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authorTejun Heo <tj@kernel.org>2008-12-03 06:41:26 -0500
committerJens Axboe <jens.axboe@oracle.com>2008-12-03 06:41:26 -0500
commit53a08807c01989c6847bb135d8d43f61c5dfdda5 (patch)
treee2297de901dc82a0336e6af28b594864792c585d /block
parentbf91db18ac2852a3ff39fe25ff56c5557c0fff78 (diff)
block: internal dequeue shouldn't start timer
blkdev_dequeue_request() and elv_dequeue_request() are equivalent and both start the timeout timer. Barrier code dequeues the original barrier request but doesn't passes the request itself to lower level driver, only broken down proxy requests; however, as the original barrier code goes through the same dequeue path and timeout timer is started on it. If barrier sequence takes long enough, this timer expires but the low level driver has no idea about this request and oops follows. Timeout timer shouldn't have been started on the original barrier request as it never goes through actual IO. This patch unexports elv_dequeue_request(), which has no external user anyway, and makes it operate on elevator proper w/o adding the timer and make blkdev_dequeue_request() call elv_dequeue_request() and add timer. Internal users which don't pass the request to driver - barrier code and end_that_request_last() - are converted to use elv_dequeue_request(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-barrier.c4
-rw-r--r--block/blk-core.c24
-rw-r--r--block/elevator.c7
3 files changed, 25 insertions, 10 deletions
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 5c99ff8d2db8..6e72d661ae42 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -161,7 +161,7 @@ static inline struct request *start_ordered(struct request_queue *q,
161 /* 161 /*
162 * Prep proxy barrier request. 162 * Prep proxy barrier request.
163 */ 163 */
164 blkdev_dequeue_request(rq); 164 elv_dequeue_request(q, rq);
165 q->orig_bar_rq = rq; 165 q->orig_bar_rq = rq;
166 rq = &q->bar_rq; 166 rq = &q->bar_rq;
167 blk_rq_init(q, rq); 167 blk_rq_init(q, rq);
@@ -219,7 +219,7 @@ int blk_do_ordered(struct request_queue *q, struct request **rqp)
219 * This can happen when the queue switches to 219 * This can happen when the queue switches to
220 * ORDERED_NONE while this request is on it. 220 * ORDERED_NONE while this request is on it.
221 */ 221 */
222 blkdev_dequeue_request(rq); 222 elv_dequeue_request(q, rq);
223 if (__blk_end_request(rq, -EOPNOTSUPP, 223 if (__blk_end_request(rq, -EOPNOTSUPP,
224 blk_rq_bytes(rq))) 224 blk_rq_bytes(rq)))
225 BUG(); 225 BUG();
diff --git a/block/blk-core.c b/block/blk-core.c
index 10e8a64a5a5b..7a779d7c69c9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1637,6 +1637,28 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
1637EXPORT_SYMBOL_GPL(blk_insert_cloned_request); 1637EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
1638 1638
1639/** 1639/**
1640 * blkdev_dequeue_request - dequeue request and start timeout timer
1641 * @req: request to dequeue
1642 *
1643 * Dequeue @req and start timeout timer on it. This hands off the
1644 * request to the driver.
1645 *
1646 * Block internal functions which don't want to start timer should
1647 * call elv_dequeue_request().
1648 */
1649void blkdev_dequeue_request(struct request *req)
1650{
1651 elv_dequeue_request(req->q, req);
1652
1653 /*
1654 * We are now handing the request to the hardware, add the
1655 * timeout handler.
1656 */
1657 blk_add_timer(req);
1658}
1659EXPORT_SYMBOL(blkdev_dequeue_request);
1660
1661/**
1640 * __end_that_request_first - end I/O on a request 1662 * __end_that_request_first - end I/O on a request
1641 * @req: the request being processed 1663 * @req: the request being processed
1642 * @error: %0 for success, < %0 for error 1664 * @error: %0 for success, < %0 for error
@@ -1774,7 +1796,7 @@ static void end_that_request_last(struct request *req, int error)
1774 blk_queue_end_tag(req->q, req); 1796 blk_queue_end_tag(req->q, req);
1775 1797
1776 if (blk_queued_rq(req)) 1798 if (blk_queued_rq(req))
1777 blkdev_dequeue_request(req); 1799 elv_dequeue_request(req->q, req);
1778 1800
1779 if (unlikely(laptop_mode) && blk_fs_request(req)) 1801 if (unlikely(laptop_mode) && blk_fs_request(req))
1780 laptop_io_completion(); 1802 laptop_io_completion();
diff --git a/block/elevator.c b/block/elevator.c
index 9ac82dde99dd..a6951f76ba0c 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -844,14 +844,7 @@ void elv_dequeue_request(struct request_queue *q, struct request *rq)
844 */ 844 */
845 if (blk_account_rq(rq)) 845 if (blk_account_rq(rq))
846 q->in_flight++; 846 q->in_flight++;
847
848 /*
849 * We are now handing the request to the hardware, add the
850 * timeout handler.
851 */
852 blk_add_timer(rq);
853} 847}
854EXPORT_SYMBOL(elv_dequeue_request);
855 848
856int elv_queue_empty(struct request_queue *q) 849int elv_queue_empty(struct request_queue *q)
857{ 850{