From 9cbb17508808f8a6bdd83354b61e126ac4fa6fed Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 31 Jul 2012 09:08:14 +0200 Subject: [PATCH] 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 ++++++++++++++++++++++ drivers/block/umem.c | 35 ++++++------------------------- drivers/md/md.c | 56 +++++--------------------------------------------- drivers/md/md.h | 8 +++++++- include/linux/blkdev.h | 8 ++++++-- 5 files changed, 49 insertions(+), 83 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index dd134d8..177ddcf 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; diff --git a/drivers/block/umem.c b/drivers/block/umem.c index 9a72277..6ef3489 100644 --- a/drivers/block/umem.c +++ b/drivers/block/umem.c @@ -513,42 +513,19 @@ static void process_page(unsigned long data) } } -struct mm_plug_cb { - struct blk_plug_cb cb; - struct cardinfo *card; -}; - static void mm_unplug(struct blk_plug_cb *cb) { - struct mm_plug_cb *mmcb = container_of(cb, struct mm_plug_cb, cb); + struct cardinfo *card = cb->data; - spin_lock_irq(&mmcb->card->lock); - activate(mmcb->card); - spin_unlock_irq(&mmcb->card->lock); - kfree(mmcb); + spin_lock_irq(&card->lock); + activate(card); + spin_unlock_irq(&card->lock); + kfree(cb); } static int mm_check_plugged(struct cardinfo *card) { - struct blk_plug *plug = current->plug; - struct mm_plug_cb *mmcb; - - if (!plug) - return 0; - - list_for_each_entry(mmcb, &plug->cb_list, cb.list) { - if (mmcb->cb.callback == mm_unplug && mmcb->card == card) - return 1; - } - /* Not currently on the callback list */ - mmcb = kmalloc(sizeof(*mmcb), GFP_ATOMIC); - if (!mmcb) - return 0; - - mmcb->card = card; - mmcb->cb.callback = mm_unplug; - list_add(&mmcb->cb.list, &plug->cb_list); - return 1; + return !!blk_check_plugged(mm_unplug, card, sizeof(struct blk_plug_cb)); } static void mm_make_request(struct request_queue *q, struct bio *bio) diff --git a/drivers/md/md.c b/drivers/md/md.c index 3438117..b493fa4 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -498,59 +498,13 @@ void md_flush_request(struct mddev *mddev, struct bio *bio) } EXPORT_SYMBOL(md_flush_request); -/* Support for plugging. - * This mirrors the plugging support in request_queue, but does not - * require having a whole queue or request structures. - * We allocate an md_plug_cb for each md device and each thread it gets - * plugged on. This links tot the private plug_handle structure in the - * personality data where we keep a count of the number of outstanding - * plugs so other code can see if a plug is active. - */ -struct md_plug_cb { - struct blk_plug_cb cb; - struct mddev *mddev; -}; - -static void plugger_unplug(struct blk_plug_cb *cb) +void md_unplug(struct blk_plug_cb *cb) { - struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb); - md_wakeup_thread(mdcb->mddev->thread); - kfree(mdcb); -} - -/* Check that an unplug wakeup will come shortly. - * If not, wakeup the md thread immediately - */ -int mddev_check_plugged(struct mddev *mddev) -{ - struct blk_plug *plug = current->plug; - struct md_plug_cb *mdcb; - - if (!plug) - return 0; - - list_for_each_entry(mdcb, &plug->cb_list, cb.list) { - if (mdcb->cb.callback == plugger_unplug && - mdcb->mddev == mddev) { - /* Already on the list, move to top */ - if (mdcb != list_first_entry(&plug->cb_list, - struct md_plug_cb, - cb.list)) - list_move(&mdcb->cb.list, &plug->cb_list); - return 1; - } - } - /* Not currently on the callback list */ - mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC); - if (!mdcb) - return 0; - - mdcb->mddev = mddev; - mdcb->cb.callback = plugger_unplug; - list_add(&mdcb->cb.list, &plug->cb_list); - return 1; + struct mddev *mddev = cb->data; + md_wakeup_thread(mddev->thread); + kfree(cb); } -EXPORT_SYMBOL_GPL(mddev_check_plugged); +EXPORT_SYMBOL(md_unplug); static inline struct mddev *mddev_get(struct mddev *mddev) { diff --git a/drivers/md/md.h b/drivers/md/md.h index 91786c4..8f998e0 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -627,6 +627,12 @@ extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask, struct mddev *mddev); extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, struct mddev *mddev); -extern int mddev_check_plugged(struct mddev *mddev); extern void md_trim_bio(struct bio *bio, int offset, int size); + +extern void md_unplug(struct blk_plug_cb *cb); +static inline int mddev_check_plugged(struct mddev *mddev) +{ + return !!blk_check_plugged(md_unplug, mddev, + sizeof(struct blk_plug_cb)); +} #endif /* _MD_MD_H */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 3816ce8..607ca22 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -922,11 +922,15 @@ struct blk_plug { }; #define BLK_MAX_REQUEST_COUNT 16 +struct blk_plug_cb; +typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *); struct blk_plug_cb { struct list_head list; - void (*callback)(struct blk_plug_cb *); + blk_plug_cb_fn callback; + void *data; }; - +extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, + void *data, int size); extern void blk_start_plug(struct blk_plug *); extern void blk_finish_plug(struct blk_plug *); extern void blk_flush_plug_list(struct blk_plug *, bool); -- 2.7.4