From:   Shaoying Xu <shaoyi@amazon.com>
To:     <stable@vger.kernel.org>
CC:     <abuehaze@amazon.com>, <peterz@infradead.org>,
        <longman@redhat.com>, Shaoying Xu <shaoyi@amazon.com>
Subject: [PATCH stable 5.10 3/7] locking/rwsem: Fold __down_{read,write}*()
Date:   Tue, 7 Feb 2023 19:01:31 +0000
Message-ID: <20230207190135.25258-4-shaoyi@amazon.com>
In-Reply-To: <20230207190135.25258-1-shaoyi@amazon.com>
References: <20230207190135.25258-1-shaoyi@amazon.com>
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From: Peter Zijlstra <peterz@infradead.org>

commit c995e638ccbbc65a76d1713c4fdcf927e7e2cb83 upstream

There's a lot needless duplication in __down_{read,write}*(), cure
that with a helper.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201207090243.GE3040@hirez.programming.kicks-ass.net
Cc: <stable@vger.kernel.org> # 5.10
Signed-off-by: Shaoying Xu <shaoyi@amazon.com>
---
 kernel/locking/rwsem.c | 45 +++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 6b62654eb0a8..46f308a01045 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1354,32 +1354,29 @@ static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
 /*
  * lock for reading
  */
-static inline void __down_read(struct rw_semaphore *sem)
+static inline int __down_read_common(struct rw_semaphore *sem, int state)
 {
 	if (!rwsem_read_trylock(sem)) {
-		rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE);
+		if (IS_ERR(rwsem_down_read_slowpath(sem, state)))
+			return -EINTR;
 		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
 	}
+	return 0;
+}
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+	__down_read_common(sem, TASK_UNINTERRUPTIBLE);
 }
 
 static inline int __down_read_interruptible(struct rw_semaphore *sem)
 {
-	if (!rwsem_read_trylock(sem)) {
-		if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE)))
-			return -EINTR;
-		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
-	}
-	return 0;
+	return __down_read_common(sem, TASK_INTERRUPTIBLE);
 }
 
 static inline int __down_read_killable(struct rw_semaphore *sem)
 {
-	if (!rwsem_read_trylock(sem)) {
-		if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_KILLABLE)))
-			return -EINTR;
-		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
-	}
-	return 0;
+	return __down_read_common(sem, TASK_KILLABLE);
 }
 
 static inline int __down_read_trylock(struct rw_semaphore *sem)
@@ -1405,22 +1402,26 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * lock for writing
  */
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	if (unlikely(!rwsem_write_trylock(sem)))
-		rwsem_down_write_slowpath(sem, TASK_UNINTERRUPTIBLE);
-}
-
-static inline int __down_write_killable(struct rw_semaphore *sem)
+static inline int __down_write_common(struct rw_semaphore *sem, int state)
 {
 	if (unlikely(!rwsem_write_trylock(sem))) {
-		if (IS_ERR(rwsem_down_write_slowpath(sem, TASK_KILLABLE)))
+		if (IS_ERR(rwsem_down_write_slowpath(sem, state)))
 			return -EINTR;
 	}
 
 	return 0;
 }
 
+static inline void __down_write(struct rw_semaphore *sem)
+{
+	__down_write_common(sem, TASK_UNINTERRUPTIBLE);
+}
+
+static inline int __down_write_killable(struct rw_semaphore *sem)
+{
+	return __down_write_common(sem, TASK_KILLABLE);
+}
+
 static inline int __down_write_trylock(struct rw_semaphore *sem)
 {
 	DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
-- 
2.38.1