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From: Mike Snitzer on 26 May 2010 01:00
On blk_init_allocated_queue_node failure, only free 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(a)redhat.com>
---
block/blk-core.c | 33 +++++++++++++++++++++++++++------
1 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 3bc5579..c0cdafd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -528,6 +528,25 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
}
EXPORT_SYMBOL(blk_alloc_queue_node);

+static void blk_free_partial_queue(struct request_queue *q)
+{
+ struct request_list *rl;
+
+ if (!q)
+ return;
+
+ /* Was blk_init_free_list the cause for failure? */
+ rl = &q->rq;
+ if (!rl->rq_pool) {
+ kmem_cache_free(blk_requestq_cachep, q);
+ return;
+ }
+
+ /* Or was elevator_init? */
+ if (!q->elevator)
+ blk_put_queue(q);
+}
+
/**
* blk_init_queue - prepare a request queue for use with a block device
* @rfn: The function to be called to process requests that have been
@@ -570,9 +589,14 @@ 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;
+
+ uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
+ q = blk_init_allocated_queue_node(uninit_q, rfn, lock, node_id);
+ if (!q)
+ blk_free_partial_queue(uninit_q);

- return blk_init_allocated_queue_node(q, rfn, lock, node_id);
+ return q;
}
EXPORT_SYMBOL(blk_init_queue_node);

@@ -592,10 +616,8 @@ 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 +640,6 @@ 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);
--
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Prev: [git pull] drm fixes
Next: padata: add parenthesis in MAX_SEQ_NR macro