locks: Split rwlocks from spinlocks

Preparatory patch for atomic_spinlocks and preempt-rt. rwlocks are
always converted to sleeping locks on preempt-rt. Split the code so
the later preempt-rt conversions can be done by excluding the separate
files.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/rwlock.h

+#ifndef __LINUX_RWLOCK_H
+#define __LINUX_RWLOCK_H
+
+#ifndef __LINUX_SPINLOCK_H
+# error "please don't include this file directly"
+#endif
+
+/*
+ * rwlock related methods
+ *
+ * split out from spinlock.h
+ *
+ * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
+ * Released under the General Public License (GPL).
+ */
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+  extern void __rwlock_init(rwlock_t *lock, const char *name,
+			    struct lock_class_key *key);
+# define rwlock_init(lock)					\
+do {								\
+	static struct lock_class_key __key;			\
+								\
+	__rwlock_init((lock), #lock, &__key);			\
+} while (0)
+#else
+# define rwlock_init(lock)					\
+	do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
+#endif
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+ extern void _raw_read_lock(rwlock_t *lock);
+#define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
+ extern int _raw_read_trylock(rwlock_t *lock);
+ extern void _raw_read_unlock(rwlock_t *lock);
+ extern void _raw_write_lock(rwlock_t *lock);
+#define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
+ extern int _raw_write_trylock(rwlock_t *lock);
+ extern void _raw_write_unlock(rwlock_t *lock);
+#else
+# define _raw_read_lock(rwlock)		__raw_read_lock(&(rwlock)->raw_lock)
+# define _raw_read_lock_flags(lock, flags) \
+		__raw_read_lock_flags(&(lock)->raw_lock, *(flags))
+# define _raw_read_trylock(rwlock)	__raw_read_trylock(&(rwlock)->raw_lock)
+# define _raw_read_unlock(rwlock)	__raw_read_unlock(&(rwlock)->raw_lock)
+# define _raw_write_lock(rwlock)	__raw_write_lock(&(rwlock)->raw_lock)
+# define _raw_write_lock_flags(lock, flags) \
+		__raw_write_lock_flags(&(lock)->raw_lock, *(flags))
+# define _raw_write_trylock(rwlock)	__raw_write_trylock(&(rwlock)->raw_lock)
+# define _raw_write_unlock(rwlock)	__raw_write_unlock(&(rwlock)->raw_lock)
+#endif
+
+#define read_can_lock(rwlock)		__raw_read_can_lock(&(rwlock)->raw_lock)
+#define write_can_lock(rwlock)		__raw_write_can_lock(&(rwlock)->raw_lock)
+
+/*
+ * Define the various rw_lock methods.  Note we define these
+ * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
+ * various methods are defined as nops in the case they are not
+ * required.
+ */
+#define read_trylock(lock)		__cond_lock(lock, _read_trylock(lock))
+#define write_trylock(lock)		__cond_lock(lock, _write_trylock(lock))
+
+#define write_lock(lock)		_write_lock(lock)
+#define read_lock(lock)			_read_lock(lock)
+
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+
+#define read_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		flags = _read_lock_irqsave(lock);	\
+	} while (0)
+#define write_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		flags = _write_lock_irqsave(lock);	\
+	} while (0)
+
+#else
+
+#define read_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		_read_lock_irqsave(lock, flags);	\
+	} while (0)
+#define write_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		_write_lock_irqsave(lock, flags);	\
+	} while (0)
+
+#endif
+
+#define read_lock_irq(lock)		_read_lock_irq(lock)
+#define read_lock_bh(lock)		_read_lock_bh(lock)
+
+#define write_lock_irq(lock)		_write_lock_irq(lock)
+#define write_lock_bh(lock)		_write_lock_bh(lock)
+
+/*
+ * We inline the unlock functions in the nondebug case:
+ */
+#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
+	!defined(CONFIG_SMP)
+# define read_unlock(lock)		_read_unlock(lock)
+# define write_unlock(lock)		_write_unlock(lock)
+# define read_unlock_irq(lock)		_read_unlock_irq(lock)
+# define write_unlock_irq(lock)		_write_unlock_irq(lock)
+#else
+# define read_unlock(lock) \
+    do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
+# define write_unlock(lock) \
+    do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
+# define read_unlock_irq(lock)			\
+do {						\
+	__raw_read_unlock(&(lock)->raw_lock);	\
+	__release(lock);			\
+	local_irq_enable();			\
+} while (0)
+# define write_unlock_irq(lock)			\
+do {						\
+	__raw_write_unlock(&(lock)->raw_lock);	\
+	__release(lock);			\
+	local_irq_enable();			\
+} while (0)
+#endif
+
+#define read_unlock_irqrestore(lock, flags)		\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		_read_unlock_irqrestore(lock, flags);	\
+	} while (0)
+#define read_unlock_bh(lock)		_read_unlock_bh(lock)
+
+#define write_unlock_irqrestore(lock, flags)		\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		_write_unlock_irqrestore(lock, flags);	\
+	} while (0)
+#define write_unlock_bh(lock)		_write_unlock_bh(lock)
+
+#define write_trylock_irqsave(lock, flags) \
+({ \
+	local_irq_save(flags); \
+	write_trylock(lock) ? \
+	1 : ({ local_irq_restore(flags); 0; }); \
+})
+
+#endif /* __LINUX_RWLOCK_H */

