4 * XenLinux virtual block device driver.
6 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
7 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
8 * Copyright (c) 2004, Christian Limpach
9 * Copyright (c) 2004, Andrew Warfield
10 * Copyright (c) 2005, Christopher Clark
11 * Copyright (c) 2005, XenSource Ltd
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License version 2
15 * as published by the Free Software Foundation; or, when distributed
16 * separately from the Linux kernel or incorporated into other
17 * software packages, subject to the following license:
19 * Permission is hereby granted, free of charge, to any person obtaining a copy
20 * of this source file (the "Software"), to deal in the Software without
21 * restriction, including without limitation the rights to use, copy, modify,
22 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
23 * and to permit persons to whom the Software is furnished to do so, subject to
24 * the following conditions:
26 * The above copyright notice and this permission notice shall be included in
27 * all copies or substantial portions of the Software.
29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
30 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
31 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
32 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
33 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
34 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
38 #include <linux/interrupt.h>
39 #include <linux/blkdev.h>
40 #include <linux/blk-mq.h>
41 #include <linux/hdreg.h>
42 #include <linux/cdrom.h>
43 #include <linux/module.h>
44 #include <linux/slab.h>
45 #include <linux/mutex.h>
46 #include <linux/scatterlist.h>
47 #include <linux/bitmap.h>
48 #include <linux/list.h>
51 #include <xen/xenbus.h>
52 #include <xen/grant_table.h>
53 #include <xen/events.h>
55 #include <xen/platform_pci.h>
57 #include <xen/interface/grant_table.h>
58 #include <xen/interface/io/blkif.h>
59 #include <xen/interface/io/protocols.h>
61 #include <asm/xen/hypervisor.h>
64 * The minimal size of segment supported by the block framework is PAGE_SIZE.
65 * When Linux is using a different page size than Xen, it may not be possible
66 * to put all the data in a single segment.
67 * This can happen when the backend doesn't support indirect descriptor and
68 * therefore the maximum amount of data that a request can carry is
69 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE = 44KB
71 * Note that we only support one extra request. So the Linux page size
72 * should be <= ( 2 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) =
75 #define HAS_EXTRA_REQ (BLKIF_MAX_SEGMENTS_PER_REQUEST < XEN_PFN_PER_PAGE)
78 BLKIF_STATE_DISCONNECTED,
79 BLKIF_STATE_CONNECTED,
80 BLKIF_STATE_SUSPENDED,
86 struct list_head node;
97 struct blkif_request req;
98 struct request *request;
99 struct grant **grants_used;
100 struct grant **indirect_grants;
101 struct scatterlist *sg;
103 enum blk_req_status status;
105 #define NO_ASSOCIATED_ID ~0UL
107 * Id of the sibling if we ever need 2 requests when handling a
110 unsigned long associated_id;
118 static DEFINE_MUTEX(blkfront_mutex);
119 static const struct block_device_operations xlvbd_block_fops;
122 * Maximum number of segments in indirect requests, the actual value used by
123 * the frontend driver is the minimum of this value and the value provided
124 * by the backend driver.
127 static unsigned int xen_blkif_max_segments = 32;
128 module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
129 MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)");
131 static unsigned int xen_blkif_max_queues = 4;
132 module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
133 MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per virtual disk");
136 * Maximum order of pages to be used for the shared ring between front and
137 * backend, 4KB page granularity is used.
139 static unsigned int xen_blkif_max_ring_order;
140 module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO);
141 MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
143 #define BLK_RING_SIZE(info) \
144 __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages)
146 #define BLK_MAX_RING_SIZE \
147 __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_GRANTS)
150 * ring-ref%u i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19
151 * characters are enough. Define to 20 to keep consistent with backend.
153 #define RINGREF_NAME_LEN (20)
155 * queue-%u would take 7 + 10(UINT_MAX) = 17 characters.
157 #define QUEUE_NAME_LEN (17)
161 * Every blkfront device can associate with one or more blkfront_ring_info,
162 * depending on how many hardware queues/rings to be used.
164 struct blkfront_ring_info {
165 /* Lock to protect data in every ring buffer. */
166 spinlock_t ring_lock;
167 struct blkif_front_ring ring;
168 unsigned int ring_ref[XENBUS_MAX_RING_GRANTS];
169 unsigned int evtchn, irq;
170 struct work_struct work;
171 struct gnttab_free_callback callback;
172 struct blk_shadow shadow[BLK_MAX_RING_SIZE];
173 struct list_head indirect_pages;
174 struct list_head grants;
175 unsigned int persistent_gnts_c;
176 unsigned long shadow_free;
177 struct blkfront_info *dev_info;
181 * We have one of these per vbd, whether ide, scsi or 'other'. They
182 * hang in private_data off the gendisk structure. We may end up
183 * putting all kinds of interesting stuff here :-)
188 struct xenbus_device *xbdev;
192 enum blkif_state connected;
193 /* Number of pages per ring buffer. */
194 unsigned int nr_ring_pages;
195 struct request_queue *rq;
196 unsigned int feature_flush;
197 unsigned int feature_discard:1;
198 unsigned int feature_secdiscard:1;
199 unsigned int discard_granularity;
200 unsigned int discard_alignment;
201 unsigned int feature_persistent:1;
202 /* Number of 4KB segments handled */
203 unsigned int max_indirect_segments;
205 struct blk_mq_tag_set tag_set;
206 struct blkfront_ring_info *rinfo;
207 unsigned int nr_rings;
210 static unsigned int nr_minors;
211 static unsigned long *minors;
212 static DEFINE_SPINLOCK(minor_lock);
214 #define GRANT_INVALID_REF 0
216 #define PARTS_PER_DISK 16
217 #define PARTS_PER_EXT_DISK 256
219 #define BLKIF_MAJOR(dev) ((dev)>>8)
220 #define BLKIF_MINOR(dev) ((dev) & 0xff)
223 #define EXTENDED (1<<EXT_SHIFT)
224 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
225 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
226 #define EMULATED_HD_DISK_MINOR_OFFSET (0)
227 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
228 #define EMULATED_SD_DISK_MINOR_OFFSET (0)
229 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
231 #define DEV_NAME "xvd" /* name in /dev */
234 * Grants are always the same size as a Xen page (i.e 4KB).
235 * A physical segment is always the same size as a Linux page.
