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authorVivek Goyal <vgoyal@redhat.com>2011-03-02 19:05:33 -0500
committerJens Axboe <jaxboe@fusionio.com>2011-03-02 19:06:49 -0500
commitda527770007fce8e4541947d47918248286da875 (patch)
treefc518172887409133e8dea827067209adfdb1c3c /block/blk-sysfs.c
parentcd25f54961273c2e4cbd47441e04832468382a5e (diff)
downloadlinux-stericsson-da527770007fce8e4541947d47918248286da875.tar.gz
block: Move blk_throtl_exit() call to blk_cleanup_queue()
Move blk_throtl_exit() in blk_cleanup_queue() as blk_throtl_exit() is written in such a way that it needs queue lock. In blk_release_queue() there is no gurantee that ->queue_lock is still around. Initially blk_throtl_exit() was in blk_cleanup_queue() but Ingo reported one problem. https://lkml.org/lkml/2010/10/23/86 And a quick fix moved blk_throtl_exit() to blk_release_queue(). commit 7ad58c028652753814054f4e3ac58f925e7343f4 Author: Jens Axboe <jaxboe@fusionio.com> Date: Sat Oct 23 20:40:26 2010 +0200 block: fix use-after-free bug in blk throttle code This patch reverts above change and does not try to shutdown the throtl work in blk_sync_queue(). By avoiding call to throtl_shutdown_timer_wq() from blk_sync_queue(), we should also avoid the problem reported by Ingo. blk_sync_queue() seems to be used only by md driver and it seems to be using it to make sure q->unplug_fn is not called as md registers its own unplug functions and it is about to free up the data structures used by unplug_fn(). Block throttle does not call back into unplug_fn() or into md. So there is no need to cancel blk throttle work. In fact I think cancelling block throttle work is bad because it might happen that some bios are throttled and scheduled to be dispatched later with the help of pending work and if work is cancelled, these bios might never be dispatched. Block layer also uses blk_sync_queue() during blk_cleanup_queue() and blk_release_queue() time. That should be safe as we are also calling blk_throtl_exit() which should make sure all the throttling related data structures are cleaned up. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block/blk-sysfs.c')
-rw-r--r--block/blk-sysfs.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 41fb69150b4d..261c75c665ae 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -471,8 +471,6 @@ static void blk_release_queue(struct kobject *kobj)
blk_sync_queue(q);
- blk_throtl_exit(q);
-
if (rl->rq_pool)
mempool_destroy(rl->rq_pool);