From dc72ef4ae35c2016fb594bcc85ce871376682174 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 20 Jul 2006 14:54:05 +0200 Subject: [PATCH] [PATCH] Add blk_start_queueing() helper CFQ implements this on its own now, but it's really block layer knowledge. Tells a device queue to start dispatching requests to the driver, taking care to unplug if needed. Also fixes the issue where as/cfq will invoke a stopped queue, which we really don't want. Signed-off-by: Jens Axboe --- block/as-iosched.c | 3 +-- block/cfq-iosched.c | 22 ++++------------------ block/ll_rw_blk.c | 25 ++++++++++++++++++++----- include/linux/blkdev.h | 1 + 4 files changed, 26 insertions(+), 25 deletions(-) diff --git a/block/as-iosched.c b/block/as-iosched.c index f6dc954893..bc13dc0b29 100644 --- a/block/as-iosched.c +++ b/block/as-iosched.c @@ -1280,8 +1280,7 @@ static void as_work_handler(void *data) unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - if (!as_queue_empty(q)) - q->request_fn(q); + blk_start_queueing(q); spin_unlock_irqrestore(q->queue_lock, flags); } diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 6fb1613d44..9f684cc66b 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1552,19 +1552,6 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) __cfq_set_active_queue(cfqd, cfqq); } -/* - * should really be a ll_rw_blk.c helper - */ -static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - request_queue_t *q = cfqd->queue; - - if (!blk_queue_plugged(q)) - q->request_fn(q); - else - __generic_unplug_device(q); -} - /* * Called when a new fs request (rq) is added (to cfqq). Check if there's * something we should do about it @@ -1593,7 +1580,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cic == cfqd->active_cic && del_timer(&cfqd->idle_slice_timer)) { cfq_slice_expired(cfqd, 0); - cfq_start_queueing(cfqd, cfqq); + blk_start_queueing(cfqd->queue); } return; } @@ -1614,7 +1601,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfq_cfqq_wait_request(cfqq)) { cfq_mark_cfqq_must_dispatch(cfqq); del_timer(&cfqd->idle_slice_timer); - cfq_start_queueing(cfqd, cfqq); + blk_start_queueing(cfqd->queue); } } else if (cfq_should_preempt(cfqd, cfqq, rq)) { /* @@ -1624,7 +1611,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, */ cfq_preempt_queue(cfqd, cfqq); cfq_mark_cfqq_must_dispatch(cfqq); - cfq_start_queueing(cfqd, cfqq); + blk_start_queueing(cfqd->queue); } } @@ -1832,8 +1819,7 @@ static void cfq_kick_queue(void *data) unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - blk_remove_plug(q); - q->request_fn(q); + blk_start_queueing(q); spin_unlock_irqrestore(q->queue_lock, flags); } diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index c6dfa88920..346be9ae31 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -2266,6 +2266,25 @@ struct request *blk_get_request(request_queue_t *q, int rw, gfp_t gfp_mask) } EXPORT_SYMBOL(blk_get_request); +/** + * blk_start_queueing - initiate dispatch of requests to device + * @q: request queue to kick into gear + * + * 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. + * + * The queue lock must be held with interrupts disabled. + */ +void blk_start_queueing(request_queue_t *q) +{ + if (!blk_queue_plugged(q)) + q->request_fn(q); + else + __generic_unplug_device(q); +} +EXPORT_SYMBOL(blk_start_queueing); + /** * blk_requeue_request - put a request back on queue * @q: request queue where request should be inserted @@ -2333,11 +2352,7 @@ void blk_insert_request(request_queue_t *q, struct request *rq, drive_stat_acct(rq, rq->nr_sectors, 1); __elv_add_request(q, rq, where, 0); - - if (blk_queue_plugged(q)) - __generic_unplug_device(q); - else - q->request_fn(q); + blk_start_queueing(q); spin_unlock_irqrestore(q->queue_lock, flags); } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 6609371c30..5d8e288db1 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -635,6 +635,7 @@ extern void blk_stop_queue(request_queue_t *q); extern void blk_sync_queue(struct request_queue *q); extern void __blk_stop_queue(request_queue_t *q); extern void blk_run_queue(request_queue_t *); +extern void blk_start_queueing(request_queue_t *); extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *); extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int); extern int blk_rq_unmap_user(struct bio *, unsigned int); -- 2.39.5