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From:   Davidlohr Bueso <dave@stgolabs.net>
To:     tglx@linutronix.de, pbonzini@redhat.com
Cc:     peterz@infradead.org, maz@kernel.org, bigeasy@linutronix.de,
        rostedt@goodmis.org, torvalds@linux-foundation.org,
        will@kernel.org, joel@joelfernandes.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        dave@stgolabs.net, Davidlohr Bueso <dbueso@suse.de>
Subject: [PATCH 2/5] rcuwait: Let rcuwait_wake_up() return whether or not a task was awoken
Date:   Thu, 23 Apr 2020 22:48:34 -0700
Message-Id: <20200424054837.5138-3-dave@stgolabs.net>
In-Reply-To: <20200424054837.5138-1-dave@stgolabs.net>
References: <20200424054837.5138-1-dave@stgolabs.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Propagating the return value of wake_up_process() back to the caller
can come in handy for future users, such as for statistics or
accounting purposes.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
 include/linux/rcuwait.h | 2 +-
 kernel/exit.c           | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 2ffe1ee6d482..6ebb23258a27 100644
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -25,7 +25,7 @@ static inline void rcuwait_init(struct rcuwait *w)
 	w->task = NULL;
 }
 
-extern void rcuwait_wake_up(struct rcuwait *w);
+extern int rcuwait_wake_up(struct rcuwait *w);
 
 /*
  * The caller is responsible for locking around rcuwait_wait_event(),
diff --git a/kernel/exit.c b/kernel/exit.c
index 9f9015f3f6b0..f3beb637acf7 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -227,8 +227,9 @@ void release_task(struct task_struct *p)
 		goto repeat;
 }
 
-void rcuwait_wake_up(struct rcuwait *w)
+int rcuwait_wake_up(struct rcuwait *w)
 {
+	int ret = 0;
 	struct task_struct *task;
 
 	rcu_read_lock();
@@ -248,8 +249,10 @@ void rcuwait_wake_up(struct rcuwait *w)
 
 	task = rcu_dereference(w->task);
 	if (task)
-		wake_up_process(task);
+		ret = wake_up_process(task);
 	rcu_read_unlock();
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(rcuwait_wake_up);
 
-- 
2.16.4