236 * Number of grants per physical segment
238 #define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE)
240 #define GRANTS_PER_INDIRECT_FRAME \
241 (XEN_PAGE_SIZE / sizeof(struct blkif_request_segment))
243 #define PSEGS_PER_INDIRECT_FRAME \
244 (GRANTS_INDIRECT_FRAME / GRANTS_PSEGS)
246 #define INDIRECT_GREFS(_grants) \
247 DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME)
249 #define GREFS(_psegs) ((_psegs) * GRANTS_PER_PSEG)
251 static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
252 static void blkfront_gather_backend_features(struct blkfront_info *info);
254 static int get_id_from_freelist(struct blkfront_ring_info *rinfo)
256 unsigned long free = rinfo->shadow_free;
258 BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info));
259 rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id;
260 rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
264 static int add_id_to_freelist(struct blkfront_ring_info *rinfo,
267 if (rinfo->shadow[id].req.u.rw.id != id)
269 if (rinfo->shadow[id].request == NULL)
271 rinfo->shadow[id].req.u.rw.id = rinfo->shadow_free;
272 rinfo->shadow[id].request = NULL;
273 rinfo->shadow_free = id;
277 static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num)
279 struct blkfront_info *info = rinfo->dev_info;
280 struct page *granted_page;
281 struct grant *gnt_list_entry, *n;
285 gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
289 if (info->feature_persistent) {
290 granted_page = alloc_page(GFP_NOIO);
292 kfree(gnt_list_entry);
295 gnt_list_entry->page = granted_page;
298 gnt_list_entry->gref = GRANT_INVALID_REF;
299 list_add(&gnt_list_entry->node, &rinfo->grants);
306 list_for_each_entry_safe(gnt_list_entry, n,
307 &rinfo->grants, node) {
308 list_del(&gnt_list_entry->node);
309 if (info->feature_persistent)
310 __free_page(gnt_list_entry->page);
311 kfree(gnt_list_entry);
318 static struct grant *get_free_grant(struct blkfront_ring_info *rinfo)
320 struct grant *gnt_list_entry;
322 BUG_ON(list_empty(&rinfo->grants));
323 gnt_list_entry = list_first_entry(&rinfo->grants, struct grant,
325 list_del(&gnt_list_entry->node);
327 if (gnt_list_entry->gref != GRANT_INVALID_REF)
328 rinfo->persistent_gnts_c--;
330 return gnt_list_entry;
333 static inline void grant_foreign_access(const struct grant *gnt_list_entry,
334 const struct blkfront_info *info)
336 gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref,
337 info->xbdev->otherend_id,
338 gnt_list_entry->page,
342 static struct grant *get_grant(grant_ref_t *gref_head,
344 struct blkfront_ring_info *rinfo)
346 struct grant *gnt_list_entry = get_free_grant(rinfo);
347 struct blkfront_info *info = rinfo->dev_info;
349 if (gnt_list_entry->gref != GRANT_INVALID_REF)
350 return gnt_list_entry;
352 /* Assign a gref to this page */
353 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
354 BUG_ON(gnt_list_entry->gref == -ENOSPC);
355 if (info->feature_persistent)
356 grant_foreign_access(gnt_list_entry, info);
358 /* Grant access to the GFN passed by the caller */
359 gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
360 info->xbdev->otherend_id,
364 return gnt_list_entry;
367 static struct grant *get_indirect_grant(grant_ref_t *gref_head,
368 struct blkfront_ring_info *rinfo)
370 struct grant *gnt_list_entry = get_free_grant(rinfo);
371 struct blkfront_info *info = rinfo->dev_info;
373 if (gnt_list_entry->gref != GRANT_INVALID_REF)
374 return gnt_list_entry;
376 /* Assign a gref to this page */
377 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
378 BUG_ON(gnt_list_entry->gref == -ENOSPC);
379 if (!info->feature_persistent) {
380 struct page *indirect_page;
382 /* Fetch a pre-allocated page to use for indirect grefs */
383 BUG_ON(list_empty(&rinfo->indirect_pages));
384 indirect_page = list_first_entry(&rinfo->indirect_pages,
386 list_del(&indirect_page->lru);
387 gnt_list_entry->page = indirect_page;
389 grant_foreign_access(gnt_list_entry, info);
391 return gnt_list_entry;
394 static const char *op_name(int op)
396 static const char *const names[] = {
397 [BLKIF_OP_READ] = "read",
398 [BLKIF_OP_WRITE] = "write",
399 [BLKIF_OP_WRITE_BARRIER] = "barrier",
400 [BLKIF_OP_FLUSH_DISKCACHE] = "flush",
401 [BLKIF_OP_DISCARD] = "discard" };
403 if (op < 0 || op >= ARRAY_SIZE(names))
411 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
413 unsigned int end = minor + nr;
416 if (end > nr_minors) {
417 unsigned long *bitmap, *old;
419 bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
424 spin_lock(&minor_lock);
425 if (end > nr_minors) {
427 memcpy(bitmap, minors,
428 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
430 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
433 spin_unlock(&minor_lock);
437 spin_lock(&minor_lock);
438 if (find_next_bit(minors, end, minor) >= end) {
439 bitmap_set(minors, minor, nr);
443 spin_unlock(&minor_lock);
448 static void xlbd_release_minors(unsigned int minor, unsigned int nr)
450 unsigned int end = minor + nr;
452 BUG_ON(end > nr_minors);
453 spin_lock(&minor_lock);
454 bitmap_clear(minors, minor, nr);
455 spin_unlock(&minor_lock);
458 static void blkif_restart_queue_callback(void *arg)
460 struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg;
461 schedule_work(&rinfo->work);
464 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
466 /* We don't have real geometry info, but let's at least return
467 values consistent with the size of the device */
468 sector_t nsect = get_capacity(bd->bd_disk);
469 sector_t cylinders = nsect;
473 sector_div(cylinders, hg->heads * hg->sectors);
474 hg->cylinders = cylinders;
475 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
476 hg->cylinders = 0xffff;
480 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
481 unsigned command, unsigned long argument)
483 struct blkfront_info *info = bdev->bd_disk->private_data;
486 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
487 command, (long)argument);
490 case CDROMMULTISESSION:
491 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
492 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
493 if (put_user(0, (char __user *)(argument + i)))
497 case CDROM_GET_CAPABILITY: {
498 struct gendisk *gd = info->gd;
499 if (gd->flags & GENHD_FL_CD)
505 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
507 return -EINVAL; /* same return as native Linux */
513 static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo,
515 struct blkif_request **ring_req)
519 *ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt);
520 rinfo->ring.req_prod_pvt++;
522 id = get_id_from_freelist(rinfo);
523 rinfo->shadow[id].request = req;
524 rinfo->shadow[id].status = REQ_WAITING;
525 rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID;
527 (*ring_req)->u.rw.id = id;
532 static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo)
534 struct blkfront_info *info = rinfo->dev_info;
535 struct blkif_request *ring_req;
538 /* Fill out a communications ring structure. */
539 id = blkif_ring_get_request(rinfo, req, &ring_req);
541 ring_req->operation = BLKIF_OP_DISCARD;
542 ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
543 ring_req->u.discard.id = id;
544 ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);
545 if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
546 ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
548 ring_req->u.discard.flag = 0;
550 /* Keep a private copy so we can reissue requests when recovering. */
551 rinfo->shadow[id].req = *ring_req;
556 struct setup_rw_req {
557 unsigned int grant_idx;
558 struct blkif_request_segment *segments;
559 struct blkfront_ring_info *rinfo;
560 struct blkif_request *ring_req;
561 grant_ref_t gref_head;
563 /* Only used when persistent grant is used and it's a read request */
565 unsigned int bvec_off;
568 bool require_extra_req;
569 struct blkif_request *extra_ring_req;
572 static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset,
573 unsigned int len, void *data)
575 struct setup_rw_req *setup = data;
577 struct grant *gnt_list_entry;
578 unsigned int fsect, lsect;
579 /* Convenient aliases */
580 unsigned int grant_idx = setup->grant_idx;
581 struct blkif_request *ring_req = setup->ring_req;
582 struct blkfront_ring_info *rinfo = setup->rinfo;
584 * We always use the shadow of the first request to store the list
585 * of grant associated to the block I/O request. This made the
586 * completion more easy to handle even if the block I/O request is
589 struct blk_shadow *shadow = &rinfo->shadow[setup->id];
591 if (unlikely(setup->require_extra_req &&
592 grant_idx >= BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
594 * We are using the second request, setup grant_idx
595 * to be the index of the segment array.
597 grant_idx -= BLKIF_MAX_SEGMENTS_PER_REQUEST;
598 ring_req = setup->extra_ring_req;
601 if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
602 (grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) {
604 kunmap_atomic(setup->segments);
606 n = grant_idx / GRANTS_PER_INDIRECT_FRAME;
607 gnt_list_entry = get_indirect_grant(&setup->gref_head, rinfo);
608 shadow->indirect_grants[n] = gnt_list_entry;
609 setup->segments = kmap_atomic(gnt_list_entry->page);
610 ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
613 gnt_list_entry = get_grant(&setup->gref_head, gfn, rinfo);
614 ref = gnt_list_entry->gref;
616 * All the grants are stored in the shadow of the first
617 * request. Therefore we have to use the global index.
619 shadow->grants_used[setup->grant_idx] = gnt_list_entry;
621 if (setup->need_copy) {
624 shared_data = kmap_atomic(gnt_list_entry->page);
626 * this does not wipe data stored outside the
627 * range sg->offset..sg->offset+sg->length.
628 * Therefore, blkback *could* see data from
629 * previous requests. This is OK as long as
630 * persistent grants are shared with just one
631 * domain. It may need refactoring if this
634 memcpy(shared_data + offset,
635 setup->bvec_data + setup->bvec_off,
638 kunmap_atomic(shared_data);
639 setup->bvec_off += len;
643 lsect = fsect + (len >> 9) - 1;
644 if (ring_req->operation != BLKIF_OP_INDIRECT) {
645 ring_req->u.rw.seg[grant_idx] =
646 (struct blkif_request_segment) {
649 .last_sect = lsect };
651 setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] =
652 (struct blkif_request_segment) {
655 .last_sect = lsect };
658 (setup->grant_idx)++;
661 static void blkif_setup_extra_req(struct blkif_request *first,
662 struct blkif_request *second)
664 uint16_t nr_segments = first->u.rw.nr_segments;
667 * The second request is only present when the first request uses
668 * all its segments. It's always the continuity of the first one.
670 first->u.rw.nr_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
672 second->u.rw.nr_segments = nr_segments - BLKIF_MAX_SEGMENTS_PER_REQUEST;
673 second->u.rw.sector_number = first->u.rw.sector_number +
674 (BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) / 512;
676 second->u.rw.handle = first->u.rw.handle;
677 second->operation = first->operation;
680 static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *rinfo)
682 struct blkfront_info *info = rinfo->dev_info;
683 struct blkif_request *ring_req, *extra_ring_req = NULL;
684 unsigned long id, extra_id = NO_ASSOCIATED_ID;
685 bool require_extra_req = false;
687 struct setup_rw_req setup = {
691 .need_copy = rq_data_dir(req) && info->feature_persistent,
695 * Used to store if we are able to queue the request by just using
696 * existing persistent grants, or if we have to get new grants,
697 * as there are not sufficiently many free.
