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Message-ID: <20180730174921.GA1807@gmail.com>
Date: Mon, 30 Jul 2018 19:49:21 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] locking fixes
Linus,
Please pull the latest locking-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-for-linus
# HEAD: c0dc373a780f4ec63e45a573b9551763abd8cd1a locking/pvqspinlock/x86: Use LOCK_PREFIX in __pv_queued_spin_unlock() assembly code
A paravirt UP-patching fix, and an I2C MUX driver lockdep warning fix.
Thanks,
Ingo
------------------>
Peter Rosin (2):
locking/rtmutex: Allow specifying a subclass for nested locking
i2c/mux, locking/core: Annotate the nested rt_mutex usage
Waiman Long (1):
locking/pvqspinlock/x86: Use LOCK_PREFIX in __pv_queued_spin_unlock() assembly code
arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
drivers/i2c/i2c-core-base.c | 2 +-
drivers/i2c/i2c-mux.c | 4 ++--
include/linux/rtmutex.h | 7 +++++++
kernel/locking/rtmutex.c | 29 +++++++++++++++++++++++++----
5 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 9ef5ee03d2d7..159622ee0674 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -43,7 +43,7 @@ asm (".pushsection .text;"
"push %rdx;"
"mov $0x1,%eax;"
"xor %edx,%edx;"
- "lock cmpxchg %dl,(%rdi);"
+ LOCK_PREFIX "cmpxchg %dl,(%rdi);"
"cmp $0x1,%al;"
"jne .slowpath;"
"pop %rdx;"
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 301285c54603..15c95aaa484c 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -624,7 +624,7 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
unsigned int flags)
{
- rt_mutex_lock(&adapter->bus_lock);
+ rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
}
/**
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 300ab4b672e4..29646aa6132e 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -144,7 +144,7 @@ static void i2c_mux_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
struct i2c_mux_priv *priv = adapter->algo_data;
struct i2c_adapter *parent = priv->muxc->parent;
- rt_mutex_lock(&parent->mux_lock);
+ rt_mutex_lock_nested(&parent->mux_lock, i2c_adapter_depth(adapter));
if (!(flags & I2C_LOCK_ROOT_ADAPTER))
return;
i2c_lock_bus(parent, flags);
@@ -181,7 +181,7 @@ static void i2c_parent_lock_bus(struct i2c_adapter *adapter,
struct i2c_mux_priv *priv = adapter->algo_data;
struct i2c_adapter *parent = priv->muxc->parent;
- rt_mutex_lock(&parent->mux_lock);
+ rt_mutex_lock_nested(&parent->mux_lock, i2c_adapter_depth(adapter));
i2c_lock_bus(parent, flags);
}
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 1b92a28dd672..6fd615a0eea9 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -106,7 +106,14 @@ static inline int rt_mutex_is_locked(struct rt_mutex *lock)
extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
extern void rt_mutex_destroy(struct rt_mutex *lock);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
+#define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
+#else
extern void rt_mutex_lock(struct rt_mutex *lock);
+#define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
+#endif
+
extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
extern int rt_mutex_timed_lock(struct rt_mutex *lock,
struct hrtimer_sleeper *timeout);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 4f014be7a4b8..2823d4163a37 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1465,6 +1465,29 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
rt_mutex_postunlock(&wake_q);
}
+static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+
+ mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+ rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+/**
+ * rt_mutex_lock_nested - lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ * @subclass: the lockdep subclass
+ */
+void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
+{
+ __rt_mutex_lock(lock, subclass);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
+#endif
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
/**
* rt_mutex_lock - lock a rt_mutex
*
@@ -1472,12 +1495,10 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
*/
void __sched rt_mutex_lock(struct rt_mutex *lock)
{
- might_sleep();
-
- mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
- rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
+ __rt_mutex_lock(lock, 0);
}
EXPORT_SYMBOL_GPL(rt_mutex_lock);
+#endif
/**
* rt_mutex_lock_interruptible - lock a rt_mutex interruptible
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