linux-kernel - [PATCH v2] md: make md_flush

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Message-Id: <20240528203149.2383260-1-linan666@huaweicloud.com>
Date: Wed, 29 May 2024 04:31:49 +0800
From: linan666@...weicloud.com
To: song@...nel.org
Cc: linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linan666@...weicloud.com,
	yukuai3@...wei.com,
	yi.zhang@...wei.com,
	houtao1@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH v2] md: make md_flush_request() more readable

From: Li Nan <linan122@...wei.com>

Setting bio to NULL and checking 'if(!bio)' is redundant and looks strange,
just consolidate them into one condition. There are no functional changes.

Suggested-by: Christoph Hellwig <hch@...radead.org>
Signed-off-by: Li Nan <linan122@...wei.com>
---
v2: Rewrite the code according to Christoph's suggestion.

 drivers/md/md.c | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index aff9118ff697..9598b4898ea9 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -654,24 +654,22 @@ bool md_flush_request(struct mddev *mddev, struct bio *bio)
 		WARN_ON(percpu_ref_is_zero(&mddev->active_io));
 		percpu_ref_get(&mddev->active_io);
 		mddev->flush_bio = bio;
-		bio = NULL;
-	}
-	spin_unlock_irq(&mddev->lock);
-
-	if (!bio) {
+		spin_unlock_irq(&mddev->lock);
 		INIT_WORK(&mddev->flush_work, submit_flushes);
 		queue_work(md_wq, &mddev->flush_work);
-	} else {
-		/* flush was performed for some other bio while we waited. */
-		if (bio->bi_iter.bi_size == 0)
-			/* an empty barrier - all done */
-			bio_endio(bio);
-		else {
-			bio->bi_opf &= ~REQ_PREFLUSH;
-			return false;
-		}
+		return true;
 	}
-	return true;
+
+	/* flush was performed for some other bio while we waited. */
+	spin_unlock_irq(&mddev->lock);
+	if (bio->bi_iter.bi_size == 0) {
+		/* pure flush without data - all done */
+		bio_endio(bio);
+		return true;
+	}
+
+	bio->bi_opf &= ~REQ_PREFLUSH;
+	return false;
 }
 EXPORT_SYMBOL(md_flush_request);
 
-- 
2.39.2