699 struct scatterlist *sg;
700 int num_sg, max_grefs, num_grant;
702 max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG;
703 if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
705 * If we are using indirect segments we need to account
706 * for the indirect grefs used in the request.
708 max_grefs += INDIRECT_GREFS(max_grefs);
711 * We have to reserve 'max_grefs' grants because persistent
712 * grants are shared by all rings.
715 if (gnttab_alloc_grant_references(max_grefs, &setup.gref_head) < 0) {
716 gnttab_request_free_callback(
718 blkif_restart_queue_callback,
724 /* Fill out a communications ring structure. */
725 id = blkif_ring_get_request(rinfo, req, &ring_req);
727 num_sg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg);
729 /* Calculate the number of grant used */
730 for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i)
731 num_grant += gnttab_count_grant(sg->offset, sg->length);
733 require_extra_req = info->max_indirect_segments == 0 &&
734 num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST;
735 BUG_ON(!HAS_EXTRA_REQ && require_extra_req);
737 rinfo->shadow[id].num_sg = num_sg;
738 if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST &&
739 likely(!require_extra_req)) {
741 * The indirect operation can only be a BLKIF_OP_READ or
744 BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA));
745 ring_req->operation = BLKIF_OP_INDIRECT;
746 ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
747 BLKIF_OP_WRITE : BLKIF_OP_READ;
748 ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
749 ring_req->u.indirect.handle = info->handle;
750 ring_req->u.indirect.nr_segments = num_grant;
752 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
753 ring_req->u.rw.handle = info->handle;
754 ring_req->operation = rq_data_dir(req) ?
755 BLKIF_OP_WRITE : BLKIF_OP_READ;
756 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
758 * Ideally we can do an unordered flush-to-disk.
759 * In case the backend onlysupports barriers, use that.
760 * A barrier request a superset of FUA, so we can
761 * implement it the same way. (It's also a FLUSH+FUA,
762 * since it is guaranteed ordered WRT previous writes.)
764 switch (info->feature_flush &
765 ((REQ_FLUSH|REQ_FUA))) {
766 case REQ_FLUSH|REQ_FUA:
767 ring_req->operation =
768 BLKIF_OP_WRITE_BARRIER;
771 ring_req->operation =
772 BLKIF_OP_FLUSH_DISKCACHE;
775 ring_req->operation = 0;
778 ring_req->u.rw.nr_segments = num_grant;
779 if (unlikely(require_extra_req)) {
780 extra_id = blkif_ring_get_request(rinfo, req,
783 * Only the first request contains the scatter-gather
786 rinfo->shadow[extra_id].num_sg = 0;
788 blkif_setup_extra_req(ring_req, extra_ring_req);
790 /* Link the 2 requests together */
791 rinfo->shadow[extra_id].associated_id = id;
792 rinfo->shadow[id].associated_id = extra_id;
796 setup.ring_req = ring_req;
799 setup.require_extra_req = require_extra_req;
800 if (unlikely(require_extra_req))
801 setup.extra_ring_req = extra_ring_req;
803 for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) {
804 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
806 if (setup.need_copy) {
807 setup.bvec_off = sg->offset;
808 setup.bvec_data = kmap_atomic(sg_page(sg));
811 gnttab_foreach_grant_in_range(sg_page(sg),
814 blkif_setup_rw_req_grant,
818 kunmap_atomic(setup.bvec_data);
821 kunmap_atomic(setup.segments);
823 /* Keep a private copy so we can reissue requests when recovering. */
824 rinfo->shadow[id].req = *ring_req;
825 if (unlikely(require_extra_req))
826 rinfo->shadow[extra_id].req = *extra_ring_req;
829 gnttab_free_grant_references(setup.gref_head);
835 * Generate a Xen blkfront IO request from a blk layer request. Reads
836 * and writes are handled as expected.
838 * @req: a request struct
840 static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo)
842 if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED))
845 if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE)))
846 return blkif_queue_discard_req(req, rinfo);
848 return blkif_queue_rw_req(req, rinfo);
851 static inline void flush_requests(struct blkfront_ring_info *rinfo)
855 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify);
858 notify_remote_via_irq(rinfo->irq);
861 static inline bool blkif_request_flush_invalid(struct request *req,
862 struct blkfront_info *info)
864 return ((req->cmd_type != REQ_TYPE_FS) ||
865 ((req->cmd_flags & REQ_FLUSH) &&
866 !(info->feature_flush & REQ_FLUSH)) ||
867 ((req->cmd_flags & REQ_FUA) &&
868 !(info->feature_flush & REQ_FUA)));
871 static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
872 const struct blk_mq_queue_data *qd)
875 struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)hctx->driver_data;
877 blk_mq_start_request(qd->rq);
878 spin_lock_irqsave(&rinfo->ring_lock, flags);
879 if (RING_FULL(&rinfo->ring))
882 if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info))
885 if (blkif_queue_request(qd->rq, rinfo))
888 flush_requests(rinfo);
889 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
890 return BLK_MQ_RQ_QUEUE_OK;
893 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
894 return BLK_MQ_RQ_QUEUE_ERROR;
897 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
898 blk_mq_stop_hw_queue(hctx);
899 return BLK_MQ_RQ_QUEUE_BUSY;
902 static int blk_mq_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
905 struct blkfront_info *info = (struct blkfront_info *)data;
907 BUG_ON(info->nr_rings <= index);
908 hctx->driver_data = &info->rinfo[index];
912 static struct blk_mq_ops blkfront_mq_ops = {
913 .queue_rq = blkif_queue_rq,
914 .map_queue = blk_mq_map_queue,
915 .init_hctx = blk_mq_init_hctx,
918 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
919 unsigned int physical_sector_size,
920 unsigned int segments)
922 struct request_queue *rq;
923 struct blkfront_info *info = gd->private_data;
925 memset(&info->tag_set, 0, sizeof(info->tag_set));
926 info->tag_set.ops = &blkfront_mq_ops;
927 info->tag_set.nr_hw_queues = info->nr_rings;
928 if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) {
930 * When indirect descriptior is not supported, the I/O request
931 * will be split between multiple request in the ring.
932 * To avoid problems when sending the request, divide by
933 * 2 the depth of the queue.
935 info->tag_set.queue_depth = BLK_RING_SIZE(info) / 2;
937 info->tag_set.queue_depth = BLK_RING_SIZE(info);
938 info->tag_set.numa_node = NUMA_NO_NODE;
939 info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
940 info->tag_set.cmd_size = 0;
941 info->tag_set.driver_data = info;
943 if (blk_mq_alloc_tag_set(&info->tag_set))
945 rq = blk_mq_init_queue(&info->tag_set);
947 blk_mq_free_tag_set(&info->tag_set);
951 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
953 if (info->feature_discard) {
954 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
955 blk_queue_max_discard_sectors(rq, get_capacity(gd));
956 rq->limits.discard_granularity = info->discard_granularity;
957 rq->limits.discard_alignment = info->discard_alignment;
958 if (info->feature_secdiscard)
959 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
962 /* Hard sector size and max sectors impersonate the equiv. hardware. */
963 blk_queue_logical_block_size(rq, sector_size);
964 blk_queue_physical_block_size(rq, physical_sector_size);
965 blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512);
967 /* Each segment in a request is up to an aligned page in size. */
968 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
969 blk_queue_max_segment_size(rq, PAGE_SIZE);
971 /* Ensure a merged request will fit in a single I/O ring slot. */
972 blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG);
974 /* Make sure buffer addresses are sector-aligned. */
975 blk_queue_dma_alignment(rq, 511);
977 /* Make sure we don't use bounce buffers. */
978 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
985 static const char *flush_info(unsigned int feature_flush)
987 switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) {
988 case REQ_FLUSH|REQ_FUA:
989 return "barrier: enabled;";
991 return "flush diskcache: enabled;";
993 return "barrier or flush: disabled;";
997 static void xlvbd_flush(struct blkfront_info *info)
999 blk_queue_flush(info->rq, info->feature_flush);
1000 pr_info("blkfront: %s: %s %s %s %s %s\n",
1001 info->gd->disk_name, flush_info(info->feature_flush),
1002 "persistent grants:", info->feature_persistent ?
