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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Will Deacon <will@kernel.org>, Waiman Long <longman@redhat.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Davidlohr Bueso <dave@stgolabs.net>
Subject: [patch 13/63] locking/rtmutex: Provide rt_mutex_slowlock_locked()
Date: Fri, 30 Jul 2021 15:50:20 +0200	[thread overview]
Message-ID: <20210730135205.906012605@linutronix.de> (raw)
In-Reply-To: <20210730135007.155909613@linutronix.de>

From: Thomas Gleixner <tglx@linutronix.de>

Split the inner workings of rt_mutex_slowlock() out into a seperate
function which can be reused by the upcoming RT lock substitutions,
e.g. for rw_semaphores.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: Add the dropped debug_rt_mutex_free_waiter() - Valentin
---
 kernel/locking/rtmutex.c     |  100 ++++++++++++++++++++++++-------------------
 kernel/locking/rtmutex_api.c |    2 
 2 files changed, 59 insertions(+), 43 deletions(-)
---
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1106,7 +1106,7 @@ static void __sched remove_waiter(struct
 }
 
 /**
- * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop
+ * rt_mutex_slowlock_block() - Perform the wait-wake-try-to-take loop
  * @lock:		 the rt_mutex to take
  * @state:		 the state the task should block in (TASK_INTERRUPTIBLE
  *			 or TASK_UNINTERRUPTIBLE)
@@ -1115,10 +1115,10 @@ static void __sched remove_waiter(struct
  *
  * Must be called with lock->wait_lock held and interrupts disabled
  */
-static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock,
-				       unsigned int state,
-				       struct hrtimer_sleeper *timeout,
-				       struct rt_mutex_waiter *waiter)
+static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock,
+					   unsigned int state,
+					   struct hrtimer_sleeper *timeout,
+					   struct rt_mutex_waiter *waiter)
 {
 	int ret = 0;
 
@@ -1168,52 +1168,37 @@ static void __sched rt_mutex_handle_dead
 	}
 }
 
-/*
- * Slow path lock function:
+/**
+ * __rt_mutex_slowlock - Locking slowpath invoked with lock::wait_lock held
+ * @lock:	The rtmutex to block lock
+ * @state:	The task state for sleeping
+ * @chwalk:	Indicator whether full or partial chainwalk is requested
+ * @waiter:	Initializer waiter for blocking
  */
-static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
-				     unsigned int state,
-				     struct hrtimer_sleeper *timeout,
-				     enum rtmutex_chainwalk chwalk)
+static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock,
+				       unsigned int state,
+				       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);
+	int ret;
 
-	/*
-	 * 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);
+	lockdep_assert_held(&lock->wait_lock);
 
 	/* 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);
 
-	/* Setup the timer, when timeout != NULL */
-	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_block(lock, state, NULL, 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);
 	}
 
 	/*
@@ -1221,14 +1206,45 @@ static int __sched rt_mutex_slowlock(str
 	 * unconditionally. We might have to fix that up.
 	 */
 	fixup_rt_mutex_waiters(lock);
+	return ret;
+}
 
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+static inline int __rt_mutex_slowlock_locked(struct rt_mutex_base *lock,
+					     unsigned int state)
+{
+	struct rt_mutex_waiter waiter;
+	int ret;
 
-	/* Remove pending timer: */
-	if (unlikely(timeout))
-		hrtimer_cancel(&timeout->timer);
+	rt_mutex_init_waiter(&waiter);
+
+	ret = __rt_mutex_slowlock(lock, state, RT_MUTEX_MIN_CHAINWALK, &waiter);
 
 	debug_rt_mutex_free_waiter(&waiter);
+	return ret;
+}
+
+/*
+ * rt_mutex_slowlock - Locking slowpath invoked when fast path fails
+ * @lock:	The rtmutex to block lock
+ * @state:	The task state for sleeping
+ */
+static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
+				     unsigned int state)
+{
+	unsigned long flags;
+	int ret;
+
+	/*
+	 * 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);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	return ret;
 }
@@ -1239,7 +1255,7 @@ static __always_inline int __rt_mutex_lo
 	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
 		return 0;
 
-	return rt_mutex_slowlock(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
+	return rt_mutex_slowlock(lock, state);
 }
 
 static int __sched __rt_mutex_slowtrylock(struct rt_mutex_base *lock)
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -342,7 +342,7 @@ int __sched rt_mutex_wait_proxy_lock(str
 	raw_spin_lock_irq(&lock->wait_lock);
 	/* sleep on the mutex */
 	set_current_state(TASK_INTERRUPTIBLE);
-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
+	ret = rt_mutex_slowlock_block(lock, TASK_INTERRUPTIBLE, to, waiter);
 	/*
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
 	 * have to fix that up.