include/linux/rwlock_types.h

+#ifndef __LINUX_RWLOCK_TYPES_H
+#define __LINUX_RWLOCK_TYPES_H
+
+/*
+ * include/linux/rwlock_types.h - generic rwlock type definitions
+ *				  and initializers
+ *
+ * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
+ * Released under the General Public License (GPL).
+ */
+typedef struct {
+	raw_rwlock_t raw_lock;
+#ifdef CONFIG_GENERIC_LOCKBREAK
+	unsigned int break_lock;
+#endif
+#ifdef CONFIG_DEBUG_SPINLOCK
+	unsigned int magic, owner_cpu;
+	void *owner;
+#endif
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map dep_map;
+#endif
+} rwlock_t;
+
+#define RWLOCK_MAGIC		0xdeaf1eed
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+#else
+# define RW_DEP_MAP_INIT(lockname)
+#endif
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+#define __RW_LOCK_UNLOCKED(lockname)					\
+	(rwlock_t)	{	.raw_lock = __RAW_RW_LOCK_UNLOCKED,	\
+				.magic = RWLOCK_MAGIC,			\
+				.owner = SPINLOCK_OWNER_INIT,		\
+				.owner_cpu = -1,			\
+				RW_DEP_MAP_INIT(lockname) }
+#else
+#define __RW_LOCK_UNLOCKED(lockname) \
+	(rwlock_t)	{	.raw_lock = __RAW_RW_LOCK_UNLOCKED,	\
+				RW_DEP_MAP_INIT(lockname) }
+#endif
+
+/*
+ * RW_LOCK_UNLOCKED defeat lockdep state tracking and is hence
+ * deprecated.
+ *
+ * Please use DEFINE_RWLOCK() or __RW_LOCK_UNLOCKED() as appropriate.
+ */
+#define RW_LOCK_UNLOCKED	__RW_LOCK_UNLOCKED(old_style_rw_init)
+
+#define DEFINE_RWLOCK(x)	rwlock_t x = __RW_LOCK_UNLOCKED(x)
+
+#endif /* __LINUX_RWLOCK_TYPES_H */

include/linux/spinlock.h

@@ -105,20 +105,6 @@ do {								\
 	do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
 #endif
 
-#ifdef CONFIG_DEBUG_SPINLOCK
-  extern void __rwlock_init(rwlock_t *lock, const char *name,
-			    struct lock_class_key *key);
-# define rwlock_init(lock)					\
-do {								\
-	static struct lock_class_key __key;			\
-								\
-	__rwlock_init((lock), #lock, &__key);			\
-} while (0)
-#else
-# define rwlock_init(lock)					\
-	do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
-#endif
-
 #define spin_is_locked(lock)	__raw_spin_is_locked(&(lock)->raw_lock)
 
 #ifdef CONFIG_GENERIC_LOCKBREAK
@@ -157,43 +143,21 @@ static inline void smp_mb__after_lock(void) { smp_mb(); }
 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
  extern int _raw_spin_trylock(spinlock_t *lock);
  extern void _raw_spin_unlock(spinlock_t *lock);
- extern void _raw_read_lock(rwlock_t *lock);
-#define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
- extern int _raw_read_trylock(rwlock_t *lock);
- extern void _raw_read_unlock(rwlock_t *lock);
- extern void _raw_write_lock(rwlock_t *lock);
-#define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
- extern int _raw_write_trylock(rwlock_t *lock);
- extern void _raw_write_unlock(rwlock_t *lock);
 #else
 # define _raw_spin_lock(lock)		__raw_spin_lock(&(lock)->raw_lock)
 # define _raw_spin_lock_flags(lock, flags) \
 		__raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 # define _raw_spin_trylock(lock)	__raw_spin_trylock(&(lock)->raw_lock)
 # define _raw_spin_unlock(lock)		__raw_spin_unlock(&(lock)->raw_lock)
-# define _raw_read_lock(rwlock)		__raw_read_lock(&(rwlock)->raw_lock)
-# define _raw_read_lock_flags(lock, flags) \
-		__raw_read_lock_flags(&(lock)->raw_lock, *(flags))
-# define _raw_read_trylock(rwlock)	__raw_read_trylock(&(rwlock)->raw_lock)
-# define _raw_read_unlock(rwlock)	__raw_read_unlock(&(rwlock)->raw_lock)
-# define _raw_write_lock(rwlock)	__raw_write_lock(&(rwlock)->raw_lock)
-# define _raw_write_lock_flags(lock, flags) \
-		__raw_write_lock_flags(&(lock)->raw_lock, *(flags))
-# define _raw_write_trylock(rwlock)	__raw_write_trylock(&(rwlock)->raw_lock)
-# define _raw_write_unlock(rwlock)	__raw_write_unlock(&(rwlock)->raw_lock)
 #endif
 
