[patch 00/14] locking/rtmutex: Spring cleaning

[patch 00/14] locking/rtmutex: Spring cleaning

[Thomas Gleixner]

While working on the rtmutex related RT bits we noticed quite some
inconsistencies and bitrot in the rtmutex code.

Mop it up.

Thanks,

	tglx
---
 b/include/linux/rtmutex.h         |   35 ---
 b/kernel/locking/Makefile         |    2 
 b/kernel/locking/rtmutex.c        |  379 +++++++++++++-------------------------
 b/kernel/locking/rtmutex_common.h |   98 ++++-----
 kernel/locking/rtmutex-debug.c    |  182 ------------------
 kernel/locking/rtmutex-debug.h    |   37 ---
 kernel/locking/rtmutex.h          |   35 ---
 7 files changed, 184 insertions(+), 584 deletions(-)

[patch 01/14] locking/rtmutex: Remove rt_mutex_timed_lock()

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

rt_mutex_timed_lock() has no callers since commit c051b21f71d1f ("rtmutex:
Confine deadlock logic to futex")

Remove it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rtmutex.h  |    3 ---
 kernel/locking/rtmutex.c |   46 ----------------------------------------------
 2 files changed, 49 deletions(-)

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -115,9 +115,6 @@ extern void rt_mutex_lock(struct rt_mute
 #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);
-
 extern int rt_mutex_trylock(struct rt_mutex *lock);
 
 extern void rt_mutex_unlock(struct rt_mutex *lock);
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1395,21 +1395,6 @@ rt_mutex_fastlock(struct rt_mutex *lock,
 }
 
 static inline int
-rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
-			struct hrtimer_sleeper *timeout,
-			enum rtmutex_chainwalk chwalk,
-			int (*slowfn)(struct rt_mutex *lock, int state,
-				      struct hrtimer_sleeper *timeout,
-				      enum rtmutex_chainwalk chwalk))
-{
-	if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
-	    likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
-		return 0;
-
-	return slowfn(lock, state, timeout, chwalk);
-}
-
-static inline int
 rt_mutex_fasttrylock(struct rt_mutex *lock,
 		     int (*slowfn)(struct rt_mutex *lock))
 {
@@ -1517,37 +1502,6 @@ int __sched __rt_mutex_futex_trylock(str
 }
 
 /**
- * rt_mutex_timed_lock - lock a rt_mutex interruptible
- *			the timeout structure is provided
- *			by the caller
- *
- * @lock:		the rt_mutex to be locked
- * @timeout:		timeout structure or NULL (no timeout)
- *
- * Returns:
- *  0		on success
- * -EINTR	when interrupted by a signal
- * -ETIMEDOUT	when the timeout expired
- */
-int
-rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
-{
-	int ret;
-
-	might_sleep();
-
-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	ret = rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
-				       RT_MUTEX_MIN_CHAINWALK,
-				       rt_mutex_slowlock);
-	if (ret)
-		mutex_release(&lock->dep_map, _RET_IP_);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
-
-/**
  * rt_mutex_trylock - try to lock a rt_mutex
  *
  * @lock:	the rt_mutex to be locked

[tip: locking/core] locking/rtmutex: Remove rt_mutex_timed_lock()

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     ba8c437e7cf3c8cc92f4b68b32b6b2217d2036d9
Gitweb:        https://git.kernel.org/tip/ba8c437e7cf3c8cc92f4b68b32b6b2217d2036d9
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:20 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:06 +01:00

locking/rtmutex: Remove rt_mutex_timed_lock()

rt_mutex_timed_lock() has no callers since commit:

  c051b21f71d1f ("rtmutex: Confine deadlock logic to futex")

Remove it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213707.465154098@linutronix.de
---
 include/linux/rtmutex.h  |  3 +---
 kernel/locking/rtmutex.c | 46 +---------------------------------------
 2 files changed, 49 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 6fd615a..32f4a35 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -115,9 +115,6 @@ extern void rt_mutex_lock(struct rt_mutex *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);
-
 extern int rt_mutex_trylock(struct rt_mutex *lock);
 
 extern void rt_mutex_unlock(struct rt_mutex *lock);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index db31bce..ca93e5d 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1395,21 +1395,6 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
 }
 
 static inline int
-rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
-			struct hrtimer_sleeper *timeout,
-			enum rtmutex_chainwalk chwalk,
-			int (*slowfn)(struct rt_mutex *lock, int state,
-				      struct hrtimer_sleeper *timeout,
-				      enum rtmutex_chainwalk chwalk))
-{
-	if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
-	    likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
-		return 0;
-
-	return slowfn(lock, state, timeout, chwalk);
-}
-
-static inline int
 rt_mutex_fasttrylock(struct rt_mutex *lock,
 		     int (*slowfn)(struct rt_mutex *lock))
 {
@@ -1517,37 +1502,6 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
 }
 
 /**
- * rt_mutex_timed_lock - lock a rt_mutex interruptible
- *			the timeout structure is provided
- *			by the caller
- *
- * @lock:		the rt_mutex to be locked
- * @timeout:		timeout structure or NULL (no timeout)
- *
- * Returns:
- *  0		on success
- * -EINTR	when interrupted by a signal
- * -ETIMEDOUT	when the timeout expired
- */
-int
-rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
-{
-	int ret;
-
-	might_sleep();
-
-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	ret = rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
-				       RT_MUTEX_MIN_CHAINWALK,
-				       rt_mutex_slowlock);
-	if (ret)
-		mutex_release(&lock->dep_map, _RET_IP_);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
-
-/**
  * rt_mutex_trylock - try to lock a rt_mutex
  *
  * @lock:	the rt_mutex to be locked

[patch 02/14] locking/rtmutex: Remove rtmutex deadlock tester leftovers

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

The following debug members of struct rtmutex are unused:

 - save_state: No users

 - file,line: Printed if ::name is NULL. This is only used for non-futex
   	      locks so ::name is never NULL

 - magic:     Assigned to NULL by rt_mutex_destroy(), no further usage

Remove them along with unused inlines and macros leftovers related to
the long gone deadlock tester.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rtmutex.h         |    7 ++-----
 kernel/locking/rtmutex-debug.c  |    7 +------
 kernel/locking/rtmutex-debug.h  |    2 --
 kernel/locking/rtmutex.c        |    3 ---
 kernel/locking/rtmutex.h        |    2 --
 kernel/locking/rtmutex_common.h |    1 -
 6 files changed, 3 insertions(+), 19 deletions(-)

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -32,10 +32,7 @@ struct rt_mutex {
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-	int			save_state;
-	const char		*name, *file;
-	int			line;
-	void			*magic;
+	const char		*name;
 #endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
@@ -60,7 +57,7 @@ struct hrtimer_sleeper;
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	, .name = #mutexname, .file = __FILE__, .line = __LINE__
+	, .name = #mutexname
 
 # define rt_mutex_init(mutex) \
 do { \
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -42,12 +42,7 @@ static void printk_task(struct task_stru
 
 static void printk_lock(struct rt_mutex *lock, int print_owner)
 {
-	if (lock->name)
-		printk(" [%p] {%s}\n",
-			lock, lock->name);
-	else
-		printk(" [%p] {%s:%d}\n",
-			lock, lock->file, lock->line);
+	printk(" [%p] {%s}\n", lock, lock->name);
 
 	if (print_owner && rt_mutex_owner(lock)) {
 		printk(".. ->owner: %p\n", lock->owner);
--- a/kernel/locking/rtmutex-debug.h
+++ b/kernel/locking/rtmutex-debug.h
@@ -22,8 +22,6 @@ extern void debug_rt_mutex_deadlock(enum
 				    struct rt_mutex_waiter *waiter,
 				    struct rt_mutex *lock);
 extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
-# define debug_rt_mutex_reset_waiter(w)			\
-	do { (w)->deadlock_lock = NULL; } while (0)
 
 static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
 						  enum rtmutex_chainwalk walk)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1594,9 +1594,6 @@ void __sched rt_mutex_futex_unlock(struc
 void rt_mutex_destroy(struct rt_mutex *lock)
 {
 	WARN_ON(rt_mutex_is_locked(lock));
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	lock->magic = NULL;
-#endif
 }
 EXPORT_SYMBOL_GPL(rt_mutex_destroy);
 
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -11,7 +11,6 @@
  * Non-debug version.
  */
 
-#define rt_mutex_deadlock_check(l)			(0)
 #define debug_rt_mutex_init_waiter(w)			do { } while (0)
 #define debug_rt_mutex_free_waiter(w)			do { } while (0)
 #define debug_rt_mutex_lock(l)				do { } while (0)
@@ -21,7 +20,6 @@
 #define debug_rt_mutex_init(m, n, k)			do { } while (0)
 #define debug_rt_mutex_deadlock(d, a ,l)		do { } while (0)
 #define debug_rt_mutex_print_deadlock(w)		do { } while (0)
-#define debug_rt_mutex_reset_waiter(w)			do { } while (0)
 
 static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
 {
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -30,7 +30,6 @@ struct rt_mutex_waiter {
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-	unsigned long		ip;
 	struct pid		*deadlock_task_pid;
 	struct rt_mutex		*deadlock_lock;
 #endif

[tip: locking/core] locking/rtmutex: Remove rtmutex deadlock tester leftovers

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     ff033d34ec7244e6d86b4bbdd917ec0d54299f31
Gitweb:        https://git.kernel.org/tip/ff033d34ec7244e6d86b4bbdd917ec0d54299f31
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:21 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00

locking/rtmutex: Remove rtmutex deadlock tester leftovers

The following debug members of struct rtmutex are unused:

 - save_state: No users

 - file,line:  Printed if ::name is NULL. This is only used for non-futex
	       locks so ::name is never NULL

 - magic:      Assigned to NULL by rt_mutex_destroy(), no further usage

Remove them along with unused inlines and macros leftovers related to
the long gone deadlock tester.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213707.630525866@linutronix.de
---
 include/linux/rtmutex.h         | 7 ++-----
 kernel/locking/rtmutex-debug.c  | 7 +------
 kernel/locking/rtmutex-debug.h  | 2 --
 kernel/locking/rtmutex.c        | 3 ---
 kernel/locking/rtmutex.h        | 2 --
 kernel/locking/rtmutex_common.h | 1 -
 6 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 32f4a35..48b334b 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -32,10 +32,7 @@ struct rt_mutex {
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-	int			save_state;
-	const char		*name, *file;
-	int			line;
-	void			*magic;
+	const char		*name;
 #endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
@@ -60,7 +57,7 @@ struct hrtimer_sleeper;
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	, .name = #mutexname, .file = __FILE__, .line = __LINE__
+	, .name = #mutexname
 
 # define rt_mutex_init(mutex) \
 do { \
diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
index 36e6910..7e411b9 100644
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -42,12 +42,7 @@ static void printk_task(struct task_struct *p)
 
 static void printk_lock(struct rt_mutex *lock, int print_owner)
 {
-	if (lock->name)
-		printk(" [%p] {%s}\n",
-			lock, lock->name);
-	else
-		printk(" [%p] {%s:%d}\n",
-			lock, lock->file, lock->line);
+	printk(" [%p] {%s}\n", lock, lock->name);
 
 	if (print_owner && rt_mutex_owner(lock)) {
 		printk(".. ->owner: %p\n", lock->owner);
diff --git a/kernel/locking/rtmutex-debug.h b/kernel/locking/rtmutex-debug.h
index fc54971..772c9b0 100644
--- a/kernel/locking/rtmutex-debug.h
+++ b/kernel/locking/rtmutex-debug.h
@@ -22,8 +22,6 @@ extern void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
 				    struct rt_mutex_waiter *waiter,
 				    struct rt_mutex *lock);
 extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
-# define debug_rt_mutex_reset_waiter(w)			\
-	do { (w)->deadlock_lock = NULL; } while (0)
 
 static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
 						  enum rtmutex_chainwalk walk)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index ca93e5d..11abc60 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1594,9 +1594,6 @@ void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
 void rt_mutex_destroy(struct rt_mutex *lock)
 {
 	WARN_ON(rt_mutex_is_locked(lock));
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	lock->magic = NULL;
-#endif
 }
 EXPORT_SYMBOL_GPL(rt_mutex_destroy);
 
diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h
index 732f96a..4dbdec1 100644
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -11,7 +11,6 @@
  * Non-debug version.
  */
 
-#define rt_mutex_deadlock_check(l)			(0)
 #define debug_rt_mutex_init_waiter(w)			do { } while (0)
 #define debug_rt_mutex_free_waiter(w)			do { } while (0)
 #define debug_rt_mutex_lock(l)				do { } while (0)
@@ -21,7 +20,6 @@
 #define debug_rt_mutex_init(m, n, k)			do { } while (0)
 #define debug_rt_mutex_deadlock(d, a ,l)		do { } while (0)
 #define debug_rt_mutex_print_deadlock(w)		do { } while (0)
-#define debug_rt_mutex_reset_waiter(w)			do { } while (0)
 
 static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
 {
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index a5007f0..aa04743 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -30,7 +30,6 @@ struct rt_mutex_waiter {
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-	unsigned long		ip;
 	struct pid		*deadlock_task_pid;
 	struct rt_mutex		*deadlock_lock;
 #endif

[patch 03/14] locking/rtmutex: Remove output from deadlock detector.

