Commit-ID: aa2bfe55366552cb7e93e8709d66e698d79ccc47 Gitweb: http://git.kernel.org/tip/aa2bfe55366552cb7e93e8709d66e698d79ccc47 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Thu, 23 Mar 2017 15:56:10 +0100 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Tue, 4 Apr 2017 11:44:05 +0200
rtmutex: Clean up 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) <pet...@infradead.org> Cc: juri.le...@arm.com Cc: bige...@linutronix.de Cc: xlp...@redhat.com Cc: rost...@goodmis.org Cc: mathieu.desnoy...@efficios.com Cc: jdesfos...@efficios.com Cc: bris...@redhat.com Link: http://lkml.kernel.org/r/20170323150216.255058...@infradead.org Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- kernel/futex.c | 7 ++++--- kernel/locking/rtmutex.c | 28 +++++++++++++--------------- kernel/locking/rtmutex_common.h | 2 +- 3 files changed, 18 insertions(+), 19 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index 414a30d..c3eebcd 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1394,7 +1394,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_ { 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 *uaddr, u32 uval, struct futex_pi_state *pi_ /* * 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; } diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 8faf472..4b1015e 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1330,7 +1330,8 @@ static inline int rt_mutex_slowtrylock(struct rt_mutex *lock) /* * 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(struct rt_mutex *lock, 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 *lock, } /* - * 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 *lock, 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(struct rt_mutex *lock, */ 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); } /** diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index a09c029..9e36aed 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -122,7 +122,7 @@ extern void rt_mutex_futex_unlock(struct rt_mutex *lock); 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"