-#define read_can_lock(rwlock)		__raw_read_can_lock(&(rwlock)->raw_lock)
-#define write_can_lock(rwlock)		__raw_write_can_lock(&(rwlock)->raw_lock)
-
 /*
- * Define the various spin_lock and rw_lock methods.  Note we define these
- * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
- * methods are defined as nops in the case they are not required.
+ * Define the various spin_lock and methods.  Note we define these
+ * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
+ * various methods are defined as nops in the case they are not
+ * required.
  */
 #define spin_trylock(lock)		__cond_lock(lock, _spin_trylock(lock))
-#define read_trylock(lock)		__cond_lock(lock, _read_trylock(lock))
-#define write_trylock(lock)		__cond_lock(lock, _write_trylock(lock))
 
 #define spin_lock(lock)			_spin_lock(lock)
 
@@ -209,9 +173,6 @@ static inline void smp_mb__after_lock(void) { smp_mb(); }
 # define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
 #endif
 
-#define write_lock(lock)		_write_lock(lock)
-#define read_lock(lock)			_read_lock(lock)
-
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 
 #define spin_lock_irqsave(lock, flags)			\
@@ -219,16 +180,6 @@ static inline void smp_mb__after_lock(void) { smp_mb(); }
 		typecheck(unsigned long, flags);	\
 		flags = _spin_lock_irqsave(lock);	\
 	} while (0)
-#define read_lock_irqsave(lock, flags)			\
-	do {						\
-		typecheck(unsigned long, flags);	\
-		flags = _read_lock_irqsave(lock);	\
-	} while (0)
-#define write_lock_irqsave(lock, flags)			\
-	do {						\
-		typecheck(unsigned long, flags);	\
-		flags = _write_lock_irqsave(lock);	\
-	} while (0)
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define spin_lock_irqsave_nested(lock, flags, subclass)			\
@@ -251,16 +202,6 @@ static inline void smp_mb__after_lock(void) { smp_mb(); }
 		typecheck(unsigned long, flags);	\
 		_spin_lock_irqsave(lock, flags);	\
 	} while (0)
-#define read_lock_irqsave(lock, flags)			\
-	do {						\
-		typecheck(unsigned long, flags);	\
-		_read_lock_irqsave(lock, flags);	\
-	} while (0)
-#define write_lock_irqsave(lock, flags)			\
-	do {						\
-		typecheck(unsigned long, flags);	\
-		_write_lock_irqsave(lock, flags);	\
-	} while (0)
 #define spin_lock_irqsave_nested(lock, flags, subclass)	\
 	spin_lock_irqsave(lock, flags)
 
@@ -269,48 +210,22 @@ static inline void smp_mb__after_lock(void) { smp_mb(); }
 #define spin_lock_irq(lock)		_spin_lock_irq(lock)
 #define spin_lock_bh(lock)		_spin_lock_bh(lock)
 
-#define read_lock_irq(lock)		_read_lock_irq(lock)
-#define read_lock_bh(lock)		_read_lock_bh(lock)
-
-#define write_lock_irq(lock)		_write_lock_irq(lock)
-#define write_lock_bh(lock)		_write_lock_bh(lock)
-
 /*
  * We inline the unlock functions in the nondebug case:
  */
 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
 	!defined(CONFIG_SMP)
 # define spin_unlock(lock)		_spin_unlock(lock)
-# define read_unlock(lock)		_read_unlock(lock)
-# define write_unlock(lock)		_write_unlock(lock)
 # define spin_unlock_irq(lock)		_spin_unlock_irq(lock)
-# define read_unlock_irq(lock)		_read_unlock_irq(lock)
-# define write_unlock_irq(lock)		_write_unlock_irq(lock)
 #else
 # define spin_unlock(lock) \
     do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
-# define read_unlock(lock) \
-    do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
-# define write_unlock(lock) \
-    do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 # define spin_unlock_irq(lock)			\
 do {						\
 	__raw_spin_unlock(&(lock)->raw_lock);	\
 	__release(lock);			\
 	local_irq_enable();			\
 } while (0)
-# define read_unlock_irq(lock)			\
-do {						\
-	__raw_read_unlock(&(lock)->raw_lock);	\
-	__release(lock);			\
-	local_irq_enable();			\
-} while (0)
-# define write_unlock_irq(lock)			\
-do {						\
-	__raw_write_unlock(&(lock)->raw_lock);	\
-	__release(lock);			\
-	local_irq_enable();			\
-} while (0)
 #endif
 