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

The rtmutex specific deadlock detector predates lockdep coverage of rtmutex
and since commit f5694788ad8da ("rt_mutex: Add lockdep annotations") it
contains a lot of redundant functionality.

 - lockdep will detect an potential deadlock before rtmutex-debug
   has a chance to do so

 - the dead lock debugging is restricted to rtmutexes which are not
   associated to futexes and have an active waiter, which is covered by
   lockdep already

Remove the redundant functionality and move actual deadlock WARN() into the
deadlock code path. The latter needs a seperate cleanup.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rtmutex.h         |    7 --
 kernel/locking/rtmutex-debug.c  |   97 ----------------------------------------
 kernel/locking/rtmutex-debug.h  |    9 ---
 kernel/locking/rtmutex.c        |    7 --
 kernel/locking/rtmutex.h        |    7 --
 kernel/locking/rtmutex_common.h |    4 -
 6 files changed, 1 insertion(+), 130 deletions(-)

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -31,9 +31,6 @@ struct rt_mutex {
 	raw_spinlock_t		wait_lock;
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	const char		*name;
-#endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
 #endif
@@ -56,8 +53,6 @@ struct hrtimer_sleeper;
 #endif
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	, .name = #mutexname
 
 # define rt_mutex_init(mutex) \
 do { \
@@ -67,7 +62,6 @@ do { \
 
  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
 # define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
 # define rt_mutex_debug_task_free(t)			do { } while (0)
 #endif
@@ -83,7 +77,6 @@ do { \
 	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
 	, .waiters = RB_ROOT_CACHED \
 	, .owner = NULL \
-	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
 	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
 
 #define DEFINE_RT_MUTEX(mutexname) \
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -32,105 +32,12 @@
 
 #include "rtmutex_common.h"
 
-static void printk_task(struct task_struct *p)
-{
-	if (p)
-		printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);
-	else
-		printk("<none>");
-}
-
-static void printk_lock(struct rt_mutex *lock, int print_owner)
-{
-	printk(" [%p] {%s}\n", lock, lock->name);
-
-	if (print_owner && rt_mutex_owner(lock)) {
-		printk(".. ->owner: %p\n", lock->owner);
-		printk(".. held by:  ");
-		printk_task(rt_mutex_owner(lock));
-		printk("\n");
-	}
-}
-
 void rt_mutex_debug_task_free(struct task_struct *task)
 {
 	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
 	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
 }
 
-/*
- * We fill out the fields in the waiter to store the information about
- * the deadlock. We print when we return. act_waiter can be NULL in
- * case of a remove waiter operation.
- */
-void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
-			     struct rt_mutex_waiter *act_waiter,
-			     struct rt_mutex *lock)
-{
-	struct task_struct *task;
-
-	if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter)
-		return;
-
-	task = rt_mutex_owner(act_waiter->lock);
-	if (task && task != current) {
-		act_waiter->deadlock_task_pid = get_pid(task_pid(task));
-		act_waiter->deadlock_lock = lock;
-	}
-}
-
-void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
-{
-	struct task_struct *task;
-
-	if (!waiter->deadlock_lock || !debug_locks)
-		return;
-
-	rcu_read_lock();
-	task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
-	if (!task) {
-		rcu_read_unlock();
-		return;
-	}
-
-	if (!debug_locks_off()) {
-		rcu_read_unlock();
-		return;
-	}
-
-	pr_warn("\n");
-	pr_warn("============================================\n");
-	pr_warn("WARNING: circular locking deadlock detected!\n");
-	pr_warn("%s\n", print_tainted());
-	pr_warn("--------------------------------------------\n");
-	printk("%s/%d is deadlocking current task %s/%d\n\n",
-	       task->comm, task_pid_nr(task),
-	       current->comm, task_pid_nr(current));
-
-	printk("\n1) %s/%d is trying to acquire this lock:\n",
-	       current->comm, task_pid_nr(current));
-	printk_lock(waiter->lock, 1);
-
-	printk("\n2) %s/%d is blocked on this lock:\n",
-		task->comm, task_pid_nr(task));
-	printk_lock(waiter->deadlock_lock, 1);
-
-	debug_show_held_locks(current);
-	debug_show_held_locks(task);
-
-	printk("\n%s/%d's [blocked] stackdump:\n\n",
-		task->comm, task_pid_nr(task));
-	show_stack(task, NULL, KERN_DEFAULT);
-	printk("\n%s/%d's [current] stackdump:\n\n",
-		current->comm, task_pid_nr(current));
-	dump_stack();
-	debug_show_all_locks();
-	rcu_read_unlock();
-
-	printk("[ turning off deadlock detection."
-	       "Please report this trace. ]\n\n");
-}
-
 void debug_rt_mutex_lock(struct rt_mutex *lock)
 {
 }
@@ -153,12 +60,10 @@ void debug_rt_mutex_proxy_unlock(struct
 void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
 {
 	memset(waiter, 0x11, sizeof(*waiter));
-	waiter->deadlock_task_pid = NULL;
 }
 
 void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
 {
-	put_pid(waiter->deadlock_task_pid);
 	memset(waiter, 0x22, sizeof(*waiter));
 }
 
@@ -168,10 +73,8 @@ void debug_rt_mutex_init(struct rt_mutex
 	 * Make sure we are not reinitializing a held lock:
 	 */
 	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
-	lock->name = name;
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	lockdep_init_map(&lock->dep_map, name, key, 0);
 #endif
 }
-
--- a/kernel/locking/rtmutex-debug.h
+++ b/kernel/locking/rtmutex-debug.h
@@ -18,18 +18,9 @@ extern void debug_rt_mutex_unlock(struct
 extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
 				      struct task_struct *powner);
 extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
-extern void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
-				    struct rt_mutex_waiter *waiter,
-				    struct rt_mutex *lock);
-extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
 
 static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
 						  enum rtmutex_chainwalk walk)
 {
 	return (waiter != NULL);
 }
-
-static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
-{
-	debug_rt_mutex_print_deadlock(w);
-}
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -579,7 +579,6 @@ static int rt_mutex_adjust_prio_chain(st
 	 * walk, we detected a deadlock.
 	 */
 	if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
-		debug_rt_mutex_deadlock(chwalk, orig_waiter, lock);
 		raw_spin_unlock(&lock->wait_lock);
 		ret = -EDEADLK;
 		goto out_unlock_pi;
@@ -1171,8 +1170,6 @@ static int __sched
 
 		raw_spin_unlock_irq(&lock->wait_lock);
 
-		debug_rt_mutex_print_deadlock(waiter);
-
 		schedule();
 
 		raw_spin_lock_irq(&lock->wait_lock);
@@ -1196,7 +1193,7 @@ static void rt_mutex_handle_deadlock(int
 	/*
 	 * Yell loudly and stop the task right here.
 	 */
-	rt_mutex_print_deadlock(w);
+	WARN(1, "rtmutex deadlock detected\n");
 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule();
@@ -1704,8 +1701,6 @@ int __rt_mutex_start_proxy_lock(struct r
 		ret = 0;
 	}
 
-	debug_rt_mutex_print_deadlock(waiter);
-
 	return ret;
 }
 
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -18,13 +18,6 @@
 #define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
 #define debug_rt_mutex_unlock(l)			do { } while (0)
 #define debug_rt_mutex_init(m, n, k)			do { } while (0)
-#define debug_rt_mutex_deadlock(d, a ,l)		do { } while (0)
-#define debug_rt_mutex_print_deadlock(w)		do { } while (0)
-
-static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
-{
-	WARN(1, "rtmutex deadlock detected\n");
-}
 
 static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w,
 						  enum rtmutex_chainwalk walk)
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -29,10 +29,6 @@ struct rt_mutex_waiter {
 	struct rb_node          pi_tree_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	struct pid		*deadlock_task_pid;
-	struct rt_mutex		*deadlock_lock;
-#endif
 	int prio;
 	u64 deadline;
 };

[tip: locking/core] locking/rtmutex: Remove output from deadlock detector.

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     5389aaaa737bf9b1d430143a15c37c6ee2d89a75
Gitweb:        https://git.kernel.org/tip/5389aaaa737bf9b1d430143a15c37c6ee2d89a75
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:22 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00

locking/rtmutex: Remove output from deadlock detector.

The rtmutex specific deadlock detector predates lockdep coverage of rtmutex
and since the following commit it contains a lot of redundant functionality:

  f5694788ad8da ("rt_mutex: Add lockdep annotations")

 - lockdep will detect an potential deadlock before rtmutex-debug
   has a chance to do so

 - the dead lock debugging is restricted to rtmutexes which are not
   associated to futexes and have an active waiter, which is covered by
   lockdep already

Remove the redundant functionality and move actual deadlock WARN() into the
deadlock code path. The latter needs a seperate cleanup.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213707.773152524@linutronix.de
---
 include/linux/rtmutex.h         |  7 +--
 kernel/locking/rtmutex-debug.c  | 97 +--------------------------------
 kernel/locking/rtmutex-debug.h  |  9 +---
 kernel/locking/rtmutex.c        |  7 +--
 kernel/locking/rtmutex.h        |  7 +--
 kernel/locking/rtmutex_common.h |  4 +-
 6 files changed, 1 insertion(+), 130 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 48b334b..0725c4b 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -31,9 +31,6 @@ struct rt_mutex {
 	raw_spinlock_t		wait_lock;
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	const char		*name;
-#endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
 #endif
@@ -56,8 +53,6 @@ struct hrtimer_sleeper;
 #endif
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	, .name = #mutexname
 
 # define rt_mutex_init(mutex) \
 do { \
@@ -67,7 +62,6 @@ do { \
 
  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
 # define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
 # define rt_mutex_debug_task_free(t)			do { } while (0)
 #endif
@@ -83,7 +77,6 @@ do { \
 	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
 	, .waiters = RB_ROOT_CACHED \
 	, .owner = NULL \
-	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
 	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
 
 #define DEFINE_RT_MUTEX(mutexname) \
diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
index 7e411b9..fb15010 100644
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -32,105 +32,12 @@
 
 #include "rtmutex_common.h"
 
-static void printk_task(struct task_struct *p)
-{
-	if (p)
-		printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);
-	else
-		printk("<none>");
-}
-
-static void printk_lock(struct rt_mutex *lock, int print_owner)
-{
-	printk(" [%p] {%s}\n", lock, lock->name);
-
-	if (print_owner && rt_mutex_owner(lock)) {
-		printk(".. ->owner: %p\n", lock->owner);
-		printk(".. held by:  ");
-		printk_task(rt_mutex_owner(lock));
-		printk("\n");
-	}
-}
-
 void rt_mutex_debug_task_free(struct task_struct *task)
 {
 	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
 	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
 }
 
-/*
- * We fill out the fields in the waiter to store the information about
- * the deadlock. We print when we return. act_waiter can be NULL in
- * case of a remove waiter operation.
- */
-void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
-			     struct rt_mutex_waiter *act_waiter,
-			     struct rt_mutex *lock)
-{
-	struct task_struct *task;
-
-	if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter)
-		return;
-
-	task = rt_mutex_owner(act_waiter->lock);
-	if (task && task != current) {
-		act_waiter->deadlock_task_pid = get_pid(task_pid(task));
-		act_waiter->deadlock_lock = lock;
-	}
-}
-
-void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
-{
-	struct task_struct *task;
-
-	if (!waiter->deadlock_lock || !debug_locks)
-		return;
-
-	rcu_read_lock();
-	task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
-	if (!task) {
-		rcu_read_unlock();
-		return;
-	}
-
-	if (!debug_locks_off()) {
-		rcu_read_unlock();
-		return;
-	}
-
-	pr_warn("\n");
-	pr_warn("============================================\n");
-	pr_warn("WARNING: circular locking deadlock detected!\n");
-	pr_warn("%s\n", print_tainted());
-	pr_warn("--------------------------------------------\n");
-	printk("%s/%d is deadlocking current task %s/%d\n\n",
-	       task->comm, task_pid_nr(task),
-	       current->comm, task_pid_nr(current));
-
-	printk("\n1) %s/%d is trying to acquire this lock:\n",
-	       current->comm, task_pid_nr(current));
-	printk_lock(waiter->lock, 1);
-
-	printk("\n2) %s/%d is blocked on this lock:\n",
-		task->comm, task_pid_nr(task));
-	printk_lock(waiter->deadlock_lock, 1);
-
-	debug_show_held_locks(current);
-	debug_show_held_locks(task);
-
-	printk("\n%s/%d's [blocked] stackdump:\n\n",
-		task->comm, task_pid_nr(task));
-	show_stack(task, NULL, KERN_DEFAULT);
-	printk("\n%s/%d's [current] stackdump:\n\n",
-		current->comm, task_pid_nr(current));
-	dump_stack();
-	debug_show_all_locks();
-	rcu_read_unlock();
-
-	printk("[ turning off deadlock detection."
-	       "Please report this trace. ]\n\n");
-}
-
 void debug_rt_mutex_lock(struct rt_mutex *lock)
 {
 }
@@ -153,12 +60,10 @@ void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
 void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
 {
 	memset(waiter, 0x11, sizeof(*waiter));
-	waiter->deadlock_task_pid = NULL;
 }
 
 void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
 {
-	put_pid(waiter->deadlock_task_pid);
 	memset(waiter, 0x22, sizeof(*waiter));
 }
 
