block: cleanup the flush plug helpers

Consolidate the various helpers into a single blk_flush_plug helper that
takes a plk_plug and the from_scheduler bool and switch all callsites to
call it directly.  Checks that the plug is non-NULL must be performed by
the caller, something that most already do anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211020144119.142582-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index db8b2fe..dfa1993 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1089,7 +1089,7 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
 		return 0;
 
 	if (current->plug)
-		blk_flush_plug_list(current->plug, false);
+		blk_flush_plug(current->plug, false);
 
 	if (blk_queue_enter(q, BLK_MQ_REQ_NOWAIT))
 		return 0;
@@ -1637,7 +1637,7 @@ struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
 }
 EXPORT_SYMBOL(blk_check_plugged);
 
-void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
+void blk_flush_plug(struct blk_plug *plug, bool from_schedule)
 {
 	if (!list_empty(&plug->cb_list))
 		flush_plug_callbacks(plug, from_schedule);
@@ -1659,11 +1659,10 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
  */
 void blk_finish_plug(struct blk_plug *plug)
 {
-	if (plug != current->plug)
-		return;
-	blk_flush_plug_list(plug, false);
-
-	current->plug = NULL;
+	if (plug == current->plug) {
+		blk_flush_plug(plug, false);
+		current->plug = NULL;
+	}
 }
 EXPORT_SYMBOL(blk_finish_plug);