From 1abec4fdbb142e3ccb6ce99832fae42129134a96 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 25 May 2010 13:15:15 -0400 Subject: [RHEL6 PATCH 3/3] block: make blk_init_free_list and elevator_init idempotent BZ 594584 Staged in Jens' 'for-linus' branch for 2.6.35 inclusion. commit 1abec4fdbb142e3ccb6ce99832fae42129134a96 Author: Mike Snitzer AuthorDate: Tue May 25 13:15:15 2010 -0400 Commit: Jens Axboe CommitDate: Fri Jun 4 13:47:06 2010 +0200 block: make blk_init_free_list and elevator_init idempotent blk_init_allocated_queue_node may fail and the caller _could_ retry. Accommodate the unlikely event that blk_init_allocated_queue_node is called on an already initialized (possibly partially) request_queue. Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe --- block/blk-core.c | 3 +++ block/elevator.c | 6 ++++-- 2 files changed, 7 insertions(+), 2 deletions(-) Index: linux-2.6/block/blk-core.c =================================================================== --- linux-2.6.orig/block/blk-core.c +++ linux-2.6/block/blk-core.c @@ -465,6 +465,9 @@ static int blk_init_free_list(struct req { struct request_list *rl = &q->rq; + if (unlikely(rl->rq_pool)) + return 0; + rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; rl->elvpriv = 0; Index: linux-2.6/block/elevator.c =================================================================== --- linux-2.6.orig/block/elevator.c +++ linux-2.6/block/elevator.c @@ -242,9 +242,11 @@ int elevator_init(struct request_queue * { struct elevator_type *e = NULL; struct elevator_queue *eq; - int ret = 0; void *data; + if (unlikely(q->elevator)) + return 0; + INIT_LIST_HEAD(&q->queue_head); q->last_merge = NULL; q->end_sector = 0; @@ -284,7 +286,7 @@ int elevator_init(struct request_queue * } elevator_attach(q, eq, data); - return ret; + return 0; } EXPORT_SYMBOL(elevator_init);