@@ -168,10 +73,8 @@ void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_cl
 	 * Make sure we are not reinitializing a held lock:
 	 */
 	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
-	lock->name = name;
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	lockdep_init_map(&lock->dep_map, name, key, 0);
 #endif
 }
-
diff --git a/kernel/locking/rtmutex-debug.h b/kernel/locking/rtmutex-debug.h
index 772c9b0..659e93e 100644
--- a/kernel/locking/rtmutex-debug.h
+++ b/kernel/locking/rtmutex-debug.h
@@ -18,18 +18,9 @@ extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
 extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
 				      struct task_struct *powner);
 extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
-extern void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
-				    struct rt_mutex_waiter *waiter,
-				    struct rt_mutex *lock);
-extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
 
 static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
 						  enum rtmutex_chainwalk walk)
 {
 	return (waiter != NULL);
 }
-
-static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
-{
-	debug_rt_mutex_print_deadlock(w);
-}
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 11abc60..4beca54 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -579,7 +579,6 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 	 * walk, we detected a deadlock.
 	 */
 	if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
-		debug_rt_mutex_deadlock(chwalk, orig_waiter, lock);
 		raw_spin_unlock(&lock->wait_lock);
 		ret = -EDEADLK;
 		goto out_unlock_pi;
@@ -1171,8 +1170,6 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 
 		raw_spin_unlock_irq(&lock->wait_lock);
 
-		debug_rt_mutex_print_deadlock(waiter);
-
 		schedule();
 
 		raw_spin_lock_irq(&lock->wait_lock);
@@ -1196,7 +1193,7 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
 	/*
 	 * Yell loudly and stop the task right here.
 	 */
-	rt_mutex_print_deadlock(w);
+	WARN(1, "rtmutex deadlock detected\n");
 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule();
@@ -1704,8 +1701,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 		ret = 0;
 	}
 
-	debug_rt_mutex_print_deadlock(waiter);
-
 	return ret;
 }
 
diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h
index 4dbdec1..d77cb82 100644
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -18,13 +18,6 @@
 #define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
 #define debug_rt_mutex_unlock(l)			do { } while (0)
 #define debug_rt_mutex_init(m, n, k)			do { } while (0)
-#define debug_rt_mutex_deadlock(d, a ,l)		do { } while (0)
-#define debug_rt_mutex_print_deadlock(w)		do { } while (0)
-
-static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
-{
-	WARN(1, "rtmutex deadlock detected\n");
-}
 
 static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w,
 						  enum rtmutex_chainwalk walk)
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index aa04743..badb2a2 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -29,10 +29,6 @@ struct rt_mutex_waiter {
 	struct rb_node          pi_tree_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	struct pid		*deadlock_task_pid;
-	struct rt_mutex		*deadlock_lock;
-#endif
 	int prio;
 	u64 deadline;
 };

[patch 04/14] locking/rtmutex: Consolidate rt_mutex_init()

[Thomas Gleixner]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

rt_mutex_init() only initializes lockdep if CONFIG_DEBUG_RT_MUTEXES is
enabled which is fine because all lockdep variants select it, but there is
no reason to do so.

Move the function outside of the CONFIG_DEBUG_RT_MUTEXES block which
removes #ifdeffery.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rtmutex.h |   12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -43,6 +43,7 @@ struct hrtimer_sleeper;
  extern int rt_mutex_debug_check_no_locks_freed(const void *from,
 						unsigned long len);
  extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
+ extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
  static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
 						       unsigned long len)
@@ -50,22 +51,15 @@ struct hrtimer_sleeper;
 	return 0;
  }
 # define rt_mutex_debug_check_no_locks_held(task)	do { } while (0)
+# define rt_mutex_debug_task_free(t)			do { } while (0)
 #endif
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-
-# define rt_mutex_init(mutex) \
+#define rt_mutex_init(mutex) \
 do { \
 	static struct lock_class_key __key; \
 	__rt_mutex_init(mutex, __func__, &__key); \
 } while (0)
 
- extern void rt_mutex_debug_task_free(struct task_struct *tsk);
-#else
-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
-# define rt_mutex_debug_task_free(t)			do { } while (0)
-#endif
-
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \
 	, .dep_map = { .name = #mutexname }

[tip: locking/core] locking/rtmutex: Consolidate rt_mutex_init()

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     1ba7cf8e3a9316daa84ee774346028f84bca2957
Gitweb:        https://git.kernel.org/tip/1ba7cf8e3a9316daa84ee774346028f84bca2957
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:23 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00

locking/rtmutex: Consolidate rt_mutex_init()

rt_mutex_init() only initializes lockdep if CONFIG_DEBUG_RT_MUTEXES=y,
which is fine because all lockdep variants select it, but there is
no reason to do so.

Move the function outside of the CONFIG_DEBUG_RT_MUTEXES block which
removes #ifdeffery.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213707.896403641@linutronix.de
---
 include/linux/rtmutex.h | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 0725c4b..243fabc 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -43,6 +43,7 @@ struct hrtimer_sleeper;
  extern int rt_mutex_debug_check_no_locks_freed(const void *from,
 						unsigned long len);
  extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
+ extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
  static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
 						       unsigned long len)
@@ -50,22 +51,15 @@ struct hrtimer_sleeper;
 	return 0;
  }
 # define rt_mutex_debug_check_no_locks_held(task)	do { } while (0)
+# define rt_mutex_debug_task_free(t)			do { } while (0)
 #endif
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-
-# define rt_mutex_init(mutex) \
+#define rt_mutex_init(mutex) \
 do { \
 	static struct lock_class_key __key; \
 	__rt_mutex_init(mutex, __func__, &__key); \
 } while (0)
 
- extern void rt_mutex_debug_task_free(struct task_struct *tsk);
-#else
-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
-# define rt_mutex_debug_task_free(t)			do { } while (0)
-#endif
-
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \
 	, .dep_map = { .name = #mutexname }

[patch 05/14] locking/rtmutex: Remove empty and unused debug stubs

[Thomas Gleixner]

No users just ballast.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rtmutex.h        |   14 ++------------
 kernel/locking/rtmutex-debug.c |    9 ---------
 kernel/locking/rtmutex.c       |   17 -----------------
 kernel/locking/rtmutex.h       |    2 --
 4 files changed, 2 insertions(+), 40 deletions(-)

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -40,18 +40,9 @@ struct rt_mutex_waiter;
 struct hrtimer_sleeper;
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
- extern int rt_mutex_debug_check_no_locks_freed(const void *from,
-						unsigned long len);
- extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
- extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
- static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
-						       unsigned long len)
- {
-	return 0;
- }
-# define rt_mutex_debug_check_no_locks_held(task)	do { } while (0)
-# define rt_mutex_debug_task_free(t)			do { } while (0)
+static inline void rt_mutex_debug_task_free(struct task_struct *tsk) { }
 #endif
 
 #define rt_mutex_init(mutex) \
@@ -88,7 +79,6 @@ static inline int rt_mutex_is_locked(str
 }
 
 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);
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -38,20 +38,11 @@ void rt_mutex_debug_task_free(struct tas
 	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
 }
 
-void debug_rt_mutex_lock(struct rt_mutex *lock)
-{
-}
-
 void debug_rt_mutex_unlock(struct rt_mutex *lock)
 {
 	DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
 }
 
-void
-debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
-{
-}
-
 void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
 {
 	DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -885,9 +885,6 @@ static int try_to_take_rt_mutex(struct r
 	raw_spin_unlock(&task->pi_lock);
 
 takeit:
-	/* We got the lock. */
-	debug_rt_mutex_lock(lock);
-
 	/*
 	 * This either preserves the RT_MUTEX_HAS_WAITERS bit if there
 	 * are still waiters or clears it.
@@ -1581,20 +1578,6 @@ void __sched rt_mutex_futex_unlock(struc
 }
 
 /**
- * rt_mutex_destroy - mark a mutex unusable
- * @lock: the mutex to be destroyed
- *
- * This function marks the mutex uninitialized, and any subsequent
- * use of the mutex is forbidden. The mutex must not be locked when
- * this function is called.
- */
-void rt_mutex_destroy(struct rt_mutex *lock)
-{
-	WARN_ON(rt_mutex_is_locked(lock));
-}
-EXPORT_SYMBOL_GPL(rt_mutex_destroy);
-
-/**
  * __rt_mutex_init - initialize the rt_mutex
  *
  * @lock:	The rt_mutex to be initialized
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -13,8 +13,6 @@
 
 #define debug_rt_mutex_init_waiter(w)			do { } while (0)
 #define debug_rt_mutex_free_waiter(w)			do { } while (0)
-#define debug_rt_mutex_lock(l)				do { } while (0)
-#define debug_rt_mutex_proxy_lock(l,p)			do { } while (0)
 #define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
 #define debug_rt_mutex_unlock(l)			do { } while (0)
 #define debug_rt_mutex_init(m, n, k)			do { } while (0)

[tip: locking/core] locking/rtmutex: Remove empty and unused debug stubs

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     fec6b6a56b6135163f45332570e4c2cc51484a64
Gitweb:        https://git.kernel.org/tip/fec6b6a56b6135163f45332570e4c2cc51484a64
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:24 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00

locking/rtmutex: Remove empty and unused debug stubs

No users, just ballast.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.001857655@linutronix.de
---
 include/linux/rtmutex.h        | 14 ++------------
 kernel/locking/rtmutex-debug.c |  9 ---------
 kernel/locking/rtmutex.c       | 17 -----------------
 kernel/locking/rtmutex.h       |  2 --
 4 files changed, 2 insertions(+), 40 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 243fabc..d1672de 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -40,18 +40,9 @@ struct rt_mutex_waiter;
 struct hrtimer_sleeper;
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
- extern int rt_mutex_debug_check_no_locks_freed(const void *from,
-						unsigned long len);
- extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
- extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
- static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
-						       unsigned long len)
- {
-	return 0;
- }
-# define rt_mutex_debug_check_no_locks_held(task)	do { } while (0)
-# define rt_mutex_debug_task_free(t)			do { } while (0)
+static inline void rt_mutex_debug_task_free(struct task_struct *tsk) { }
 #endif
 
 #define rt_mutex_init(mutex) \
@@ -88,7 +79,6 @@ 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);
diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
index fb15010..df584c9 100644
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -38,20 +38,11 @@ void rt_mutex_debug_task_free(struct task_struct *task)
 	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
 }
 
-void debug_rt_mutex_lock(struct rt_mutex *lock)
-{
-}
-
 void debug_rt_mutex_unlock(struct rt_mutex *lock)
 {
 	DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
 }
 
-void
-debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
-{
-}
-
 void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
 {
 	DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 4beca54..82cb963 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -885,9 +885,6 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 	raw_spin_unlock(&task->pi_lock);
 
 takeit:
-	/* We got the lock. */
-	debug_rt_mutex_lock(lock);
-
 	/*
 	 * This either preserves the RT_MUTEX_HAS_WAITERS bit if there
 	 * are still waiters or clears it.
@@ -1581,20 +1578,6 @@ void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
 }
 
 /**
- * rt_mutex_destroy - mark a mutex unusable
- * @lock: the mutex to be destroyed
- *
- * This function marks the mutex uninitialized, and any subsequent
- * use of the mutex is forbidden. The mutex must not be locked when
- * this function is called.
- */
-void rt_mutex_destroy(struct rt_mutex *lock)
-{
-	WARN_ON(rt_mutex_is_locked(lock));
-}
-EXPORT_SYMBOL_GPL(rt_mutex_destroy);
-
-/**
  * __rt_mutex_init - initialize the rt_mutex
  *
  * @lock:	The rt_mutex to be initialized
diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h
index d77cb82..1e484ab 100644
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -13,8 +13,6 @@
 
