Messages in this thread Patch in this message | | | Date | Fri, 27 Nov 2009 15:09:16 +0000 | From | "Jan Beulich" <> | Subject | [PATCH] x86: slightly shorten __ticket_spin_trylock() |
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Since the callers generally expect a boolean value, there's no need to zero-extend the outcome of the comparison. It just requires that all of x86' trylock implementations return bool instead of int.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- arch/x86/include/asm/paravirt.h | 4 ++-- arch/x86/include/asm/paravirt_types.h | 2 +- arch/x86/include/asm/spinlock.h | 17 ++++++++--------- arch/x86/xen/spinlock.c | 2 +- 4 files changed, 12 insertions(+), 13 deletions(-)
--- linux-2.6.32-rc8/arch/x86/include/asm/paravirt.h +++ 2.6.32-rc8-x86-spin-trylock-simplify/arch/x86/include/asm/paravirt.h @@ -753,9 +753,9 @@ static __always_inline void __raw_spin_l PVOP_VCALL2(pv_lock_ops.spin_lock_flags, lock, flags); } -static __always_inline int __raw_spin_trylock(struct raw_spinlock *lock) +static __always_inline bool __raw_spin_trylock(struct raw_spinlock *lock) { - return PVOP_CALL1(int, pv_lock_ops.spin_trylock, lock); + return PVOP_CALL1(bool, pv_lock_ops.spin_trylock, lock); } static __always_inline void __raw_spin_unlock(struct raw_spinlock *lock) --- linux-2.6.32-rc8/arch/x86/include/asm/paravirt_types.h +++ 2.6.32-rc8-x86-spin-trylock-simplify/arch/x86/include/asm/paravirt_types.h @@ -324,7 +324,7 @@ struct pv_lock_ops { int (*spin_is_contended)(struct raw_spinlock *lock); void (*spin_lock)(struct raw_spinlock *lock); void (*spin_lock_flags)(struct raw_spinlock *lock, unsigned long flags); - int (*spin_trylock)(struct raw_spinlock *lock); + bool (*spin_trylock)(struct raw_spinlock *lock); void (*spin_unlock)(struct raw_spinlock *lock); }; --- linux-2.6.32-rc8/arch/x86/include/asm/spinlock.h +++ 2.6.32-rc8-x86-spin-trylock-simplify/arch/x86/include/asm/spinlock.h @@ -77,9 +77,10 @@ static __always_inline void __ticket_spi : "memory", "cc"); } -static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock) +static __always_inline bool __ticket_spin_trylock(raw_spinlock_t *lock) { - int tmp, new; + int tmp; + union { int i; bool b; } new; asm volatile("movzwl %2, %0\n\t" "cmpb %h0,%b0\n\t" @@ -88,12 +89,11 @@ static __always_inline int __ticket_spin LOCK_PREFIX "cmpxchgw %w1,%2\n\t" "1:" "sete %b1\n\t" - "movzbl %b1,%0\n\t" : "=&a" (tmp), "=&q" (new), "+m" (lock->slock) : : "memory", "cc"); - return tmp; + return new.b; } static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock) @@ -127,10 +127,10 @@ static __always_inline void __ticket_spi : "memory", "cc"); } -static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock) +static __always_inline bool __ticket_spin_trylock(raw_spinlock_t *lock) { int tmp; - int new; + union { int i; bool b; } new; asm volatile("movl %2,%0\n\t" "movl %0,%1\n\t" @@ -141,12 +141,11 @@ static __always_inline int __ticket_spin LOCK_PREFIX "cmpxchgl %1,%2\n\t" "1:" "sete %b1\n\t" - "movzbl %b1,%0\n\t" : "=&a" (tmp), "=&q" (new), "+m" (lock->slock) : : "memory", "cc"); - return tmp; + return new.b; } static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock) @@ -190,7 +189,7 @@ static __always_inline void __raw_spin_l __ticket_spin_lock(lock); } -static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock) +static __always_inline bool __raw_spin_trylock(raw_spinlock_t *lock) { return __ticket_spin_trylock(lock); } --- linux-2.6.32-rc8/arch/x86/xen/spinlock.c +++ 2.6.32-rc8-x86-spin-trylock-simplify/arch/x86/xen/spinlock.c @@ -136,7 +136,7 @@ static int xen_spin_is_contended(struct return xl->spinners != 0; } -static int xen_spin_trylock(struct raw_spinlock *lock) +static bool xen_spin_trylock(struct raw_spinlock *lock) { struct xen_spinlock *xl = (struct xen_spinlock *)lock; u8 old = 1;
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