block: remove blk_needs_flush_plug

blk_needs_flush_plug fails to account for the cb_list, which needs flushing as well. Remove it and just check if there is a plug instead of poking into the internals of the plug structure. Signed-off-by: Christoph Hellwig <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jens Axboe <[email protected]>
niw · Feb 2, 2022 · b1f866b · b1f866b
1 parent a7c50c9
commit b1f866b
Show file tree

Hide file tree

Showing 4 changed files with 3 additions and 16 deletions.
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
@@ -2301,7 +2301,7 @@ void wakeup_flusher_threads(enum wb_reason reason)
 	/*
 	 * If we are expecting writeback progress we must submit plugged IO.
 	 */
-	if (blk_needs_flush_plug(current))
+	if (current->plug)
 		blk_flush_plug(current->plug, true);
 
 	rcu_read_lock();

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
@@ -1055,14 +1055,6 @@ extern void blk_finish_plug(struct blk_plug *);
 
 void blk_flush_plug(struct blk_plug *plug, bool from_schedule);
 
-static inline bool blk_needs_flush_plug(struct task_struct *tsk)
-{
-	struct blk_plug *plug = tsk->plug;
-
-	return plug &&
-		 (plug->mq_list || !list_empty(&plug->cb_list));
-}
-
 int blkdev_issue_flush(struct block_device *bdev);
 long nr_blockdev_pages(void);
 #else /* CONFIG_BLOCK */
@@ -1086,11 +1078,6 @@ static inline void blk_flush_plug(struct blk_plug *plug, bool async)
 {
 }
 
-static inline bool blk_needs_flush_plug(struct task_struct *tsk)
-{
-	return false;
-}
-
 static inline int blkdev_issue_flush(struct block_device *bdev)
 {
 	return 0;

diff --git a/kernel/exit.c b/kernel/exit.c
@@ -735,7 +735,7 @@ void __noreturn do_exit(long code)
 	struct task_struct *tsk = current;
 	int group_dead;
 
-	WARN_ON(blk_needs_flush_plug(tsk));
+	WARN_ON(tsk->plug);
 
 	/*
 	 * If do_dead is called because this processes oopsed, it's possible

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -6344,7 +6344,7 @@ static inline void sched_submit_work(struct task_struct *tsk)
 	 * If we are going to sleep and we have plugged IO queued,
 	 * make sure to submit it to avoid deadlocks.
 	 */
-	if (blk_needs_flush_plug(tsk))
+	if (tsk->plug)
 		blk_flush_plug(tsk->plug, true);
 }