max vq size */
1262 	sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
1263 
1264 	/* We can handle whatever the host told us to handle. */
1265 	lim->max_segments = sg_elems;
1266 
1267 	/* No real sector limit. */
1268 	lim->max_hw_sectors = UINT_MAX;
1269 
1270 	max_dma_size = virtio_max_dma_size(vdev);
1271 	max_size = max_dma_size > U32_MAX ? U32_MAX : max_dma_size;
1272 
1273 	/* Host can optionally specify maximum segment size and number of
1274 	 * segments. */
1275 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
1276 				   struct virtio_blk_config, size_max, &v);
1277 	if (!err)
1278 		max_size = min(max_size, v);
1279 
1280 	lim->max_segment_size = max_size;
1281 
1282 	/* Host can optionally specify the block size of the device */
1283 	virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
1284 				   struct virtio_blk_config, blk_size,
1285 				   &lim->logical_block_size);
1286 
1287 	/* Use topology information if available */
1288 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1289 				   struct virtio_blk_config, physical_block_exp,
1290 				   &physical_block_exp);
1291 	if (!err && physical_block_exp)
1292 		lim->physical_block_size =
1293 			lim->logical_block_size * (1 << physical_block_exp);
1294 
1295 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1296 				   struct virtio_blk_config, alignment_offset,
1297 				   &alignment_offset);
1298 	if (!err && alignment_offset)
1299 		lim->alignment_offset =
1300 			lim->logical_block_size * alignment_offset;
1301 
1302 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1303 				   struct virtio_blk_config, min_io_size,
1304 				   &min_io_size);
1305 	if (!err && min_io_size)
1306 		lim->io_min = lim->logical_block_size * min_io_size;
1307 
1308 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
1309 				   struct virtio_blk_config, opt_io_size,
1310 				   &opt_io_size);
1311 	if (!err && opt_io_size)
1312 		lim->io_opt = lim->logical_block_size * opt_io_size;
1313 
1314 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
1315 		virtio_cread(vdev, struct virtio_blk_config,
1316 			     discard_sector_alignment, &discard_granularity);
1317 
1318 		virtio_cread(vdev, struct virtio_blk_config,
1319 			     max_discard_sectors, &v);
1320 		lim->max_hw_discard_sectors = v ? v : UINT_MAX;
1321 
1322 		virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
1323 			     &max_discard_segs);
1324 	}
1325 
1326 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
1327 		virtio_cread(vdev, struct virtio_blk_config,
1328 			     max_write_zeroes_sectors, &v);
1329 		lim->max_write_zeroes_sectors = v ? v : UINT_MAX;
1330 	}
1331 
1332 	/* The discard and secure erase limits are combined since the Linux
1333 	 * block layer uses the same limit for both commands.
1334 	 *
1335 	 * If both VIRTIO_BLK_F_SECURE_ERASE and VIRTIO_BLK_F_DISCARD features
1336 	 * are negotiated, we will use the minimum between the limits.
1337 	 *
1338 	 * discard sector alignment is set to the minimum between discard_sector_alignment
1339 	 * and secure_erase_sector_alignment.
1340 	 *
1341 	 * max discard sectors is set to the minimum between max_discard_seg and
1342 	 * max_secure_erase_seg.
1343 	 */
1344 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1345 
1346 		virtio_cread(vdev, struct virtio_blk_config,
1347 			     secure_erase_sector_alignment, &v);
1348 
1349 		/* secure_erase_sector_alignment should not be zero, the device should set a
1350 		 * valid number of sectors.
1351 		 */
1352 		if (!v) {
1353 			dev_err(&vdev->dev,
1354 				"virtio_blk: secure_erase_sector_alignment can't be 0\n");
1355 			return -EINVAL;
1356 		}
1357 
1358 		discard_granularity = min_not_zero(discard_granularity, v);
1359 
1360 		virtio_cread(vdev, struct virtio_blk_config,
1361 			     max_secure_erase_sectors, &v);
1362 
1363 		/* max_secure_erase_sectors should not be zero, the device should set a
1364 		 * valid number of sectors.
