diff options
Diffstat (limited to 'drivers/block/xen-blkfront.c')
-rw-r--r-- | drivers/block/xen-blkfront.c | 256 |
1 files changed, 135 insertions, 121 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 286cf1afad78..35b9bcad9db9 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -152,6 +152,10 @@ static unsigned int xen_blkif_max_ring_order; module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444); MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); +static bool __read_mostly xen_blkif_trusted = true; +module_param_named(trusted, xen_blkif_trusted, bool, 0644); +MODULE_PARM_DESC(trusted, "Is the backend trusted"); + #define BLK_RING_SIZE(info) \ __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) @@ -198,6 +202,7 @@ struct blkfront_info struct gendisk *gd; u16 sector_size; unsigned int physical_sector_size; + unsigned long vdisk_info; int vdevice; blkif_vdev_t handle; enum blkif_state connected; @@ -208,7 +213,11 @@ struct blkfront_info unsigned int feature_fua:1; unsigned int feature_discard:1; unsigned int feature_secdiscard:1; + /* Connect-time cached feature_persistent parameter */ + unsigned int feature_persistent_parm:1; + /* Persistent grants feature negotiation result */ unsigned int feature_persistent:1; + unsigned int bounce:1; unsigned int discard_granularity; unsigned int discard_alignment; /* Number of 4KB segments handled */ @@ -228,8 +237,6 @@ static unsigned int nr_minors; static unsigned long *minors; static DEFINE_SPINLOCK(minor_lock); -#define GRANT_INVALID_REF 0 - #define PARTS_PER_DISK 16 #define PARTS_PER_EXT_DISK 256 @@ -311,8 +318,8 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) if (!gnt_list_entry) goto out_of_memory; - if (info->feature_persistent) { - granted_page = alloc_page(GFP_NOIO); + if (info->bounce) { + granted_page = alloc_page(GFP_NOIO | __GFP_ZERO); if (!granted_page) { kfree(gnt_list_entry); goto out_of_memory; @@ -320,7 +327,7 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) gnt_list_entry->page = granted_page; } - gnt_list_entry->gref = GRANT_INVALID_REF; + gnt_list_entry->gref = INVALID_GRANT_REF; list_add(&gnt_list_entry->node, &rinfo->grants); i++; } @@ -331,7 +338,7 @@ out_of_memory: list_for_each_entry_safe(gnt_list_entry, n, &rinfo->grants, node) { list_del(&gnt_list_entry->node); - if (info->feature_persistent) + if (info->bounce) __free_page(gnt_list_entry->page); kfree(gnt_list_entry); i--; @@ -349,7 +356,7 @@ static struct grant *get_free_grant(struct blkfront_ring_info *rinfo) node); list_del(&gnt_list_entry->node); - if (gnt_list_entry->gref != GRANT_INVALID_REF) + if (gnt_list_entry->gref != INVALID_GRANT_REF) rinfo->persistent_gnts_c--; return gnt_list_entry; @@ -371,13 +378,13 @@ static struct grant *get_grant(grant_ref_t *gref_head, struct grant *gnt_list_entry = get_free_grant(rinfo); struct blkfront_info *info = rinfo->dev_info; - if (gnt_list_entry->gref != GRANT_INVALID_REF) + if (gnt_list_entry->gref != INVALID_GRANT_REF) return gnt_list_entry; /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); - if (info->feature_persistent) + if (info->bounce) grant_foreign_access(gnt_list_entry, info); else { /* Grant access to the GFN passed by the caller */ @@ -395,13 +402,13 @@ static struct grant *get_indirect_grant(grant_ref_t *gref_head, struct grant *gnt_list_entry = get_free_grant(rinfo); struct blkfront_info *info = rinfo->dev_info; - if (gnt_list_entry->gref != GRANT_INVALID_REF) + if (gnt_list_entry->gref != INVALID_GRANT_REF) return gnt_list_entry; /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); - if (!info->feature_persistent) { + if (!info->bounce) { struct page *indirect_page; /* Fetch a pre-allocated page to use for indirect grefs */ @@ -505,6 +512,7 @@ static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg) static int blkif_ioctl(struct block_device *bdev, fmode_t mode, unsigned command, unsigned long argument) { + struct blkfront_info *info = bdev->bd_disk->private_data; int i; switch (command) { @@ -514,9 +522,9 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode, return -EFAULT; return 0; case CDROM_GET_CAPABILITY: - if (bdev->bd_disk->flags & GENHD_FL_CD) - return 0; - return -EINVAL; + if (!