From f39f0efddad61d3a13f0a4e9807d8c1c927963f7 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 24 Feb 2010 09:54:54 +0100
Subject: [PATCH] rwsem: Make inner lock raw

commit a359d62fa46b9c41621fec1c3b31730cfc436b40 in tip.

There is no reason to convert the lock protecting rwsems (the
ownerless variant) to a sleeping spinlock on -rt. Convert it to raw.

[PG: since tip, some instances were up'd to irqsave/restore in mainline]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/arch/powerpc/include/asm/rwsem.h b/arch/powerpc/include/asm/rwsem.h
index c2494d4..accf580 100644
--- a/arch/powerpc/include/asm/rwsem.h
+++ b/arch/powerpc/include/asm/rwsem.h
@@ -30,7 +30,7 @@ struct rw_anon_semaphore {
 #define RWSEM_WAITING_BIAS		(-0x00010000)
 #define RWSEM_ACTIVE_READ_BIAS		RWSEM_ACTIVE_BIAS
 #define RWSEM_ACTIVE_WRITE_BIAS		(RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
-	spinlock_t		wait_lock;
+	raw_spinlock_t		wait_lock;
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
@@ -44,7 +44,7 @@ struct rw_anon_semaphore {
 #endif
 
 #define __RWSEM_ANON_INITIALIZER(name) \
-	{ RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
+	{ RWSEM_UNLOCKED_VALUE, __RAW_SPIN_LOCK_UNLOCKED((name).wait_lock), \
 	  LIST_HEAD_INIT((name).wait_list) __RWSEM_ANON_DEP_MAP_INIT(name) }
 
 #define DECLARE_ANON_RWSEM(name)		\
@@ -178,7 +178,7 @@ static inline int anon_rwsem_is_locked(struct rw_anon_semaphore *sem)
 struct rw_semaphore {
 	/* XXX this should be able to be an atomic_t  -- paulus */
 	signed int		count;
-	spinlock_t		wait_lock;
+	raw_spinlock_t		wait_lock;
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
@@ -192,7 +192,7 @@ struct rw_semaphore {
 #endif
 
 #define __RWSEM_INITIALIZER(name) \
-	{ RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
+	{ RWSEM_UNLOCKED_VALUE, __RAW_SPIN_LOCK_UNLOCKED((name).wait_lock), \
 	  LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) }
 
 #define DECLARE_RWSEM(name)		\
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h
index 286cba2..42f8a37 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -78,7 +78,7 @@ typedef signed long rwsem_count_t;
 
 struct rw_anon_semaphore {
 	rwsem_count_t		count;
-	spinlock_t		wait_lock;
+	raw_spinlock_t		wait_lock;
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
@@ -93,7 +93,7 @@ struct rw_anon_semaphore {
 
 #define __RWSEM_ANON_INITIALIZER(name)				\
 {								\
-	RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
+	RWSEM_UNLOCKED_VALUE, __RAW_SPIN_LOCK_UNLOCKED((name).wait_lock), \
 	LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) \
 }
 
@@ -282,7 +282,7 @@ static inline int anon_rwsem_is_locked(struct rw_anon_semaphore *sem)
 
 struct rw_semaphore {
 	signed long		count;
-	spinlock_t		wait_lock;
+	raw_spinlock_t		wait_lock;
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
@@ -296,7 +296,7 @@ struct rw_semaphore {
 #endif
 
 #define __RWSEM_INITIALIZER(name) \
-{ 0, __SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
+{ 0, __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
   __RWSEM_DEP_MAP_INIT(name) }
 
 #define DECLARE_RWSEM(name) \
diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
index 17df0dc..6608521 100644
--- a/include/linux/rwsem-spinlock.h
+++ b/include/linux/rwsem-spinlock.h
@@ -33,7 +33,7 @@ struct rwsem_waiter;
  */
 struct rw_anon_semaphore {
 	__s32			activity;
-	spinlock_t		wait_lock;
+	raw_spinlock_t		wait_lock;
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
@@ -47,7 +47,7 @@ struct rw_anon_semaphore {
 #endif
 
 #define __RWSEM_ANON_INITIALIZER(name) \
-{ 0, __SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
+{ 0, __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
   __RWSEM_ANON_DEP_MAP_INIT(name) }
 
 #define DECLARE_ANON_RWSEM(name) \
@@ -89,7 +89,7 @@ extern void __downgrade_write(struct rw_anon_semaphore *sem);
  */
 struct rw_semaphore {
 	__s32			activity;
-	spinlock_t		wait_lock;
+	raw_spinlock_t		wait_lock;
 	struct list_head	wait_list;
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
@@ -103,7 +103,7 @@ struct rw_semaphore {
 #endif
 
 #define __RWSEM_INITIALIZER(name) \
-{ 0, __SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
+{ 0, __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
   __RWSEM_DEP_MAP_INIT(name) }
 
 #define DECLARE_RWSEM(name) \
diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
index dea1aea..26b7766 100644
--- a/lib/rwsem-spinlock.c
+++ b/lib/rwsem-spinlock.c
@@ -22,9 +22,9 @@ int anon_rwsem_is_locked(struct rw_anon_semaphore *sem)
 	int ret = 1;
 	unsigned long flags;
 
