1 files changed, 125 insertions, 0 deletions

diff --git a/include/linux/rwlock.h b/include/linux/rwlock.h
new file mode 100644
index 000000000000..71e0b00b6f2c
--- /dev/null
+++ b/include/linux/rwlock.h
@@ -0,0 +1,125 @@
+#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(lock); } while (0)
+#endif
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+ extern void do_raw_read_lock(rwlock_t *lock);
+#define do_raw_read_lock_flags(lock, flags) do_raw_read_lock(lock)
+ extern int do_raw_read_trylock(rwlock_t *lock);
+ extern void do_raw_read_unlock(rwlock_t *lock);
+ extern void do_raw_write_lock(rwlock_t *lock);
+#define do_raw_write_lock_flags(lock, flags) do_raw_write_lock(lock)
+ extern int do_raw_write_trylock(rwlock_t *lock);
+ extern void do_raw_write_unlock(rwlock_t *lock);
+#else
+# define do_raw_read_lock(rwlock)       arch_read_lock(&(rwlock)->raw_lock)
+# define do_raw_read_lock_flags(lock, flags) \
+                arch_read_lock_flags(&(lock)->raw_lock, *(flags))
+# define do_raw_read_trylock(rwlock)    arch_read_trylock(&(rwlock)->raw_lock)
+# define do_raw_read_unlock(rwlock)     arch_read_unlock(&(rwlock)->raw_lock)
+# define do_raw_write_lock(rwlock)      arch_write_lock(&(rwlock)->raw_lock)
+# define do_raw_write_lock_flags(lock, flags) \
+                arch_write_lock_flags(&(lock)->raw_lock, *(flags))
+# define do_raw_write_trylock(rwlock)   arch_write_trylock(&(rwlock)->raw_lock)
+# define do_raw_write_unlock(rwlock)    arch_write_unlock(&(rwlock)->raw_lock)
+#endif
+
+#define read_can_lock(rwlock)           arch_read_can_lock(&(rwlock)->raw_lock)
+#define write_can_lock(rwlock)          arch_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, _raw_read_trylock(lock))
+#define write_trylock(lock)     __cond_lock(lock, _raw_write_trylock(lock))
+
+#define write_lock(lock)        _raw_write_lock(lock)
+#define read_lock(lock)         _raw_read_lock(lock)
+
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+
+#define read_lock_irqsave(lock, flags)                  \
+        do {                                            \
+                typecheck(unsigned long, flags);        \
+                flags = _raw_read_lock_irqsave(lock);   \
+        } while (0)
+#define write_lock_irqsave(lock, flags)                 \
+        do {                                            \
+                typecheck(unsigned long, flags);        \
+                flags = _raw_write_lock_irqsave(lock);  \
+        } while (0)
+
+#else
+
+#define read_lock_irqsave(lock, flags)                  \
+        do {                                            \
+                typecheck(unsigned long, flags);        \
+                _raw_read_lock_irqsave(lock, flags);    \
+        } while (0)
+#define write_lock_irqsave(lock, flags)                 \
+        do {                                            \
+                typecheck(unsigned long, flags);        \
+                _raw_write_lock_irqsave(lock, flags);   \
+        } while (0)
+
+#endif
+
+#define read_lock_irq(lock)             _raw_read_lock_irq(lock)
+#define read_lock_bh(lock)              _raw_read_lock_bh(lock)
+#define write_lock_irq(lock)            _raw_write_lock_irq(lock)
+#define write_lock_bh(lock)             _raw_write_lock_bh(lock)
+#define read_unlock(lock)               _raw_read_unlock(lock)
+#define write_unlock(lock)              _raw_write_unlock(lock)
+#define read_unlock_irq(lock)           _raw_read_unlock_irq(lock)
+#define write_unlock_irq(lock)          _raw_write_unlock_irq(lock)
+
+#define read_unlock_irqrestore(lock, flags)                     \
+        do {                                                    \
+                typecheck(unsigned long, flags);                \
+                _raw_read_unlock_irqrestore(lock, flags);       \
+        } while (0)
+#define read_unlock_bh(lock)            _raw_read_unlock_bh(lock)
+
+#define write_unlock_irqrestore(lock, flags)            \
+        do {                                            \
+                typecheck(unsigned long, flags);        \
+                _raw_write_unlock_irqrestore(lock, flags);      \
+        } while (0)
+#define write_unlock_bh(lock)           _raw_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 */