提交 a538cd03 编写于 作者: T Tejun Heo 提交者: Jens Axboe

block: merge blk_invoke_request_fn() into __blk_run_queue()

__blk_run_queue wraps blk_invoke_request_fn() such that it
additionally removes plug and bails out early if the queue is empty.
Both extra operations have their own pending mechanisms and don't
cause any harm correctness-wise when they are done superflously.

The only user of blk_invoke_request_fn() being blk_start_queue(),
there isn't much reason to keep both functions around.  Merge
blk_invoke_request_fn() into __blk_run_queue() and make
blk_start_queue() use __blk_run_queue() instead.

[ Impact: merge two subtly different internal functions ]
Signed-off-by: NTejun Heo <tj@kernel.org>
上级 db2dbb12
......@@ -333,24 +333,6 @@ void blk_unplug(struct request_queue *q)
}
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
*/
if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
q->request_fn(q);
queue_flag_clear(QUEUE_FLAG_REENTER, q);
} else {
queue_flag_set(QUEUE_FLAG_PLUGGED, q);
kblockd_schedule_work(q, &q->unplug_work);
}
}
/**
* blk_start_queue - restart a previously stopped queue
* @q: The &struct request_queue in question
......@@ -365,7 +347,7 @@ void blk_start_queue(struct request_queue *q)
WARN_ON(!irqs_disabled());
queue_flag_clear(QUEUE_FLAG_STOPPED, q);
blk_invoke_request_fn(q);
__blk_run_queue(q);
}
EXPORT_SYMBOL(blk_start_queue);
......@@ -425,12 +407,23 @@ void __blk_run_queue(struct request_queue *q)
{
blk_remove_plug(q);
if (unlikely(blk_queue_stopped(q)))
return;
if (elv_queue_empty(q))
return;
/*
* Only recurse once to avoid overrunning the stack, let the unplug
* handling reinvoke the handler shortly if we already got there.
*/
if (!elv_queue_empty(q))
blk_invoke_request_fn(q);
if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
q->request_fn(q);
queue_flag_clear(QUEUE_FLAG_REENTER, q);
} else {
queue_flag_set(QUEUE_FLAG_PLUGGED, q);
kblockd_schedule_work(q, &q->unplug_work);
}
}
EXPORT_SYMBOL(__blk_run_queue);
......
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