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 <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 826d07078902..f84cce42fc58 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -467,6 +467,9 @@ static int blk_init_free_list(struct request_queue *q)
 {
         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;