[PATCH] refcount: introduce refcount_is_one() helper function

* [PATCH] refcount: introduce refcount_is_one() helper function
@ 2021-11-18  3:53 Yajun Deng
  2021-11-18  7:42 ` Peter Zijlstra
  2021-11-18  8:12 ` yajun.deng
  0 siblings, 2 replies; 6+ messages in thread
From: Yajun Deng @ 2021-11-18  3:53 UTC (permalink / raw)
  To: will, peterz, boqun.feng; +Cc: linux-kernel, Yajun Deng

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


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