linux-kernel - [PATCH] seqlock: Use while instead of if+goto in __read_seqcount

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Message-Id: <20200409134558.90863-1-songmuchun@bytedance.com>
Date:   Thu,  9 Apr 2020 21:45:58 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     peterz@...radead.org, mingo@...hat.com, will@...nel.org,
        mingo@...nel.org
Cc:     linux-kernel@...r.kernel.org,
        Muchun Song <songmuchun@...edance.com>
Subject: [PATCH] seqlock: Use while instead of if+goto in __read_seqcount_begin

The creators of the C language gave us the while keyword. Let's use
that instead of synthesizing it from if+goto.

Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 include/linux/seqlock.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 8b97204f35a77..7bdea019814ce 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -125,12 +125,8 @@ static inline unsigned __read_seqcount_begin(const seqcount_t *s)
 {
 	unsigned ret;
 
-repeat:
-	ret = READ_ONCE(s->sequence);
-	if (unlikely(ret & 1)) {
+	while (unlikely((ret = READ_ONCE(s->sequence)) & 1))
 		cpu_relax();
-		goto repeat;
-	}
 	kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX);
 	return ret;
 }
-- 
2.11.0