diff options
| -rw-r--r-- | drivers/block/xen-blkfront.c | 105 |
1 files changed, 74 insertions, 31 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index cbd9f6b910a3..ddd9a098bc67 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -104,7 +104,7 @@ struct blkfront_info struct work_struct work; struct gnttab_free_callback callback; struct blk_shadow shadow[BLK_RING_SIZE]; - struct list_head persistent_gnts; + struct list_head grants; unsigned int persistent_gnts_c; unsigned long shadow_free; unsigned int feature_flush; @@ -175,15 +175,17 @@ static int fill_grant_buffer(struct blkfront_info *info, int num) if (!gnt_list_entry) goto out_of_memory; - granted_page = alloc_page(GFP_NOIO); - if (!granted_page) { - kfree(gnt_list_entry); - goto out_of_memory; + if (info->feature_persistent) { + granted_page = alloc_page(GFP_NOIO); + if (!granted_page) { + kfree(gnt_list_entry); + goto out_of_memory; + } + gnt_list_entry->pfn = page_to_pfn(granted_page); } - gnt_list_entry->pfn = page_to_pfn(granted_page); gnt_list_entry->gref = GRANT_INVALID_REF; - list_add(&gnt_list_entry->node, &info->persistent_gnts); + list_add(&gnt_list_entry->node, &info->grants); i++; } @@ -191,9 +193,10 @@ static int fill_grant_buffer(struct blkfront_info *info, int num) out_of_memory: list_for_each_entry_safe(gnt_list_entry, n, - &info->persistent_gnts, node) { + &info->grants, node) { list_del(&gnt_list_entry->node); - __free_page(pfn_to_page(gnt_list_entry->pfn)); + if (info->feature_persistent) + __free_page(pfn_to_page(gnt_list_entry->pfn)); kfree(gnt_list_entry); i--; } @@ -202,14 +205,14 @@ out_of_memory: } static struct grant *get_grant(grant_ref_t *gref_head, + unsigned long pfn, struct blkfront_info *info) { struct grant *gnt_list_entry; unsigned long buffer_mfn; - BUG_ON(list_empty(&info->persistent_gnts)); - gnt_list_entry = list_first_entry(&info->persistent_gnts, struct grant, - node); + BUG_ON(list_empty(&info->grants)); + gnt_list_entry = list_first_entry(&info->grants, struct grant, node); list_del(&gnt_list_entry->node); if (gnt_list_entry->gref != GRANT_INVALID_REF) { @@ -220,6 +223,10 @@ static struct grant *get_grant(grant_ref_t *gref_head, /* 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) { + BUG_ON(!pfn); + gnt_list_entry->pfn = pfn; + } buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn); gnttab_grant_foreign_access_ref(gnt_list_entry->gref, info->xbdev->otherend_id, @@ -430,12 +437,12 @@ static int blkif_queue_request(struct request *req) fsect = sg->offset >> 9; lsect = fsect + (sg->length >> 9) - 1; - gnt_list_entry = get_grant(&gref_head, info); + gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info); ref = gnt_list_entry->gref; info->shadow[id].grants_used[i] = gnt_list_entry; - if (rq_data_dir(req)) { + if (rq_data_dir(req) && info->feature_persistent) { char *bvec_data; void *shared_data; @@ -828,16 +835,17 @@ static void blkif_free(struct blkfront_info *info, int suspend) blk_stop_queue(info->rq); /* Remove all persistent grants */ - if (!list_empty(&info->persistent_gnts)) { + if (!list_empty(&info->grants)) { list_for_each_entry_safe(persistent_gnt, n, - &info->persistent_gnts, node) { + &info->grants, node) { list_del(&persistent_gnt->node); if (persistent_gnt->gref != GRANT_INVALID_REF) { gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); info->persistent_gnts_c--; } - __free_page(pfn_to_page(persistent_gnt->pfn)); + if (info->feature_persistent) + __free_page(pfn_to_page(persistent_gnt->pfn)); kfree(persistent_gnt); } } @@ -874,7 +882,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, nseg = s->req.u.rw.nr_segments; - if (bret->operation == BLKIF_OP_READ) { + if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { /* * Copy the data received from the backend into the bvec. * Since bv_offset can be different than 0, and bv_len different @@ -902,7 +910,10 