Jetpack/kernel/kernel-4.9/rt-patches/0141-sched-ttwu-Return-succ...

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From 38c65f32bbd8541c9c4a2ad015542601c4e6ec24 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 13 Dec 2011 21:42:19 +0100
Subject: [PATCH 141/352] sched: ttwu: Return success when only changing the
saved_state value
When a task blocks on a rt lock, it saves the current state in
p->saved_state, so a lock related wake up will not destroy the
original state.
When a real wakeup happens, while the task is running due to a lock
wakeup already, we update p->saved_state to TASK_RUNNING, but we do
not return success, which might cause another wakeup in the waitqueue
code and the task remains in the waitqueue list. Return success in
that case as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/sched/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index aef6bcd..00fd716 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2066,8 +2066,10 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
* if the wakeup condition is true.
*/
if (!(wake_flags & WF_LOCK_SLEEPER)) {
- if (p->saved_state & state)
+ if (p->saved_state & state) {
p->saved_state = TASK_RUNNING;
+ success = 1;
+ }
}
goto out;
}
--
2.7.4