1003 "enabled;" : "disabled;", "indirect descriptors:",
1004 info->max_indirect_segments ? "enabled;" : "disabled;");
1007 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
1010 major = BLKIF_MAJOR(vdevice);
1011 *minor = BLKIF_MINOR(vdevice);
1013 case XEN_IDE0_MAJOR:
1014 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
1015 *minor = ((*minor / 64) * PARTS_PER_DISK) +
1016 EMULATED_HD_DISK_MINOR_OFFSET;
1018 case XEN_IDE1_MAJOR:
1019 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
1020 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
1021 EMULATED_HD_DISK_MINOR_OFFSET;
1023 case XEN_SCSI_DISK0_MAJOR:
1024 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
1025 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
1027 case XEN_SCSI_DISK1_MAJOR:
1028 case XEN_SCSI_DISK2_MAJOR:
1029 case XEN_SCSI_DISK3_MAJOR:
1030 case XEN_SCSI_DISK4_MAJOR:
1031 case XEN_SCSI_DISK5_MAJOR:
1032 case XEN_SCSI_DISK6_MAJOR:
1033 case XEN_SCSI_DISK7_MAJOR:
1034 *offset = (*minor / PARTS_PER_DISK) +
1035 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
1036 EMULATED_SD_DISK_NAME_OFFSET;
1038 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
1039 EMULATED_SD_DISK_MINOR_OFFSET;
1041 case XEN_SCSI_DISK8_MAJOR:
1042 case XEN_SCSI_DISK9_MAJOR:
1043 case XEN_SCSI_DISK10_MAJOR:
1044 case XEN_SCSI_DISK11_MAJOR:
1045 case XEN_SCSI_DISK12_MAJOR:
1046 case XEN_SCSI_DISK13_MAJOR:
1047 case XEN_SCSI_DISK14_MAJOR:
1048 case XEN_SCSI_DISK15_MAJOR:
1049 *offset = (*minor / PARTS_PER_DISK) +
1050 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
1051 EMULATED_SD_DISK_NAME_OFFSET;
1053 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
1054 EMULATED_SD_DISK_MINOR_OFFSET;
1057 *offset = *minor / PARTS_PER_DISK;
1060 printk(KERN_WARNING "blkfront: your disk configuration is "
1061 "incorrect, please use an xvd device instead\n");
1067 static char *encode_disk_name(char *ptr, unsigned int n)
1070 ptr = encode_disk_name(ptr, n / 26 - 1);
1071 *ptr = 'a' + n % 26;
1075 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
1076 struct blkfront_info *info,
1077 u16 vdisk_info, u16 sector_size,
1078 unsigned int physical_sector_size)
1083 unsigned int offset;
1088 BUG_ON(info->gd != NULL);
1089 BUG_ON(info->rq != NULL);
1091 if ((info->vdevice>>EXT_SHIFT) > 1) {
1092 /* this is above the extended range; something is wrong */
1093 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
1097 if (!VDEV_IS_EXTENDED(info->vdevice)) {
1098 err = xen_translate_vdev(info->vdevice, &minor, &offset);
1101 nr_parts = PARTS_PER_DISK;
1103 minor = BLKIF_MINOR_EXT(info->vdevice);
1104 nr_parts = PARTS_PER_EXT_DISK;
1105 offset = minor / nr_parts;
1106 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
1107 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
1108 "emulated IDE disks,\n\t choose an xvd device name"
1109 "from xvde on\n", info->vdevice);
1111 if (minor >> MINORBITS) {
1112 pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
1113 info->vdevice, minor);
1117 if ((minor % nr_parts) == 0)
1118 nr_minors = nr_parts;
1120 err = xlbd_reserve_minors(minor, nr_minors);
1125 gd = alloc_disk(nr_minors);
1129 strcpy(gd->disk_name, DEV_NAME);
1130 ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
1131 BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
1135 snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
1136 "%d", minor & (nr_parts - 1));
1138 gd->major = XENVBD_MAJOR;
1139 gd->first_minor = minor;
1140 gd->fops = &xlvbd_block_fops;
1141 gd->private_data = info;
1142 gd->driverfs_dev = &(info->xbdev->dev);
1143 set_capacity(gd, capacity);
1145 if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size,
1146 info->max_indirect_segments ? :
1147 BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
1152 info->rq = gd->queue;
1157 if (vdisk_info & VDISK_READONLY)
1160 if (vdisk_info & VDISK_REMOVABLE)
1161 gd->flags |= GENHD_FL_REMOVABLE;
1163 if (vdisk_info & VDISK_CDROM)
1164 gd->flags |= GENHD_FL_CD;
1169 xlbd_release_minors(minor, nr_minors);
1174 static void xlvbd_release_gendisk(struct blkfront_info *info)
1176 unsigned int minor, nr_minors, i;
1178 if (info->rq == NULL)
1181 /* No more blkif_request(). */
1182 blk_mq_stop_hw_queues(info->rq);
1184 for (i = 0; i < info->nr_rings; i++) {
1185 struct blkfront_ring_info *rinfo = &info->rinfo[i];
1187 /* No more gnttab callback work. */
1188 gnttab_cancel_free_callback(&rinfo->callback);
1190 /* Flush gnttab callback work. Must be done with no locks held. */
1191 flush_work(&rinfo->work);
1194 del_gendisk(info->gd);
1196 minor = info->gd->first_minor;
1197 nr_minors = info->gd->minors;
1198 xlbd_release_minors(minor, nr_minors);
1200 blk_cleanup_queue(info->rq);
1201 blk_mq_free_tag_set(&info->tag_set);
1208 /* Already hold rinfo->ring_lock. */
1209 static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo)
1211 if (!RING_FULL(&rinfo->ring))
1212 blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true);
1215 static void kick_pending_request_queues(struct blkfront_ring_info *rinfo)
1217 unsigned long flags;
1219 spin_lock_irqsave(&rinfo->ring_lock, flags);
1220 kick_pending_request_queues_locked(rinfo);
1221 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
1224 static void blkif_restart_queue(struct work_struct *work)
1226 struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work);
1228 if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED)
1229 kick_pending_request_queues(rinfo);
1232 static void blkif_free_ring(struct blkfront_ring_info *rinfo)
1234 struct grant *persistent_gnt, *n;
1235 struct blkfront_info *info = rinfo->dev_info;
1239 * Remove indirect pages, this only happens when using indirect
1240 * descriptors but not persistent grants
1242 if (!list_empty(&rinfo->indirect_pages)) {
1243 struct page *indirect_page, *n;
1245 BUG_ON(info->feature_persistent);
1246 list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
1247 list_del(&indirect_page->lru);
1248 __free_page(indirect_page);
1252 /* Remove all persistent grants. */
1253 if (!list_empty(&rinfo->grants)) {
1254 list_for_each_entry_safe(persistent_gnt, n,
1255 &rinfo->grants, node) {
1256 list_del(&persistent_gnt->node);
1257 if (persistent_gnt->gref != GRANT_INVALID_REF) {
1258 gnttab_end_foreign_access(persistent_gnt->gref,
1260 rinfo->persistent_gnts_c--;
1262 if (info->feature_persistent)
1263 __free_page(persistent_gnt->page);
1264 kfree(persistent_gnt);
1267 BUG_ON(rinfo->persistent_gnts_c != 0);
1269 for (i = 0; i < BLK_RING_SIZE(info); i++) {
1271 * Clear persistent grants present in requests already
1272 * on the shared ring
1274 if (!rinfo->shadow[i].request)
1277 segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
1278 rinfo->shadow[i].req.u.indirect.nr_segments :
1279 rinfo->shadow[i].req.u.rw.nr_segments;
1280 for (j = 0; j < segs; j++) {
1281 persistent_gnt = rinfo->shadow[i].grants_used[j];
1282 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
1283 if (info->feature_persistent)
1284 __free_page(persistent_gnt->page);
1285 kfree(persistent_gnt);
1288 if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT)
1290 * If this is not an indirect operation don't try to
1291 * free indirect segments
1295 for (j = 0; j < INDIRECT_GREFS(segs); j++) {
1296 persistent_gnt = rinfo->shadow[i].indirect_grants[j];
1297 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
1298 __free_page(persistent_gnt->page);
1299 kfree(persistent_gnt);
1303 kfree(rinfo->shadow[i].grants_used);
1304 rinfo->shadow[i].grants_used = NULL;
1305 kfree(rinfo->shadow[i].indirect_grants);
1306 rinfo->shadow[i].indirect_grants = NULL;
1307 kfree(rinfo->shadow[i].sg);
1308 rinfo->shadow[i].sg = NULL;
1311 /* No more gnttab callback work. */
1312 gnttab_cancel_free_callback(&rinfo->callback);
1314 /* Flush gnttab callback work. Must be done with no locks held. */
1315 flush_work(&rinfo->work);
1317 /* Free resources associated with old device channel. */
1318 for (i = 0; i < info->nr_ring_pages; i++) {
1319 if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
1320 gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
1321 rinfo->ring_ref[i] = GRANT_INVALID_REF;
1324 free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * PAGE_SIZE));
1325 rinfo->ring.sring = NULL;
1328 unbind_from_irqhandler(rinfo->irq, rinfo);
1329 rinfo->evtchn = rinfo->irq = 0;
1332 static void blkif_free(struct blkfront_info *info, int suspend)
1336 /* Prevent new requests being issued until we fix things up. */
1337 info->connected = suspend ?
