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| author | Pankaj Gupta <pankaj.gupta@cloud.ionos.com> | 2020-11-11 06:16:57 +0100 |
|---|---|---|
| committer | Song Liu <songliubraving@fb.com> | 2020-11-30 19:12:34 +0100 |
| commit | 204d1a6434158ac655fc4037f29742b9b6103f0e (patch) | |
| tree | 73691a29783d479cadda64c08f45517ac503ace1 /drivers/md/md.c | |
| parent | md: improve variable names in md_flush_request() (diff) | |
| download | linux-204d1a6434158ac655fc4037f29742b9b6103f0e.tar.xz linux-204d1a6434158ac655fc4037f29742b9b6103f0e.zip | |
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: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Diffstat (limited to 'drivers/md/md.c')
| -rw-r--r-- | drivers/md/md.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 3992e8c5c0d6..a0998ad6388c 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -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; |