[PATCH] Directed yield: cpu_relax variants for spinlocks and rw-locks

[pandora-kernel.git] / include / asm-parisc / spinlock.h

diff --git a/include/asm-parisc/spinlock.h b/include/asm-parisc/spinlock.h
index 7c3f406..e182553 100644 (file)
--- a/include/asm-parisc/spinlock.h
+++ b/include/asm-parisc/spinlock.h
@@ -11,18 +11,25 @@ static inline int __raw_spin_is_locked(raw_spinlock_t *x)
        return *a == 0;
 }
 
-#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define __raw_spin_lock(lock) __raw_spin_lock_flags(lock, 0)
 #define __raw_spin_unlock_wait(x) \
                do { cpu_relax(); } while (__raw_spin_is_locked(x))
 
-static inline void __raw_spin_lock(raw_spinlock_t *x)
+static inline void __raw_spin_lock_flags(raw_spinlock_t *x,
+                                        unsigned long flags)
 {
        volatile unsigned int *a;
 
        mb();
        a = __ldcw_align(x);
        while (__ldcw(a) == 0)
-               while (*a == 0);
+               while (*a == 0)
+                       if (flags & PSW_SM_I) {
+                               local_irq_enable();
+                               cpu_relax();
+                               local_irq_disable();
+                       } else
+                               cpu_relax();
        mb();
 }
 
@@ -60,26 +67,20 @@ static inline int __raw_spin_trylock(raw_spinlock_t *x)
 
 static  __inline__ void __raw_read_lock(raw_rwlock_t *rw)
 {
-       unsigned long flags;
-       local_irq_save(flags);
        __raw_spin_lock(&rw->lock);
 
        rw->counter++;
 
        __raw_spin_unlock(&rw->lock);
-       local_irq_restore(flags);
 }
 
 static  __inline__ void __raw_read_unlock(raw_rwlock_t *rw)
 {
-       unsigned long flags;
-       local_irq_save(flags);
        __raw_spin_lock(&rw->lock);
 
        rw->counter--;
 
        __raw_spin_unlock(&rw->lock);
-       local_irq_restore(flags);
 }
 
 /* write_lock is less trivial.  We optimistically grab the lock and check
@@ -133,14 +134,26 @@ static  __inline__ int __raw_write_trylock(raw_rwlock_t *rw)
        return 1;
 }
 
-static __inline__ int __raw_is_read_locked(raw_rwlock_t *rw)
+/*
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static __inline__ int __raw_read_can_lock(raw_rwlock_t *rw)
 {
-       return rw->counter > 0;
+       return rw->counter >= 0;
 }
 
-static __inline__ int __raw_is_write_locked(raw_rwlock_t *rw)
+/*
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static __inline__ int __raw_write_can_lock(raw_rwlock_t *rw)
 {
-       return rw->counter < 0;
+       return !rw->counter;
 }
 
+#define _raw_spin_relax(lock)  cpu_relax()
+#define _raw_read_relax(lock)  cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
 #endif /* __ASM_SPINLOCK_H */