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authorVivek Goyal <vgoyal@redhat.com>2011-03-02 19:04:42 -0500
committerJens Axboe <jaxboe@fusionio.com>2011-03-02 19:06:49 -0500
commitc94a96ac93b4f5b8d1ff8430b1afa1a25610cf53 (patch)
tree3cc138b16df4c0802ec42868a6d1f2eed42ba695 /block/blk-settings.c
parent53f22956effe1c9e7961b8c6e4362ecca5e460b7 (diff)
downloadlinux-linaro-stable-c94a96ac93b4f5b8d1ff8430b1afa1a25610cf53.tar.gz
block: Initialize ->queue_lock to internal lock at queue allocation time
There does not seem to be a clear convention whether q->queue_lock is initialized or not when blk_cleanup_queue() is called. In the past it was not necessary but now blk_throtl_exit() takes up queue lock by default and needs queue lock to be available. In fact elevator_exit() code also has similar requirement just that it is less stringent in the sense that elevator_exit() is called only if elevator is initialized. Two problems have been noticed because of ambiguity about spin lock status. - If a driver calls blk_alloc_queue() and then soon calls blk_cleanup_queue() almost immediately, (because some other driver structure allocation failed or some other error happened) then blk_throtl_exit() will run into issues as queue lock is not initialized. Loop driver ran into this issue recently and I noticed error paths in md driver too. Similar error paths should exist in other drivers too. - If some driver provided external spin lock and zapped the lock before blk_cleanup_queue(), then it can lead to issues. So this patch initializes the default queue lock at queue allocation time. block throttling code is one of the users of queue lock and it is initialized at the queue allocation time, so it makes sense to initialize ->queue_lock also to internal lock. A driver can overide that lock later. This will take care of the issue where a driver does not have to worry about initializing the queue lock to default before calling blk_cleanup_queue() Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r--block/blk-settings.c7
1 files changed, 0 insertions, 7 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 36c8c1f2af18..df649fa59ded 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -176,13 +176,6 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
/*
- * If the caller didn't supply a lock, fall back to our embedded
- * per-queue locks
- */
- if (!q->queue_lock)
- q->queue_lock = &q->__queue_lock;
-
- /*
* by default assume old behaviour and bounce for any highmem page
*/
blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);