From 9cbb17508808f8a6bdd83354b61e126ac4fa6fed Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 31 Jul 2012 09:08:14 +0200 Subject: blk: centralize non-request unplug handling. Both md and umem has similar code for getting notified on an blk_finish_plug event. Centralize this code in block/ and allow each driver to provide its distinctive difference. Signed-off-by: NeilBrown Signed-off-by: Jens Axboe --- block/blk-core.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index dd134d834d58..177ddcf356e6 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2927,6 +2927,31 @@ static void flush_plug_callbacks(struct blk_plug *plug) } } +struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, + int size) +{ + struct blk_plug *plug = current->plug; + struct blk_plug_cb *cb; + + if (!plug) + return NULL; + + list_for_each_entry(cb, &plug->cb_list, list) + if (cb->callback == unplug && cb->data == data) + return cb; + + /* Not currently on the callback list */ + BUG_ON(size < sizeof(*cb)); + cb = kzalloc(size, GFP_ATOMIC); + if (cb) { + cb->data = data; + cb->callback = unplug; + list_add(&cb->list, &plug->cb_list); + } + return cb; +} +EXPORT_SYMBOL(blk_check_plugged); + void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) { struct request_queue *q; -- cgit v1.2.3-59-g8ed1b From 2a7d5559b346574057dce4672d1ed9aaa9d1e685 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Tue, 31 Jul 2012 09:08:15 +0200 Subject: block: stack unplug MD raid1 prepares to dispatch request in unplug callback. If make_request in low level queue also uses unplug callback to dispatch request, the low level queue's unplug callback will not be called. Recheck the callback list helps this case. Signed-off-by: Shaohua Li Signed-off-by: NeilBrown Signed-off-by: Jens Axboe --- block/blk-core.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 177ddcf356e6..35bf4fe8234c 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2913,17 +2913,16 @@ static void flush_plug_callbacks(struct blk_plug *plug) { LIST_HEAD(callbacks); - if (list_empty(&plug->cb_list)) - return; - - list_splice_init(&plug->cb_list, &callbacks); + while (!list_empty(&plug->cb_list)) { + list_splice_init(&plug->cb_list, &callbacks); - while (!list_empty(&callbacks)) { - struct blk_plug_cb *cb = list_first_entry(&callbacks, + while (!list_empty(&callbacks)) { + struct blk_plug_cb *cb = list_first_entry(&callbacks, struct blk_plug_cb, list); - list_del(&cb->list); - cb->callback(cb); + list_del(&cb->list); + cb->callback(cb); + } } } -- cgit v1.2.3-59-g8ed1b From 74018dc3063a2c729fc73041c0a9f03aac995920 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 31 Jul 2012 09:08:15 +0200 Subject: blk: pass from_schedule to non-request unplug functions. This will allow md/raid to know why the unplug was called, and will be able to act according - if !from_schedule it is safe to perform tasks which could themselves schedule. Signed-off-by: NeilBrown Signed-off-by: Jens Axboe --- block/blk-core.c | 6 +++--- drivers/block/umem.c | 2 +- drivers/md/md.c | 2 +- drivers/md/md.h | 2 +- include/linux/blkdev.h | 2 +- 5 files changed, 7 insertions(+), 7 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 35bf4fe8234c..4b4dbdfbca89 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2909,7 +2909,7 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth, } -static void flush_plug_callbacks(struct blk_plug *plug) +static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) { LIST_HEAD(callbacks); @@ -2921,7 +2921,7 @@ static void flush_plug_callbacks(struct blk_plug *plug) struct blk_plug_cb, list); list_del(&cb->list); - cb->callback(cb); + cb->callback(cb, from_schedule); } } } @@ -2961,7 +2961,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) BUG_ON(plug->magic != PLUG_MAGIC); - flush_plug_callbacks(plug); + flush_plug_callbacks(plug, from_schedule); if (list_empty(&plug->list)) return; diff --git a/drivers/block/umem.c b/drivers/block/umem.c index 6ef3489568e3..eb0d8216f557 100644 --- a/drivers/block/umem.c +++ b/drivers/block/umem.c @@ -513,7 +513,7 @@ static void process_page(unsigned long data) } } -static void mm_unplug(struct blk_plug_cb *cb) +static void mm_unplug(struct blk_plug_cb *cb, bool from_schedule) { struct cardinfo *card = cb->data; diff --git a/drivers/md/md.c b/drivers/md/md.c index b493fa417387..db02d2efb76f 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -498,7 +498,7 @@ void md_flush_request(struct mddev *mddev, struct bio *bio) } EXPORT_SYMBOL(md_flush_request); -void md_unplug(struct blk_plug_cb *cb) +void md_unplug(struct blk_plug_cb *cb, bool from_schedule) { struct mddev *mddev = cb->data; md_wakeup_thread(mddev->thread); diff --git a/drivers/md/md.h b/drivers/md/md.h index 8f998e08fb87..f385b038589d 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -629,7 +629,7 @@ extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, struct mddev *mddev); extern void md_trim_bio(struct bio *bio, int offset, int size); -extern void md_unplug(struct blk_plug_cb *cb); +extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule); static inline int mddev_check_plugged(struct mddev *mddev) { return !!blk_check_plugged(md_unplug, mddev, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 607ca228f47e..4e72a9d48232 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -923,7 +923,7 @@ struct blk_plug { #define BLK_MAX_REQUEST_COUNT 16 struct blk_plug_cb; -typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *); +typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool); struct blk_plug_cb { struct list_head list; blk_plug_cb_fn callback; -- cgit v1.2.3-59-g8ed1b