1365 		 */
1366 		if (!v) {
1367 			dev_err(&vdev->dev,
1368 				"virtio_blk: max_secure_erase_sectors can't be 0\n");
1369 			return -EINVAL;
1370 		}
1371 
1372 		lim->max_secure_erase_sectors = v;
1373 
1374 		virtio_cread(vdev, struct virtio_blk_config,
1375 			     max_secure_erase_seg, &v);
1376 
1377 		/* max_secure_erase_seg should not be zero, the device should set a
1378 		 * valid number of segments
1379 		 */
1380 		if (!v) {
1381 			dev_err(&vdev->dev,
1382 				"virtio_blk: max_secure_erase_seg can't be 0\n");
1383 			return -EINVAL;
1384 		}
1385 
1386 		max_discard_segs = min_not_zero(max_discard_segs, v);
1387 	}
1388 
1389 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD) ||
1390 	    virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
1391 		/* max_discard_seg and discard_granularity will be 0 only
1392 		 * if max_discard_seg and discard_sector_alignment fields in the virtio
1393 		 * config are 0 and VIRTIO_BLK_F_SECURE_ERASE feature is not negotiated.
1394 		 * In this case, we use default values.
1395 		 */
1396 		if (!max_discard_segs)
1397 			max_discard_segs = sg_elems;
1398 
1399 		lim->max_discard_segments =
1400 			min(max_discard_segs, MAX_DISCARD_SEGMENTS);
1401 
1402 		if (discard_granularity)
1403 			lim->discard_granularity =
1404 				discard_granularity << SECTOR_SHIFT;
1405 		else
1406 			lim->discard_granularity = lim->logical_block_size;
1407 	}
1408 
1409 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_ZONED)) {
1410 		u8 model;
1411 
1412 		virtio_cread(vdev, struct virtio_blk_config, zoned.model, &model);
1413 		switch (model) {
1414 		case VIRTIO_BLK_Z_NONE:
1415 		case VIRTIO_BLK_Z_HA:
1416 			/* treat host-aware devices as non-zoned */
1417 			return 0;
1418 		case VIRTIO_BLK_Z_HM:
1419 			err = virtblk_read_zoned_limits(vblk, lim);
1420 			if (err)
1421 				return err;
1422 			break;
1423 		default:
1424 			dev_err(&vdev->dev, "unsupported zone model %d\n", model);
1425 			return -EINVAL;
1426 		}
1427 	}
1428 
1429 	return 0;
1430 }
1431 
virtblk_probe(struct virtio_device * vdev)1432 static int virtblk_probe(struct virtio_device *vdev)
1433 {
1434 	struct virtio_blk *vblk;
1435 	struct queue_limits lim = {
1436 		.features		= BLK_FEAT_ROTATIONAL,
1437 		.logical_block_size	= SECTOR_SIZE,
1438 	};
1439 	int err, index;
1440 	unsigned int queue_depth;
1441 
1442 	if (!vdev->config->get) {
1443 		dev_err(&vdev->dev, "%s failure: config access disabled\n",
1444 			__func__);
1445 		return -EINVAL;
1446 	}
1447 
1448 	err = ida_alloc_range(&vd_index_ida, 0,
1449 			      minor_to_index(1 << MINORBITS) - 1, GFP_KERNEL);
1450 	if (err < 0)
1451 		goto out;
1452 	index = err;
1453 
1454 	vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
1455 	if (!vblk) {
1456 		err = -ENOMEM;
1457 		goto out_free_index;
1458 	}
1459 
1460 	mutex_init(&vblk->vdev_mutex);
1461 
1462 	vblk->vdev = vdev;
1463 
1464 	INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
1465 
1466 	err = init_vq(vblk);
1467 	if (err)
1468 		goto out_free_vblk;
1469 
1470 	/* Default queue sizing is to fill the ring. */
1471 	if (!virtblk_queue_depth) {
1472 		queue_depth = vblk->vqs[0].vq->num_free;
1473 		/* ... but without indirect descs, we use 2 descs per req */
1474 		if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
1475 			queue_depth /= 2;
1476 	} else {
