vserver 1.9.5.x5

[linux-2.6.git] / include / asm-i386 / spinlock.h

diff --git a/include/asm-i386/spinlock.h b/include/asm-i386/spinlock.h
index 89ad2d7..f9ff31f 100644 (file)
--- a/include/asm-i386/spinlock.h
+++ b/include/asm-i386/spinlock.h
@@ -15,10 +15,13 @@ asmlinkage int printk(const char * fmt, ...)
  */
 
 typedef struct {
-       volatile unsigned int lock;
+       volatile unsigned int slock;
 #ifdef CONFIG_DEBUG_SPINLOCK
        unsigned magic;
 #endif
+#ifdef CONFIG_PREEMPT
+       unsigned int break_lock;
+#endif
 } spinlock_t;
 
 #define SPINLOCK_MAGIC 0xdead4ead
@@ -40,7 +43,7 @@ typedef struct {
  * We make no fairness assumptions. They have a cost.
  */
 
-#define spin_is_locked(x)      (*(volatile signed char *)(&(x)->lock) <= 0)
+#define spin_is_locked(x)      (*(volatile signed char *)(&(x)->slock) <= 0)
 #define spin_unlock_wait(x)    do { barrier(); } while(spin_is_locked(x))
 
 #define spin_lock_string \
@@ -75,12 +78,12 @@ typedef struct {
  * (except on PPro SMP or if we are using OOSTORE)
  * (PPro errata 66, 92)
  */
- 
+
 #if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE)
 
 #define spin_unlock_string \
        "movb $1,%0" \
-               :"=m" (lock->lock) : : "memory"
+               :"=m" (lock->slock) : : "memory"
 
 
 static inline void _raw_spin_unlock(spinlock_t *lock)
@@ -98,7 +101,7 @@ static inline void _raw_spin_unlock(spinlock_t *lock)
 
 #define spin_unlock_string \
        "xchgb %b0, %1" \
-               :"=q" (oldval), "=m" (lock->lock) \
+               :"=q" (oldval), "=m" (lock->slock) \
                :"0" (oldval) : "memory"
 
 static inline void _raw_spin_unlock(spinlock_t *lock)
@@ -120,7 +123,7 @@ static inline int _raw_spin_trylock(spinlock_t *lock)
        char oldval;
        __asm__ __volatile__(
                "xchgb %b0,%1"
-               :"=q" (oldval), "=m" (lock->lock)
+               :"=q" (oldval), "=m" (lock->slock)
                :"0" (0) : "memory");
        return oldval > 0;
 }
@@ -135,7 +138,7 @@ static inline void _raw_spin_lock(spinlock_t *lock)
 #endif
        __asm__ __volatile__(
                spin_lock_string
-               :"=m" (lock->lock) : : "memory");
+               :"=m" (lock->slock) : : "memory");
 }
 
 static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
@@ -148,7 +151,7 @@ static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
 #endif
        __asm__ __volatile__(
                spin_lock_string_flags
-               :"=m" (lock->lock) : "r" (flags) : "memory");
+               :"=m" (lock->slock) : "r" (flags) : "memory");
 }
 
 /*
@@ -166,6 +169,9 @@ typedef struct {
 #ifdef CONFIG_DEBUG_SPINLOCK
        unsigned magic;
 #endif
+#ifdef CONFIG_PREEMPT
+       unsigned int break_lock;
+#endif
 } rwlock_t;
 
 #define RWLOCK_MAGIC   0xdeaf1eed
@@ -180,7 +186,17 @@ typedef struct {
 
 #define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
 
-#define rwlock_is_locked(x) ((x)->lock != RW_LOCK_BIAS)
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define read_can_lock(x) ((int)(x)->lock > 0)
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
 
 /*
  * On x86, we implement read-write locks as a 32-bit counter
@@ -212,6 +228,16 @@ static inline void _raw_write_lock(rwlock_t *rw)
 #define _raw_read_unlock(rw)           asm volatile("lock ; incl %0" :"=m" ((rw)->lock) : : "memory")
 #define _raw_write_unlock(rw)  asm volatile("lock ; addl $" RW_LOCK_BIAS_STR ",%0":"=m" ((rw)->lock) : : "memory")
 
+static inline int _raw_read_trylock(rwlock_t *lock)
+{
+       atomic_t *count = (atomic_t *)lock;
+       atomic_dec(count);
+       if (atomic_read(count) >= 0)
+               return 1;
+       atomic_inc(count);
+       return 0;
+}
+
 static inline int _raw_write_trylock(rwlock_t *lock)
 {
        atomic_t *count = (atomic_t *)lock;