linux-kernel - [patch 2/8] sched: Make cond_resched_*lock() variants consistent vs. might

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Date:   Thu, 23 Sep 2021 18:54:37 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Paul McKenney <paulmck@...ux.vnet.ibm.com>,
        Sebastian Siewior <bigeasy@...utronix.de>
Subject: [patch 2/8] sched: Make cond_resched_*lock() variants consistent vs.
 might_sleep()

Commit 3427445afd26 ("sched: Exclude cond_resched() from nested sleep
test") removed the task state check of __might_sleep() for
cond_resched_lock() because cond_resched_lock() is not a voluntary
scheduling point which blocks. It's a preemption point which requires the
lock holder to release the spin lock.

The same rationale applies to cond_resched_rwlock_read/write(), but those
were not touched.

Make it consistent and use the non-state checking __might_resched() there
as well.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 include/linux/sched.h |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2054,14 +2054,14 @@ extern int __cond_resched_rwlock_write(r
 	__cond_resched_lock(lock);					\
 })
 
-#define cond_resched_rwlock_read(lock) ({			\
-	__might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
-	__cond_resched_rwlock_read(lock);			\
+#define cond_resched_rwlock_read(lock) ({				\
+	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
+	__cond_resched_rwlock_read(lock);				\
 })
 
-#define cond_resched_rwlock_write(lock) ({			\
-	__might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
-	__cond_resched_rwlock_write(lock);			\
+#define cond_resched_rwlock_write(lock) ({				\
+	__might_resched(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
+	__cond_resched_rwlock_write(lock);				\
 })
 
 static inline void cond_resched_rcu(void)