blk-cgroup: Allow sleeping while dynamically allocating a group
Currently, all the cfq_group or throtl_group allocations happen while
we are holding ->queue_lock and sleeping is not allowed.
Soon, we will move to per cpu stats and also need to allocate the
per group stats. As one can not call alloc_percpu() from atomic
context as it can sleep, we need to drop ->queue_lock, allocate the
group, retake the lock and continue processing.
In throttling code, I check the queue DEAD flag again to make sure
that driver did not call blk_cleanup_queue() in the mean time.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index 3fe00a1..9e8e297 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1550,7 +1550,8 @@
goto end_io;
}
- blk_throtl_bio(q, &bio);
+ if (blk_throtl_bio(q, &bio))
+ goto end_io;
/*
* If bio = NULL, bio has been throttled and will be submitted