linux-kernel - [PATCH 2/4] locking/rt: Remove one __cond_lock() in RT's spin_trylock

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Message-ID: <20240812104200.2239232-3-bigeasy@linutronix.de>
Date: Mon, 12 Aug 2024 12:39:03 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: linux-kernel@...r.kernel.org
Cc: tglx@...utronix.de,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Will Deacon <will@...nel.org>,
	Waiman Long <longman@...hat.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 2/4] locking/rt: Remove one __cond_lock() in RT's spin_trylock_irqsave()

spin_trylock_irqsave() has a __cond_lock() wrapper which points to
__spin_trylock_irqsave(). The function then invokes spin_trylock() which
has another __cond_lock() finally pointing to rt_spin_trylock().

The compiler has no problem to parse this but sparse does not recognise
that users of spin_trylock_irqsave() acquire a conditional lock and
complains.

Remove one layer of __cond_lock() so that sparse recognises conditional
locking.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 include/linux/spinlock_rt.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
index babc3e0287791..f9f14e135be7b 100644
--- a/include/linux/spinlock_rt.h
+++ b/include/linux/spinlock_rt.h
@@ -132,7 +132,7 @@ static __always_inline void spin_unlock_irqrestore(spinlock_t *lock,
 #define spin_trylock_irq(lock)				\
 	__cond_lock(lock, rt_spin_trylock(lock))
 
-#define __spin_trylock_irqsave(lock, flags)		\
+#define spin_trylock_irqsave(lock, flags)		\
 ({							\
 	int __locked;					\
 							\
@@ -142,9 +142,6 @@ static __always_inline void spin_unlock_irqrestore(spinlock_t *lock,
 	__locked;					\
 })
 
-#define spin_trylock_irqsave(lock, flags)		\
-	__cond_lock(lock, __spin_trylock_irqsave(lock, flags))
-
 #define spin_is_contended(lock)		(((void)(lock), 0))
 
 static inline int spin_is_locked(spinlock_t *lock)
-- 
2.45.2