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, * we add it at the head of the list, so it will be * reused first. */ - list_add(&s->grants_used[i]->node, &info->persistent_gnts); + if (!info->feature_persistent) + pr_alert_ratelimited("backed has not unmapped grant: %u\n", + s->grants_used[i]->gref); + list_add(&s->grants_used[i]->node, &info->grants); info->persistent_gnts_c++; } else { /* @@ -913,7 +924,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, */ gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL); s->grants_used[i]->gref = GRANT_INVALID_REF; - list_add_tail(&s->grants_used[i]->node, &info->persistent_gnts); + list_add_tail(&s->grants_used[i]->node, &info->grants); } } } @@ -1052,12 +1063,6 @@ static int setup_blkring(struct xenbus_device *dev, for (i = 0; i < BLK_RING_SIZE; i++) sg_init_table(info->shadow[i].sg, BLKIF_MAX_SEGMENTS_PER_REQUEST); - /* Allocate memory for grants */ - err = fill_grant_buffer(info, BLK_RING_SIZE * - BLKIF_MAX_SEGMENTS_PER_REQUEST); - if (err) - goto fail; - err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring)); if (err < 0) { free_page((unsigned long)sring); @@ -1216,7 +1221,7 @@ static int blkfront_probe(struct xenbus_device *dev, spin_lock_init(&info->io_lock); info->xbdev = dev; info->vdevice = vdevice; - INIT_LIST_HEAD(&info->persistent_gnts); + INIT_LIST_HEAD(&info->grants); info->persistent_gnts_c = 0; info->connected = BLKIF_STATE_DISCONNECTED; INIT_WORK(&info->work, blkif_restart_queue); @@ -1245,7 +1250,8 @@ static int blkif_recover(struct blkfront_info *info) int i; struct blkif_request *req; struct blk_shadow *copy; - int j; + unsigned int persistent; + int j, rc; /* Stage 1: Make a safe copy of the shadow state. */ copy = kmemdup(info->shadow, sizeof(info->shadow), @@ -1260,6 +1266,24 @@ static int blkif_recover(struct blkfront_info *info) info->shadow_free = info->ring.req_prod_pvt; info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; + /* Check if the backend supports persistent grants */ + rc = xenbus_gather(XBT_NIL, info->xbdev->otherend, + "feature-persistent", "%u", &persistent, + NULL); + if (rc) + info->feature_persistent = 0; + else + info->feature_persistent = persistent; + + /* Allocate memory for grants */ + rc = fill_grant_buffer(info, BLK_RING_SIZE * + BLKIF_MAX_SEGMENTS_PER_REQUEST); + if (rc) { + xenbus_dev_fatal(info->xbdev, rc, "setting grant buffer failed"); + kfree(copy); + return rc; + } + /* Stage 3: Find pending requests and requeue them. */ for (i = 0; i < BLK_RING_SIZE; i++) { /* Not in use? */ @@ -1324,8 +1348,12 @@ static int blkfront_resume(struct xenbus_device *dev) blkif_free(info, info->connected == BLKIF_STATE_CONNECTED); err = talk_to_blkback(dev, info); - if (info->connected == BLKIF_STATE_SUSPENDED && !err) - err = blkif_recover(info); + + /* + * We have to wait for the backend to switch to + * connected state, since we want to read which + * features it supports. + */ return err; } @@ -1429,9 +1457,16 @@ static void blkfront_connect(struct blkfront_info *info) sectors); set_capacity(info->gd, sectors); revalidate_disk(info->gd); + return; - /* fall through */ case BLKIF_STATE_SUSPENDED: + /* + * If we are recovering from suspension, we need to wait + * for the backend to announce it's features before + * reconnecting, we need to know if the backend supports + * persistent grants. + */ + blkif_recover(info); return; default: @@ -1499,6 +1534,14 @@ static void blkfront_connect(struct blkfront_info *info) else info->feature_persistent = persistent; + /* Allocate memory for grants */ + err = fill_grant_buffer(info, BLK_RING_SIZE * + BLKIF_MAX_SEGMENTS_PER_REQUEST); + if (err) { + xenbus_dev_fatal(info->xbdev, err, "setting grant buffer failed"); + return; + } + err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); if (err) { xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s", |