From ace3eedad2f89901297f8ac0c8e257619064be19 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 12 Oct 2017 16:14:22 +0200 Subject: [PATCH 167/323] locking/rtmutex: Provide rt_mutex_slowlock_locked() Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.215-rt107.tar.xz This is the inner-part of rt_mutex_slowlock(), required for rwsem-rt. Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior --- kernel/locking/rtmutex.c | 67 +++++++++++++++++++-------------- kernel/locking/rtmutex_common.h | 7 ++++ 2 files changed, 45 insertions(+), 29 deletions(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index c3f3c23fefef8..395a3e8b24635 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1234,35 +1234,16 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock, } } -/* - * Slow path lock function: - */ -static int __sched -rt_mutex_slowlock(struct rt_mutex *lock, int state, - struct hrtimer_sleeper *timeout, - enum rtmutex_chainwalk chwalk) +int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state, + struct hrtimer_sleeper *timeout, + enum rtmutex_chainwalk chwalk, + struct rt_mutex_waiter *waiter) { - struct rt_mutex_waiter waiter; - unsigned long flags; - int ret = 0; - - rt_mutex_init_waiter(&waiter); - - /* - * Technically we could use raw_spin_[un]lock_irq() here, but this can - * be called in early boot if the cmpxchg() fast path is disabled - * (debug, no architecture support). In this case we will acquire the - * rtmutex with lock->wait_lock held. But we cannot unconditionally - * enable interrupts in that early boot case. So we need to use the - * irqsave/restore variants. - */ - raw_spin_lock_irqsave(&lock->wait_lock, flags); + int ret; /* Try to acquire the lock again: */ - if (try_to_take_rt_mutex(lock, current, NULL)) { - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); + if (try_to_take_rt_mutex(lock, current, NULL)) return 0; - } set_current_state(state); @@ -1270,16 +1251,16 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, if (unlikely(timeout)) hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); - ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk); + ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk); if (likely(!ret)) /* sleep on the mutex */ - ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); + ret = __rt_mutex_slowlock(lock, state, timeout, waiter); if (unlikely(ret)) { __set_current_state(TASK_RUNNING); - remove_waiter(lock, &waiter); - rt_mutex_handle_deadlock(ret, chwalk, &waiter); + remove_waiter(lock, waiter); + rt_mutex_handle_deadlock(ret, chwalk, waiter); } /* @@ -1287,6 +1268,34 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, * unconditionally. We might have to fix that up. */ fixup_rt_mutex_waiters(lock); + return ret; +} + +/* + * Slow path lock function: + */ +static int __sched +rt_mutex_slowlock(struct rt_mutex *lock, int state, + struct hrtimer_sleeper *timeout, + enum rtmutex_chainwalk chwalk) +{ + struct rt_mutex_waiter waiter; + unsigned long flags; + int ret = 0; + + rt_mutex_init_waiter(&waiter); + + /* + * Technically we could use raw_spin_[un]lock_irq() here, but this can + * be called in early boot if the cmpxchg() fast path is disabled + * (debug, no architecture support). In this case we will acquire the + * rtmutex with lock->wait_lock held. But we cannot unconditionally + * enable interrupts in that early boot case. So we need to use the + * irqsave/restore variants. + */ + raw_spin_lock_irqsave(&lock->wait_lock, flags); + + ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, &waiter); raw_spin_unlock_irqrestore(&lock->wait_lock, flags); diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index 37cd6b3bf6f43..b5a2affa59d58 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -15,6 +15,7 @@ #include #include +#include /* * This is the control structure for tasks blocked on a rt_mutex, @@ -153,6 +154,12 @@ 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); +/* RW semaphore special interface */ + +int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state, + struct hrtimer_sleeper *timeout, + enum rtmutex_chainwalk chwalk, + struct rt_mutex_waiter *waiter); #ifdef CONFIG_DEBUG_RT_MUTEXES # include "rtmutex-debug.h" -- 2.44.0