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| author | Jens Axboe <jaxboe@fusionio.com> | 2011-04-12 10:17:31 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-04-12 10:17:31 +0200 |
| commit | f75664570d8b75469cc468f23c2b27220984983b (patch) | |
| tree | 48f1e9b8576892cab65361e39b874e0e07d3b32a | |
| parent | 188112722cce083c8f1a7d0d84f55c2cd885920c (diff) | |
| download | linux-f75664570d8b75469cc468f23c2b27220984983b.tar.gz linux-f75664570d8b75469cc468f23c2b27220984983b.tar.bz2 linux-f75664570d8b75469cc468f23c2b27220984983b.zip | |
block: add callback function for unplug notification
MD would like to know when a queue is unplugged, so it can flush
it's bitmap writes. Add such a callback.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| -rw-r--r-- | block/blk-core.c | 3 | ||||
| -rw-r--r-- | block/blk-settings.c | 16 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 3 |
3 files changed, 22 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 0c0ea10e61ea..76850fc9cf23 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2672,6 +2672,9 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth) { trace_block_unplug_io(q, depth); __blk_run_queue(q, false); + + if (q->unplugged_fn) + q->unplugged_fn(q); } static void flush_plug_list(struct blk_plug *plug) diff --git a/block/blk-settings.c b/block/blk-settings.c index 1fa769293597..eb949045bb12 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -790,6 +790,22 @@ void blk_queue_flush(struct request_queue *q, unsigned int flush) } EXPORT_SYMBOL_GPL(blk_queue_flush); +/** + * blk_queue_unplugged - register a callback for an unplug event + * @q: the request queue for the device + * @fn: the function to call + * + * Some stacked drivers may need to know when IO is dispatched on an + * unplug event. By registrering a callback here, they will be notified + * when someone flushes their on-stack queue plug. The function will be + * called with the queue lock held. + */ +void blk_queue_unplugged(struct request_queue *q, unplugged_fn *fn) +{ + q->unplugged_fn = fn; +} +EXPORT_SYMBOL(blk_queue_unplugged); + static int __init blk_settings_init(void) { blk_max_low_pfn = max_low_pfn - 1; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 32176cc8e715..c07ffafac5d4 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -196,6 +196,7 @@ typedef void (request_fn_proc) (struct request_queue *q); typedef int (make_request_fn) (struct request_queue *q, struct bio *bio); typedef int (prep_rq_fn) (struct request_queue *, struct request *); typedef void (unprep_rq_fn) (struct request_queue *, struct request *); +typedef void (unplugged_fn) (struct request_queue *); struct bio_vec; struct bvec_merge_data { @@ -283,6 +284,7 @@ struct request_queue rq_timed_out_fn *rq_timed_out_fn; dma_drain_needed_fn *dma_drain_needed; lld_busy_fn *lld_busy_fn; + unplugged_fn *unplugged_fn; /* * Dispatch queue sorting @@ -841,6 +843,7 @@ extern void blk_queue_dma_alignment(struct request_queue *, int); extern void blk_queue_update_dma_alignment(struct request_queue *, int); extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *); extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *); +extern void blk_queue_unplugged(struct request_queue *, unplugged_fn *); extern void blk_queue_rq_timeout(struct request_queue *, unsigned int); extern void blk_queue_flush(struct request_queue *q, unsigned int flush); extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); |