diff options
Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
-rw-r--r-- | drivers/block/xen-blkback/blkback.c | 66 |
1 files changed, 43 insertions, 23 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 4b97b86da926..64c60edcdfbc 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -299,7 +299,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, BUG_ON(num != 0); } -static void unmap_purged_grants(struct work_struct *work) +void xen_blkbk_unmap_purged_grants(struct work_struct *work) { struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; @@ -375,7 +375,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif) pr_debug(DRV_PFX "Going to purge %u persistent grants\n", num_clean); - INIT_LIST_HEAD(&blkif->persistent_purge_list); + BUG_ON(!list_empty(&blkif->persistent_purge_list)); root = &blkif->persistent_gnts; purge_list: foreach_grant_safe(persistent_gnt, n, root, node) { @@ -420,7 +420,6 @@ finished: blkif->vbd.overflow_max_grants = 0; /* We can defer this work */ - INIT_WORK(&blkif->persistent_purge_work, unmap_purged_grants); schedule_work(&blkif->persistent_purge_work); pr_debug(DRV_PFX "Purged %u/%u\n", (total - num_clean), total); return; @@ -625,9 +624,23 @@ purge_gnt_list: print_stats(blkif); } - /* Since we are shutting down remove all pages from the buffer */ - shrink_free_pagepool(blkif, 0 /* All */); + /* Drain pending purge work */ + flush_work(&blkif->persistent_purge_work); + if (log_stats) + print_stats(blkif); + + blkif->xenblkd = NULL; + xen_blkif_put(blkif); + + return 0; +} + +/* + * Remove persistent grants and empty the pool of free pages + */ +void xen_blkbk_free_caches(struct xen_blkif *blkif) +{ /* Free all persistent grant pages */ if (!RB_EMPTY_ROOT(&blkif->persistent_gnts)) free_persistent_gnts(blkif, &blkif->persistent_gnts, @@ -636,13 +649,8 @@ purge_gnt_list: BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); blkif->persistent_gnt_c = 0; - if (log_stats) - print_stats(blkif); - - blkif->xenblkd = NULL; - xen_blkif_put(blkif); - - return 0; + /* Since we are shutting down remove all pages from the buffer */ + shrink_free_pagepool(blkif, 0 /* All */); } /* @@ -838,7 +846,7 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req, struct grant_page **pages = pending_req->indirect_pages; struct xen_blkif *blkif = pending_req->blkif; int indirect_grefs, rc, n, nseg, i; - struct blkif_request_segment_aligned *segments = NULL; + struct blkif_request_segment *segments = NULL; nseg = pending_req->nr_pages; indirect_grefs = INDIRECT_PAGES(nseg); @@ -934,9 +942,7 @@ static void xen_blk_drain_io(struct xen_blkif *blkif) { atomic_set(&blkif->drain, 1); do { - /* The initial value is one, and one refcnt taken at the - * start of the xen_blkif_schedule thread. */ - if (atomic_read(&blkif->refcnt) <= 2) + if (atomic_read(&blkif->inflight) == 0) break; wait_for_completion_interruptible_timeout( &blkif->drain_complete, HZ); @@ -976,17 +982,30 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) * the proper response on the ring. */ if (atomic_dec_and_test(&pending_req->pendcnt)) { - xen_blkbk_unmap(pending_req->blkif, + struct xen_blkif *blkif = pending_req->blkif; + + xen_blkbk_unmap(blkif, pending_req->segments, pending_req->nr_pages); - make_response(pending_req->blkif, pending_req->id, + make_response(blkif, pending_req->id, pending_req->operation, pending_req->status); - xen_blkif_put(pending_req->blkif); - if (atomic_read(&pending_req->blkif->refcnt) <= 2) { - if (atomic_read(&pending_req->blkif->drain)) - complete(&pending_req->blkif->drain_complete); + free_req(blkif, pending_req); + /* + * Make sure the request is freed before releasing blkif, + * or there could be a race between free_req and the + * cleanup done in xen_blkif_free during shutdown. + * + * NB: The fact that we might try to wake up pending_free_wq + * before drain_complete (in case there's a drain going on) + * it's not a problem with our current implementation + * because we can assure there's no thread waiting on + * pending_free_wq if there's a drain going on, but it has + * to be taken into account if the current model is changed. + */ + if (atomic_dec_and_test(&blkif->inflight) && atomic_read(&blkif->drain)) { + complete(&blkif->drain_complete); } - free_req(pending_req->blkif, pending_req); + xen_blkif_put(blkif); } } @@ -1240,6 +1259,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, * below (in "!bio") if we are handling a BLKIF_OP_DISCARD. */ xen_blkif_get(blkif); + atomic_inc(&blkif->inflight); for (i = 0; i < nseg; i++) { while ((bio == NULL) || |