Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760700Ab2FDOnE (ORCPT ); Mon, 4 Jun 2012 10:43:04 -0400 Received: from mexforward.lss.emc.com ([128.222.32.20]:37522 "EHLO mexforward.lss.emc.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755240Ab2FDOnC (ORCPT ); Mon, 4 Jun 2012 10:43:02 -0400 From: Tao Guo To: linux-kernel@vger.kernel.org Cc: Tao Guo , Tao Guo , Neil Brown , Jens Axboe , , Andrew Morton Subject: [PATCH 1/2] block: Move general unplug callback function from md/raid to blk-core Date: Mon, 4 Jun 2012 10:41:50 -0400 Message-Id: <1338820911-4733-1-git-send-email-glorioustao@gmail.com> X-Mailer: git-send-email 1.7.7.6 X-EMM-MHVC: 1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8258 Lines: 263 Other components may also require an unplug callback, so move this function from md/raid to block generic layer. Signed-off-by: Tao Guo Cc: Neil Brown Cc: Jens Axboe Cc: Cc: Andrew Morton Cc: --- block/blk-core.c | 36 ++++++++++++++++++++++++++++++++- block/blk-settings.c | 1 + block/blk.h | 1 - drivers/md/md.c | 51 ++++------------------------------------------- drivers/md/md.h | 3 -- drivers/md/raid1.c | 2 +- drivers/md/raid5.c | 4 +- include/linux/blkdev.h | 8 ++++++- 8 files changed, 51 insertions(+), 55 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 3c923a7..5639a3d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2840,6 +2840,39 @@ void blk_start_plug(struct blk_plug *plug) } EXPORT_SYMBOL(blk_start_plug); +/* Check that an unplug wakeup will come shortly. + */ +bool blk_check_plugged(struct request_queue *q, plug_cb_fn cb_fn) +{ + struct blk_plug *plug = current->plug; + struct blk_plug_cb *cb; + + if (!plug) + return false; + + list_for_each_entry(cb, &plug->cb_list, list) { + if (cb->cb_fn == cb_fn && cb->q == q) { + /* Already on the list, move to top */ + if (cb != list_first_entry(&plug->cb_list, + struct blk_plug_cb, + list)) + list_move(&cb->list, &plug->cb_list); + return true; + } + } + /* Not currently on the callback list */ + cb = kmalloc(sizeof(*cb), GFP_ATOMIC); + if (!cb) + return false; + + cb->q = q; + cb->cb_fn = cb_fn; + atomic_inc(&q->plug_cnt); + list_add(&cb->list, &plug->cb_list); + return true; +} +EXPORT_SYMBOL(blk_check_plugged); + static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) { struct request *rqa = container_of(a, struct request, queuelist); @@ -2897,7 +2930,8 @@ static void flush_plug_callbacks(struct blk_plug *plug) struct blk_plug_cb, list); list_del(&cb->list); - cb->callback(cb); + cb->cb_fn(cb); + kfree(cb); } } diff --git a/block/blk-settings.c b/block/blk-settings.c index d3234fc..c54d603 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -181,6 +181,7 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) blk_queue_dma_alignment(q, 511); blk_queue_congestion_threshold(q); q->nr_batching = BLK_BATCH_REQ; + atomic_set(&q->plug_cnt, 0); blk_set_default_limits(&q->limits); diff --git a/block/blk.h b/block/blk.h index 85f6ae4..a62195b 100644 --- a/block/blk.h +++ b/block/blk.h @@ -33,7 +33,6 @@ bool __blk_end_bidi_request(struct request *rq, int error, void blk_rq_timed_out_timer(unsigned long data); void blk_delete_timer(struct request *); void blk_add_timer(struct request *); -void __generic_unplug_device(struct request_queue *); /* * Internal atomic flags for request handling diff --git a/drivers/md/md.c b/drivers/md/md.c index 1c2f904..08b64ef 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -498,25 +498,11 @@ 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) +static void mddev_unplug(struct blk_plug_cb *cb) { - struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb); - if (atomic_dec_and_test(&mdcb->mddev->plug_cnt)) - md_wakeup_thread(mdcb->mddev->thread); - kfree(mdcb); + struct mddev *mddev = cb->q->queuedata; + if (atomic_dec_and_test(&cb->q->plug_cnt)) + md_wakeup_thread(mddev->thread); } /* Check that an unplug wakeup will come shortly. @@ -524,33 +510,7 @@ static void plugger_unplug(struct blk_plug_cb *cb) */ 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; - atomic_inc(&mddev->plug_cnt); - list_add(&mdcb->cb.list, &plug->cb_list); - return 1; + return blk_check_plugged(mddev->queue, mddev_unplug); } EXPORT_SYMBOL_GPL(mddev_check_plugged); @@ -602,7 +562,6 @@ void mddev_init(struct mddev *mddev) atomic_set(&mddev->active, 1); atomic_set(&mddev->openers, 0); atomic_set(&mddev->active_io, 0); - atomic_set(&mddev->plug_cnt, 0); spin_lock_init(&mddev->write_lock); atomic_set(&mddev->flush_pending, 0); init_waitqueue_head(&mddev->sb_wait); diff --git a/drivers/md/md.h b/drivers/md/md.h index 7b4a3c3..91786c4 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -266,9 +266,6 @@ struct mddev { int new_chunk_sectors; int reshape_backwards; - atomic_t plug_cnt; /* If device is expecting - * more bios soon. - */ struct md_thread *thread; /* management thread */ struct md_thread *sync_thread; /* doing resync or reconstruct */ sector_t curr_resync; /* last block scheduled */ diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 835de71..6e6d65f 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2170,7 +2170,7 @@ static void raid1d(struct mddev *mddev) blk_start_plug(&plug); for (;;) { - if (atomic_read(&mddev->plug_cnt) == 0) + if (atomic_read(&mddev->queue->plug_cnt) == 0) flush_pending_writes(conf); spin_lock_irqsave(&conf->device_lock, flags); diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index d267672..e98bf00 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -4521,7 +4521,7 @@ static void raid5d(struct mddev *mddev) while (1) { struct bio *bio; - if (atomic_read(&mddev->plug_cnt) == 0 && + if (atomic_read(&mddev->queue->plug_cnt) == 0 && !list_empty(&conf->bitmap_list)) { /* Now is a good time to flush some bitmap updates */ conf->seq_flush++; @@ -4531,7 +4531,7 @@ static void raid5d(struct mddev *mddev) conf->seq_write = conf->seq_flush; activate_bit_delay(conf); } - if (atomic_read(&mddev->plug_cnt) == 0) + if (atomic_read(&mddev->queue->plug_cnt) == 0) raid5_activate_delayed(conf); while ((bio = remove_bio_from_retry(conf))) { diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ba43f40..69945e4 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -316,6 +316,9 @@ struct request_queue { * ll_rw_blk doesn't touch it. */ void *queuedata; + atomic_t plug_cnt; /* If device is expecting + * more bios soon. + */ /* * various queue flags, see QUEUE_* below @@ -914,12 +917,15 @@ struct blk_plug { struct blk_plug_cb { struct list_head list; - void (*callback)(struct blk_plug_cb *); + struct request_queue *q; + void (*cb_fn)(struct blk_plug_cb *); }; +typedef void (plug_cb_fn) (struct blk_plug_cb *cb); 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); +extern bool blk_check_plugged(struct request_queue *q, plug_cb_fn cb_fn); static inline void blk_flush_plug(struct task_struct *tsk) { -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/