 #define spin_unlock_irqrestore(lock, flags)		\
@@ -320,20 +235,6 @@ do {						\
 	} while (0)
 #define spin_unlock_bh(lock)		_spin_unlock_bh(lock)
 
-#define read_unlock_irqrestore(lock, flags)		\
-	do {						\
-		typecheck(unsigned long, flags);	\
-		_read_unlock_irqrestore(lock, flags);	\
-	} while (0)
-#define read_unlock_bh(lock)		_read_unlock_bh(lock)
-
-#define write_unlock_irqrestore(lock, flags)		\
-	do {						\
-		typecheck(unsigned long, flags);	\
-		_write_unlock_irqrestore(lock, flags);	\
-	} while (0)
-#define write_unlock_bh(lock)		_write_unlock_bh(lock)
-
 #define spin_trylock_bh(lock)	__cond_lock(lock, _spin_trylock_bh(lock))
 
 #define spin_trylock_irq(lock) \
@@ -350,13 +251,6 @@ do {						\
 	1 : ({ local_irq_restore(flags); 0; }); \
 })
 
-#define write_trylock_irqsave(lock, flags) \
-({ \
-	local_irq_save(flags); \
-	write_trylock(lock) ? \
-	1 : ({ local_irq_restore(flags); 0; }); \
-})
-
 /*
  * Pull the atomic_t declaration:
  * (asm-mips/atomic.h needs above definitions)
@@ -380,4 +274,6 @@ extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
  */
 #define spin_can_lock(lock)	(!spin_is_locked(lock))
 
+#include <linux/rwlock.h>
+
 #endif /* __LINUX_SPINLOCK_H */

include/linux/spinlock_types.h

@@ -33,22 +33,6 @@ typedef struct {
 
 #define SPINLOCK_MAGIC		0xdead4ead
 
-typedef struct {
-	raw_rwlock_t raw_lock;
-#ifdef CONFIG_GENERIC_LOCKBREAK
-	unsigned int break_lock;
-#endif
-#ifdef CONFIG_DEBUG_SPINLOCK
-	unsigned int magic, owner_cpu;
-	void *owner;
-#endif
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	struct lockdep_map dep_map;
-#endif
-} rwlock_t;
-
-#define RWLOCK_MAGIC		0xdeaf1eed
-
 #define SPINLOCK_OWNER_INIT	((void *)-1L)
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -57,12 +41,6 @@ typedef struct {
 # define SPIN_DEP_MAP_INIT(lockname)
 #endif
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
-#else
-# define RW_DEP_MAP_INIT(lockname)
-#endif
-
 #ifdef CONFIG_DEBUG_SPINLOCK
 # define __SPIN_LOCK_UNLOCKED(lockname)					\
 	(spinlock_t)	{	.raw_lock = __RAW_SPIN_LOCK_UNLOCKED,	\
@@ -70,31 +48,22 @@ typedef struct {
 				.owner = SPINLOCK_OWNER_INIT,		\
 				.owner_cpu = -1,			\
 				SPIN_DEP_MAP_INIT(lockname) }
-#define __RW_LOCK_UNLOCKED(lockname)					\
-	(rwlock_t)	{	.raw_lock = __RAW_RW_LOCK_UNLOCKED,	\
-				.magic = RWLOCK_MAGIC,			\
-				.owner = SPINLOCK_OWNER_INIT,		\
-				.owner_cpu = -1,			\
-				RW_DEP_MAP_INIT(lockname) }
 #else
 # define __SPIN_LOCK_UNLOCKED(lockname) \
 	(spinlock_t)	{	.raw_lock = __RAW_SPIN_LOCK_UNLOCKED,	\
 				SPIN_DEP_MAP_INIT(lockname) }
-#define __RW_LOCK_UNLOCKED(lockname) \
-	(rwlock_t)	{	.raw_lock = __RAW_RW_LOCK_UNLOCKED,	\
-				RW_DEP_MAP_INIT(lockname) }
 #endif
 