(info->vdisk_info & VDISK_CDROM)) + return -EINVAL; + return 0; default: return -EINVAL; } @@ -574,7 +582,7 @@ struct setup_rw_req { struct blkif_request *ring_req; grant_ref_t gref_head; unsigned int id; - /* Only used when persistent grant is used and it's a read request */ + /* Only used when persistent grant is used and it's a write request */ bool need_copy; unsigned int bvec_off; char *bvec_data; @@ -703,7 +711,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri .grant_idx = 0, .segments = NULL, .rinfo = rinfo, - .need_copy = rq_data_dir(req) && info->feature_persistent, + .need_copy = rq_data_dir(req) && info->bounce, }; /* @@ -942,13 +950,13 @@ static void blkif_set_queue_limits(struct blkfront_info *info) blk_queue_flag_set(QUEUE_FLAG_VIRT, rq); if (info->feature_discard) { - blk_queue_flag_set(QUEUE_FLAG_DISCARD, rq); blk_queue_max_discard_sectors(rq, get_capacity(gd)); rq->limits.discard_granularity = info->discard_granularity ?: info->physical_sector_size; rq->limits.discard_alignment = info->discard_alignment; if (info->feature_secdiscard) - blk_queue_flag_set(QUEUE_FLAG_SECERASE, rq); + blk_queue_max_secure_erase_sectors(rq, + get_capacity(gd)); } /* Hard sector size and max sectors impersonate the equiv. hardware. */ @@ -981,11 +989,12 @@ static void xlvbd_flush(struct blkfront_info *info) { blk_queue_write_cache(info->rq, info->feature_flush ? true : false, info->feature_fua ? true : false); - pr_info("blkfront: %s: %s %s %s %s %s\n", + pr_info("blkfront: %s: %s %s %s %s %s %s %s\n", info->gd->disk_name, flush_info(info), "persistent grants:", info->feature_persistent ? "enabled;" : "disabled;", "indirect descriptors:", - info->max_indirect_segments ? "enabled;" : "disabled;"); + info->max_indirect_segments ? "enabled;" : "disabled;", + "bounce buffer:", info->bounce ? "enabled" : "disabled;"); } static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) @@ -1057,9 +1066,8 @@ static char *encode_disk_name(char *ptr, unsigned int n) } static int xlvbd_alloc_gendisk(blkif_sector_t capacity, - struct blkfront_info *info, - u16 vdisk_info, u16 sector_size, - unsigned int physical_sector_size) + struct blkfront_info *info, u16 sector_size, + unsigned int physical_sector_size) { struct gendisk *gd; int nr_minors = 1; @@ -1157,15 +1165,11 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity, xlvbd_flush(info); - if (vdisk_info & VDISK_READONLY) + if (info->vdisk_info & VDISK_READONLY) set_disk_ro(gd, 1); - - if (vdisk_info & VDISK_REMOVABLE) + if (info->vdisk_info & VDISK_REMOVABLE) gd->flags |= GENHD_FL_REMOVABLE; - if (vdisk_info & VDISK_CDROM) - gd->flags |= GENHD_FL_CD; - return 0; out_free_tag_set: @@ -1212,7 +1216,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) if (!list_empty(&rinfo->indirect_pages)) { struct page *indirect_page, *n; - BUG_ON(info->feature_persistent); + BUG_ON(info->bounce); list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { list_del(&indirect_page->lru); __free_page(indirect_page); @@ -1224,12 +1228,12 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) list_for_each_entry_safe(persistent_gnt, n, &rinfo->grants, node) { list_del(&persistent_gnt->node); - if (persistent_gnt->gref != GRANT_INVALID_REF) { + if (persistent_gnt->gref != INVALID_GRANT_REF) { gnttab_end_foreign_access(persistent_gnt->gref, - 0, 0UL); + NULL); rinfo->persistent_gnts_c--; } - if (info->feature_persistent) + if (info->bounce) __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1249,8 +1253,8 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) rinfo->shadow[i].req.u.rw.nr_segments; for (j = 0; j < segs; j++) { persistent_gnt = rinfo->shadow[i].grants_used[j]; - gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); - if (info->feature_persistent) + gnttab_end_foreign_access(persistent_gnt->gref, NULL); + if (info->bounce) __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1264,7 +1268,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) for (j = 0; j < INDIRECT_GREFS(segs); j++) { persistent_gnt = rinfo->shadow[i].indirect_grants[j]; - gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); + gnttab_end_foreign_access(persistent_gnt->gref, NULL); __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1285,14 +1289,8 @@ free_shadow: flush_work(&rinfo->work); /* Free resources associated with old device channel. */ - for (i = 0; i < info->nr_ring_pages; i++) { - if (rinfo->ring_ref[i] != GRANT_INVALID_REF) { - gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0); - rinfo->ring_ref[i] = GRANT_INVALID_REF; - } - } - free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * XEN_PAGE_SIZE)); - rinfo->ring.sring = NULL; + xenbus_teardown_ring((void **)&rinfo->ring.sring, info->nr_ring_pages, + rinfo->ring_ref); if (rinfo->irq) unbind_from_irqhandler(rinfo->irq, rinfo); @@ -1375,9 +1373,15 @@ static int blkif_get_final_status(enum blk_req_status s1, return BLKIF_RSP_OKAY; } -static bool blkif_completion(unsigned long *id, - struct blkfront_ring_info *rinfo, - struct blkif_response *bret) +/* + * Return values: + * 1 response processed. + * 0 missing further responses. + * -1 error while processing. + */ +static int blkif_completion(unsigned long *id, + struct blkfront_ring_info *rinfo, + struct blkif_response *bret) { int i = 0; struct scatterlist *sg; @@ -1400,7 +1404,7 @@ static bool blkif_completion(unsigned long *id, /* Wait the second response if not yet here. */ if (s2->status < REQ_DONE) - return false; + return 0; bret->status = blkif_get_final_status(s->status, s2->status); @@ -1433,7 +1437,7 @@ static bool blkif_completion(unsigned long *id, data.s = s; num_sg = s->num_sg; - if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { + if (bret->operation == BLKIF_OP_READ && info->bounce) { for_each_sg(s->sg, sg, num_sg, i) { BUG_ON(sg->offset + sg->length > PAGE_SIZE); @@ -1451,57 +1455,58 @@ static bool blkif_completion(unsigned long *id, } /* Add the persistent grant into the list of free grants */ for (i = 0; i < num_grant; i++) { - if (gnttab_query_foreign_access(s->grants_used[i]->gref)) { + if (!gnttab_try_end_foreign_access(s->grants_used[i]->gref)) { /* * If the grant is still mapped by the backend (the * backend has chosen to make this grant persistent) * we add it at the head of the list, so it will be * reused first. */ - if (!info->feature_persistent) - pr_alert_ratelimited("backed has not unmapped grant: %u\n", - s->grants_used[i]->gref); + if (!info->feature_persistent) { + pr_alert("backed has not unmapped grant: %u\n", + s->grants_used[i]->gref); + return -1; + } list_add(&s->grants_used[i]->node, &rinfo->grants); rinfo->persistent_gnts_c++; } else { /* - * If the grant is not mapped by the backend we end the - * foreign access and add it to the tail of the list, - * so it will not be picked again unless we run out of - * persistent grants. + * If the grant is not mapped by the backend we add it + * to the tail of the list, so it will not be picked + * again unless we run out of persistent grants. */ - gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL); - s->grants_used[i]->gref = GRANT_INVALID_REF; + s->grants_used[i]->gref = INVALID_GRANT_REF; list_add_tail(&s->grants_used[i]->node, &rinfo->grants); } } if (s->req.operation == BLKIF_OP_INDIRECT) { for (i = 0; i < INDIRECT_GREFS(num_grant); i++) { - if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) { - if (!info->feature_persistent) - pr_alert_ratelimited("backed has not unmapped grant: %u\n", - s->indirect_grants[i]->gref); + if (!gnttab_try_end_foreign_access(s->indirect_grants[i]->gref)) { + if (!info->feature_persistent) { + pr_alert("backed has not unmapped grant: %u\n", + s->indirect_grants[i]->gref); + return -1; + } list_add(&s->indirect_grants[i]->node, &rinfo->grants); rinfo->persistent_gnts_c++; } else { struct page *indirect_page; - gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL); /* * Add the used indirect page back to the list of * available pages for indirect grefs. */ - if (!info->feature_persistent) { + if (!info->bounce) { indirect_page = s->indirect_grants[i]->page; list_add(&indirect_page->lru, &rinfo->indirect_pages); } - s->indirect_grants[i]->gref = GRANT_INVALID_REF; + s->indirect_grants[i]->gref = INVALID_GRANT_REF; list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants); } } } - return true; + return 1; } static irqreturn_t blkif_interrupt(int irq, void *dev_id) @@ -1567,12 +1572,17 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) } if (bret.operation != BLKIF_OP_DISCARD) { + int ret; + /* * We may need to wait for an extra response if the * I/O request is split in 