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author | Jens Axboe <jaxboe@fusionio.com> | 2011-04-12 10:17:31 +0200 |
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committer | Jens Axboe <jaxboe@fusionio.com> | 2011-04-12 10:17:31 +0200 |
commit | f75664570d8b75469cc468f23c2b27220984983b (patch) | |
tree | 48f1e9b8576892cab65361e39b874e0e07d3b32a /block | |
parent | 188112722cce083c8f1a7d0d84f55c2cd885920c (diff) | |
download | linux-3.10-f75664570d8b75469cc468f23c2b27220984983b.tar.gz linux-3.10-f75664570d8b75469cc468f23c2b27220984983b.tar.bz2 linux-3.10-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>
Diffstat (limited to 'block')
-rw-r--r-- | block/blk-core.c | 3 | ||||
-rw-r--r-- | block/blk-settings.c | 16 |
2 files changed, 19 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 0c0ea10e61e..76850fc9cf2 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 1fa76929359..eb949045bb1 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; |