[1/2] block: remove blk_needs_flush_plug

Commit Message

Christoph Hellwig Jan. 27, 2022, 7:05 a.m. UTC

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 <[e-mail]>
---
 fs/fs-writeback.c      |  2 +-
 include/linux/blkdev.h | 13 -------------
 kernel/exit.c          |  2 +-
 kernel/sched/core.c    |  2 +-
 4 files changed, 3 insertions(+), 16 deletions(-)

Comments

Jens Axboe Jan. 27, 2022, 5:19 p.m. UTC | #1

On Thu, 27 Jan 2022 08:05:48 +0100, Christoph Hellwig wrote:
> 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.
> 
> 

Applied, thanks!

[1/2] block: remove blk_needs_flush_plug
      commit: 1642097f8e40bf81c9c5976879a561eb098fc6d8
[2/2] block: check that there is a plug in blk_flush_plug
      commit: 1741f0be918539f186e8262d4bd020629c60b400

Best regards,

Patch

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f8d7fe6db989e..f4ce38f6fc31c 100644
--- 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
index 85c38c3a89c35..95176802ccc92 100644
--- 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
index b00a25bb4ab93..11fc6c9df9f28 100644
--- 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
index 2e4ae00e52d14..ccaa17e5a8306 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6345,7 +6345,7 @@  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);
 }