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authorBart Van Assche <bvanassche@acm.org>2012-11-28 13:46:45 +0100
committerJens Axboe <axboe@kernel.dk>2012-12-06 14:33:00 +0100
commit24faf6f604efe18236bded4303009fc252913bf0 (patch)
treebc4d35a38c44a37ffd718089729ae59b23d50d99 /include/linux/blkdev.h
parent704605711ef048a7c6ad2ec599f15d2e0baf86b2 (diff)
downloadvexpress-lsk-24faf6f604efe18236bded4303009fc252913bf0.tar.gz
block: Make blk_cleanup_queue() wait until request_fn finished
Some request_fn implementations, e.g. scsi_request_fn(), unlock the queue lock internally. This may result in multiple threads executing request_fn for the same queue simultaneously. Keep track of the number of active request_fn calls and make sure that blk_cleanup_queue() waits until all active request_fn invocations have finished. A block driver may start cleaning up resources needed by its request_fn as soon as blk_cleanup_queue() finished, so blk_cleanup_queue() must wait for all outstanding request_fn invocations to finish. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reported-by: Chanho Min <chanho.min@lge.com> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blkdev.h')
-rw-r--r--include/linux/blkdev.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8bc46c250ca..c9d233e727f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -378,6 +378,12 @@ struct request_queue {
unsigned int nr_sorted;
unsigned int in_flight[2];
+ /*
+ * Number of active block driver functions for which blk_drain_queue()
+ * must wait. Must be incremented around functions that unlock the
+ * queue_lock internally, e.g. scsi_request_fn().
+ */
+ unsigned int request_fn_active;
unsigned int rq_timeout;
struct timer_list timeout;