1477 		queue_depth = virtblk_queue_depth;
1478 	}
1479 
1480 	memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
1481 	vblk->tag_set.ops = &virtio_mq_ops;
1482 	vblk->tag_set.queue_depth = queue_depth;
1483 	vblk->tag_set.numa_node = NUMA_NO_NODE;
1484 	vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1485 	vblk->tag_set.cmd_size =
1486 		sizeof(struct virtblk_req) +
1487 		sizeof(struct scatterlist) * VIRTIO_BLK_INLINE_SG_CNT;
1488 	vblk->tag_set.driver_data = vblk;
1489 	vblk->tag_set.nr_hw_queues = vblk->num_vqs;
1490 	vblk->tag_set.nr_maps = 1;
1491 	if (vblk->io_queues[HCTX_TYPE_POLL])
1492 		vblk->tag_set.nr_maps = 3;
1493 
1494 	err = blk_mq_alloc_tag_set(&vblk->tag_set);
1495 	if (err)
1496 		goto out_free_vq;
1497 
1498 	err = virtblk_read_limits(vblk, &lim);
1499 	if (err)
1500 		goto out_free_tags;
1501 
1502 	if (virtblk_get_cache_mode(vdev))
1503 		lim.features |= BLK_FEAT_WRITE_CACHE;
1504 
1505 	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, &lim, vblk);
1506 	if (IS_ERR(vblk->disk)) {
1507 		err = PTR_ERR(vblk->disk);
1508 		goto out_free_tags;
1509 	}
1510 
1511 	virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
1512 
1513 	vblk->disk->major = major;
1514 	vblk->disk->first_minor = index_to_minor(index);
1515 	vblk->disk->minors = 1 << PART_BITS;
1516 	vblk->disk->private_data = vblk;
1517 	vblk->disk->fops = &virtblk_fops;
1518 	vblk->index = index;
1519 
1520 	/* If disk is read-only in the host, the guest should obey */
1521 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
1522 		set_disk_ro(vblk->disk, 1);
1523 
1524 	virtblk_update_capacity(vblk, false);
1525 	virtio_device_ready(vdev);
1526 
1527 	/*
1528 	 * All steps that follow use the VQs therefore they need to be
1529 	 * placed after the virtio_device_ready() call above.
1530 	 */
1531 	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
1532 	    (lim.features & BLK_FEAT_ZONED)) {
1533 		err = blk_revalidate_disk_zones(vblk->disk);
1534 		if (err)
1535 			goto out_cleanup_disk;
1536 	}
1537 
1538 	err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
1539 	if (err)
1540 		goto out_cleanup_disk;
1541 
1542 	return 0;
1543 
1544 out_cleanup_disk:
1545 	put_disk(vblk->disk);
1546 out_free_tags:
1547 	blk_mq_free_tag_set(&vblk->tag_set);
1548 out_free_vq:
1549 	vdev->config->del_vqs(vdev);
1550 	kfree(vblk->vqs);
1551 out_free_vblk:
1552 	kfree(vblk);
1553 out_free_index:
1554 	ida_free(&vd_index_ida, index);
1555 out:
1556 	return err;
1557 }
1558 
virtblk_remove(struct virtio_device * vdev)1559 static void virtblk_remove(struct virtio_device *vdev)
1560 {
1561 	struct virtio_blk *vblk = vdev->priv;
1562 
1563 	/* Make sure no work handler is accessing the device. */
1564 	flush_work(&vblk->config_work);
1565 
1566 	del_gendisk(vblk->disk);
1567 	blk_mq_free_tag_set(&vblk->tag_set);
1568 
1569 	mutex_lock(&vblk->vdev_mutex);
1570 
1571 	/* Stop all the virtqueues. */
1572 	virtio_reset_device(vdev);
1573 
1574 	/* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
1575 	vblk->vdev = NULL;
1576 
1577 	vdev->config->del_vqs(vdev);
1578 	kfree(vblk->vqs);
1579 
1580 	mutex_unlock(&vblk->vdev_mutex);
1581 
1582 	put_disk(vblk->disk);
1583 }
1584 
1585 #ifdef CONFIG_PM_SLEEP
virtblk_freeze(struct virtio_device * vdev)1586 static int virtblk_freeze(struct virtio_device *vdev)
1587 {