-	if (spin_trylock_irqsave(&sem->wait_lock, flags)) {
+	if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) {
 		ret = (sem->activity != 0);
-		spin_unlock_irqrestore(&sem->wait_lock, flags);
+		raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 	}
 	return ret;
 }
@@ -44,7 +44,7 @@ void __init_anon_rwsem(struct rw_anon_semaphore *sem, const char *name,
 	lockdep_init_map(&sem->dep_map, name, key, 0);
 #endif
 	sem->activity = 0;
-	spin_lock_init(&sem->wait_lock);
+	raw_spin_lock_init(&sem->wait_lock);
 	INIT_LIST_HEAD(&sem->wait_list);
 }
 EXPORT_SYMBOL(__init_anon_rwsem);
@@ -145,12 +145,12 @@ void __sched __down_read(struct rw_anon_semaphore *sem)
 	struct task_struct *tsk;
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
 		/* granted */
 		sem->activity++;
-		spin_unlock_irqrestore(&sem->wait_lock, flags);
+		raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 		goto out;
 	}
 
@@ -165,7 +165,7 @@ void __sched __down_read(struct rw_anon_semaphore *sem)
 	list_add_tail(&waiter.list, &sem->wait_list);
 
 	/* we don't need to touch the semaphore struct anymore */
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	/* wait to be given the lock */
 	for (;;) {
@@ -189,7 +189,7 @@ int __down_read_trylock(struct rw_anon_semaphore *sem)
 	int ret = 0;
 
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
 		/* granted */
@@ -197,7 +197,7 @@ int __down_read_trylock(struct rw_anon_semaphore *sem)
 		ret = 1;
 	}
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	return ret;
 }
@@ -212,12 +212,12 @@ void __sched __down_write_nested(struct rw_anon_semaphore *sem, int subclass)
 	struct task_struct *tsk;
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (sem->activity == 0 && list_empty(&sem->wait_list)) {
 		/* granted */
 		sem->activity = -1;
-		spin_unlock_irqrestore(&sem->wait_lock, flags);
+		raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 		goto out;
 	}
 
@@ -232,7 +232,7 @@ void __sched __down_write_nested(struct rw_anon_semaphore *sem, int subclass)
 	list_add_tail(&waiter.list, &sem->wait_list);
 
 	/* we don't need to touch the semaphore struct anymore */
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	/* wait to be given the lock */
 	for (;;) {
@@ -260,7 +260,7 @@ int __down_write_trylock(struct rw_anon_semaphore *sem)
 	unsigned long flags;
 	int ret = 0;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (sem->activity == 0 && list_empty(&sem->wait_list)) {
 		/* granted */
@@ -268,7 +268,7 @@ int __down_write_trylock(struct rw_anon_semaphore *sem)
 		ret = 1;
 	}
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	return ret;
 }
@@ -280,12 +280,12 @@ void __up_read(struct rw_anon_semaphore *sem)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (--sem->activity == 0 && !list_empty(&sem->wait_list))
 		sem = __rwsem_wake_one_writer(sem);
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
 
 /*
@@ -295,13 +295,13 @@ void __up_write(struct rw_anon_semaphore *sem)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	sem->activity = 0;
 	if (!list_empty(&sem->wait_list))
 		sem = __rwsem_do_wake(sem, 1);
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
 
 /*
@@ -312,12 +312,12 @@ void __downgrade_write(struct rw_anon_semaphore *sem)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	sem->activity = 1;
 	if (!list_empty(&sem->wait_list))
 		sem = __rwsem_do_wake(sem, 0);
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
 
diff --git a/lib/rwsem.c b/lib/rwsem.c
index 72eaba5..47f5a75 100644
--- a/lib/rwsem.c
+++ b/lib/rwsem.c
@@ -22,7 +22,7 @@ void __init_anon_rwsem(struct rw_anon_semaphore *sem, const char *name,
 	lockdep_init_map(&sem->dep_map, name, key, 0);
 #endif
 	sem->count = RWSEM_UNLOCKED_VALUE;
-	spin_lock_init(&sem->wait_lock);
+	raw_spin_lock_init(&sem->wait_lock);
 	INIT_LIST_HEAD(&sem->wait_list);
 }
 EXPORT_SYMBOL(__init_anon_rwsem);
@@ -155,7 +155,7 @@ rwsem_down_failed_common(struct rw_anon_semaphore *sem,
 	set_task_state(tsk, TASK_UNINTERRUPTIBLE);
 
 	/* set up my own style of waitqueue */
-	spin_lock_irq(&sem->wait_lock);
+	raw_spin_lock_irq(&sem->wait_lock);
 	waiter->task = tsk;
 	get_task_struct(tsk);
 
@@ -168,7 +168,7 @@ rwsem_down_failed_common(struct rw_anon_semaphore *sem,
 	if (!(count & RWSEM_ACTIVE_MASK))
 		sem = __rwsem_do_wake(sem, 0);
 
-	spin_unlock_irq(&sem->wait_lock);
+	raw_spin_unlock_irq(&sem->wait_lock);
 
 	/* wait to be given the lock */
 	for (;;) {
@@ -219,13 +219,13 @@ asmregparm struct rw_anon_semaphore *rwsem_wake(struct rw_anon_semaphore *sem)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	/* do nothing if list empty */
 	if (!list_empty(&sem->wait_list))
 		sem = __rwsem_do_wake(sem, 0);
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	return sem;
 }
@@ -240,13 +240,13 @@ rwsem_downgrade_wake(struct rw_anon_semaphore *sem)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&sem->wait_lock, flags);
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
 
 	/* do nothing if list empty */
 	if (!list_empty(&sem->wait_list))
 		sem = __rwsem_do_wake(sem, 1);
 
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	return sem;
 }
-- 
1.7.4