  parent reply	other threads:[~2021-07-30 14:20 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 13:50 [patch 00/63] locking, sched: The PREEMPT-RT locking infrastructure Thomas Gleixner
2021-07-30 13:50 ` [patch 01/63] sched: Split out the wakeup state check Thomas Gleixner
2021-07-30 13:50 ` [patch 02/63] sched: Introduce TASK_RTLOCK_WAIT Thomas Gleixner
2021-07-30 13:50 ` [patch 03/63] sched: Prepare for RT sleeping spin/rwlocks Thomas Gleixner
2021-08-01 15:30   ` Mike Galbraith
2021-08-03  9:48     ` Peter Zijlstra
2021-08-03 14:04       ` Thomas Gleixner
2021-08-03 14:51         ` Peter Zijlstra
2021-08-03 20:11           ` Thomas Gleixner
2021-07-30 13:50 ` [patch 04/63] sched: Rework the __schedule() preempt argument Thomas Gleixner
2021-07-30 13:50 ` [patch 05/63] sched: Provide schedule point for RT locks Thomas Gleixner
2021-07-30 13:50 ` [patch 06/63] sched/wake_q: Provide WAKE_Q_HEAD_INITIALIZER Thomas Gleixner
2021-07-30 13:50 ` [patch 07/63] media/atomisp: Use lockdep instead of *mutex_is_locked() Thomas Gleixner
2021-07-30 13:50 ` [patch 08/63] rtmutex: Remove rt_mutex_is_locked() Thomas Gleixner
2021-07-30 13:50 ` [patch 09/63] rtmutex: Convert macros to inlines Thomas Gleixner
2021-07-30 13:50 ` [patch 10/63] rtmutex: Switch to try_cmpxchg() Thomas Gleixner
2021-07-30 13:50 ` [patch 11/63] rtmutex: Split API and implementation Thomas Gleixner
2021-07-30 13:50 ` [patch 12/63] rtmutex: Split out the inner parts of struct rtmutex Thomas Gleixner
2021-07-30 13:50 ` Thomas Gleixner [this message]
2021-07-30 13:50 ` [patch 14/63] rtmutex: Provide rt_mutex_base_is_locked() Thomas Gleixner
2021-07-30 13:50 ` [patch 15/63] locking: Add base code for RT rw_semaphore and rwlock Thomas Gleixner
2021-08-04 19:37   ` Waiman Long
2021-08-05  9:04     ` Thomas Gleixner
2021-08-05 14:59       ` Waiman Long
2021-07-30 13:50 ` [patch 16/63] locking/rwsem: Add rtmutex based R/W semaphore implementation Thomas Gleixner
2021-07-30 13:50 ` [patch 17/63] locking/rtmutex: Add wake_state to rt_mutex_waiter Thomas Gleixner
2021-07-30 13:50 ` [patch 18/63] locking/rtmutex: Provide rt_wake_q and helpers Thomas Gleixner
2021-07-30 13:50 ` [patch 19/63] locking/rtmutex: Use rt_mutex_wake_q_head Thomas Gleixner
2021-07-30 13:50 ` [patch 20/63] locking/rtmutex: Prepare RT rt_mutex_wake_q for RT locks Thomas Gleixner
2021-07-30 13:50 ` [patch 21/63] locking/rtmutex: Guard regular sleeping locks specific functions Thomas Gleixner
2021-07-30 13:50 ` [patch 22/63] locking/spinlock: Split the lock types header Thomas Gleixner
2021-08-04 21:17   ` Waiman Long
2021-08-05  8:54     ` Thomas Gleixner
2021-07-30 13:50 ` [patch 23/63] locking/rtmutex: Prevent future include recursion hell Thomas Gleixner
2021-07-30 13:50 ` [patch 24/63] locking/lockdep: Reduce includes in debug_locks.h Thomas Gleixner
2021-07-30 13:50 ` [patch 25/63] rbtree: Split out the rbtree type definitions Thomas Gleixner
2021-07-30 13:50 ` [patch 26/63] locking/rtmutex: Include only rbtree types Thomas Gleixner
2021-07-30 13:50 ` [patch 27/63] locking/spinlock: Provide RT specific spinlock type Thomas Gleixner
2021-07-30 13:50 ` [patch 28/63] locking/spinlock: Provide RT variant header Thomas Gleixner
2021-07-30 13:50 ` [patch 29/63] locking/rtmutex: Provide the spin/rwlock core lock function Thomas Gleixner
2021-07-30 13:50 ` [patch 30/63] locking/spinlock: Provide RT variant Thomas Gleixner
2021-08-04 23:34   ` Waiman Long
2021-08-05  8:54     ` Thomas Gleixner
2021-07-30 13:50 ` [patch 31/63] locking/rwlock: " Thomas Gleixner
2021-07-30 13:50 ` [patch 32/63] locking/mutex: Consolidate core headers Thomas Gleixner
2021-07-30 13:50 ` [patch 33/63] locking/mutex: Move waiter to core header Thomas Gleixner
