146 lines
4.1 KiB
Diff
146 lines
4.1 KiB
Diff
From: Peter Zijlstra <peterz@infradead.org>
|
|
Date: Thu, 23 Mar 2017 15:56:10 +0100
|
|
Subject: [PATCH 4/9] rtmutex: Clean up
|
|
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.8-rt5.tar.xz
|
|
|
|
Previous patches changed the meaning of the return value of
|
|
rt_mutex_slowunlock(); update comments and code to reflect this.
|
|
|
|
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
|
|
Cc: juri.lelli@arm.com
|
|
Cc: bigeasy@linutronix.de
|
|
Cc: xlpang@redhat.com
|
|
Cc: rostedt@goodmis.org
|
|
Cc: mathieu.desnoyers@efficios.com
|
|
Cc: jdesfossez@efficios.com
|
|
Cc: bristot@redhat.com
|
|
Link: http://lkml.kernel.org/r/20170323150216.255058238@infradead.org
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
---
|
|
kernel/futex.c | 7 ++++---
|
|
kernel/locking/rtmutex.c | 28 +++++++++++++---------------
|
|
kernel/locking/rtmutex_common.h | 2 +-
|
|
3 files changed, 18 insertions(+), 19 deletions(-)
|
|
|
|
--- a/kernel/futex.c
|
|
+++ b/kernel/futex.c
|
|
@@ -1394,7 +1394,7 @@ static int wake_futex_pi(u32 __user *uad
|
|
{
|
|
u32 uninitialized_var(curval), newval;
|
|
struct task_struct *new_owner;
|
|
- bool deboost = false;
|
|
+ bool postunlock = false;
|
|
DEFINE_WAKE_Q(wake_q);
|
|
int ret = 0;
|
|
|
|
@@ -1455,12 +1455,13 @@ static int wake_futex_pi(u32 __user *uad
|
|
/*
|
|
* We've updated the uservalue, this unlock cannot fail.
|
|
*/
|
|
- deboost = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
|
|
+ postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
|
|
|
|
out_unlock:
|
|
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
|
|
|
|
- rt_mutex_postunlock(&wake_q, deboost);
|
|
+ if (postunlock)
|
|
+ rt_mutex_postunlock(&wake_q);
|
|
|
|
return ret;
|
|
}
|
|
--- a/kernel/locking/rtmutex.c
|
|
+++ b/kernel/locking/rtmutex.c
|
|
@@ -1330,7 +1330,8 @@ static inline int rt_mutex_slowtrylock(s
|
|
|
|
/*
|
|
* Slow path to release a rt-mutex.
|
|
- * Return whether the current task needs to undo a potential priority boosting.
|
|
+ *
|
|
+ * Return whether the current task needs to call rt_mutex_postunlock().
|
|
*/
|
|
static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
|
|
struct wake_q_head *wake_q)
|
|
@@ -1401,8 +1402,7 @@ static bool __sched rt_mutex_slowunlock(
|
|
|
|
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
|
|
|
|
- /* check PI boosting */
|
|
- return true;
|
|
+ return true; /* call rt_mutex_postunlock() */
|
|
}
|
|
|
|
/*
|
|
@@ -1449,15 +1449,14 @@ rt_mutex_fasttrylock(struct rt_mutex *lo
|
|
}
|
|
|
|
/*
|
|
- * Undo pi boosting (if necessary) and wake top waiter.
|
|
+ * Performs the wakeup of the the top-waiter and re-enables preemption.
|
|
*/
|
|
-void rt_mutex_postunlock(struct wake_q_head *wake_q, bool deboost)
|
|
+void rt_mutex_postunlock(struct wake_q_head *wake_q)
|
|
{
|
|
wake_up_q(wake_q);
|
|
|
|
/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
|
|
- if (deboost)
|
|
- preempt_enable();
|
|
+ preempt_enable();
|
|
}
|
|
|
|
static inline void
|
|
@@ -1466,14 +1465,12 @@ rt_mutex_fastunlock(struct rt_mutex *loc
|
|
struct wake_q_head *wqh))
|
|
{
|
|
DEFINE_WAKE_Q(wake_q);
|
|
- bool deboost;
|
|
|
|
if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
|
|
return;
|
|
|
|
- deboost = slowfn(lock, &wake_q);
|
|
-
|
|
- rt_mutex_postunlock(&wake_q, deboost);
|
|
+ if (slowfn(lock, &wake_q))
|
|
+ rt_mutex_postunlock(&wake_q);
|
|
}
|
|
|
|
/**
|
|
@@ -1593,19 +1590,20 @@ bool __sched __rt_mutex_futex_unlock(str
|
|
*/
|
|
preempt_disable();
|
|
|
|
- return true; /* deboost and wakeups */
|
|
+ return true; /* call postunlock() */
|
|
}
|
|
|
|
void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
|
|
{
|
|
DEFINE_WAKE_Q(wake_q);
|
|
- bool deboost;
|
|
+ bool postunlock;
|
|
|
|
raw_spin_lock_irq(&lock->wait_lock);
|
|
- deboost = __rt_mutex_futex_unlock(lock, &wake_q);
|
|
+ postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
|
|
raw_spin_unlock_irq(&lock->wait_lock);
|
|
|
|
- rt_mutex_postunlock(&wake_q, deboost);
|
|
+ if (postunlock)
|
|
+ rt_mutex_postunlock(&wake_q);
|
|
}
|
|
|
|
/**
|
|
--- a/kernel/locking/rtmutex_common.h
|
|
+++ b/kernel/locking/rtmutex_common.h
|
|
@@ -122,7 +122,7 @@ extern void rt_mutex_futex_unlock(struct
|
|
extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
|
|
struct wake_q_head *wqh);
|
|
|
|
-extern void rt_mutex_postunlock(struct wake_q_head *wake_q, bool deboost);
|
|
+extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
|
|
|
|
#ifdef CONFIG_DEBUG_RT_MUTEXES
|
|
# include "rtmutex-debug.h"
|