 /*
- * SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED defeat lockdep state tracking and
- * are hence deprecated.
- * Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or
- * __SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate.
+ * SPIN_LOCK_UNLOCKED defeats lockdep state tracking and is hence
+ * deprecated.
+ * Please use DEFINE_SPINLOCK() or __SPIN_LOCK_UNLOCKED() as
+ * appropriate.
  */
 #define SPIN_LOCK_UNLOCKED	__SPIN_LOCK_UNLOCKED(old_style_spin_init)
-#define RW_LOCK_UNLOCKED	__RW_LOCK_UNLOCKED(old_style_rw_init)
 
 #define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
-#define DEFINE_RWLOCK(x)	rwlock_t x = __RW_LOCK_UNLOCKED(x)
+
+#include <linux/rwlock_types.h>
 
 #endif /* __LINUX_SPINLOCK_TYPES_H */

kernel/Makefile

@@ -45,9 +45,9 @@ obj-$(CONFIG_USE_GENERIC_SMP_HELPERS) += smp.o
 ifneq ($(CONFIG_SMP),y)
 obj-y += up.o
 endif
-obj-$(CONFIG_SMP) += spinlock.o
-obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
-obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
+obj-$(CONFIG_SMP) += spinlock.o rwlock.o
+obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o rwlock.o
+obj-$(CONFIG_PROVE_LOCKING) += spinlock.o rwlock.o
 obj-$(CONFIG_UID16) += uid16.o
 obj-$(CONFIG_MODULES) += module.o
 obj-$(CONFIG_KALLSYMS) += kallsyms.o

kernel/lock-internals.h

+/*
+ * Macros shared by spinlock.c and rwlock.c
+ */
+/*
+ * This could be a long-held lock. We both prepare to spin for a long
+ * time (making _this_ CPU preemptable if possible), and we also signal
+ * towards that other CPU that it should break the lock ASAP.
+ *
+ * (We do this in a function because inlining it would be excessive.)
+ */
+
+#define BUILD_LOCK_OPS(op, locktype)					\
+void __lockfunc _##op##_lock(locktype##_t *lock)			\
+{									\
+	for (;;) {							\
+		preempt_disable();					\
+		if (likely(_raw_##op##_trylock(lock)))			\
+			break;						\
+		preempt_enable();					\
+									\
+		if (!(lock)->break_lock)				\
+			(lock)->break_lock = 1;				\
+		while (!op##_can_lock(lock) && (lock)->break_lock)	\
+			_raw_##op##_relax(&lock->raw_lock);		\
+	}								\
+	(lock)->break_lock = 0;						\
+}									\
+									\
+EXPORT_SYMBOL(_##op##_lock);						\
+									\
+unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock)	\
+{									\
+	unsigned long flags;						\
+									\
+	for (;;) {							\
+		preempt_disable();					\
+		local_irq_save(flags);					\
+		if (likely(_raw_##op##_trylock(lock)))			\
+			break;						\
+		local_irq_restore(flags);				\
+		preempt_enable();					\
+									\
+		if (!(lock)->break_lock)				\
+			(lock)->break_lock = 1;				\
+		while (!op##_can_lock(lock) && (lock)->break_lock)	\
+			_raw_##op##_relax(&lock->raw_lock);		\
+	}								\
+	(lock)->break_lock = 0;						\
+	return flags;							\
+}									\
+									\
+EXPORT_SYMBOL(_##op##_lock_irqsave);					\
+									\
+void __lockfunc _##op##_lock_irq(locktype##_t *lock)			\
+{									\
+	_##op##_lock_irqsave(lock);					\
+}									\
+									\
+EXPORT_SYMBOL(_##op##_lock_irq);					\
+									\
+void __lockfunc _##op##_lock_bh(locktype##_t *lock)			\
+{									\
+	unsigned long flags;						\
+									\
+	/*							*/	\
+	/* Careful: we must exclude softirqs too, hence the	*/	\
+	/* irq-disabling. We use the generic preemption-aware	*/	\
+	/* function:						*/	\
+	/**/								\
+	flags = _##op##_lock_irqsave(lock);				\
+	local_bh_disable();						\
+	local_irq_restore(flags);					\
+}									\
+									\
+EXPORT_SYMBOL(_##op##_lock_bh)