2021-07-30 13:50 ` [patch 34/63] locking/ww_mutex: Move ww_mutex declarations into ww_mutex.h Thomas Gleixner
2021-07-30 13:50 ` [patch 35/63] locking/mutex: Make mutex::wait_lock raw Thomas Gleixner
2021-07-30 13:50 ` [patch 36/63] locking/ww_mutex: Simplify lockdep annotation Thomas Gleixner
2021-07-30 13:50 ` [patch 37/63] locking/ww_mutex: Gather mutex_waiter initialization Thomas Gleixner
2021-07-30 13:50 ` [patch 38/63] locking/ww_mutex: Split up ww_mutex_unlock() Thomas Gleixner
2021-07-30 13:50 ` [patch 39/63] locking/ww_mutex: Split W/W implementation logic Thomas Gleixner
2021-07-30 13:50 ` [patch 40/63] locking/ww_mutex: Remove __sched annotation Thomas Gleixner
2021-07-30 13:50 ` [patch 41/63] locking/ww_mutex: Abstract waiter iteration Thomas Gleixner
2021-07-30 13:50 ` [patch 42/63] locking/ww_mutex: Abstract waiter enqueueing Thomas Gleixner
2021-07-30 13:50 ` [patch 43/63] locking/ww_mutex: Abstract mutex accessors Thomas Gleixner
2021-07-30 13:50 ` [patch 44/63] locking/ww_mutex: Abstract mutex types Thomas Gleixner
2021-07-30 13:50 ` [patch 45/63] locking/ww_mutex: Abstract internal lock access Thomas Gleixner
2021-07-30 13:50 ` [patch 46/63] locking/ww_mutex: Implement rt_mutex accessors Thomas Gleixner
2021-07-30 13:50 ` [patch 47/63] locking/ww_mutex: Add RT priority to W/W order Thomas Gleixner
2021-07-30 13:50 ` [patch 48/63] locking/ww_mutex: Add rt_mutex based lock type and accessors Thomas Gleixner
2021-07-30 13:50 ` [patch 49/63] locking/rtmutex: Extend the rtmutex core to support ww_mutex Thomas Gleixner
2021-07-30 13:50 ` [patch 50/63] locking/ww_mutex: Implement rtmutex based ww_mutex API functions Thomas Gleixner
2021-07-31 13:26   ` Mike Galbraith
2021-08-01 21:18     ` Thomas Gleixner
2021-07-30 13:50 ` [patch 51/63] locking/rtmutex: Add mutex variant for RT Thomas Gleixner
2021-07-30 13:50 ` [patch 52/63] lib/test_lockup: Adapt to changed variables Thomas Gleixner
2021-07-30 13:51 ` [patch 53/63] futex: Validate waiter correctly in futex_proxy_trylock_atomic() Thomas Gleixner
2021-07-30 13:51 ` [patch 54/63] futex: Cleanup stale comments Thomas Gleixner
2021-07-30 13:51 ` [patch 55/63] futex: Correct the number of requeued waiters for PI Thomas Gleixner
2021-07-30 13:51 ` [patch 56/63] futex: Restructure futex_requeue() Thomas Gleixner
2021-07-30 13:51 ` [patch 57/63] futex: Clarify comment in futex_requeue() Thomas Gleixner
2021-07-30 13:51 ` [patch 58/63] futex: Prevent requeue_pi() lock nesting issue on RT Thomas Gleixner
2021-08-02 12:56   ` Peter Zijlstra
2021-08-02 13:10     ` Peter Zijlstra
2021-08-02 14:35       ` Thomas Gleixner
2021-08-02 14:34     ` Thomas Gleixner
2021-08-03 10:28     ` Peter Zijlstra
2021-08-03 21:10       ` Thomas Gleixner
2021-08-03 10:07   ` Peter Zijlstra
2021-08-03 21:10     ` Thomas Gleixner
2021-08-03 11:20   ` Peter Zijlstra
2021-08-03 21:22     ` Thomas Gleixner
2021-07-30 13:51 ` [patch 59/63] rtmutex: Prevent lockdep false positive with PI futexes Thomas Gleixner
2021-07-30 13:51 ` [patch 60/63] preempt: Adjust PREEMPT_LOCK_OFFSET for RT Thomas Gleixner
2021-07-30 13:51 ` [patch 61/63] locking/rtmutex: Implement equal priority lock stealing Thomas Gleixner
2021-07-30 13:51 ` [patch 62/63] locking/rtmutex: Add adaptive spinwait mechanism Thomas Gleixner
2021-08-04 12:30   ` Peter Zijlstra
2021-08-04 17:49     ` Thomas Gleixner
2021-07-30 13:51 ` [patch 63/63] locking/rtmutex: Use adaptive spinwait for all rtmutex based locks Thomas Gleixner
     [not found] ` <20210803063217.2325-1-hdanton@sina.com>
2021-08-03  9:10   ` [patch 30/63] locking/spinlock: Provide RT variant Thomas Gleixner
2021-08-03 12:37 ` [patch 00/63] locking, sched: The PREEMPT-RT locking infrastructure Daniel Bristot de Oliveira

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