133 lines
4.6 KiB
Diff
133 lines
4.6 KiB
Diff
From 7b9bd3a70ec2f8e37ae56250752926873d2169f1 Mon Sep 17 00:00:00 2001
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Message-Id: <7b9bd3a70ec2f8e37ae56250752926873d2169f1.1601675153.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Tue, 19 Nov 2019 09:25:04 +0100
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Subject: [PATCH 311/333] locking: Make spinlock_t and rwlock_t a RCU section
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on RT
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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[ Upstream commit 84440022a0e1c8c936d61f8f97593674a295d409 ]
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On !RT a locked spinlock_t and rwlock_t disables preemption which
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implies a RCU read section. There is code that relies on that behaviour.
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Add an explicit RCU read section on RT while a sleeping lock (a lock
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which would disables preemption on !RT) acquired.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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---
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kernel/locking/rtmutex.c | 6 ++++++
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kernel/locking/rwlock-rt.c | 6 ++++++
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2 files changed, 12 insertions(+)
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diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
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index 63b3d6f306fa..c7d3ae01b4e5 100644
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--- a/kernel/locking/rtmutex.c
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+++ b/kernel/locking/rtmutex.c
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@@ -1142,6 +1142,7 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
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void __lockfunc rt_spin_lock(spinlock_t *lock)
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{
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sleeping_lock_inc();
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+ rcu_read_lock();
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migrate_disable();
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spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
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rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
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@@ -1157,6 +1158,7 @@ void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
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void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
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{
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sleeping_lock_inc();
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+ rcu_read_lock();
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migrate_disable();
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spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
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rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
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@@ -1170,6 +1172,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock)
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spin_release(&lock->dep_map, 1, _RET_IP_);
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rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
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migrate_enable();
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+ rcu_read_unlock();
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sleeping_lock_dec();
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}
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EXPORT_SYMBOL(rt_spin_unlock);
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@@ -1201,6 +1204,7 @@ int __lockfunc rt_spin_trylock(spinlock_t *lock)
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ret = __rt_mutex_trylock(&lock->lock);
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if (ret) {
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spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
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+ rcu_read_lock();
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} else {
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migrate_enable();
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sleeping_lock_dec();
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@@ -1217,6 +1221,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
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ret = __rt_mutex_trylock(&lock->lock);
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if (ret) {
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sleeping_lock_inc();
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+ rcu_read_lock();
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migrate_disable();
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spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
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} else
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@@ -1233,6 +1238,7 @@ int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags)
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ret = __rt_mutex_trylock(&lock->lock);
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if (ret) {
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sleeping_lock_inc();
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+ rcu_read_lock();
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migrate_disable();
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spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
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}
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diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
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index c3b91205161c..0ae8c62ea832 100644
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--- a/kernel/locking/rwlock-rt.c
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+++ b/kernel/locking/rwlock-rt.c
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@@ -310,6 +310,7 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock)
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ret = do_read_rt_trylock(rwlock);
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if (ret) {
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rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
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+ rcu_read_lock();
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} else {
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migrate_enable();
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sleeping_lock_dec();
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@@ -327,6 +328,7 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock)
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ret = do_write_rt_trylock(rwlock);
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if (ret) {
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rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
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+ rcu_read_lock();
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} else {
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migrate_enable();
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sleeping_lock_dec();
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@@ -338,6 +340,7 @@ EXPORT_SYMBOL(rt_write_trylock);
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void __lockfunc rt_read_lock(rwlock_t *rwlock)
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{
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sleeping_lock_inc();
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+ rcu_read_lock();
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migrate_disable();
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rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
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do_read_rt_lock(rwlock);
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@@ -347,6 +350,7 @@ EXPORT_SYMBOL(rt_read_lock);
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void __lockfunc rt_write_lock(rwlock_t *rwlock)
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{
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sleeping_lock_inc();
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+ rcu_read_lock();
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migrate_disable();
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rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
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do_write_rt_lock(rwlock);
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@@ -358,6 +362,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock)
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rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
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do_read_rt_unlock(rwlock);
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migrate_enable();
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+ rcu_read_unlock();
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sleeping_lock_dec();
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}
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EXPORT_SYMBOL(rt_read_unlock);
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@@ -367,6 +372,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock)
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rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
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do_write_rt_unlock(rwlock);
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migrate_enable();
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+ rcu_read_unlock();
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sleeping_lock_dec();
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}
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EXPORT_SYMBOL(rt_write_unlock);
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--
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2.17.1
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