Revert "block: add callback function for unplug notification"

MD can't use this since it really requires us to be able to
keep more than a single piece of state for the unplug. Commit
048c9374 added the required support for MD, so get rid of this
now unused code.

This reverts commit f75664570d8b75469cc468f23c2b27220984983b.

Conflicts:

	block/blk-core.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

2 files changed, 0 insertions, 19 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 77edf0512338..09b262811fff 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2674,9 +2674,6 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
 {
         trace_block_unplug(q, depth, !from_schedule);
         __blk_run_queue(q, from_schedule);
-
-        if (q->unplugged_fn)
-                q->unplugged_fn(q);
 }
 
 static void flush_plug_callbacks(struct blk_plug *plug)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index eb949045bb12..1fa769293597 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -790,22 +790,6 @@ 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;