 #define debug_rt_mutex_init_waiter(w)			do { } while (0)
 #define debug_rt_mutex_free_waiter(w)			do { } while (0)
-#define debug_rt_mutex_lock(l)				do { } while (0)
-#define debug_rt_mutex_proxy_lock(l,p)			do { } while (0)
 #define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
 #define debug_rt_mutex_unlock(l)			do { } while (0)
 #define debug_rt_mutex_init(m, n, k)			do { } while (0)

[patch 06/14] locking/rtmutex: Move rt_mutex_debug_task_free() to rtmutex.c

[Thomas Gleixner]

Prepare for removing the header maze.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex-debug.c |    6 ------
 kernel/locking/rtmutex.c       |    8 ++++++++
 2 files changed, 8 insertions(+), 6 deletions(-)

--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -32,12 +32,6 @@
 
 #include "rtmutex_common.h"
 
-void rt_mutex_debug_task_free(struct task_struct *task)
-{
-	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
-	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
-}
-
 void debug_rt_mutex_unlock(struct rt_mutex *lock)
 {
 	DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1828,3 +1828,11 @@ bool rt_mutex_cleanup_proxy_lock(struct
 
 	return cleanup;
 }
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+void rt_mutex_debug_task_free(struct task_struct *task)
+{
+	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
+	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+}
+#endif

[tip: locking/core] locking/rtmutex: Move rt_mutex_debug_task_free() to rtmutex.c

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     1238b7032101ba420a114f64b86a8e3de609d0e8
Gitweb:        https://git.kernel.org/tip/1238b7032101ba420a114f64b86a8e3de609d0e8
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:25 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00

locking/rtmutex: Move rt_mutex_debug_task_free() to rtmutex.c

Prepare for removing the header maze.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.096477462@linutronix.de
---
 kernel/locking/rtmutex-debug.c | 6 ------
 kernel/locking/rtmutex.c       | 8 ++++++++
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
index df584c9..f1a83ec 100644
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -32,12 +32,6 @@
 
 #include "rtmutex_common.h"
 
-void rt_mutex_debug_task_free(struct task_struct *task)
-{
-	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
-	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
-}
-
 void debug_rt_mutex_unlock(struct rt_mutex *lock)
 {
 	DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 82cb963..a18ee0c 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1814,3 +1814,11 @@ bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
 
 	return cleanup;
 }
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+void rt_mutex_debug_task_free(struct task_struct *task)
+{
+	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
+	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+}
+#endif

[patch 07/14] locking/rtmutex: Inline chainwalk depth check

[Thomas Gleixner]

There is no point for this wrapper at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -343,14 +343,9 @@ static void rt_mutex_adjust_prio(struct
 static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
 					  enum rtmutex_chainwalk chwalk)
 {
-	/*
-	 * This is just a wrapper function for the following call,
-	 * because debug_rt_mutex_detect_deadlock() smells like a magic
-	 * debug feature and I wanted to keep the cond function in the
-	 * main source file along with the comments instead of having
-	 * two of the same in the headers.
-	 */
-	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEX))
+		return waiter != NULL;
+	return chwalk == RT_MUTEX_FULL_CHAINWALK;
 }
 
 /*

[tip: locking/core] locking/rtmutex: Inline chainwalk depth check

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     31120afb21f5892aa981af635b425a074e978cab
Gitweb:        https://git.kernel.org/tip/31120afb21f5892aa981af635b425a074e978cab
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:26 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:07 +01:00

locking/rtmutex: Inline chainwalk depth check

There is no point for this wrapper at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.195031688@linutronix.de
---
 kernel/locking/rtmutex.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index a18ee0c..0eac57c 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -343,14 +343,9 @@ static void rt_mutex_adjust_prio(struct task_struct *p)
 static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
 					  enum rtmutex_chainwalk chwalk)
 {
-	/*
-	 * This is just a wrapper function for the following call,
-	 * because debug_rt_mutex_detect_deadlock() smells like a magic
-	 * debug feature and I wanted to keep the cond function in the
-	 * main source file along with the comments instead of having
-	 * two of the same in the headers.
-	 */
-	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEX))
+		return waiter != NULL;
+	return chwalk == RT_MUTEX_FULL_CHAINWALK;
 }
 
 /*

[patch 08/14] locking/rtmutex: Remove pointless CONFIG_RT_MUTEXES=n stubs

[Thomas Gleixner]

None of these functions is used when CONFIG_RT_MUTEXES=n.

Remove the gunk. Remove pointless comments and clean up the coding style
mess while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex_common.h |   56 +++++++---------------------------------
 1 file changed, 11 insertions(+), 45 deletions(-)

--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -23,29 +23,25 @@
  * @tree_entry:		pi node to enqueue into the mutex waiters tree
  * @pi_tree_entry:	pi node to enqueue into the mutex owner waiters tree
  * @task:		task reference to the blocked task
+ * @lock:		Pointer to the rt_mutex on which the waiter blocks
+ * @prio:		Priority of the waiter
+ * @deadline:		Deadline of the waiter if applicable
  */
 struct rt_mutex_waiter {
-	struct rb_node          tree_entry;
-	struct rb_node          pi_tree_entry;
+	struct rb_node		tree_entry;
+	struct rb_node		pi_tree_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
-	int prio;
-	u64 deadline;
+	int			prio;
+	u64			deadline;
 };
 
-/*
- * Various helpers to access the waiters-tree:
- */
-
-#ifdef CONFIG_RT_MUTEXES
-
 static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
 {
 	return !RB_EMPTY_ROOT(&lock->waiters.rb_root);
 }
 
-static inline struct rt_mutex_waiter *
-rt_mutex_top_waiter(struct rt_mutex *lock)
+static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock)
 {
 	struct rb_node *leftmost = rb_first_cached(&lock->waiters);
 	struct rt_mutex_waiter *w = NULL;
@@ -62,42 +58,12 @@ static inline int task_has_pi_waiters(st
 	return !RB_EMPTY_ROOT(&p->pi_waiters.rb_root);
 }
 
-static inline struct rt_mutex_waiter *
-task_top_pi_waiter(struct task_struct *p)
-{
-	return rb_entry(p->pi_waiters.rb_leftmost,
-			struct rt_mutex_waiter, pi_tree_entry);
-}
-
-#else
-
-static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
-{
-	return false;
-}
-
-static inline struct rt_mutex_waiter *
-rt_mutex_top_waiter(struct rt_mutex *lock)
-{
-	return NULL;
-}
-
-static inline int task_has_pi_waiters(struct task_struct *p)
-{
-	return false;
-}
-
-static inline struct rt_mutex_waiter *
-task_top_pi_waiter(struct task_struct *p)
+static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p)
 {
-	return NULL;
+	return rb_entry(p->pi_waiters.rb_leftmost, struct rt_mutex_waiter,
+			pi_tree_entry);
 }
 
-#endif
-
-/*
- * lock->owner state tracking:
- */
 #define RT_MUTEX_HAS_WAITERS	1UL
 
 static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)

[tip: locking/core] locking/rtmutex: Remove pointless CONFIG_RT_MUTEXES=n stubs

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     18970ac4e37011fd0c709b6c2a640f01eecf2dd7
Gitweb:        https://git.kernel.org/tip/18970ac4e37011fd0c709b6c2a640f01eecf2dd7
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:27 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:08 +01:00

locking/rtmutex: Remove pointless CONFIG_RT_MUTEXES=n stubs

None of these functions is used when CONFIG_RT_MUTEXES=n.

Remove the gunk. Remove pointless comments and clean up the coding style
mess while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.305191020@linutronix.de
---
 kernel/locking/rtmutex_common.h | 56 ++++++--------------------------
 1 file changed, 11 insertions(+), 45 deletions(-)

diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index badb2a2..0350ae3 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -23,29 +23,25 @@
  * @tree_entry:		pi node to enqueue into the mutex waiters tree
  * @pi_tree_entry:	pi node to enqueue into the mutex owner waiters tree
  * @task:		task reference to the blocked task
+ * @lock:		Pointer to the rt_mutex on which the waiter blocks
+ * @prio:		Priority of the waiter
+ * @deadline:		Deadline of the waiter if applicable
  */
 struct rt_mutex_waiter {
-	struct rb_node          tree_entry;
-	struct rb_node          pi_tree_entry;
+	struct rb_node		tree_entry;
+	struct rb_node		pi_tree_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
-	int prio;
-	u64 deadline;
+	int			prio;
+	u64			deadline;
 };
 
-/*
- * Various helpers to access the waiters-tree:
- */
-
-#ifdef CONFIG_RT_MUTEXES
-
 static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
 {
 	return !RB_EMPTY_ROOT(&lock->waiters.rb_root);
 }
 
-static inline struct rt_mutex_waiter *
-rt_mutex_top_waiter(struct rt_mutex *lock)
+static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock)
 {
 	struct rb_node *leftmost = rb_first_cached(&lock->waiters);
 	struct rt_mutex_waiter *w = NULL;
@@ -62,42 +58,12 @@ static inline int task_has_pi_waiters(struct task_struct *p)
 	return !RB_EMPTY_ROOT(&p->pi_waiters.rb_root);
 }
 
-static inline struct rt_mutex_waiter *
-task_top_pi_waiter(struct task_struct *p)
-{
-	return rb_entry(p->pi_waiters.rb_leftmost,
-			struct rt_mutex_waiter, pi_tree_entry);
-}
-
-#else
-
-static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
-{
-	return false;
-}
-
-static inline struct rt_mutex_waiter *
-rt_mutex_top_waiter(struct rt_mutex *lock)
-{
-	return NULL;
-}
-
-static inline int task_has_pi_waiters(struct task_struct *p)
-{
-	return false;
-}
-
-static inline struct rt_mutex_waiter *
-task_top_pi_waiter(struct task_struct *p)
+static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p)
 {
-	return NULL;
+	return rb_entry(p->pi_waiters.rb_leftmost, struct rt_mutex_waiter,
+			pi_tree_entry);
 }
 
-#endif
-
-/*
- * lock->owner state tracking:
- */
 #define RT_MUTEX_HAS_WAITERS	1UL
 
 static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)

[patch 09/14] locking/rtmutex: Decrapify __rt_mutex_init()

[Thomas Gleixner]

The conditional debug handling is just another layer of obfuscation. Split
the function so rt_mutex_init_proxy_locked() can invoke the inner init and
__rt_mutex_init() gets the full treatment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c        |   11 ++++-------
 kernel/locking/rtmutex_common.h |    7 +++++++
 2 files changed, 11 insertions(+), 7 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1586,12 +1586,10 @@ void __sched rt_mutex_futex_unlock(struc
 void __rt_mutex_init(struct rt_mutex *lock, const char *name,
 		     struct lock_class_key *key)
 {
-	lock->owner = NULL;
-	raw_spin_lock_init(&lock->wait_lock);
-	lock->waiters = RB_ROOT_CACHED;
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
 
-	if (name && key)
-		debug_rt_mutex_init(lock, name, key);
+	__rt_mutex_basic_init(lock);
 }
 EXPORT_SYMBOL_GPL(__rt_mutex_init);
 
@@ -1612,8 +1610,7 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
 void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				struct task_struct *proxy_owner)
 {
-	__rt_mutex_init(lock, NULL, NULL);
-	debug_rt_mutex_proxy_lock(lock, proxy_owner);
+	__rt_mutex_basic_init(lock);
 	rt_mutex_set_owner(lock, proxy_owner);
 }
 
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -88,6 +88,13 @@ enum rtmutex_chainwalk {
 	RT_MUTEX_FULL_CHAINWALK,
 };
 
+static inline void __rt_mutex_basic_init(struct rt_mutex *lock)
+{
+	lock->owner = NULL;
+	raw_spin_lock_init(&lock->wait_lock);
+	lock->waiters = RB_ROOT_CACHED;
+}
+
 /*
  * PI-futex support (proxy locking functions, etc.):
  */

[tip: locking/core] locking/rtmutex: Decrapify __rt_mutex_init()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     c86c6bdd1099f398706b59b145148f3d39a587b7
Gitweb:        https://git.kernel.org/tip/c86c6bdd1099f398706b59b145148f3d39a587b7
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:28 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:08 +01:00

locking/rtmutex: Decrapify __rt_mutex_init()

The conditional debug handling is just another layer of obfuscation. Split
the function so rt_mutex_init_proxy_locked() can invoke the inner init and
__rt_mutex_init() gets the full treatment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.400351704@linutronix.de
---
 kernel/locking/rtmutex.c        | 11 ++++-------
 kernel/locking/rtmutex_common.h |  7 +++++++
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 0eac57c..c9c2ab5 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1586,12 +1586,10 @@ void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
 void __rt_mutex_init(struct rt_mutex *lock, const char *name,
 		     struct lock_class_key *key)
 {
-	lock->owner = NULL;
-	raw_spin_lock_init(&lock->wait_lock);
-	lock->waiters = RB_ROOT_CACHED;
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
 