1338 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
1339 /* No more blkif_request(). */
1341 blk_mq_stop_hw_queues(info->rq);
1343 for (i = 0; i < info->nr_rings; i++)
1344 blkif_free_ring(&info->rinfo[i]);
1351 struct copy_from_grant {
1352 const struct blk_shadow *s;
1353 unsigned int grant_idx;
1354 unsigned int bvec_offset;
1358 static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset,
1359 unsigned int len, void *data)
1361 struct copy_from_grant *info = data;
1363 /* Convenient aliases */
1364 const struct blk_shadow *s = info->s;
1366 shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page);
1368 memcpy(info->bvec_data + info->bvec_offset,
1369 shared_data + offset, len);
1371 info->bvec_offset += len;
1374 kunmap_atomic(shared_data);
1377 static enum blk_req_status blkif_rsp_to_req_status(int rsp)
1381 case BLKIF_RSP_OKAY:
1383 case BLKIF_RSP_EOPNOTSUPP:
1384 return REQ_EOPNOTSUPP;
1385 case BLKIF_RSP_ERROR:
1393 * Get the final status of the block request based on two ring response
1395 static int blkif_get_final_status(enum blk_req_status s1,
1396 enum blk_req_status s2)
1398 BUG_ON(s1 == REQ_WAITING);
1399 BUG_ON(s2 == REQ_WAITING);
1401 if (s1 == REQ_ERROR || s2 == REQ_ERROR)
1402 return BLKIF_RSP_ERROR;
1403 else if (s1 == REQ_EOPNOTSUPP || s2 == REQ_EOPNOTSUPP)
1404 return BLKIF_RSP_EOPNOTSUPP;
1405 return BLKIF_RSP_OKAY;
1408 static bool blkif_completion(unsigned long *id,
1409 struct blkfront_ring_info *rinfo,
1410 struct blkif_response *bret)
1413 struct scatterlist *sg;
1414 int num_sg, num_grant;
1415 struct blkfront_info *info = rinfo->dev_info;
1416 struct blk_shadow *s = &rinfo->shadow[*id];
1417 struct copy_from_grant data = {
1421 num_grant = s->req.operation == BLKIF_OP_INDIRECT ?
1422 s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
1424 /* The I/O request may be split in two. */
1425 if (unlikely(s->associated_id != NO_ASSOCIATED_ID)) {
1426 struct blk_shadow *s2 = &rinfo->shadow[s->associated_id];
1428 /* Keep the status of the current response in shadow. */
1429 s->status = blkif_rsp_to_req_status(bret->status);
1431 /* Wait the second response if not yet here. */
1432 if (s2->status == REQ_WAITING)
1435 bret->status = blkif_get_final_status(s->status,
1439 * All the grants is stored in the first shadow in order
1440 * to make the completion code simpler.
1442 num_grant += s2->req.u.rw.nr_segments;
1445 * The two responses may not come in order. Only the
1446 * first request will store the scatter-gather list.
1448 if (s2->num_sg != 0) {
1449 /* Update "id" with the ID of the first response. */
1450 *id = s->associated_id;
1455 * We don't need anymore the second request, so recycling
1458 if (add_id_to_freelist(rinfo, s->associated_id))
1459 WARN(1, "%s: can't recycle the second part (id = %ld) of the request\n",
1460 info->gd->disk_name, s->associated_id);
1466 if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
1467 for_each_sg(s->sg, sg, num_sg, i) {
1468 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
1470 data.bvec_offset = sg->offset;
1471 data.bvec_data = kmap_atomic(sg_page(sg));
1473 gnttab_foreach_grant_in_range(sg_page(sg),
1476 blkif_copy_from_grant,
1479 kunmap_atomic(data.bvec_data);
1482 /* Add the persistent grant into the list of free grants */
1483 for (i = 0; i < num_grant; i++) {
1484 if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
1486 * If the grant is still mapped by the backend (the
1487 * backend has chosen to make this grant persistent)
1488 * we add it at the head of the list, so it will be
1491 if (!info->feature_persistent)
1492 pr_alert_ratelimited("backed has not unmapped grant: %u\n",
1493 s->grants_used[i]->gref);
1494 list_add(&s->grants_used[i]->node, &rinfo->grants);
1495 rinfo->persistent_gnts_c++;
1498 * If the grant is not mapped by the backend we end the
1499 * foreign access and add it to the tail of the list,
1500 * so it will not be picked again unless we run out of
1501 * persistent grants.
1503 gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
1504 s->grants_used[i]->gref = GRANT_INVALID_REF;
1505 list_add_tail(&s->grants_used[i]->node, &rinfo->grants);
1508 if (s->req.operation == BLKIF_OP_INDIRECT) {
1509 for (i = 0; i < INDIRECT_GREFS(num_grant); i++) {
1510 if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
1511 if (!info->feature_persistent)
1512 pr_alert_ratelimited("backed has not unmapped grant: %u\n",
1513 s->indirect_grants[i]->gref);
1514 list_add(&s->indirect_grants[i]->node, &rinfo->grants);
1515 rinfo->persistent_gnts_c++;
1517 struct page *indirect_page;
1519 gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
1521 * Add the used indirect page back to the list of
1522 * available pages for indirect grefs.
1524 if (!info->feature_persistent) {
1525 indirect_page = s->indirect_grants[i]->page;
1526 list_add(&indirect_page->lru, &rinfo->indirect_pages);
1528 s->indirect_grants[i]->gref = GRANT_INVALID_REF;
1529 list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants);
1537 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
1539 struct request *req;
1540 struct blkif_response *bret;
1542 unsigned long flags;
1543 struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id;
1544 struct blkfront_info *info = rinfo->dev_info;
1547 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
1550 spin_lock_irqsave(&rinfo->ring_lock, flags);
1552 rp = rinfo->ring.sring->rsp_prod;
1553 rmb(); /* Ensure we see queued responses up to 'rp'. */
1555 for (i = rinfo->ring.rsp_cons; i != rp; i++) {
1558 bret = RING_GET_RESPONSE(&rinfo->ring, i);
1561 * The backend has messed up and given us an id that we would
1562 * never have given to it (we stamp it up to BLK_RING_SIZE -
1563 * look in get_id_from_freelist.
1565 if (id >= BLK_RING_SIZE(info)) {
1566 WARN(1, "%s: response to %s has incorrect id (%ld)\n",
1567 info->gd->disk_name, op_name(bret->operation), id);
1568 /* We can't safely get the 'struct request' as
1569 * the id is busted. */
1572 req = rinfo->shadow[id].request;
1574 if (bret->operation != BLKIF_OP_DISCARD) {
1576 * We may need to wait for an extra response if the
1577 * I/O request is split in 2
1579 if (!blkif_completion(&id, rinfo, bret))
1583 if (add_id_to_freelist(rinfo, id)) {
1584 WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
1585 info->gd->disk_name, op_name(bret->operation), id);
1589 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
1590 switch (bret->operation) {
1591 case BLKIF_OP_DISCARD:
1592 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
1593 struct request_queue *rq = info->rq;
1594 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
1595 info->gd->disk_name, op_name(bret->operation));
1596 error = -EOPNOTSUPP;
1597 info->feature_discard = 0;
1598 info->feature_secdiscard = 0;
1599 queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
1600 queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
1602 blk_mq_complete_request(req, error);
1604 case BLKIF_OP_FLUSH_DISKCACHE:
1605 case BLKIF_OP_WRITE_BARRIER:
1606 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
1607 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
1608 info->gd->disk_name, op_name(bret->operation));
1609 error = -EOPNOTSUPP;
1611 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
1612 rinfo->shadow[id].req.u.rw.nr_segments == 0)) {
1613 printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
1614 info->gd->disk_name, op_name(bret->operation));
1615 error = -EOPNOTSUPP;
1617 if (unlikely(error)) {
1618 if (error == -EOPNOTSUPP)
1620 info->feature_flush = 0;
1625 case BLKIF_OP_WRITE:
1626 if (unlikely(bret->status != BLKIF_RSP_OKAY))
1627 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
1628 "request: %x\n", bret->status);
1630 blk_mq_complete_request(req, error);
1637 rinfo->ring.rsp_cons = i;
1639 if (i != rinfo->ring.req_prod_pvt) {
1641 RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do);
1645 rinfo->ring.sring->rsp_event = i + 1;
1647 kick_pending_request_queues_locked(rinfo);
1649 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
1655 static int setup_blkring(struct xenbus_device *dev,
1656 struct blkfront_ring_info *rinfo)
1658 struct blkif_sring *sring;
1660 struct blkfront_info *info = rinfo->dev_info;
1661 unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE;
1662 grant_ref_t gref[XENBUS_MAX_RING_GRANTS];
1664 for (i = 0; i < info->nr_ring_pages; i++)
1665 rinfo->ring_ref[i] = GRANT_INVALID_REF;
1667 sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
1668 get_order(ring_size));
1670 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
1673 SHARED_RING_INIT(sring);
1674 FRONT_RING_INIT(&rinfo->ring, sring, ring_size);
1676 err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref);
1678 free_pages((unsigned long)sring, get_order(ring_size));
1679 rinfo->ring.sring = NULL;
1682 for (i = 0; i < info->nr_ring_pages; i++)
1683 rinfo->ring_ref[i] = gref[i];
1685 err = xenbus_alloc_evtchn(dev, &rinfo->evtchn);
1689 err = bind_evtchn_to_irqhandler(rinfo->evtchn, blkif_interrupt, 0,
1692 xenbus_dev_fatal(dev, err,
1693 "bind_evtchn_to_irqhandler failed");
1700 blkif_free(info, 0);
1705 * Write out per-ring/queue nodes including ring-ref and event-channel, and each
1706 * ring buffer may have multi pages depending on ->nr_ring_pages.
