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Commit f7566457 authored by Jens Axboe's avatar Jens Axboe
Browse files

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: default avatarJens Axboe <jaxboe@fusionio.com>
parent 18811272

block/blk-core.c

+3 −0
Original line number Diff line number Diff line
@@ -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)

block/blk-settings.c

+16 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/blkdev.h

+3 −0
Original line number Diff line number Diff line
@@ -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);