kernel/rwlock.c

+/*
+ * Copyright (2004) Linus Torvalds
+ *
+ * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
+ *
+ * Copyright (2004, 2005) Ingo Molnar
+ *
+ * This file contains the spinlock/rwlock implementations for the
+ * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
+ *
+ * Note that some architectures have special knowledge about the
+ * stack frames of these functions in their profile_pc. If you
+ * change anything significant here that could change the stack
+ * frame contact the architecture maintainers.
+ */
+
+#include <linux/linkage.h>
+#include <linux/preempt.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+#include <linux/module.h>
+
+#include "lock-internals.h"
+
+int __lockfunc _read_trylock(rwlock_t *lock)
+{
+	preempt_disable();
+	if (_raw_read_trylock(lock)) {
+		rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
+		return 1;
+	}
+
+	preempt_enable();
+	return 0;
+}
+EXPORT_SYMBOL(_read_trylock);
+
+int __lockfunc _write_trylock(rwlock_t *lock)
+{
+	preempt_disable();
+	if (_raw_write_trylock(lock)) {
+		rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+		return 1;
+	}
+
+	preempt_enable();
+	return 0;
+}
+EXPORT_SYMBOL(_write_trylock);
+
+/*
+ * If lockdep is enabled then we use the non-preemption spin-ops
+ * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
+ * not re-enabled during lock-acquire (which the preempt-spin-ops do):
+ */
+#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
+
+void __lockfunc _read_lock(rwlock_t *lock)
+{
+	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
+}
+EXPORT_SYMBOL(_read_lock);
+
+unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED_FLAGS(lock, _raw_read_trylock, _raw_read_lock,
+			     _raw_read_lock_flags, &flags);
+	return flags;
+}
+EXPORT_SYMBOL(_read_lock_irqsave);
+
+void __lockfunc _read_lock_irq(rwlock_t *lock)
+{
+	local_irq_disable();
+	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
+}
+EXPORT_SYMBOL(_read_lock_irq);
+
+void __lockfunc _read_lock_bh(rwlock_t *lock)
+{
+	local_bh_disable();
+	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
+}
+EXPORT_SYMBOL(_read_lock_bh);
+
+unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED_FLAGS(lock, _raw_write_trylock, _raw_write_lock,
+			     _raw_write_lock_flags, &flags);
+	return flags;
+}
+EXPORT_SYMBOL(_write_lock_irqsave);
+
+void __lockfunc _write_lock_irq(rwlock_t *lock)
+{
+	local_irq_disable();
+	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
+}
+EXPORT_SYMBOL(_write_lock_irq);
+
+void __lockfunc _write_lock_bh(rwlock_t *lock)
+{
+	local_bh_disable();
+	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
+}
+EXPORT_SYMBOL(_write_lock_bh);
+
+void __lockfunc _write_lock(rwlock_t *lock)
+{
+	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
+}
+
+EXPORT_SYMBOL(_write_lock);
+
+#else /* CONFIG_PREEMPT: */
+
+/*
+ * Build preemption-friendly versions of the following
+ * lock-spinning functions:
+ *
+ *         _[read|write]_lock()
+ *         _[read|write]_lock_irq()
+ *         _[read|write]_lock_irqsave()
+ *         _[read|write]_lock_bh()
+ */
+BUILD_LOCK_OPS(read, rwlock);
+BUILD_LOCK_OPS(write, rwlock);
+
+#endif /* CONFIG_PREEMPT */
+
+void __lockfunc _write_unlock(rwlock_t *lock)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_write_unlock(lock);
+	preempt_enable();
+}
+EXPORT_SYMBOL(_write_unlock);
+
+void __lockfunc _read_unlock(rwlock_t *lock)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_read_unlock(lock);
+	preempt_enable();
+}
+EXPORT_SYMBOL(_read_unlock);
+
+void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_read_unlock(lock);
+	local_irq_restore(flags);
+	preempt_enable();
+}
+EXPORT_SYMBOL(_read_unlock_irqrestore);
+
+void __lockfunc _read_unlock_irq(rwlock_t *lock)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_read_unlock(lock);
+	local_irq_enable();
+	preempt_enable();
+}
+EXPORT_SYMBOL(_read_unlock_irq);
+
+void __lockfunc _read_unlock_bh(rwlock_t *lock)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_read_unlock(lock);
+	preempt_enable_no_resched();
+	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
+}
+EXPORT_SYMBOL(_read_unlock_bh);
+
+void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_write_unlock(lock);
+	local_irq_restore(flags);
+	preempt_enable();
+}
+EXPORT_SYMBOL(_write_unlock_irqrestore);
+
+void __lockfunc _write_unlock_irq(rwlock_t *lock)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_write_unlock(lock);
+	local_irq_enable();
+	preempt_enable();
+}
+EXPORT_SYMBOL(_write_unlock_irq);
+
+void __lockfunc _write_unlock_bh(rwlock_t *lock)
+{
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
+	_raw_write_unlock(lock);
+	preempt_enable_no_resched();
+	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
+}
+EXPORT_SYMBOL(_write_unlock_bh);
+