1708 static int write_per_ring_nodes(struct xenbus_transaction xbt,
1709 struct blkfront_ring_info *rinfo, const char *dir)
1713 const char *message = NULL;
1714 struct blkfront_info *info = rinfo->dev_info;
1716 if (info->nr_ring_pages == 1) {
1717 err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]);
1719 message = "writing ring-ref";
1720 goto abort_transaction;
1723 for (i = 0; i < info->nr_ring_pages; i++) {
1724 char ring_ref_name[RINGREF_NAME_LEN];
1726 snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
1727 err = xenbus_printf(xbt, dir, ring_ref_name,
1728 "%u", rinfo->ring_ref[i]);
1730 message = "writing ring-ref";
1731 goto abort_transaction;
1736 err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
1738 message = "writing event-channel";
1739 goto abort_transaction;
1745 xenbus_transaction_end(xbt, 1);
1747 xenbus_dev_fatal(info->xbdev, err, "%s", message);
1752 /* Common code used when first setting up, and when resuming. */
1753 static int talk_to_blkback(struct xenbus_device *dev,
1754 struct blkfront_info *info)
1756 const char *message = NULL;
1757 struct xenbus_transaction xbt;
1759 unsigned int i, max_page_order = 0;
1760 unsigned int ring_page_order = 0;
1762 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1763 "max-ring-page-order", "%u", &max_page_order);
1765 info->nr_ring_pages = 1;
1767 ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
1768 info->nr_ring_pages = 1 << ring_page_order;
1771 for (i = 0; i < info->nr_rings; i++) {
1772 struct blkfront_ring_info *rinfo = &info->rinfo[i];
1774 /* Create shared ring, alloc event channel. */
1775 err = setup_blkring(dev, rinfo);
1777 goto destroy_blkring;
1781 err = xenbus_transaction_start(&xbt);
1783 xenbus_dev_fatal(dev, err, "starting transaction");
1784 goto destroy_blkring;
1787 if (info->nr_ring_pages > 1) {
1788 err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u",
1791 message = "writing ring-page-order";
1792 goto abort_transaction;
1796 /* We already got the number of queues/rings in _probe */
1797 if (info->nr_rings == 1) {
1798 err = write_per_ring_nodes(xbt, &info->rinfo[0], dev->nodename);
1800 goto destroy_blkring;
1805 err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u",
1808 message = "writing multi-queue-num-queues";
1809 goto abort_transaction;
1812 pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN;
1813 path = kmalloc(pathsize, GFP_KERNEL);
1816 message = "ENOMEM while writing ring references";
1817 goto abort_transaction;
1820 for (i = 0; i < info->nr_rings; i++) {
1821 memset(path, 0, pathsize);
1822 snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i);
1823 err = write_per_ring_nodes(xbt, &info->rinfo[i], path);
1826 goto destroy_blkring;
1831 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
1832 XEN_IO_PROTO_ABI_NATIVE);
1834 message = "writing protocol";
1835 goto abort_transaction;
1837 err = xenbus_printf(xbt, dev->nodename,
1838 "feature-persistent", "%u", 1);
1841 "writing persistent grants feature to xenbus");
1843 err = xenbus_transaction_end(xbt, 0);
1847 xenbus_dev_fatal(dev, err, "completing transaction");
1848 goto destroy_blkring;
1851 for (i = 0; i < info->nr_rings; i++) {
1853 struct blkfront_ring_info *rinfo = &info->rinfo[i];
1855 for (j = 0; j < BLK_RING_SIZE(info); j++)
1856 rinfo->shadow[j].req.u.rw.id = j + 1;
1857 rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
1859 xenbus_switch_state(dev, XenbusStateInitialised);
1864 xenbus_transaction_end(xbt, 1);
1866 xenbus_dev_fatal(dev, err, "%s", message);
1868 blkif_free(info, 0);
1871 dev_set_drvdata(&dev->dev, NULL);
1876 static int negotiate_mq(struct blkfront_info *info)
1878 unsigned int backend_max_queues = 0;
1882 BUG_ON(info->nr_rings);
1884 /* Check if backend supports multiple queues. */
1885 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1886 "multi-queue-max-queues", "%u", &backend_max_queues);
1888 backend_max_queues = 1;
1890 info->nr_rings = min(backend_max_queues, xen_blkif_max_queues);
1891 /* We need at least one ring. */
1892 if (!info->nr_rings)
1895 info->rinfo = kzalloc(sizeof(struct blkfront_ring_info) * info->nr_rings, GFP_KERNEL);
1897 xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure");
1901 for (i = 0; i < info->nr_rings; i++) {
1902 struct blkfront_ring_info *rinfo;
1904 rinfo = &info->rinfo[i];
1905 INIT_LIST_HEAD(&rinfo->indirect_pages);
1906 INIT_LIST_HEAD(&rinfo->grants);
1907 rinfo->dev_info = info;
1908 INIT_WORK(&rinfo->work, blkif_restart_queue);
1909 spin_lock_init(&rinfo->ring_lock);
1914 * Entry point to this code when a new device is created. Allocate the basic
1915 * structures and the ring buffer for communication with the backend, and
1916 * inform the backend of the appropriate details for those. Switch to
1917 * Initialised state.
1919 static int blkfront_probe(struct xenbus_device *dev,
1920 const struct xenbus_device_id *id)
1923 struct blkfront_info *info;
1925 /* FIXME: Use dynamic device id if this is not set. */
1926 err = xenbus_scanf(XBT_NIL, dev->nodename,
1927 "virtual-device", "%i", &vdevice);
1929 /* go looking in the extended area instead */
1930 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
1933 xenbus_dev_fatal(dev, err, "reading virtual-device");
1938 if (xen_hvm_domain()) {
1941 /* no unplug has been done: do not hook devices != xen vbds */
1942 if (xen_has_pv_and_legacy_disk_devices()) {
1945 if (!VDEV_IS_EXTENDED(vdevice))
1946 major = BLKIF_MAJOR(vdevice);
1948 major = XENVBD_MAJOR;
1950 if (major != XENVBD_MAJOR) {
1952 "%s: HVM does not support vbd %d as xen block device\n",
1957 /* do not create a PV cdrom device if we are an HVM guest */
1958 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
1961 if (strncmp(type, "cdrom", 5) == 0) {
1967 info = kzalloc(sizeof(*info), GFP_KERNEL);
1969 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
1974 err = negotiate_mq(info);
1980 mutex_init(&info->mutex);
1981 info->vdevice = vdevice;
1982 info->connected = BLKIF_STATE_DISCONNECTED;
1984 /* Front end dir is a number, which is used as the id. */
1985 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
1986 dev_set_drvdata(&dev->dev, info);
1991 static void split_bio_end(struct bio *bio)
1993 struct split_bio *split_bio = bio->bi_private;
1995 if (atomic_dec_and_test(&split_bio->pending)) {
1996 split_bio->bio->bi_phys_segments = 0;
1997 split_bio->bio->bi_error = bio->bi_error;
1998 bio_endio(split_bio->bio);
2004 static int blkif_recover(struct blkfront_info *info)
2006 unsigned int i, r_index;
2007 struct request *req, *n;
2008 struct blk_shadow *copy;
2010 struct bio *bio, *cloned_bio;
2011 struct bio_list bio_list, merge_bio;
2012 unsigned int segs, offset;
2014 struct split_bio *split_bio;
2015 struct list_head requests;
2017 blkfront_gather_backend_features(info);
2018 segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
2019 blk_queue_max_segments(info->rq, segs);
2020 bio_list_init(&bio_list);
2021 INIT_LIST_HEAD(&requests);
2023 for (r_index = 0; r_index < info->nr_rings; r_index++) {
2024 struct blkfront_ring_info *rinfo;
2026 rinfo = &info->rinfo[r_index];
2027 /* Stage 1: Make a safe copy of the shadow state. */
2028 copy = kmemdup(rinfo->shadow, sizeof(rinfo->shadow),
2029 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
2033 /* Stage 2: Set up free list. */
2034 memset(&rinfo->shadow, 0, sizeof(rinfo->shadow));
2035 for (i = 0; i < BLK_RING_SIZE(info); i++)
2036 rinfo->shadow[i].req.u.rw.id = i+1;
2037 rinfo->shadow_free = rinfo->ring.req_prod_pvt;
2038 rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
2040 rc = blkfront_setup_indirect(rinfo);
2046 for (i = 0; i < BLK_RING_SIZE(info); i++) {
2048 if (!copy[i].request)
2052 * Get the bios in the request so we can re-queue them.