-	if (name && key)
-		debug_rt_mutex_init(lock, name, key);
+	__rt_mutex_basic_init(lock);
 }
 EXPORT_SYMBOL_GPL(__rt_mutex_init);
 
@@ -1612,8 +1610,7 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
 void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				struct task_struct *proxy_owner)
 {
-	__rt_mutex_init(lock, NULL, NULL);
-	debug_rt_mutex_proxy_lock(lock, proxy_owner);
+	__rt_mutex_basic_init(lock);
 	rt_mutex_set_owner(lock, proxy_owner);
 }
 
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 0350ae3..1e11855 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -88,6 +88,13 @@ enum rtmutex_chainwalk {
 	RT_MUTEX_FULL_CHAINWALK,
 };
 
+static inline void __rt_mutex_basic_init(struct rt_mutex *lock)
+{
+	lock->owner = NULL;
+	raw_spin_lock_init(&lock->wait_lock);
+	lock->waiters = RB_ROOT_CACHED;
+}
+
 /*
  * PI-futex support (proxy locking functions, etc.):
  */

[patch 10/14] locking/rtmutex: Move debug functions as inlines into common header

[Thomas Gleixner]

There is no value in having two header files providing just empty stubs and
a C file which implements trivial debug functions which can just be inlined.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/Makefile         |    2 -
 kernel/locking/rtmutex-debug.c  |   65 ----------------------------------------
 kernel/locking/rtmutex-debug.h  |   26 ----------------
 kernel/locking/rtmutex.h        |   24 --------------
 kernel/locking/rtmutex_common.h |   30 +++++++++++++++---
 5 files changed, 25 insertions(+), 122 deletions(-)

--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -12,7 +12,6 @@ ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_lockdep_proc.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
-CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
 endif
 
 obj-$(CONFIG_DEBUG_IRQFLAGS) += irqflag-debug.o
@@ -26,7 +25,6 @@ obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
-obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
--- a/kernel/locking/rtmutex-debug.c
+++ /dev/null
@@ -1,65 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *  Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This code is based on the rt.c implementation in the preempt-rt tree.
- * Portions of said code are
- *
- *  Copyright (C) 2004  LynuxWorks, Inc., Igor Manyilov, Bill Huey
- *  Copyright (C) 2006  Esben Nielsen
- *  Copyright (C) 2006  Kihon Technologies Inc.,
- *			Steven Rostedt <rostedt@goodmis.org>
- *
- * See rt.c in preempt-rt for proper credits and further information
- */
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/sched/debug.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/syscalls.h>
-#include <linux/interrupt.h>
-#include <linux/rbtree.h>
-#include <linux/fs.h>
-#include <linux/debug_locks.h>
-
-#include "rtmutex_common.h"
-
-void debug_rt_mutex_unlock(struct rt_mutex *lock)
-{
-	DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
-}
-
-void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
-{
-	DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
-}
-
-void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
-{
-	memset(waiter, 0x11, sizeof(*waiter));
-}
-
-void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
-{
-	memset(waiter, 0x22, sizeof(*waiter));
-}
-
-void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key)
-{
-	/*
-	 * Make sure we are not reinitializing a held lock:
-	 */
-	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	lockdep_init_map(&lock->dep_map, name, key, 0);
-#endif
-}
--- a/kernel/locking/rtmutex-debug.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains macros used solely by rtmutex.c. Debug version.
- */
-
-extern void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
-extern void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter);
-extern void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
-extern void debug_rt_mutex_lock(struct rt_mutex *lock);
-extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
-extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
-				      struct task_struct *powner);
-extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
-
-static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
-						  enum rtmutex_chainwalk walk)
-{
-	return (waiter != NULL);
-}
--- a/kernel/locking/rtmutex.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains macros used solely by rtmutex.c.
- * Non-debug version.
- */
-
-#define debug_rt_mutex_init_waiter(w)			do { } while (0)
-#define debug_rt_mutex_free_waiter(w)			do { } while (0)
-#define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
-#define debug_rt_mutex_unlock(l)			do { } while (0)
-#define debug_rt_mutex_init(m, n, k)			do { } while (0)
-
-static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w,
-						  enum rtmutex_chainwalk walk)
-{
-	return walk == RT_MUTEX_FULL_CHAINWALK;
-}
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -13,6 +13,7 @@
 #ifndef __KERNEL_RTMUTEX_COMMON_H
 #define __KERNEL_RTMUTEX_COMMON_H
 
+#include <linux/debug_locks.h>
 #include <linux/rtmutex.h>
 #include <linux/sched/wake_q.h>
 
@@ -124,10 +125,29 @@ extern bool __rt_mutex_futex_unlock(stru
 
 extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# include "rtmutex-debug.h"
-#else
-# include "rtmutex.h"
-#endif
+/* Debug functions */
+static inline void debug_rt_mutex_unlock(struct rt_mutex *lock)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
+}
+
+static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
+}
+
+static inline void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		memset(waiter, 0x11, sizeof(*waiter));
+}
+
+static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		memset(waiter, 0x22, sizeof(*waiter));
+}
 
 #endif

[tip: locking/core] locking/rtmutex: Move debug functions as inlines into common header

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     143d13d824e4ae416433eb92eb428b6771f94f00
Gitweb:        https://git.kernel.org/tip/143d13d824e4ae416433eb92eb428b6771f94f00
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:29 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:08 +01:00

locking/rtmutex: Move debug functions as inlines into common header

There is no value in having two header files providing just empty stubs and
a C file which implements trivial debug functions which can just be inlined.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.503445251@linutronix.de
---
 kernel/locking/Makefile         |  2 +-
 kernel/locking/rtmutex-debug.c  | 65 +--------------------------------
 kernel/locking/rtmutex-debug.h  | 26 +-------------
 kernel/locking/rtmutex.h        | 24 +------------
 kernel/locking/rtmutex_common.h | 30 ++++++++++++---
 5 files changed, 25 insertions(+), 122 deletions(-)
 delete mode 100644 kernel/locking/rtmutex-debug.c
 delete mode 100644 kernel/locking/rtmutex-debug.h
 delete mode 100644 kernel/locking/rtmutex.h

diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 8838f1d..3572808 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -12,7 +12,6 @@ ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_lockdep_proc.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
-CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
 endif
 
 obj-$(CONFIG_DEBUG_IRQFLAGS) += irqflag-debug.o
@@ -26,7 +25,6 @@ obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
-obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
deleted file mode 100644
index f1a83ec..0000000
--- a/kernel/locking/rtmutex-debug.c
+++ /dev/null
@@ -1,65 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *  Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This code is based on the rt.c implementation in the preempt-rt tree.
- * Portions of said code are
- *
- *  Copyright (C) 2004  LynuxWorks, Inc., Igor Manyilov, Bill Huey
- *  Copyright (C) 2006  Esben Nielsen
- *  Copyright (C) 2006  Kihon Technologies Inc.,
- *			Steven Rostedt <rostedt@goodmis.org>
- *
- * See rt.c in preempt-rt for proper credits and further information
- */
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/sched/debug.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/syscalls.h>
-#include <linux/interrupt.h>
-#include <linux/rbtree.h>
-#include <linux/fs.h>
-#include <linux/debug_locks.h>
-
-#include "rtmutex_common.h"
-
-void debug_rt_mutex_unlock(struct rt_mutex *lock)
-{
-	DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
-}
-
-void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
-{
-	DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
-}
-
-void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
-{
-	memset(waiter, 0x11, sizeof(*waiter));
-}
-
-void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
-{
-	memset(waiter, 0x22, sizeof(*waiter));
-}
-
-void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key)
-{
-	/*
-	 * Make sure we are not reinitializing a held lock:
-	 */
-	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	lockdep_init_map(&lock->dep_map, name, key, 0);
-#endif
-}
diff --git a/kernel/locking/rtmutex-debug.h b/kernel/locking/rtmutex-debug.h
deleted file mode 100644
index 659e93e..0000000
--- a/kernel/locking/rtmutex-debug.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains macros used solely by rtmutex.c. Debug version.
- */
-
-extern void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
-extern void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter);
-extern void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
-extern void debug_rt_mutex_lock(struct rt_mutex *lock);
-extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
-extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
-				      struct task_struct *powner);
-extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
-
-static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
-						  enum rtmutex_chainwalk walk)
-{
-	return (waiter != NULL);
-}
diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h
deleted file mode 100644
index 1e484ab..0000000
--- a/kernel/locking/rtmutex.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains macros used solely by rtmutex.c.
- * Non-debug version.
- */
-
-#define debug_rt_mutex_init_waiter(w)			do { } while (0)
-#define debug_rt_mutex_free_waiter(w)			do { } while (0)
-#define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
-#define debug_rt_mutex_unlock(l)			do { } while (0)
-#define debug_rt_mutex_init(m, n, k)			do { } while (0)
-
-static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w,
-						  enum rtmutex_chainwalk walk)
-{
-	return walk == RT_MUTEX_FULL_CHAINWALK;
-}
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 1e11855..8456db5 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -13,6 +13,7 @@
 #ifndef __KERNEL_RTMUTEX_COMMON_H
 #define __KERNEL_RTMUTEX_COMMON_H
 
+#include <linux/debug_locks.h>
 #include <linux/rtmutex.h>
 #include <linux/sched/wake_q.h>
 
@@ -123,10 +124,29 @@ extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
 
 extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# include "rtmutex-debug.h"
-#else
-# include "rtmutex.h"
-#endif
+/* Debug functions */
+static inline void debug_rt_mutex_unlock(struct rt_mutex *lock)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
+}
+
+static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
+}
+
+static inline void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		memset(waiter, 0x11, sizeof(*waiter));
+}
+
+static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		memset(waiter, 0x22, sizeof(*waiter));
+}
 
 #endif

[patch 11/14] locking/rtmutex: Make text section and inlining consistent

[Thomas Gleixner]

rtmutex is half __sched and the other half is not. If the compiler decides
to not inline larger static functions then part of the code ends up in the
regular text section.

There are also quite some performance related small helpers which are
either static or plain inline. Force inline those which make sense and mark
the rest __sched.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |  152 +++++++++++++++++++++++------------------------
 1 file changed, 76 insertions(+), 76 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -49,7 +49,7 @@
  * set this bit before looking at the lock.
  */
 
-static void
+static __always_inline void
 rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
 {
 	unsigned long val = (unsigned long)owner;
@@ -60,13 +60,13 @@ rt_mutex_set_owner(struct rt_mutex *lock
 	WRITE_ONCE(lock->owner, (struct task_struct *)val);
 }
 
-static inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	lock->owner = (struct task_struct *)
 			((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
-static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -149,7 +149,7 @@ static void fixup_rt_mutex_waiters(struc
  * all future threads that attempt to [Rmw] the lock to the slowpath. As such
  * relaxed semantics suffice.
  */
-static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -165,8 +165,8 @@ static inline void mark_rt_mutex_waiters
  * 2) Drop lock->wait_lock
  * 3) Try to unlock the lock with cmpxchg
  */
-static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
-					unsigned long flags)
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+						 unsigned long flags)
 	__releases(lock->wait_lock)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
@@ -204,7 +204,7 @@ static inline bool unlock_rt_mutex_safe(
 # define rt_mutex_cmpxchg_acquire(l,c,n)	(0)
 # define rt_mutex_cmpxchg_release(l,c,n)	(0)
 
-static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	lock->owner = (struct task_struct *)
 			((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
@@ -213,8 +213,8 @@ static inline void mark_rt_mutex_waiters
 /*
  * Simple slow path only version: lock->owner is protected by lock->wait_lock.
  */
-static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
-					unsigned long flags)
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+						 unsigned long flags)
 	__releases(lock->wait_lock)
 {
 	lock->owner = NULL;
@@ -229,9 +229,8 @@ static inline bool unlock_rt_mutex_safe(
 #define task_to_waiter(p)	\
 	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
 
-static inline int
-rt_mutex_waiter_less(struct rt_mutex_waiter *left,
-		     struct rt_mutex_waiter *right)
+static __always_inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left,
+						struct rt_mutex_waiter *right)
 {
 	if (left->prio < right->prio)
 		return 1;
@@ -248,9 +247,8 @@ rt_mutex_waiter_less(struct rt_mutex_wai
 	return 0;
 }
 