kernel/spinlock.c

@@ -21,6 +21,8 @@
 #include <linux/debug_locks.h>
 #include <linux/module.h>
 
+#include "lock-internals.h"
+
 int __lockfunc _spin_trylock(spinlock_t *lock)
 {
 	preempt_disable();
@@ -28,38 +30,11 @@ int __lockfunc _spin_trylock(spinlock_t *lock)
 		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 		return 1;
 	}
-	
 	preempt_enable();
 	return 0;
 }
 EXPORT_SYMBOL(_spin_trylock);
 
-int __lockfunc _read_trylock(rwlock_t *lock)
-{
-	preempt_disable();
-	if (_raw_read_trylock(lock)) {
-		rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
-		return 1;
-	}
-
-	preempt_enable();
-	return 0;
-}
-EXPORT_SYMBOL(_read_trylock);
-
-int __lockfunc _write_trylock(rwlock_t *lock)
-{
-	preempt_disable();
-	if (_raw_write_trylock(lock)) {
-		rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
-		return 1;
-	}
-
-	preempt_enable();
-	return 0;
-}
-EXPORT_SYMBOL(_write_trylock);
-
 /*
  * If lockdep is enabled then we use the non-preemption spin-ops
  * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
@@ -67,14 +42,6 @@ EXPORT_SYMBOL(_write_trylock);
  */
 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
 
-void __lockfunc _read_lock(rwlock_t *lock)
-{
-	preempt_disable();
-	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
-}
-EXPORT_SYMBOL(_read_lock);
-
 unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
 {
 	unsigned long flags;
@@ -114,173 +81,26 @@ void __lockfunc _spin_lock_bh(spinlock_t *lock)
 }
 EXPORT_SYMBOL(_spin_lock_bh);
 
-unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	preempt_disable();
-	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED_FLAGS(lock, _raw_read_trylock, _raw_read_lock,
-			     _raw_read_lock_flags, &flags);
-	return flags;
-}
-EXPORT_SYMBOL(_read_lock_irqsave);
-
-void __lockfunc _read_lock_irq(rwlock_t *lock)
-{
-	local_irq_disable();
-	preempt_disable();
-	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
-}
-EXPORT_SYMBOL(_read_lock_irq);
-
-void __lockfunc _read_lock_bh(rwlock_t *lock)
-{
-	local_bh_disable();
-	preempt_disable();
-	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
-}
-EXPORT_SYMBOL(_read_lock_bh);
-
-unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	preempt_disable();
-	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED_FLAGS(lock, _raw_write_trylock, _raw_write_lock,
-			     _raw_write_lock_flags, &flags);
-	return flags;
-}
-EXPORT_SYMBOL(_write_lock_irqsave);
-
-void __lockfunc _write_lock_irq(rwlock_t *lock)
-{
-	local_irq_disable();
-	preempt_disable();
-	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
-}
-EXPORT_SYMBOL(_write_lock_irq);
-
-void __lockfunc _write_lock_bh(rwlock_t *lock)
-{
-	local_bh_disable();
-	preempt_disable();
-	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
-}
-EXPORT_SYMBOL(_write_lock_bh);
-
 void __lockfunc _spin_lock(spinlock_t *lock)
 {
 	preempt_disable();
 	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
 }
-
 EXPORT_SYMBOL(_spin_lock);
 
-void __lockfunc _write_lock(rwlock_t *lock)
-{
-	preempt_disable();
-	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
-}
-
-EXPORT_SYMBOL(_write_lock);
-
 #else /* CONFIG_PREEMPT: */
 