2054 if (copy[i].request->cmd_flags &
2055 (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
2057 * Flush operations don't contain bios, so
2058 * we need to requeue the whole request
2060 list_add(©[i].request->queuelist, &requests);
2063 merge_bio.head = copy[i].request->bio;
2064 merge_bio.tail = copy[i].request->biotail;
2065 bio_list_merge(&bio_list, &merge_bio);
2066 copy[i].request->bio = NULL;
2067 blk_end_request_all(copy[i].request, 0);
2072 xenbus_switch_state(info->xbdev, XenbusStateConnected);
2074 /* Now safe for us to use the shared ring */
2075 info->connected = BLKIF_STATE_CONNECTED;
2077 for (r_index = 0; r_index < info->nr_rings; r_index++) {
2078 struct blkfront_ring_info *rinfo;
2080 rinfo = &info->rinfo[r_index];
2081 /* Kick any other new requests queued since we resumed */
2082 kick_pending_request_queues(rinfo);
2085 list_for_each_entry_safe(req, n, &requests, queuelist) {
2086 /* Requeue pending requests (flush or discard) */
2087 list_del_init(&req->queuelist);
2088 BUG_ON(req->nr_phys_segments > segs);
2089 blk_mq_requeue_request(req);
2091 blk_mq_kick_requeue_list(info->rq);
2093 while ((bio = bio_list_pop(&bio_list)) != NULL) {
2094 /* Traverse the list of pending bios and re-queue them */
2095 if (bio_segments(bio) > segs) {
2097 * This bio has more segments than what we can
2098 * handle, we have to split it.
2100 pending = (bio_segments(bio) + segs - 1) / segs;
2101 split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO);
2102 BUG_ON(split_bio == NULL);
2103 atomic_set(&split_bio->pending, pending);
2104 split_bio->bio = bio;
2105 for (i = 0; i < pending; i++) {
2106 offset = (i * segs * XEN_PAGE_SIZE) >> 9;
2107 size = min((unsigned int)(segs * XEN_PAGE_SIZE) >> 9,
2108 (unsigned int)bio_sectors(bio) - offset);
2109 cloned_bio = bio_clone(bio, GFP_NOIO);
2110 BUG_ON(cloned_bio == NULL);
2111 bio_trim(cloned_bio, offset, size);
2112 cloned_bio->bi_private = split_bio;
2113 cloned_bio->bi_end_io = split_bio_end;
2114 submit_bio(cloned_bio->bi_rw, cloned_bio);
2117 * Now we have to wait for all those smaller bios to
2118 * end, so we can also end the "parent" bio.
2122 /* We don't need to split this bio */
2123 submit_bio(bio->bi_rw, bio);
2130 * We are reconnecting to the backend, due to a suspend/resume, or a backend
2131 * driver restart. We tear down our blkif structure and recreate it, but
2132 * leave the device-layer structures intact so that this is transparent to the
2133 * rest of the kernel.
2135 static int blkfront_resume(struct xenbus_device *dev)
2137 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
2140 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
2142 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
2144 err = negotiate_mq(info);
2148 err = talk_to_blkback(dev, info);
2151 * We have to wait for the backend to switch to
2152 * connected state, since we want to read which
2153 * features it supports.
2159 static void blkfront_closing(struct blkfront_info *info)
2161 struct xenbus_device *xbdev = info->xbdev;
2162 struct block_device *bdev = NULL;
2164 mutex_lock(&info->mutex);
2166 if (xbdev->state == XenbusStateClosing) {
2167 mutex_unlock(&info->mutex);
2172 bdev = bdget_disk(info->gd, 0);
2174 mutex_unlock(&info->mutex);
2177 xenbus_frontend_closed(xbdev);
2181 mutex_lock(&bdev->bd_mutex);
2183 if (bdev->bd_openers) {
2184 xenbus_dev_error(xbdev, -EBUSY,
2185 "Device in use; refusing to close");
2186 xenbus_switch_state(xbdev, XenbusStateClosing);
2188 xlvbd_release_gendisk(info);
2189 xenbus_frontend_closed(xbdev);
2192 mutex_unlock(&bdev->bd_mutex);
2196 static void blkfront_setup_discard(struct blkfront_info *info)
2199 unsigned int discard_granularity;
2200 unsigned int discard_alignment;
2201 unsigned int discard_secure;
2203 info->feature_discard = 1;
2204 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2205 "discard-granularity", "%u", &discard_granularity,
2206 "discard-alignment", "%u", &discard_alignment,
2209 info->discard_granularity = discard_granularity;
2210 info->discard_alignment = discard_alignment;
2212 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2213 "discard-secure", "%d", &discard_secure,
2216 info->feature_secdiscard = !!discard_secure;
2219 static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
2221 unsigned int psegs, grants;
2223 struct blkfront_info *info = rinfo->dev_info;
2225 if (info->max_indirect_segments == 0) {
2227 grants = BLKIF_MAX_SEGMENTS_PER_REQUEST;
2230 * When an extra req is required, the maximum
2231 * grants supported is related to the size of the
2232 * Linux block segment.
2234 grants = GRANTS_PER_PSEG;
2238 grants = info->max_indirect_segments;
2239 psegs = grants / GRANTS_PER_PSEG;
2241 err = fill_grant_buffer(rinfo,
2242 (grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info));
2246 if (!info->feature_persistent && info->max_indirect_segments) {
2248 * We are using indirect descriptors but not persistent
2249 * grants, we need to allocate a set of pages that can be
2250 * used for mapping indirect grefs
2252 int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info);
2254 BUG_ON(!list_empty(&rinfo->indirect_pages));
2255 for (i = 0; i < num; i++) {
2256 struct page *indirect_page = alloc_page(GFP_NOIO);
2259 list_add(&indirect_page->lru, &rinfo->indirect_pages);
2263 for (i = 0; i < BLK_RING_SIZE(info); i++) {
2264 rinfo->shadow[i].grants_used = kzalloc(
2265 sizeof(rinfo->shadow[i].grants_used[0]) * grants,
2267 rinfo->shadow[i].sg = kzalloc(sizeof(rinfo->shadow[i].sg[0]) * psegs, GFP_NOIO);
2268 if (info->max_indirect_segments)
2269 rinfo->shadow[i].indirect_grants = kzalloc(
2270 sizeof(rinfo->shadow[i].indirect_grants[0]) *
2271 INDIRECT_GREFS(grants),
2273 if ((rinfo->shadow[i].grants_used == NULL) ||
2274 (rinfo->shadow[i].sg == NULL) ||
2275 (info->max_indirect_segments &&
2276 (rinfo->shadow[i].indirect_grants == NULL)))
2278 sg_init_table(rinfo->shadow[i].sg, psegs);
2285 for (i = 0; i < BLK_RING_SIZE(info); i++) {
2286 kfree(rinfo->shadow[i].grants_used);
2287 rinfo->shadow[i].grants_used = NULL;
2288 kfree(rinfo->shadow[i].sg);
2289 rinfo->shadow[i].sg = NULL;
2290 kfree(rinfo->shadow[i].indirect_grants);
2291 rinfo->shadow[i].indirect_grants = NULL;
2293 if (!list_empty(&rinfo->indirect_pages)) {
2294 struct page *indirect_page, *n;
2295 list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
2296 list_del(&indirect_page->lru);
2297 __free_page(indirect_page);
2304 * Gather all backend feature-*
2306 static void blkfront_gather_backend_features(struct blkfront_info *info)
2309 int barrier, flush, discard, persistent;
2310 unsigned int indirect_segments;
2312 info->feature_flush = 0;
2314 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2315 "feature-barrier", "%d", &barrier,
2319 * If there's no "feature-barrier" defined, then it means
2320 * we're dealing with a very old backend which writes
2321 * synchronously; nothing to do.
