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author | Jens Axboe <jens.axboe@oracle.com> | 2008-10-14 09:51:06 +0200 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-17 08:46:57 +0200 |
commit | 80a4b58e36b63d7b0b592beb1bd6410aadeeb63c (patch) | |
tree | a37df7feb2db67254cc8927730828e87706b2205 /block/blk-core.c | |
parent | ee2e992cc28553f6c4dd1ab5483c8733c393626b (diff) | |
download | kernel_samsung_crespo-80a4b58e36b63d7b0b592beb1bd6410aadeeb63c.zip kernel_samsung_crespo-80a4b58e36b63d7b0b592beb1bd6410aadeeb63c.tar.gz kernel_samsung_crespo-80a4b58e36b63d7b0b592beb1bd6410aadeeb63c.tar.bz2 |
block: only call ->request_fn when the queue is not stopped
Callers should use either blk_run_queue/__blk_run_queue, or
blk_start_queueing() to invoke request handling instead of calling
->request_fn() directly as that does not take the queue stopped
flag into account.
Also add appropriate comments on the above functions to detail
their usage.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-core.c')
-rw-r--r-- | block/blk-core.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 2d053b5..91532f2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -325,6 +325,9 @@ EXPORT_SYMBOL(blk_unplug); static void blk_invoke_request_fn(struct request_queue *q) { + if (unlikely(blk_queue_stopped(q))) + return; + /* * one level of recursion is ok and is much faster than kicking * the unplug handling @@ -399,8 +402,13 @@ void blk_sync_queue(struct request_queue *q) EXPORT_SYMBOL(blk_sync_queue); /** - * blk_run_queue - run a single device queue + * __blk_run_queue - run a single device queue * @q: The queue to run + * + * Description: + * See @blk_run_queue. This variant must be called with the queue lock + * held and interrupts disabled. + * */ void __blk_run_queue(struct request_queue *q) { @@ -418,6 +426,12 @@ EXPORT_SYMBOL(__blk_run_queue); /** * blk_run_queue - run a single device queue * @q: The queue to run + * + * Description: + * Invoke request handling on this queue, if it has pending work to do. + * May be used to restart queueing when a request has completed. Also + * See @blk_start_queueing. + * */ void blk_run_queue(struct request_queue *q) { @@ -884,7 +898,8 @@ EXPORT_SYMBOL(blk_get_request); * * This is basically a helper to remove the need to know whether a queue * is plugged or not if someone just wants to initiate dispatch of requests - * for this queue. + * for this queue. Should be used to start queueing on a device outside + * of ->request_fn() context. Also see @blk_run_queue. * * The queue lock must be held with interrupts disabled. */ |