-static inline int
-rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
-		      struct rt_mutex_waiter *right)
+static __always_inline int rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
+						 struct rt_mutex_waiter *right)
 {
 	if (left->prio != right->prio)
 		return 0;
@@ -270,18 +268,18 @@ rt_mutex_waiter_equal(struct rt_mutex_wa
 #define __node_2_waiter(node) \
 	rb_entry((node), struct rt_mutex_waiter, tree_entry)
 
-static inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
+static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
 {
 	return rt_mutex_waiter_less(__node_2_waiter(a), __node_2_waiter(b));
 }
 
-static void
+static __always_inline void
 rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 {
 	rb_add_cached(&waiter->tree_entry, &lock->waiters, __waiter_less);
 }
 
-static void
+static __always_inline void
 rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 {
 	if (RB_EMPTY_NODE(&waiter->tree_entry))
@@ -294,18 +292,19 @@ rt_mutex_dequeue(struct rt_mutex *lock,
 #define __node_2_pi_waiter(node) \
 	rb_entry((node), struct rt_mutex_waiter, pi_tree_entry)
 
-static inline bool __pi_waiter_less(struct rb_node *a, const struct rb_node *b)
+static __always_inline bool
+__pi_waiter_less(struct rb_node *a, const struct rb_node *b)
 {
 	return rt_mutex_waiter_less(__node_2_pi_waiter(a), __node_2_pi_waiter(b));
 }
 
-static void
+static __always_inline void
 rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
 {
 	rb_add_cached(&waiter->pi_tree_entry, &task->pi_waiters, __pi_waiter_less);
 }
 
-static void
+static __always_inline void
 rt_mutex_dequeue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
 {
 	if (RB_EMPTY_NODE(&waiter->pi_tree_entry))
@@ -315,7 +314,7 @@ rt_mutex_dequeue_pi(struct task_struct *
 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
 }
 
-static void rt_mutex_adjust_prio(struct task_struct *p)
+static __always_inline void rt_mutex_adjust_prio(struct task_struct *p)
 {
 	struct task_struct *pi_task = NULL;
 
@@ -340,8 +339,9 @@ static void rt_mutex_adjust_prio(struct
  * deadlock detection is disabled independent of the detect argument
  * and the config settings.
  */
-static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
-					  enum rtmutex_chainwalk chwalk)
+static __always_inline bool
+rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
+			      enum rtmutex_chainwalk chwalk)
 {
 	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEX))
 		return waiter != NULL;
@@ -353,7 +353,7 @@ static bool rt_mutex_cond_detect_deadloc
  */
 int max_lock_depth = 1024;
 
-static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
+static __always_inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
 {
 	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
 }
@@ -421,12 +421,12 @@ static inline struct rt_mutex *task_bloc
  *	  unlock(lock->wait_lock);		release [L]
  *	  goto again;
  */
-static int rt_mutex_adjust_prio_chain(struct task_struct *task,
-				      enum rtmutex_chainwalk chwalk,
-				      struct rt_mutex *orig_lock,
-				      struct rt_mutex *next_lock,
-				      struct rt_mutex_waiter *orig_waiter,
-				      struct task_struct *top_task)
+static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
+					      enum rtmutex_chainwalk chwalk,
+					      struct rt_mutex *orig_lock,
+					      struct rt_mutex *next_lock,
+					      struct rt_mutex_waiter *orig_waiter,
+					      struct task_struct *top_task)
 {
 	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
 	struct rt_mutex_waiter *prerequeue_top_waiter;
@@ -778,8 +778,9 @@ static int rt_mutex_adjust_prio_chain(st
  * @waiter: The waiter that is queued to the lock's wait tree if the
  *	    callsite called task_blocked_on_lock(), otherwise NULL
  */
-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
-				struct rt_mutex_waiter *waiter)
+static int __sched
+try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+		     struct rt_mutex_waiter *waiter)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -896,10 +897,10 @@ static int try_to_take_rt_mutex(struct r
  *
  * This must be called with lock->wait_lock held and interrupts disabled
  */
-static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
-				   struct rt_mutex_waiter *waiter,
-				   struct task_struct *task,
-				   enum rtmutex_chainwalk chwalk)
+static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock,
+					   struct rt_mutex_waiter *waiter,
+					   struct task_struct *task,
+					   enum rtmutex_chainwalk chwalk)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
 	struct rt_mutex_waiter *top_waiter = waiter;
@@ -985,8 +986,8 @@ static int task_blocks_on_rt_mutex(struc
  *
  * Called with lock->wait_lock held and interrupts disabled.
  */
-static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
-				    struct rt_mutex *lock)
+static void __sched mark_wakeup_next_waiter(struct wake_q_head *wake_q,
+					    struct rt_mutex *lock)
 {
 	struct rt_mutex_waiter *waiter;
 
@@ -1035,8 +1036,8 @@ static void mark_wakeup_next_waiter(stru
  * Must be called with lock->wait_lock held and interrupts disabled. I must
  * have just failed to try_to_take_rt_mutex().
  */
-static void remove_waiter(struct rt_mutex *lock,
-			  struct rt_mutex_waiter *waiter)
+static void __sched remove_waiter(struct rt_mutex *lock,
+				  struct rt_mutex_waiter *waiter)
 {
 	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
 	struct task_struct *owner = rt_mutex_owner(lock);
@@ -1093,7 +1094,7 @@ static void remove_waiter(struct rt_mute
  *
  * Called from sched_setscheduler
  */
-void rt_mutex_adjust_pi(struct task_struct *task)
+void __sched rt_mutex_adjust_pi(struct task_struct *task)
 {
 	struct rt_mutex_waiter *waiter;
 	struct rt_mutex *next_lock;
@@ -1116,7 +1117,7 @@ void rt_mutex_adjust_pi(struct task_stru
 				   next_lock, NULL, task);
 }
 
-void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+void __sched rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
 {
 	debug_rt_mutex_init_waiter(waiter);
 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
@@ -1134,10 +1135,9 @@ void rt_mutex_init_waiter(struct rt_mute
  *
  * Must be called with lock->wait_lock held and interrupts disabled
  */
-static int __sched
-__rt_mutex_slowlock(struct rt_mutex *lock, int state,
-		    struct hrtimer_sleeper *timeout,
-		    struct rt_mutex_waiter *waiter)
+static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+				       struct hrtimer_sleeper *timeout,
+				       struct rt_mutex_waiter *waiter)
 {
 	int ret = 0;
 
@@ -1172,8 +1172,8 @@ static int __sched
 	return ret;
 }
 
-static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
-				     struct rt_mutex_waiter *w)
+static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
+					     struct rt_mutex_waiter *w)
 {
 	/*
 	 * If the result is not -EDEADLOCK or the caller requested
@@ -1195,10 +1195,9 @@ static void rt_mutex_handle_deadlock(int
 /*
  * Slow path lock function:
  */
-static int __sched
-rt_mutex_slowlock(struct rt_mutex *lock, int state,
-		  struct hrtimer_sleeper *timeout,
-		  enum rtmutex_chainwalk chwalk)
+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;
@@ -1257,7 +1256,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
 	return ret;
 }
 
-static inline int __rt_mutex_slowtrylock(struct rt_mutex *lock)
+static int __sched __rt_mutex_slowtrylock(struct rt_mutex *lock)
 {
 	int ret = try_to_take_rt_mutex(lock, current, NULL);
 
@@ -1273,7 +1272,7 @@ static inline int __rt_mutex_slowtrylock
 /*
  * Slow path try-lock function:
  */
-static inline int rt_mutex_slowtrylock(struct rt_mutex *lock)
+static int __sched rt_mutex_slowtrylock(struct rt_mutex *lock)
 {
 	unsigned long flags;
 	int ret;
@@ -1371,7 +1370,7 @@ static bool __sched rt_mutex_slowunlock(
  * The atomic acquire/release ops are compiled away, when either the
  * architecture does not support cmpxchg or when debugging is enabled.
  */
-static inline int
+static __always_inline int
 rt_mutex_fastlock(struct rt_mutex *lock, int state,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
@@ -1383,7 +1382,7 @@ rt_mutex_fastlock(struct rt_mutex *lock,
 	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
 }
 
-static inline int
+static __always_inline int
 rt_mutex_fasttrylock(struct rt_mutex *lock,
 		     int (*slowfn)(struct rt_mutex *lock))
 {
@@ -1396,7 +1395,7 @@ rt_mutex_fasttrylock(struct rt_mutex *lo
 /*
  * Performs the wakeup of the top-waiter and re-enables preemption.
  */
-void rt_mutex_postunlock(struct wake_q_head *wake_q)
+void __sched rt_mutex_postunlock(struct wake_q_head *wake_q)
 {
 	wake_up_q(wake_q);
 
@@ -1404,7 +1403,7 @@ void rt_mutex_postunlock(struct wake_q_h
 	preempt_enable();
 }
 
-static inline void
+static __always_inline void
 rt_mutex_fastunlock(struct rt_mutex *lock,
 		    bool (*slowfn)(struct rt_mutex *lock,
 				   struct wake_q_head *wqh))
@@ -1418,7 +1417,8 @@ rt_mutex_fastunlock(struct rt_mutex *loc
 		rt_mutex_postunlock(&wake_q);
 }
 
-static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
+static __always_inline void __rt_mutex_lock(struct rt_mutex *lock,
+					    unsigned int subclass)
 {
 	might_sleep();
 
@@ -1536,7 +1536,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_unlock);
  * @wake_q:	The wake queue head from which to get the next lock waiter
  */
 bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				    struct wake_q_head *wake_q)
+				     struct wake_q_head *wake_q)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1583,7 +1583,7 @@ void __sched rt_mutex_futex_unlock(struc
  *
  * Initializing of a locked rt_mutex is not allowed
  */
-void __rt_mutex_init(struct rt_mutex *lock, const char *name,
+void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name,
 		     struct lock_class_key *key)
 {
 	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
@@ -1607,8 +1607,8 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
  * possible at this point because the pi_state which contains the rtmutex
  * is not yet visible to other tasks.
  */
-void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
-				struct task_struct *proxy_owner)
+void __sched rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+					struct task_struct *proxy_owner)
 {
 	__rt_mutex_basic_init(lock);
 	rt_mutex_set_owner(lock, proxy_owner);
@@ -1626,7 +1626,7 @@ void rt_mutex_init_proxy_locked(struct r
  * possible because it belongs to the pi_state which is about to be freed
  * and it is not longer visible to other tasks.
  */
-void rt_mutex_proxy_unlock(struct rt_mutex *lock)
+void __sched rt_mutex_proxy_unlock(struct rt_mutex *lock)
 {
 	debug_rt_mutex_proxy_unlock(lock);
 	rt_mutex_set_owner(lock, NULL);
@@ -1651,9 +1651,9 @@ void rt_mutex_proxy_unlock(struct rt_mut
  *
  * Special API call for PI-futex support.
  */
-int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-			      struct rt_mutex_waiter *waiter,
-			      struct task_struct *task)
+int __sched __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+					struct rt_mutex_waiter *waiter,
+					struct task_struct *task)
 {
 	int ret;
 
@@ -1698,9 +1698,9 @@ int __rt_mutex_start_proxy_lock(struct r
  *
  * Special API call for PI-futex support.
  */
-int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-			      struct rt_mutex_waiter *waiter,
-			      struct task_struct *task)
+int __sched rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+				      struct rt_mutex_waiter *waiter,
+				      struct task_struct *task)
 {
 	int ret;
 
@@ -1730,9 +1730,9 @@ int rt_mutex_start_proxy_lock(struct rt_
  *
  * Special API call for PI-futex support
  */
-int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
-			       struct hrtimer_sleeper *to,
-			       struct rt_mutex_waiter *waiter)
+int __sched rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
+				     struct hrtimer_sleeper *to,
+				     struct rt_mutex_waiter *waiter)
 {
 	int ret;
 
@@ -1770,8 +1770,8 @@ int rt_mutex_wait_proxy_lock(struct rt_m
  *
  * Special API call for PI-futex support
  */
-bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
-				 struct rt_mutex_waiter *waiter)
+bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
+					 struct rt_mutex_waiter *waiter)
 {
 	bool cleanup = false;
 

[tip: locking/core] locking/rtmutex: Make text section and inlining consistent

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     3934afd2a81eb3a5cb52e64677adcc0983487c62
Gitweb:        https://git.kernel.org/tip/3934afd2a81eb3a5cb52e64677adcc0983487c62
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:30 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:06:08 +01:00

locking/rtmutex: Make text section and inlining consistent

rtmutex is half __sched and the other half is not. If the compiler decides
to not inline larger static functions then part of the code ends up in the
regular text section.

