From: Dmitry Ilvokhin <d@ilvokhin.com>
Date: Thu, 4 Jun 2026 07:15:06 +0000 (+0000)
Subject: locking/percpu-rwsem: Extract __percpu_up_read()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7cfa62cf9432df67b1c95a59984a03a3bc023f98;p=thirdparty%2Flinux.git

locking/percpu-rwsem: Extract __percpu_up_read()

Move the percpu_up_read() slowpath out of the inline function into a new
__percpu_up_read() to avoid binary size increase from adding a
tracepoint to an inlined function.

Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Link: https://patch.msgid.link/3dd2a1b9ab4f469e1892766cb63f41d6b0f53d29.1780506267.git.d@ilvokhin.com
---

diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index c8cb010d655eb..39d5bf8e65625 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -107,6 +107,8 @@ static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
 	return ret;
 }
 
+extern void __percpu_up_read(struct percpu_rw_semaphore *sem);
+
 static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 {
 	rwsem_release(&sem->dep_map, _RET_IP_);
@@ -118,18 +120,7 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 	if (likely(rcu_sync_is_idle(&sem->rss))) {
 		this_cpu_dec(*sem->read_count);
 	} else {
-		/*
-		 * slowpath; reader will only ever wake a single blocked
-		 * writer.
-		 */
-		smp_mb(); /* B matches C */
-		/*
-		 * In other words, if they see our decrement (presumably to
-		 * aggregate zero, as that is the only time it matters) they
-		 * will also see our critical section.
-		 */
-		this_cpu_dec(*sem->read_count);
-		rcuwait_wake_up(&sem->writer);
+		__percpu_up_read(sem);
 	}
 	preempt_enable();
 }
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index ef234469baaca..f3ee7a0d60472 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -288,3 +288,21 @@ void percpu_up_write(struct percpu_rw_semaphore *sem)
 	rcu_sync_exit(&sem->rss);
 }
 EXPORT_SYMBOL_GPL(percpu_up_write);
+
+void __percpu_up_read(struct percpu_rw_semaphore *sem)
+{
+	lockdep_assert_preemption_disabled();
+	/*
+	 * slowpath; reader will only ever wake a single blocked
+	 * writer.
+	 */
+	smp_mb(); /* B matches C */
+	/*
+	 * In other words, if they see our decrement (presumably to
+	 * aggregate zero, as that is the only time it matters) they
+	 * will also see our critical section.
+	 */
+	this_cpu_dec(*sem->read_count);
+	rcuwait_wake_up(&sem->writer);
+}
+EXPORT_SYMBOL_GPL(__percpu_up_read);