-/*
- * This could be a long-held lock. We both prepare to spin for a long
- * time (making _this_ CPU preemptable if possible), and we also signal
- * towards that other CPU that it should break the lock ASAP.
- *
- * (We do this in a function because inlining it would be excessive.)
- */
-
-#define BUILD_LOCK_OPS(op, locktype)					\
-void __lockfunc _##op##_lock(locktype##_t *lock)			\
-{									\
-	for (;;) {							\
-		preempt_disable();					\
-		if (likely(_raw_##op##_trylock(lock)))			\
-			break;						\
-		preempt_enable();					\
-									\
-		if (!(lock)->break_lock)				\
-			(lock)->break_lock = 1;				\
-		while (!op##_can_lock(lock) && (lock)->break_lock)	\
-			_raw_##op##_relax(&lock->raw_lock);		\
-	}								\
-	(lock)->break_lock = 0;						\
-}									\
-									\
-EXPORT_SYMBOL(_##op##_lock);						\
-									\
-unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock)	\
-{									\
-	unsigned long flags;						\
-									\
-	for (;;) {							\
-		preempt_disable();					\
-		local_irq_save(flags);					\
-		if (likely(_raw_##op##_trylock(lock)))			\
-			break;						\
-		local_irq_restore(flags);				\
-		preempt_enable();					\
-									\
-		if (!(lock)->break_lock)				\
-			(lock)->break_lock = 1;				\
-		while (!op##_can_lock(lock) && (lock)->break_lock)	\
-			_raw_##op##_relax(&lock->raw_lock);		\
-	}								\
-	(lock)->break_lock = 0;						\
-	return flags;							\
-}									\
-									\
-EXPORT_SYMBOL(_##op##_lock_irqsave);					\
-									\
-void __lockfunc _##op##_lock_irq(locktype##_t *lock)			\
-{									\
-	_##op##_lock_irqsave(lock);					\
-}									\
-									\
-EXPORT_SYMBOL(_##op##_lock_irq);					\
-									\
-void __lockfunc _##op##_lock_bh(locktype##_t *lock)			\
-{									\
-	unsigned long flags;						\
-									\
-	/*							*/	\
-	/* Careful: we must exclude softirqs too, hence the	*/	\
-	/* irq-disabling. We use the generic preemption-aware	*/	\
-	/* function:						*/	\
-	/**/								\
-	flags = _##op##_lock_irqsave(lock);				\
-	local_bh_disable();						\
-	local_irq_restore(flags);					\
-}									\
-									\
-EXPORT_SYMBOL(_##op##_lock_bh)
-
 /*
  * Build preemption-friendly versions of the following
  * lock-spinning functions:
  *
- *         _[spin|read|write]_lock()
- *         _[spin|read|write]_lock_irq()
- *         _[spin|read|write]_lock_irqsave()
- *         _[spin|read|write]_lock_bh()
+ *         _spin_lock()
+ *         _spin_lock_irq()
+ *         _spin_lock_irqsave()
+ *         _spin_lock_bh()
  */
 BUILD_LOCK_OPS(spin, spinlock);
-BUILD_LOCK_OPS(read, rwlock);
-BUILD_LOCK_OPS(write, rwlock);
 
 #endif /* CONFIG_PREEMPT */
 
@@ -326,22 +146,6 @@ void __lockfunc _spin_unlock(spinlock_t *lock)
 }
 EXPORT_SYMBOL(_spin_unlock);
 
-void __lockfunc _write_unlock(rwlock_t *lock)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_write_unlock(lock);
-	preempt_enable();
-}
-EXPORT_SYMBOL(_write_unlock);
-
-void __lockfunc _read_unlock(rwlock_t *lock)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_read_unlock(lock);
-	preempt_enable();
-}
-EXPORT_SYMBOL(_read_unlock);
-
 void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 {
 	spin_release(&lock->dep_map, 1, _RET_IP_);
@@ -369,60 +173,6 @@ void __lockfunc _spin_unlock_bh(spinlock_t *lock)
 }
 EXPORT_SYMBOL(_spin_unlock_bh);
 
-void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_read_unlock(lock);
-	local_irq_restore(flags);
-	preempt_enable();
-}
-EXPORT_SYMBOL(_read_unlock_irqrestore);
-
-void __lockfunc _read_unlock_irq(rwlock_t *lock)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_read_unlock(lock);
-	local_irq_enable();
-	preempt_enable();
-}
-EXPORT_SYMBOL(_read_unlock_irq);
-
-void __lockfunc _read_unlock_bh(rwlock_t *lock)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_read_unlock(lock);
-	preempt_enable_no_resched();
-	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
-}
-EXPORT_SYMBOL(_read_unlock_bh);
-
-void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_write_unlock(lock);
-	local_irq_restore(flags);
-	preempt_enable();
-}
-EXPORT_SYMBOL(_write_unlock_irqrestore);
-
-void __lockfunc _write_unlock_irq(rwlock_t *lock)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_write_unlock(lock);
-	local_irq_enable();
-	preempt_enable();
-}
-EXPORT_SYMBOL(_write_unlock_irq);
-
-void __lockfunc _write_unlock_bh(rwlock_t *lock)
-{
-	rwlock_release(&lock->dep_map, 1, _RET_IP_);
-	_raw_write_unlock(lock);
-	preempt_enable_no_resched();
-	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
-}
-EXPORT_SYMBOL(_write_unlock_bh);
-
 int __lockfunc _spin_trylock_bh(spinlock_t *lock)
 {
 	local_bh_disable();