From:   Yajun Deng <yajun.deng@linux.dev>
To:     will@kernel.org, peterz@infradead.org, boqun.feng@gmail.com
Cc:     linux-kernel@vger.kernel.org, Yajun Deng <yajun.deng@linux.dev>
Subject: [PATCH] refcount: introduce refcount_is_one() helper function
Date:   Thu, 18 Nov 2021 11:53:28 +0800
Message-Id: <20211118035328.5730-1-yajun.deng@linux.dev>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

There are many cases where it is necessary to determine if refcount is one,
introduce refcount_is_one() helper function for these cases.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
 include/linux/refcount.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index b8a6e387f8f9..1cc23c0e7454 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -147,6 +147,11 @@ static inline unsigned int refcount_read(const refcount_t *r)
 	return atomic_read(&r->refs);
 }
 
+static inline bool refcount_is_one(const refcount_t *r)
+{
+	return refcount_read(r) == 1;
+}
+
 static inline __must_check bool __refcount_add_not_zero(int i, refcount_t *r, int *oldp)
 {
 	int old = refcount_read(r);
-- 
2.32.0