From 80a4b58e36b63d7b0b592beb1bd6410aadeeb63c Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 14 Oct 2008 09:51:06 +0200 Subject: 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 --- block/blk-core.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 2d053b58441..91532f2d2fa 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. */ -- cgit v1.2.3-18-g5258 From 496aa8a98f5ab22ced46be5dc2087cdf3d029bd7 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Thu, 16 Oct 2008 07:46:23 +0200 Subject: block: fix current kernel-doc warnings Fix block kernel-doc warnings: Warning(linux-2.6.27-git4//fs/block_dev.c:1272): No description found for parameter 'path' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'cpu' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'part' Warning(/var/linsrc/linux-2.6.27-git4//block/genhd.c:544): No description found for parameter 'partno' Signed-off-by: Randy Dunlap Signed-off-by: Jens Axboe --- block/blk-core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 91532f2d2fa..8517264eb71 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1018,8 +1018,9 @@ static void part_round_stats_single(int cpu, struct hd_struct *part, } /** - * part_round_stats() - Round off the performance stats on a struct - * disk_stats. + * part_round_stats() - Round off the performance stats on a struct disk_stats. + * @cpu: cpu number for stats access + * @part: target partition * * The average IO queue length and utilisation statistics are maintained * by observing the current state of the queue length and the amount of -- cgit v1.2.3-18-g5258 From 713ada9ba94f2ad874cffd074b83e3dc681ca82f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 16 Oct 2008 13:44:57 +0200 Subject: block: move q->unplug_work initialization modprobe loop; rmmod loop effectively creates a blk_queue and destroys it which results in q->unplug_work being canceled without it ever being initialized. Therefore, move the initialization of q->unplug_work from blk_queue_make_request() to blk_alloc_queue*(). Reported-by: Alexey Dobriyan Signed-off-by: Peter Zijlstra Signed-off-by: Jens Axboe --- block/blk-core.c | 1 + 1 file changed, 1 insertion(+) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 8517264eb71..fcbd56dd41f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -515,6 +515,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) init_timer(&q->unplug_timer); setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); INIT_LIST_HEAD(&q->timeout_list); + INIT_WORK(&q->unplug_work, blk_unplug_work); kobject_init(&q->kobj, &blk_queue_ktype); -- cgit v1.2.3-18-g5258 From f73e2d13a16cc88c4faa4729967f92bfeec8a142 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 17 Oct 2008 14:03:08 +0200 Subject: block: remove __generic_unplug_device() from exports The only out-of-core user is IDE, and that should be using blk_start_queueing() instead. Signed-off-by: Jens Axboe --- block/blk-core.c | 1 - 1 file changed, 1 deletion(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index fcbd56dd41f..81a49600497 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -257,7 +257,6 @@ void __generic_unplug_device(struct request_queue *q) q->request_fn(q); } -EXPORT_SYMBOL(__generic_unplug_device); /** * generic_unplug_device - fire a request queue -- cgit v1.2.3-18-g5258