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 <hch@lst.de>
Link: https://lore.kernel.org/r/20220127070549.1377856-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f8d7fe6..f4ce38f 100644 (file)
--- 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 99a4384..f902a1c 100644 (file)
--- 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 b00a25b..11fc6c9 100644 (file)
--- 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 848eaa0..3487bb9 100644 (file)
--- 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);
 }