block: avoid unconditionally freeing previously allocated request_queue

On blk_init_allocated_queue_node failure, only free the request_queue if
it is wasn't previously allocated outside the block layer
(e.g. blk_init_queue_node was blk_init_allocated_queue_node caller).

This addresses an interface bug introduced by the following commit:
01effb0 block: allow initialization of previously allocated
request_queue

Otherwise the request_queue may be free'd out from underneath a caller
that is managing the request_queue directly (e.g. caller uses
blk_alloc_queue + blk_init_allocated_queue_node).

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

1 files changed, 11 insertions, 6 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 3bc5579d6f54..826d07078902 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -570,9 +570,17 @@ EXPORT_SYMBOL(blk_init_queue);
 struct request_queue *
 blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
 {
-        struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id);
+        struct request_queue *uninit_q, *q;
 
-        return blk_init_allocated_queue_node(q, rfn, lock, node_id);
+        uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
+        if (!uninit_q)
+                return NULL;
+
+        q = blk_init_allocated_queue_node(uninit_q, rfn, lock, node_id);
+        if (!q)
+                blk_cleanup_queue(uninit_q);
+
+        return q;
 }
 EXPORT_SYMBOL(blk_init_queue_node);
 
@@ -592,10 +600,8 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
                 return NULL;
 
         q->node = node_id;
-        if (blk_init_free_list(q)) {
-                kmem_cache_free(blk_requestq_cachep, q);
+        if (blk_init_free_list(q))
                 return NULL;
-        }
 
         q->request_fn           = rfn;
         q->prep_rq_fn           = NULL;
@@ -618,7 +624,6 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
                 return q;
         }
 
-        blk_put_queue(q);
         return NULL;
 }
 EXPORT_SYMBOL(blk_init_allocated_queue_node);