Merge branches 'x86/asm', 'x86/cleanups', 'x86/cpudetect', 'x86/debug', 'x86/doc...

[cascardo/linux.git] / arch / x86 / include / asm / spinlock.h

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index d17c919..139b424 100644 (file)
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -172,70 +172,8 @@ static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
        return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1;
 }
 
-#ifdef CONFIG_PARAVIRT
-/*
- * Define virtualization-friendly old-style lock byte lock, for use in
- * pv_lock_ops if desired.
- *
- * This differs from the pre-2.6.24 spinlock by always using xchgb
- * rather than decb to take the lock; this allows it to use a
- * zero-initialized lock structure.  It also maintains a 1-byte
- * contention counter, so that we can implement
- * __byte_spin_is_contended.
- */
-struct __byte_spinlock {
-       s8 lock;
-       s8 spinners;
-};
-
-static inline int __byte_spin_is_locked(raw_spinlock_t *lock)
-{
-       struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
-       return bl->lock != 0;
-}
-
-static inline int __byte_spin_is_contended(raw_spinlock_t *lock)
-{
-       struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
-       return bl->spinners != 0;
-}
-
-static inline void __byte_spin_lock(raw_spinlock_t *lock)
-{
-       struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
-       s8 val = 1;
-
-       asm("1: xchgb %1, %0\n"
-           "   test %1,%1\n"
-           "   jz 3f\n"
-           "   " LOCK_PREFIX "incb %2\n"
-           "2: rep;nop\n"
-           "   cmpb $1, %0\n"
-           "   je 2b\n"
-           "   " LOCK_PREFIX "decb %2\n"
-           "   jmp 1b\n"
-           "3:"
-           : "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory");
-}
-
-static inline int __byte_spin_trylock(raw_spinlock_t *lock)
-{
-       struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
-       u8 old = 1;
-
-       asm("xchgb %1,%0"
-           : "+m" (bl->lock), "+q" (old) : : "memory");
+#ifndef CONFIG_PARAVIRT
 
-       return old == 0;
-}
-
-static inline void __byte_spin_unlock(raw_spinlock_t *lock)
-{
-       struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
-       smp_wmb();
-       bl->lock = 0;
-}
-#else  /* !CONFIG_PARAVIRT */
 static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
 {
        return __ticket_spin_is_locked(lock);
@@ -267,7 +205,7 @@ static __always_inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
        __raw_spin_lock(lock);
 }
 
-#endif /* CONFIG_PARAVIRT */
+#endif
 
 static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
 {
@@ -329,8 +267,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *lock)
 {
        atomic_t *count = (atomic_t *)lock;
 
-       atomic_dec(count);
-       if (atomic_read(count) >= 0)
+       if (atomic_dec_return(count) >= 0)
                return 1;
        atomic_inc(count);
        return 0;