There are also quite some performance related small helpers which are
either static or plain inline. Force inline those which make sense and mark
the rest __sched.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.601876710@linutronix.de
---
 kernel/locking/rtmutex.c | 152 +++++++++++++++++++-------------------
 1 file changed, 76 insertions(+), 76 deletions(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index c9c2ab5..3612821 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -49,7 +49,7 @@
  * set this bit before looking at the lock.
  */
 
-static void
+static __always_inline void
 rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
 {
 	unsigned long val = (unsigned long)owner;
@@ -60,13 +60,13 @@ rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
 	WRITE_ONCE(lock->owner, (struct task_struct *)val);
 }
 
-static inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	lock->owner = (struct task_struct *)
 			((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
-static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -149,7 +149,7 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
  * all future threads that attempt to [Rmw] the lock to the slowpath. As such
  * relaxed semantics suffice.
  */
-static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	unsigned long owner, *p = (unsigned long *) &lock->owner;
 
@@ -165,8 +165,8 @@ static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
  * 2) Drop lock->wait_lock
  * 3) Try to unlock the lock with cmpxchg
  */
-static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
-					unsigned long flags)
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+						 unsigned long flags)
 	__releases(lock->wait_lock)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
@@ -204,7 +204,7 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
 # define rt_mutex_cmpxchg_acquire(l,c,n)	(0)
 # define rt_mutex_cmpxchg_release(l,c,n)	(0)
 
-static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
 {
 	lock->owner = (struct task_struct *)
 			((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
@@ -213,8 +213,8 @@ static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
 /*
  * Simple slow path only version: lock->owner is protected by lock->wait_lock.
  */
-static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
-					unsigned long flags)
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+						 unsigned long flags)
 	__releases(lock->wait_lock)
 {
 	lock->owner = NULL;
@@ -229,9 +229,8 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
 #define task_to_waiter(p)	\
 	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
 
-static inline int
-rt_mutex_waiter_less(struct rt_mutex_waiter *left,
-		     struct rt_mutex_waiter *right)
+static __always_inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left,
+						struct rt_mutex_waiter *right)
 {
 	if (left->prio < right->prio)
 		return 1;
@@ -248,9 +247,8 @@ rt_mutex_waiter_less(struct rt_mutex_waiter *left,
 	return 0;
 }
 
-static inline int
-rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
-		      struct rt_mutex_waiter *right)
+static __always_inline int rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
+						 struct rt_mutex_waiter *right)
 {
 	if (left->prio != right->prio)
 		return 0;
@@ -270,18 +268,18 @@ rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
 #define __node_2_waiter(node) \
 	rb_entry((node), struct rt_mutex_waiter, tree_entry)
 
-static inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
+static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
 {
 	return rt_mutex_waiter_less(__node_2_waiter(a), __node_2_waiter(b));
 }
 
-static void
+static __always_inline void
 rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 {
 	rb_add_cached(&waiter->tree_entry, &lock->waiters, __waiter_less);
 }
 
-static void
+static __always_inline void
 rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 {
 	if (RB_EMPTY_NODE(&waiter->tree_entry))
@@ -294,18 +292,19 @@ rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 #define __node_2_pi_waiter(node) \
 	rb_entry((node), struct rt_mutex_waiter, pi_tree_entry)
 
-static inline bool __pi_waiter_less(struct rb_node *a, const struct rb_node *b)
+static __always_inline bool
+__pi_waiter_less(struct rb_node *a, const struct rb_node *b)
 {
 	return rt_mutex_waiter_less(__node_2_pi_waiter(a), __node_2_pi_waiter(b));
 }
 
-static void
+static __always_inline void
 rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
 {
 	rb_add_cached(&waiter->pi_tree_entry, &task->pi_waiters, __pi_waiter_less);
 }
 
-static void
+static __always_inline void
 rt_mutex_dequeue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
 {
 	if (RB_EMPTY_NODE(&waiter->pi_tree_entry))
@@ -315,7 +314,7 @@ rt_mutex_dequeue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
 }
 
-static void rt_mutex_adjust_prio(struct task_struct *p)
+static __always_inline void rt_mutex_adjust_prio(struct task_struct *p)
 {
 	struct task_struct *pi_task = NULL;
 
@@ -340,8 +339,9 @@ static void rt_mutex_adjust_prio(struct task_struct *p)
  * deadlock detection is disabled independent of the detect argument
  * and the config settings.
  */
-static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
-					  enum rtmutex_chainwalk chwalk)
+static __always_inline bool
+rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
+			      enum rtmutex_chainwalk chwalk)
 {
 	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEX))
 		return waiter != NULL;
@@ -353,7 +353,7 @@ static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
  */
 int max_lock_depth = 1024;
 
-static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
+static __always_inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
 {
 	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
 }
@@ -421,12 +421,12 @@ static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
  *	  unlock(lock->wait_lock);		release [L]
  *	  goto again;
  */
-static int rt_mutex_adjust_prio_chain(struct task_struct *task,
-				      enum rtmutex_chainwalk chwalk,
-				      struct rt_mutex *orig_lock,
-				      struct rt_mutex *next_lock,
-				      struct rt_mutex_waiter *orig_waiter,
-				      struct task_struct *top_task)
+static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
+					      enum rtmutex_chainwalk chwalk,
+					      struct rt_mutex *orig_lock,
+					      struct rt_mutex *next_lock,
+					      struct rt_mutex_waiter *orig_waiter,
+					      struct task_struct *top_task)
 {
 	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
 	struct rt_mutex_waiter *prerequeue_top_waiter;
@@ -778,8 +778,9 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
  * @waiter: The waiter that is queued to the lock's wait tree if the
  *	    callsite called task_blocked_on_lock(), otherwise NULL
  */
-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
-				struct rt_mutex_waiter *waiter)
+static int __sched
+try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+		     struct rt_mutex_waiter *waiter)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -896,10 +897,10 @@ takeit:
  *
  * This must be called with lock->wait_lock held and interrupts disabled
  */
-static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
-				   struct rt_mutex_waiter *waiter,
-				   struct task_struct *task,
-				   enum rtmutex_chainwalk chwalk)
+static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock,
+					   struct rt_mutex_waiter *waiter,
+					   struct task_struct *task,
+					   enum rtmutex_chainwalk chwalk)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
 	struct rt_mutex_waiter *top_waiter = waiter;
@@ -985,8 +986,8 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
  *
  * Called with lock->wait_lock held and interrupts disabled.
  */
-static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
-				    struct rt_mutex *lock)
+static void __sched mark_wakeup_next_waiter(struct wake_q_head *wake_q,
+					    struct rt_mutex *lock)
 {
 	struct rt_mutex_waiter *waiter;
 
@@ -1035,8 +1036,8 @@ static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
  * Must be called with lock->wait_lock held and interrupts disabled. I must
  * have just failed to try_to_take_rt_mutex().
  */
-static void remove_waiter(struct rt_mutex *lock,
-			  struct rt_mutex_waiter *waiter)
+static void __sched remove_waiter(struct rt_mutex *lock,
+				  struct rt_mutex_waiter *waiter)
 {
 	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
 	struct task_struct *owner = rt_mutex_owner(lock);
@@ -1093,7 +1094,7 @@ static void remove_waiter(struct rt_mutex *lock,
  *
  * Called from sched_setscheduler
  */
-void rt_mutex_adjust_pi(struct task_struct *task)
+void __sched rt_mutex_adjust_pi(struct task_struct *task)
 {
 	struct rt_mutex_waiter *waiter;
 	struct rt_mutex *next_lock;
@@ -1116,7 +1117,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
 				   next_lock, NULL, task);
 }
 
-void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+void __sched rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
 {
 	debug_rt_mutex_init_waiter(waiter);
 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
@@ -1134,10 +1135,9 @@ void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
  *
  * Must be called with lock->wait_lock held and interrupts disabled
  */
-static int __sched
-__rt_mutex_slowlock(struct rt_mutex *lock, int state,
-		    struct hrtimer_sleeper *timeout,
-		    struct rt_mutex_waiter *waiter)
+static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+				       struct hrtimer_sleeper *timeout,
+				       struct rt_mutex_waiter *waiter)
 {
 	int ret = 0;
 
@@ -1172,8 +1172,8 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	return ret;
 }
 
-static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
-				     struct rt_mutex_waiter *w)
+static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
+					     struct rt_mutex_waiter *w)
 {
 	/*
 	 * If the result is not -EDEADLOCK or the caller requested
@@ -1195,10 +1195,9 @@ 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)
+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;
@@ -1257,7 +1256,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	return ret;
 }
 
-static inline int __rt_mutex_slowtrylock(struct rt_mutex *lock)
+static int __sched __rt_mutex_slowtrylock(struct rt_mutex *lock)
 {
 	int ret = try_to_take_rt_mutex(lock, current, NULL);
 
@@ -1273,7 +1272,7 @@ static inline int __rt_mutex_slowtrylock(struct rt_mutex *lock)
 /*
  * Slow path try-lock function:
  */
-static inline int rt_mutex_slowtrylock(struct rt_mutex *lock)
+static int __sched rt_mutex_slowtrylock(struct rt_mutex *lock)
 {
 	unsigned long flags;
 	int ret;
@@ -1371,7 +1370,7 @@ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
  * The atomic acquire/release ops are compiled away, when either the
  * architecture does not support cmpxchg or when debugging is enabled.
  */
-static inline int
+static __always_inline int
 rt_mutex_fastlock(struct rt_mutex *lock, int state,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
@@ -1383,7 +1382,7 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
 	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
 }
 
-static inline int
+static __always_inline int
 rt_mutex_fasttrylock(struct rt_mutex *lock,
 		     int (*slowfn)(struct rt_mutex *lock))
 {
@@ -1396,7 +1395,7 @@ rt_mutex_fasttrylock(struct rt_mutex *lock,
 /*
  * Performs the wakeup of the top-waiter and re-enables preemption.
  */
-void rt_mutex_postunlock(struct wake_q_head *wake_q)
+void __sched rt_mutex_postunlock(struct wake_q_head *wake_q)
 {
 	wake_up_q(wake_q);
 
@@ -1404,7 +1403,7 @@ void rt_mutex_postunlock(struct wake_q_head *wake_q)
 	preempt_enable();
 }
 
-static inline void
+static __always_inline void
 rt_mutex_fastunlock(struct rt_mutex *lock,
 		    bool (*slowfn)(struct rt_mutex *lock,
 				   struct wake_q_head *wqh))
@@ -1418,7 +1417,8 @@ 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)
+static __always_inline void __rt_mutex_lock(struct rt_mutex *lock,
+					    unsigned int subclass)
 {
 	might_sleep();
 
@@ -1536,7 +1536,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_unlock);
  * @wake_q:	The wake queue head from which to get the next lock waiter
  */
 bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				    struct wake_q_head *wake_q)
+				     struct wake_q_head *wake_q)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1583,7 +1583,7 @@ void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
  *
  * Initializing of a locked rt_mutex is not allowed
  */
-void __rt_mutex_init(struct rt_mutex *lock, const char *name,
+void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name,
 		     struct lock_class_key *key)
 {
 	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
@@ -1607,8 +1607,8 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
  * possible at this point because the pi_state which contains the rtmutex
  * is not yet visible to other tasks.
  */
-void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
-				struct task_struct *proxy_owner)
+void __sched rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+					struct task_struct *proxy_owner)
 {
 	__rt_mutex_basic_init(lock);
 	rt_mutex_set_owner(lock, proxy_owner);
@@ -1626,7 +1626,7 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
  * possible because it belongs to the pi_state which is about to be freed
  * and it is not longer visible to other tasks.
  */
-void rt_mutex_proxy_unlock(struct rt_mutex *lock)
+void __sched rt_mutex_proxy_unlock(struct rt_mutex *lock)
 {
 	debug_rt_mutex_proxy_unlock(lock);
 	rt_mutex_set_owner(lock, NULL);
@@ -1651,9 +1651,9 @@ void rt_mutex_proxy_unlock(struct rt_mutex *lock)
  *
  * Special API call for PI-futex support.
  */
-int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-			      struct rt_mutex_waiter *waiter,
-			      struct task_struct *task)
+int __sched __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+					struct rt_mutex_waiter *waiter,
+					struct task_struct *task)
 {
 	int ret;
 
@@ -1698,9 +1698,9 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
  *
  * Special API call for PI-futex support.
  */
-int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
-			      struct rt_mutex_waiter *waiter,
-			      struct task_struct *task)
+int __sched rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+				      struct rt_mutex_waiter *waiter,
+				      struct task_struct *task)
 {
 	int ret;
 
@@ -1730,9 +1730,9 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
  *
  * Special API call for PI-futex support
  */
-int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
-			       struct hrtimer_sleeper *to,
-			       struct rt_mutex_waiter *waiter)
+int __sched rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
+				     struct hrtimer_sleeper *to,
+				     struct rt_mutex_waiter *waiter)
 {
 	int ret;
 
@@ -1770,8 +1770,8 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
  *
  * Special API call for PI-futex support
  */
-bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
-				 struct rt_mutex_waiter *waiter)
+bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
+					 struct rt_mutex_waiter *waiter)
 {
 	bool cleanup = false;
 

[patch 12/14] locking/rtmutex: Consolidate the fast/slowpath invocation

[Thomas Gleixner]

The indirection via a function pointer (which is at least optimized into a
tail call by the compiler) is making the code hard to read.