1588 	struct virtio_blk *vblk = vdev->priv;
1589 	struct request_queue *q = vblk->disk->queue;
1590 
1591 	/* Ensure no requests in virtqueues before deleting vqs. */
1592 	blk_mq_freeze_queue(q);
1593 	blk_mq_quiesce_queue_nowait(q);
1594 	blk_mq_unfreeze_queue(q);
1595 
1596 	/* Ensure we don't receive any more interrupts */
1597 	virtio_reset_device(vdev);
1598 
1599 	/* Make sure no work handler is accessing the device. */
1600 	flush_work(&vblk->config_work);
1601 
1602 	vdev->config->del_vqs(vdev);
1603 	kfree(vblk->vqs);
1604 
1605 	return 0;
1606 }
1607 
virtblk_restore(struct virtio_device * vdev)1608 static int virtblk_restore(struct virtio_device *vdev)
1609 {
1610 	struct virtio_blk *vblk = vdev->priv;
1611 	int ret;
1612 
1613 	ret = init_vq(vdev->priv);
1614 	if (ret)
1615 		return ret;
1616 
1617 	virtio_device_ready(vdev);
1618 	blk_mq_unquiesce_queue(vblk->disk->queue);
1619 
1620 	return 0;
1621 }
1622 #endif
1623 
1624 static const struct virtio_device_id id_table[] = {
1625 	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
1626 	{ 0 },
1627 };
1628 
1629 static unsigned int features_legacy[] = {
1630 	VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1631 	VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1632 	VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1633 	VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1634 	VIRTIO_BLK_F_SECURE_ERASE,
1635 }
1636 ;
1637 static unsigned int features[] = {
1638 	VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
1639 	VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1640 	VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
1641 	VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
1642 	VIRTIO_BLK_F_SECURE_ERASE, VIRTIO_BLK_F_ZONED,
1643 };
1644 
1645 static struct virtio_driver virtio_blk = {
1646 	.feature_table			= features,
1647 	.feature_table_size		= ARRAY_SIZE(features),
1648 	.feature_table_legacy		= features_legacy,
1649 	.feature_table_size_legacy	= ARRAY_SIZE(features_legacy),
1650 	.driver.name			= KBUILD_MODNAME,
1651 	.id_table			= id_table,
1652 	.probe				= virtblk_probe,
1653 	.remove				= virtblk_remove,
1654 	.config_changed			= virtblk_config_changed,
1655 #ifdef CONFIG_PM_SLEEP
1656 	.freeze				= virtblk_freeze,
1657 	.restore			= virtblk_restore,
1658 #endif
1659 };
1660 
virtio_blk_init(void)1661 static int __init virtio_blk_init(void)
1662 {
1663 	int error;
1664 
1665 	virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
1666 	if (!virtblk_wq)
1667 		return -ENOMEM;
1668 
1669 	major = register_blkdev(0, "virtblk");
1670 	if (major < 0) {
1671 		error = major;
1672 		goto out_destroy_workqueue;
1673 	}
1674 
1675 	error = register_virtio_driver(&virtio_blk);
1676 	if (error)
1677 		goto out_unregister_blkdev;
1678 	return 0;
1679 
1680 out_unregister_blkdev:
1681 	unregister_blkdev(major, "virtblk");
1682 out_destroy_workqueue:
1683 	destroy_workqueue(virtblk_wq);
1684 	return error;
1685 }
1686 
virtio_blk_fini(void)1687 static void __exit virtio_blk_fini(void)
1688 {
1689 	unregister_virtio_driver(&virtio_blk);
1690 	unregister_blkdev(major, "virtblk");
1691 	destroy_workqueue(virtblk_wq);
1692 }
1693 module_init(virtio_blk_init);
1694 module_exit(virtio_blk_fini);
1695 
1696 MODULE_DEVICE_TABLE(virtio, id_table);
1697 MODULE_DESCRIPTION("Virtio block driver");
1698 MODULE_LICENSE("GPL");
1699