2 */ - if (!blkif_completion(&id, rinfo, &bret)) + ret = blkif_completion(&id, rinfo, &bret); + if (!ret) continue; + if (unlikely(ret < 0)) + goto err; } if (add_id_to_freelist(rinfo, id)) { @@ -1596,8 +1606,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) blkif_req(req)->error = BLK_STS_NOTSUPP; info->feature_discard = 0; info->feature_secdiscard = 0; - blk_queue_flag_clear(QUEUE_FLAG_DISCARD, rq); - blk_queue_flag_clear(QUEUE_FLAG_SECERASE, rq); + blk_queue_max_discard_sectors(rq, 0); + blk_queue_max_secure_erase_sectors(rq, 0); } break; case BLKIF_OP_FLUSH_DISKCACHE: @@ -1671,31 +1681,16 @@ static int setup_blkring(struct xenbus_device *dev, struct blkfront_ring_info *rinfo) { struct blkif_sring *sring; - int err, i; + int err; struct blkfront_info *info = rinfo->dev_info; unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE; - grant_ref_t gref[XENBUS_MAX_RING_GRANTS]; - for (i = 0; i < info->nr_ring_pages; i++) - rinfo->ring_ref[i] = GRANT_INVALID_REF; - - sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH, - get_order(ring_size)); - if (!sring) { - xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); - return -ENOMEM; - } - SHARED_RING_INIT(sring); - FRONT_RING_INIT(&rinfo->ring, sring, ring_size); - - err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref); - if (err < 0) { - free_pages((unsigned long)sring, get_order(ring_size)); - rinfo->ring.sring = NULL; + err = xenbus_setup_ring(dev, GFP_NOIO, (void **)&sring, + info->nr_ring_pages, rinfo->ring_ref); + if (err) goto fail; - } - for (i = 0; i < info->nr_ring_pages; i++) - rinfo->ring_ref[i] = gref[i]; + + XEN_FRONT_RING_INIT(&rinfo->ring, sring, ring_size); err = xenbus_alloc_evtchn(dev, &rinfo->evtchn); if (err) @@ -1764,6 +1759,12 @@ abort_transaction: return err; } +/* Enable the persistent grants feature. */ +static bool feature_persistent = true; +module_param(feature_persistent, bool, 0644); +MODULE_PARM_DESC(feature_persistent, + "Enables the persistent grants feature"); + /* Common code used when first setting up, and when resuming. */ static int talk_to_blkback(struct xenbus_device *dev, struct blkfront_info *info) @@ -1778,6 +1779,10 @@ static int talk_to_blkback(struct xenbus_device *dev, if (!info) return -ENODEV; + /* Check if backend is trusted. */ + info->bounce = !xen_blkif_trusted || + !xenbus_read_unsigned(dev->nodename, "trusted", 1); + max_page_order = xenbus_read_unsigned(info->xbdev->otherend, "max-ring-page-order", 0); ring_page_order = min(xen_blkif_max_ring_order, max_page_order); @@ -1851,8 +1856,9 @@ again: message = "writing protocol"; goto abort_transaction; } + info->feature_persistent_parm = feature_persistent; err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", - info->feature_persistent); + info->feature_persistent_parm); if (err) dev_warn(&dev->dev, "writing persistent grants feature to xenbus"); @@ -1920,12 +1926,6 @@ static int negotiate_mq(struct blkfront_info *info) return 0; } -/* Enable the persistent grants feature. */ -static bool feature_persistent = true; -module_param(feature_persistent, bool, 0644); -MODULE_PARM_DESC(feature_persistent, - "Enables the persistent grants feature"); - /* * Entry point to this code when a new device is created. Allocate the basic * structures and the ring buffer for communication with the backend, and @@ -1992,8 +1992,6 @@ static int blkfront_probe(struct xenbus_device *dev, info->vdevice = vdevice; info->connected = BLKIF_STATE_DISCONNECTED; - info->feature_persistent = feature_persistent; - /* Front end dir is a number, which is used as the id. */ info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); dev_set_drvdata(&dev->dev, info); @@ -2128,9 +2126,11 @@ static void blkfront_closing(struct blkfront_info *info) return; /* No more blkif_request(). */ - blk_mq_stop_hw_queues(info->rq); - blk_set_queue_dying(info->rq); - set_capacity(info->gd, 0); + if (info->rq && info->gd) { + blk_mq_stop_hw_queues(info->rq); + blk_mark_disk_dead(info->gd); + set_capacity(info->gd, 0); + } for_each_rinfo(info, rinfo, i) { /* No more gnttab callback work. */ @@ -2185,17 +2185,18 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) if (err) goto out_of_memory; - if (!info->feature_persistent && info->max_indirect_segments) { + if (!info->bounce && info->max_indirect_segments) { /* - * We are using indirect descriptors but not persistent - * grants, we need to allocate a set of pages that can be + * We are using indirect descriptors but don't have a bounce + * buffer, we need to allocate a set of pages that can be * used for mapping indirect grefs */ int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info); BUG_ON(!list_empty(&rinfo->indirect_pages)); for (i = 0; i < num; i++) { - struct page *indirect_page = alloc_page(GFP_KERNEL); + struct page *indirect_page = alloc_page(GFP_KERNEL | + __GFP_ZERO); if (!indirect_page) goto out_of_memory; list_add(&indirect_page->lru, &rinfo->indirect_pages); @@ -2284,10 +2285,12 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) blkfront_setup_discard(info); - if (info->feature_persistent) + if (info->feature_persistent_parm) info->feature_persistent = !!xenbus_read_unsigned(info->xbdev->otherend, "feature-persistent", 0); + if (info->feature_persistent) + info->bounce = true; indirect_segments = xenbus_read_unsigned(info->xbdev->otherend, "feature-max-indirect-segments", 0); @@ -2313,7 +2316,6 @@ static void blkfront_connect(struct blkfront_info *info) unsigned long long sectors; unsigned long sector_size; unsigned int physical_sector_size; - unsigned int binfo; int err, i; struct blkfront_ring_info *rinfo; @@ -2351,7 +2353,7 @@ static void blkfront_connect(struct blkfront_info *info) err = xenbus_gather(XBT_NIL, info->xbdev->otherend, "sectors", "%llu", §ors, - "info", "%u", &binfo, + "info", "%u", &info->vdisk_info, "sector-size", "%lu", §or_size, NULL); if (err) { @@ -2380,7 +2382,7 @@ static void blkfront_connect(struct blkfront_info *info) } } - err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size, + err = xlvbd_alloc_gendisk(sectors, info, sector_size, physical_sector_size); if (err) { xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", @@ -2397,7 +2399,7 @@ static void blkfront_connect(struct blkfront_info *info) err = device_add_disk(&info->xbdev->dev, info->gd, NULL); if (err) { - blk_cleanup_disk(info->gd); + put_disk(info->gd); blk_mq_free_tag_set(&info->tag_set); info->rq = NULL; goto fail; @@ -2472,16 +2474,19 @@ static int blkfront_remove(struct xenbus_device *xbdev) dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename); - del_gendisk(info->gd); + if (info->gd) + del_gendisk(info->gd); mutex_lock(&blkfront_mutex); list_del(&info->info_list); mutex_unlock(&blkfront_mutex); blkif_free(info, 0); - xlbd_release_minors(info->gd->first_minor, info->gd->minors); - blk_cleanup_disk(info->gd); - blk_mq_free_tag_set(&info->tag_set); + if (info->gd) { + xlbd_release_minors(info->gd->first_minor, info->gd->minors); + put_disk(info->gd); + blk_mq_free_tag_set(&info->tag_set); + } kfree(info); return 0; @@ -2525,6 +2530,7 @@ static void purge_persistent_grants(struct blkfront_info *info) for_each_rinfo(info, rinfo, i) { struct grant *gnt_list_entry, *tmp; + LIST_HEAD(grants); spin_lock_irqsave(&rinfo->ring_lock, flags); @@ -2535,17 +2541,18 @@ static void purge_persistent_grants(struct blkfront_info *info) list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants, node) { - if (gnt_list_entry->gref == GRANT_INVALID_REF || - gnttab_query_foreign_access(gnt_list_entry->gref)) + if (gnt_list_entry->gref == INVALID_GRANT_REF || + !gnttab_try_end_foreign_access(gnt_list_entry->gref)) continue; list_del(&gnt_list_entry->node); - gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); rinfo->persistent_gnts_c--; - gnt_list_entry->gref = GRANT_INVALID_REF; - list_add_tail(&gnt_list_entry->node, &rinfo->grants); + gnt_list_entry->gref = INVALID_GRANT_REF; + list_add_tail(&gnt_list_entry->node, &grants); } + list_splice_tail(&grants, &rinfo->grants); + spin_unlock_irqrestore(&rinfo->ring_lock, flags); } } @@ -2555,6 +2562,13 @@ static void blkfront_delay_work(struct work_struct *work) struct blkfront_info *info; bool need_schedule_work = false; + /* + * Note that when using bounce buffers but not persistent grants + * there's no need to run blkfront_delay_work because grants are + * revoked in blkif_completion or else an error is reported and the + * connection is closed. + */ + mutex_lock(&blkfront_mutex); list_for_each_entry(info, &info_list, info_list) { |