Clean it up and move the futex related trylock functions down to the futex
section.

Move the wake_q wakeup into rt_mutex_slowunlock(). No point in handing it
to the caller. The futex code uses a different function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |  129 +++++++++++++++++------------------------------
 1 file changed, 49 insertions(+), 80 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1299,13 +1299,24 @@ static int __sched rt_mutex_slowtrylock(
 }
 
 /*
+ * Performs the wakeup of the top-waiter and re-enables preemption.
+ */
+void __sched rt_mutex_postunlock(struct wake_q_head *wake_q)
+{
+	wake_up_q(wake_q);
+
+	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
+	preempt_enable();
+}
+
+/*
  * Slow path to release a rt-mutex.
  *
  * Return whether the current task needs to call rt_mutex_postunlock().
  */
-static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
-					struct wake_q_head *wake_q)
+static void __sched rt_mutex_slowunlock(struct rt_mutex *lock)
 {
+	DEFINE_WAKE_Q(wake_q);
 	unsigned long flags;
 
 	/* irqsave required to support early boot calls */
@@ -1347,7 +1358,7 @@ static bool __sched rt_mutex_slowunlock(
 	while (!rt_mutex_has_waiters(lock)) {
 		/* Drops lock->wait_lock ! */
 		if (unlock_rt_mutex_safe(lock, flags) == true)
-			return false;
+			return;
 		/* Relock the rtmutex and try again */
 		raw_spin_lock_irqsave(&lock->wait_lock, flags);
 	}
@@ -1358,10 +1369,10 @@ static bool __sched rt_mutex_slowunlock(
 	 *
 	 * Queue the next waiter for wakeup once we release the wait_lock.
 	 */
-	mark_wakeup_next_waiter(wake_q, lock);
+	mark_wakeup_next_waiter(&wake_q, lock);
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
-	return true; /* call rt_mutex_postunlock() */
+	rt_mutex_postunlock(&wake_q);
 }
 
 /*
@@ -1370,60 +1381,20 @@ static bool __sched rt_mutex_slowunlock(
  * The atomic acquire/release ops are compiled away, when either the
  * architecture does not support cmpxchg or when debugging is enabled.
  */
-static __always_inline int
-rt_mutex_fastlock(struct rt_mutex *lock, int state,
-		  int (*slowfn)(struct rt_mutex *lock, int state,
-				struct hrtimer_sleeper *timeout,
-				enum rtmutex_chainwalk chwalk))
+static __always_inline int __rt_mutex_lock(struct rt_mutex *lock, long state)
 {
-	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
-		return 0;
+	int ret;
 
-	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
-}
+	might_sleep();
 
-static __always_inline int
-rt_mutex_fasttrylock(struct rt_mutex *lock,
-		     int (*slowfn)(struct rt_mutex *lock))
-{
 	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
-		return 1;
-
-	return slowfn(lock);
-}
-
-/*
- * Performs the wakeup of the top-waiter and re-enables preemption.
- */
-void __sched rt_mutex_postunlock(struct wake_q_head *wake_q)
-{
-	wake_up_q(wake_q);
-
-	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
-	preempt_enable();
-}
-
-static __always_inline void
-rt_mutex_fastunlock(struct rt_mutex *lock,
-		    bool (*slowfn)(struct rt_mutex *lock,
-				   struct wake_q_head *wqh))
-{
-	DEFINE_WAKE_Q(wake_q);
-
-	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
-		return;
-
-	if (slowfn(lock, &wake_q))
-		rt_mutex_postunlock(&wake_q);
-}
+		return 0;
 
-static __always_inline void __rt_mutex_lock(struct rt_mutex *lock,
-					    unsigned int subclass)
-{
-	might_sleep();
+	ret = rt_mutex_slowlock(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
+	if (ret)
+		mutex_release(&lock->dep_map, _RET_IP_);
 
-	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
+	return ret;
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -1435,7 +1406,8 @@ static __always_inline void __rt_mutex_l
  */
 void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
 {
-	__rt_mutex_lock(lock, subclass);
+	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	__rt_mutex_lock(lock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
 
@@ -1448,7 +1420,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
  */
 void __sched rt_mutex_lock(struct rt_mutex *lock)
 {
-	__rt_mutex_lock(lock, 0);
+	__rt_mutex_lock(lock, TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock);
 #endif
@@ -1464,32 +1436,10 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
  */
 int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
 {
-	int ret;
-
-	might_sleep();
-
-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	ret = rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, rt_mutex_slowlock);
-	if (ret)
-		mutex_release(&lock->dep_map, _RET_IP_);
-
-	return ret;
+	return __rt_mutex_lock(lock, TASK_INTERRUPTIBLE);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
-/*
- * Futex variant, must not use fastpath.
- */
-int __sched rt_mutex_futex_trylock(struct rt_mutex *lock)
-{
-	return rt_mutex_slowtrylock(lock);
-}
-
-int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
-{
-	return __rt_mutex_slowtrylock(lock);
-}
-
 /**
  * rt_mutex_trylock - try to lock a rt_mutex
  *
@@ -1508,7 +1458,10 @@ int __sched rt_mutex_trylock(struct rt_m
 	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
 		return 0;
 
-	ret = rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return 1;
+
+	ret = rt_mutex_slowtrylock(lock);
 	if (ret)
 		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 
@@ -1524,10 +1477,26 @@ EXPORT_SYMBOL_GPL(rt_mutex_trylock);
 void __sched rt_mutex_unlock(struct rt_mutex *lock)
 {
 	mutex_release(&lock->dep_map, _RET_IP_);
-	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+		return;
+
+	rt_mutex_slowunlock(lock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_unlock);
 
+/*
+ * Futex variants, must not use fastpath.
+ */
+int __sched rt_mutex_futex_trylock(struct rt_mutex *lock)
+{
+	return rt_mutex_slowtrylock(lock);
+}
+
+int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
+{
+	return __rt_mutex_slowtrylock(lock);
+}
+
 /**
  * __rt_mutex_futex_unlock - Futex variant, that since futex variants
  * do not use the fast-path, can be simple and will not need to retry.

Re: [patch 12/14] locking/rtmutex: Consolidate the fast/slowpath invocation

[Thomas Gleixner]

On Tue, Mar 23 2021 at 22:30, Thomas Gleixner wrote:

Ignore this one. I shot myself in the foot....

[patch 13/14] locking/rtmutex: Fix misleading comment in rt_mutex_postunlock()

[Thomas Gleixner]

Preemption is disabled in mark_wakeup_next_waiter() not in
rt_mutex_slowunlock().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1305,7 +1305,7 @@ void __sched rt_mutex_postunlock(struct
 {
 	wake_up_q(wake_q);
 
-	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
+	/* Pairs with preempt_disable() in mark_wakeup_next_waiter() */
 	preempt_enable();
 }
 

[tip: locking/core] locking/rtmutex: Fix misleading comment in rt_mutex_postunlock()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     5677c86221d14c18c6edea59d8f0f02e36e2b2db
Gitweb:        https://git.kernel.org/tip/5677c86221d14c18c6edea59d8f0f02e36e2b2db
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:32 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:08:16 +01:00

locking/rtmutex: Fix misleading comment in rt_mutex_postunlock()

Preemption is disabled in mark_wakeup_next_waiter() not in
rt_mutex_slowunlock().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.809432652@linutronix.de
---
 kernel/locking/rtmutex.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 3612821..bece7aa 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1399,7 +1399,7 @@ void __sched rt_mutex_postunlock(struct wake_q_head *wake_q)
 {
 	wake_up_q(wake_q);
 
-	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
+	/* Pairs with preempt_disable() in mark_wakeup_next_waiter() */
 	preempt_enable();
 }
 

[patch 14/14] locking/rtmutex: Restrict the trylock WARN_ON() to debug

[Thomas Gleixner]

The warning as written is expensive and not really required for a
production kernel. Make it depend on rt mutex debugging and use !in_task()
for the condition which generates far better code and gives the same
answer.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1445,9 +1445,8 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock_interrup
  *
  * @lock:	the rt_mutex to be locked
  *
- * This function can only be called in thread context. It's safe to
- * call it from atomic regions, but not from hard interrupt or soft
- * interrupt context.
+ * This function can only be called in thread context. It's safe to call it
+ * from atomic regions, but not from hard or soft interrupt context.
  *
  * Returns 1 on success and 0 on contention
  */
@@ -1455,7 +1454,7 @@ int __sched rt_mutex_trylock(struct rt_m
 {
 	int ret;
 
-	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+	if (IS_ENABLED(CONFIG_RT_MUTEX_DEBUG) && WARN_ON_ONCE(!in_task()))
 		return 0;
 
 	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))

[tip: locking/core] locking/rtmutex: Restrict the trylock WARN_ON() to debug

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     3ac7d0ecf0e18b44c2c7dc968ce5afc5beadf17c
Gitweb:        https://git.kernel.org/tip/3ac7d0ecf0e18b44c2c7dc968ce5afc5beadf17c
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 23 Mar 2021 22:30:33 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Mar 2021 08:08:16 +01:00

locking/rtmutex: Restrict the trylock WARN_ON() to debug

The warning as written is expensive and not really required for a
production kernel. Make it depend on rt mutex debugging and use !in_task()
for the condition which generates far better code and gives the same
answer.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323213708.908341972@linutronix.de
---
 kernel/locking/rtmutex.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index bece7aa..d584e32 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1495,9 +1495,8 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
  *
  * @lock:	the rt_mutex to be locked
  *
- * This function can only be called in thread context. It's safe to
- * call it from atomic regions, but not from hard interrupt or soft
- * interrupt context.
+ * This function can only be called in thread context. It's safe to call it
+ * from atomic regions, but not from hard or soft interrupt context.
  *
  * Returns 1 on success and 0 on contention
  */
@@ -1505,7 +1504,7 @@ int __sched rt_mutex_trylock(struct rt_mutex *lock)
 {
 	int ret;
 
-	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+	if (IS_ENABLED(CONFIG_RT_MUTEX_DEBUG) && WARN_ON_ONCE(!in_task()))
 		return 0;
 
 	ret = rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);

Re: [patch 00/14] locking/rtmutex: Spring cleaning

[Thomas Gleixner]

On Tue, Mar 23 2021 at 22:30, Thomas Gleixner wrote:
> While working on the rtmutex related RT bits we noticed quite some
> inconsistencies and bitrot in the rtmutex code.

Sorry, forgot to mention that this is based on

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core

and also available from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git rtmutex

as a combo.

Thanks,

 	tglx

[patch V2 07/15] locking/rtmutex: Inline chainwalk depth check

[Thomas Gleixner]

There is no point for this wrapper at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -343,14 +343,9 @@ static void rt_mutex_adjust_prio(struct
 static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
 					  enum rtmutex_chainwalk chwalk)
 {
-	/*
-	 * This is just a wrapper function for the following call,
-	 * because debug_rt_mutex_detect_deadlock() smells like a magic
-	 * debug feature and I wanted to keep the cond function in the
-	 * main source file along with the comments instead of having
-	 * two of the same in the headers.
-	 */
-	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEX))
+		return waiter != NULL;
+	return chwalk == RT_MUTEX_FULL_CHAINWALK;
 }
 
 /*

[tip: locking/core] locking/rtmutex: Inline chainwalk depth check

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     f7efc4799f8114ba85b68584f83293f435009de4
Gitweb:        https://git.kernel.org/tip/f7efc4799f8114ba85b68584f83293f435009de4
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Fri, 26 Mar 2021 16:29:36 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 29 Mar 2021 15:57:03 +02:00

locking/rtmutex: Inline chainwalk depth check

There is no point for this wrapper at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210326153943.754254046@linutronix.de
---
 kernel/locking/rtmutex.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 8a934db..2c77e72 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -343,14 +343,9 @@ static void rt_mutex_adjust_prio(struct task_struct *p)
 static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
 					  enum rtmutex_chainwalk chwalk)
 {
-	/*
-	 * This is just a wrapper function for the following call,
-	 * because debug_rt_mutex_detect_deadlock() smells like a magic
-	 * debug feature and I wanted to keep the cond function in the
-	 * main source file along with the comments instead of having
-	 * two of the same in the headers.
-	 */
-	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEX))
+		return waiter != NULL;
+	return chwalk == RT_MUTEX_FULL_CHAINWALK;
 }
 
 /*