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From 2263182a5f18a0abbe7ba2d582f42308580bbd31 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 12 Oct 2017 16:14:22 +0200
Subject: [PATCH 140/347] rtmutex: Provide rt_mutex_slowlock_locked()
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
This is the inner-part of rt_mutex_slowlock(), required for rwsem-rt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
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 333c4b7aa8e8..e9255b28de8f 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1244,35 +1244,16 @@ 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);
@@ -1280,16 +1261,16 @@ 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);
}
/*
@@ -1297,6 +1278,34 @@ 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 202e2b0d1251..66deb94765fb 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -15,6 +15,7 @@
#include <linux/rtmutex.h>
#include <linux/sched/wake_q.h>
+#include <linux/sched/debug.h>
/*
* This is the control structure for tasks blocked on a rt_mutex,
@@ -158,6 +159,12 @@ 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"
--
2.36.1
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