Merge branch 'md-fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into block-5.11

Pull MD fix from Song.

* 'md-fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: Set prev_flush_start and flush_bio in an atomic way

Author: axboe

drivers/md/md.c

@@ -639,8 +639,10 @@ static void md_submit_flush_data(struct work_struct *ws)
 	 * could wait for this and below md_handle_request could wait for those
 	 * bios because of suspend check
 	 */
+	spin_lock_irq(&mddev->lock);
 	mddev->prev_flush_start = mddev->start_flush;
 	mddev->flush_bio = NULL;
+	spin_unlock_irq(&mddev->lock);
 	wake_up(&mddev->sb_wait);
 
 	if (bio->bi_iter.bi_size == 0) {