146 lines
4.1 KiB
Diff
146 lines
4.1 KiB
Diff
From: Peter Zijlstra <peterz@infradead.org>
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Date: Thu, 23 Mar 2017 15:56:10 +0100
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Subject: [PATCH 4/9] rtmutex: Clean up
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.9-rt7.tar.xz
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Previous patches changed the meaning of the return value of
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rt_mutex_slowunlock(); update comments and code to reflect this.
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Cc: juri.lelli@arm.com
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Cc: bigeasy@linutronix.de
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Cc: xlpang@redhat.com
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Cc: rostedt@goodmis.org
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Cc: mathieu.desnoyers@efficios.com
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Cc: jdesfossez@efficios.com
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Cc: bristot@redhat.com
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Link: http://lkml.kernel.org/r/20170323150216.255058238@infradead.org
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/futex.c | 7 ++++---
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kernel/locking/rtmutex.c | 28 +++++++++++++---------------
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kernel/locking/rtmutex_common.h | 2 +-
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3 files changed, 18 insertions(+), 19 deletions(-)
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--- a/kernel/futex.c
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+++ b/kernel/futex.c
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@@ -1394,7 +1394,7 @@ static int wake_futex_pi(u32 __user *uad
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{
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u32 uninitialized_var(curval), newval;
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struct task_struct *new_owner;
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- bool deboost = false;
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+ bool postunlock = false;
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DEFINE_WAKE_Q(wake_q);
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int ret = 0;
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@@ -1455,12 +1455,13 @@ static int wake_futex_pi(u32 __user *uad
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/*
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* We've updated the uservalue, this unlock cannot fail.
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*/
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- deboost = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
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+ postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
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out_unlock:
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raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
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- rt_mutex_postunlock(&wake_q, deboost);
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+ if (postunlock)
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+ rt_mutex_postunlock(&wake_q);
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return ret;
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}
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--- a/kernel/locking/rtmutex.c
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+++ b/kernel/locking/rtmutex.c
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@@ -1330,7 +1330,8 @@ static inline int rt_mutex_slowtrylock(s
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/*
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* Slow path to release a rt-mutex.
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- * Return whether the current task needs to undo a potential priority boosting.
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+ *
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+ * Return whether the current task needs to call rt_mutex_postunlock().
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*/
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static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
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struct wake_q_head *wake_q)
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@@ -1401,8 +1402,7 @@ static bool __sched rt_mutex_slowunlock(
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raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
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- /* check PI boosting */
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- return true;
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+ return true; /* call rt_mutex_postunlock() */
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}
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/*
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@@ -1449,15 +1449,14 @@ rt_mutex_fasttrylock(struct rt_mutex *lo
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}
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/*
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- * Undo pi boosting (if necessary) and wake top waiter.
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+ * Performs the wakeup of the the top-waiter and re-enables preemption.
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*/
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-void rt_mutex_postunlock(struct wake_q_head *wake_q, bool deboost)
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+void rt_mutex_postunlock(struct wake_q_head *wake_q)
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{
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wake_up_q(wake_q);
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/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
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- if (deboost)
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- preempt_enable();
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+ preempt_enable();
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}
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static inline void
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@@ -1466,14 +1465,12 @@ rt_mutex_fastunlock(struct rt_mutex *loc
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struct wake_q_head *wqh))
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{
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DEFINE_WAKE_Q(wake_q);
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- bool deboost;
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if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
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return;
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- deboost = slowfn(lock, &wake_q);
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-
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- rt_mutex_postunlock(&wake_q, deboost);
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+ if (slowfn(lock, &wake_q))
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+ rt_mutex_postunlock(&wake_q);
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}
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/**
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@@ -1593,19 +1590,20 @@ bool __sched __rt_mutex_futex_unlock(str
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*/
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preempt_disable();
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- return true; /* deboost and wakeups */
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+ return true; /* call postunlock() */
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}
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void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
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{
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DEFINE_WAKE_Q(wake_q);
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- bool deboost;
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+ bool postunlock;
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raw_spin_lock_irq(&lock->wait_lock);
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- deboost = __rt_mutex_futex_unlock(lock, &wake_q);
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+ postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
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raw_spin_unlock_irq(&lock->wait_lock);
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- rt_mutex_postunlock(&wake_q, deboost);
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+ if (postunlock)
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+ rt_mutex_postunlock(&wake_q);
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}
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/**
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--- a/kernel/locking/rtmutex_common.h
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+++ b/kernel/locking/rtmutex_common.h
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@@ -122,7 +122,7 @@ extern void rt_mutex_futex_unlock(struct
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extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
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struct wake_q_head *wqh);
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-extern void rt_mutex_postunlock(struct wake_q_head *wake_q, bool deboost);
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+extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
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#ifdef CONFIG_DEBUG_RT_MUTEXES
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# include "rtmutex-debug.h"
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