Commit 204d1a64 authored by Pankaj Gupta's avatar Pankaj Gupta Committed by Song Liu
Browse files

md: add comments in md_flush_request() 



Request coalescing logic is dependent on flush time update in other
context. This patch adds comments to understand the code flow better.

Signed-off-by: default avatarPankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent 81ba3c24

drivers/md/md.c

+4 −0
Original line number Diff line number Diff line
@@ -662,10 +662,14 @@ bool md_flush_request(struct mddev *mddev, struct bio *bio) 
{

	ktime_t req_start = ktime_get_boottime();

	spin_lock_irq(&mddev->lock);

	/* flush requests wait until ongoing flush completes,

	 * hence coalescing all the pending requests.

	 */

	wait_event_lock_irq(mddev->sb_wait,

			    !mddev->flush_bio ||

			    ktime_after(mddev->prev_flush_start, req_start),

			    mddev->lock);

	/* new request after previous flush is completed */

	if (!ktime_after(mddev->prev_flush_start, req_start)) {

		WARN_ON(mddev->flush_bio);

		mddev->flush_bio = bio;