2323 * If there are barriers, then we use flush.
2325 if (!err && barrier)
2326 info->feature_flush = REQ_FLUSH | REQ_FUA;
2328 * And if there is "feature-flush-cache" use that above
2331 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2332 "feature-flush-cache", "%d", &flush,
2336 info->feature_flush = REQ_FLUSH;
2338 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2339 "feature-discard", "%d", &discard,
2342 if (!err && discard)
2343 blkfront_setup_discard(info);
2345 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2346 "feature-persistent", "%u", &persistent,
2349 info->feature_persistent = 0;
2351 info->feature_persistent = persistent;
2353 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2354 "feature-max-indirect-segments", "%u", &indirect_segments,
2357 info->max_indirect_segments = 0;
2359 info->max_indirect_segments = min(indirect_segments,
2360 xen_blkif_max_segments);
2364 * Invoked when the backend is finally 'ready' (and has told produced
2365 * the details about the physical device - #sectors, size, etc).
2367 static void blkfront_connect(struct blkfront_info *info)
2369 unsigned long long sectors;
2370 unsigned long sector_size;
2371 unsigned int physical_sector_size;
2375 switch (info->connected) {
2376 case BLKIF_STATE_CONNECTED:
2378 * Potentially, the back-end may be signalling
2379 * a capacity change; update the capacity.
2381 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
2382 "sectors", "%Lu", §ors);
2383 if (XENBUS_EXIST_ERR(err))
2385 printk(KERN_INFO "Setting capacity to %Lu\n",
2387 set_capacity(info->gd, sectors);
2388 revalidate_disk(info->gd);
2391 case BLKIF_STATE_SUSPENDED:
2393 * If we are recovering from suspension, we need to wait
2394 * for the backend to announce it's features before
2395 * reconnecting, at least we need to know if the backend
2396 * supports indirect descriptors, and how many.
2398 blkif_recover(info);
2405 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
2406 __func__, info->xbdev->otherend);
2408 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2409 "sectors", "%llu", §ors,
2410 "info", "%u", &binfo,
2411 "sector-size", "%lu", §or_size,
2414 xenbus_dev_fatal(info->xbdev, err,
2415 "reading backend fields at %s",
2416 info->xbdev->otherend);
2421 * physcial-sector-size is a newer field, so old backends may not
2422 * provide this. Assume physical sector size to be the same as
2423 * sector_size in that case.
2425 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
2426 "physical-sector-size", "%u", &physical_sector_size);
2428 physical_sector_size = sector_size;
2430 blkfront_gather_backend_features(info);
2431 for (i = 0; i < info->nr_rings; i++) {
2432 err = blkfront_setup_indirect(&info->rinfo[i]);
2434 xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
2435 info->xbdev->otherend);
2436 blkif_free(info, 0);
2441 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
2442 physical_sector_size);
2444 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
2445 info->xbdev->otherend);
2449 xenbus_switch_state(info->xbdev, XenbusStateConnected);
2451 /* Kick pending requests. */
2452 info->connected = BLKIF_STATE_CONNECTED;
2453 for (i = 0; i < info->nr_rings; i++)
2454 kick_pending_request_queues(&info->rinfo[i]);
2462 * Callback received when the backend's state changes.
2464 static void blkback_changed(struct xenbus_device *dev,
2465 enum xenbus_state backend_state)
2467 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
2469 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
2471 switch (backend_state) {
2472 case XenbusStateInitWait:
2473 if (dev->state != XenbusStateInitialising)
2475 if (talk_to_blkback(dev, info))
2477 case XenbusStateInitialising:
2478 case XenbusStateInitialised:
2479 case XenbusStateReconfiguring:
2480 case XenbusStateReconfigured:
2481 case XenbusStateUnknown:
2484 case XenbusStateConnected:
2485 if (dev->state != XenbusStateInitialised) {
2486 if (talk_to_blkback(dev, info))
2489 blkfront_connect(info);
2492 case XenbusStateClosed:
2493 if (dev->state == XenbusStateClosed)
2495 /* Missed the backend's Closing state -- fallthrough */
2496 case XenbusStateClosing:
2498 blkfront_closing(info);
2503 static int blkfront_remove(struct xenbus_device *xbdev)
2505 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
2506 struct block_device *bdev = NULL;
2507 struct gendisk *disk;
2509 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
2511 blkif_free(info, 0);
2513 mutex_lock(&info->mutex);
2517 bdev = bdget_disk(disk, 0);
2520 mutex_unlock(&info->mutex);
2528 * The xbdev was removed before we reached the Closed
2529 * state. See if it's safe to remove the disk. If the bdev
2530 * isn't closed yet, we let release take care of it.
2533 mutex_lock(&bdev->bd_mutex);
2534 info = disk->private_data;
2536 dev_warn(disk_to_dev(disk),
2537 "%s was hot-unplugged, %d stale handles\n",
2538 xbdev->nodename, bdev->bd_openers);
2540 if (info && !bdev->bd_openers) {
2541 xlvbd_release_gendisk(info);
2542 disk->private_data = NULL;
2546 mutex_unlock(&bdev->bd_mutex);
2552 static int blkfront_is_ready(struct xenbus_device *dev)
2554 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
2556 return info->is_ready && info->xbdev;
2559 static int blkif_open(struct block_device *bdev, fmode_t mode)
2561 struct gendisk *disk = bdev->bd_disk;
2562 struct blkfront_info *info;
2565 mutex_lock(&blkfront_mutex);
2567 info = disk->private_data;
2574 mutex_lock(&info->mutex);
2577 /* xbdev is closed */
2580 mutex_unlock(&info->mutex);
2583 mutex_unlock(&blkfront_mutex);
2587 static void blkif_release(struct gendisk *disk, fmode_t mode)
2589 struct blkfront_info *info = disk->private_data;
2590 struct block_device *bdev;
2591 struct xenbus_device *xbdev;
2593 mutex_lock(&blkfront_mutex);
2595 bdev = bdget_disk(disk, 0);
2598 WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
2601 if (bdev->bd_openers)
2605 * Check if we have been instructed to close. We will have
2606 * deferred this request, because the bdev was still open.
2609 mutex_lock(&info->mutex);
2610 xbdev = info->xbdev;
2612 if (xbdev && xbdev->state == XenbusStateClosing) {
2613 /* pending switch to state closed */
2614 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
2615 xlvbd_release_gendisk(info);
2616 xenbus_frontend_closed(info->xbdev);
2619 mutex_unlock(&info->mutex);
2622 /* sudden device removal */
2623 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
2624 xlvbd_release_gendisk(info);
2625 disk->private_data = NULL;
2632 mutex_unlock(&blkfront_mutex);
2635 static const struct block_device_operations xlvbd_block_fops =
2637 .owner = THIS_MODULE,
2639 .release = blkif_release,
2640 .getgeo = blkif_getgeo,
2641 .ioctl = blkif_ioctl,
2645 static const struct xenbus_device_id blkfront_ids[] = {
2650 static struct xenbus_driver blkfront_driver = {
2651 .ids = blkfront_ids,
2652 .probe = blkfront_probe,
2653 .remove = blkfront_remove,
2654 .resume = blkfront_resume,
2655 .otherend_changed = blkback_changed,
2656 .is_ready = blkfront_is_ready,
2659 static int __init xlblk_init(void)
2662 int nr_cpus = num_online_cpus();
2667 if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
2668 pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
2669 xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
2670 xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
2673 if (xen_blkif_max_queues > nr_cpus) {
2674 pr_info("Invalid max_queues (%d), will use default max: %d.\n",
2675 xen_blkif_max_queues, nr_cpus);
2676 xen_blkif_max_queues = nr_cpus;
2679 if (!xen_has_pv_disk_devices())
2682 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
2683 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
2684 XENVBD_MAJOR, DEV_NAME);
2688 ret = xenbus_register_frontend(&blkfront_driver);
2690 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
2696 module_init(xlblk_init);
2699 static void __exit xlblk_exit(void)
2701 xenbus_unregister_driver(&blkfront_driver);
2702 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
2705 module_exit(xlblk_exit);
2707 MODULE_DESCRIPTION("Xen virtual block device frontend");
2708 MODULE_LICENSE("GPL");
2709 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
2710 MODULE_ALIAS("xen:vbd");
2711 MODULE_ALIAS("xenblk");