From 2ff810a7ef38b55ba6c7b80bb7ff22847fd3be69 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 14 Aug 2014 13:27:30 -0400 Subject: [PATCH] locking/rwlock, x86: Clean up asm/spinlock*.h to remove old rwlock code As the x86 architecture now uses qrwlock for its read/write lock implementation, it is no longer necessary to keep the old rwlock code around. This patch removes the old rwlock code in the asm/spinlock.h and asm/spinlock_types.h files. Now the ARCH_USE_QUEUE_RWLOCK config parameter cannot be removed from x86/Kconfig or there will be a compilation error. Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Cc: Scott J Norton Cc: Dave Jones Cc: Linus Torvalds Cc: Waiman Long Link: http://lkml.kernel.org/r/1408037251-45918-2-git-send-email-Waiman.Long@hp.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/spinlock.h | 81 +-------------------------- arch/x86/include/asm/spinlock_types.h | 4 -- 2 files changed, 2 insertions(+), 83 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 54f1c8068c02..9295016485c9 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -187,7 +187,6 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) cpu_relax(); } -#ifndef CONFIG_QUEUE_RWLOCK /* * Read-write spinlocks, allowing multiple readers * but only one writer. @@ -198,91 +197,15 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) * irq-safe write-lock, but readers can get non-irqsafe * read-locks. * - * On x86, we implement read-write locks as a 32-bit counter - * with the high bit (sign) being the "contended" bit. + * On x86, we implement read-write locks using the generic qrwlock with + * x86 specific optimization. */ -/** - * read_can_lock - would read_trylock() succeed? - * @lock: the rwlock in question. - */ -static inline int arch_read_can_lock(arch_rwlock_t *lock) -{ - return lock->lock > 0; -} - -/** - * write_can_lock - would write_trylock() succeed? - * @lock: the rwlock in question. - */ -static inline int arch_write_can_lock(arch_rwlock_t *lock) -{ - return lock->write == WRITE_LOCK_CMP; -} - -static inline void arch_read_lock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX READ_LOCK_SIZE(dec) " (%0)\n\t" - "jns 1f\n" - "call __read_lock_failed\n\t" - "1:\n" - ::LOCK_PTR_REG (rw) : "memory"); -} - -static inline void arch_write_lock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX WRITE_LOCK_SUB(%1) "(%0)\n\t" - "jz 1f\n" - "call __write_lock_failed\n\t" - "1:\n" - ::LOCK_PTR_REG (&rw->write), "i" (RW_LOCK_BIAS) - : "memory"); -} - -static inline int arch_read_trylock(arch_rwlock_t *lock) -{ - READ_LOCK_ATOMIC(t) *count = (READ_LOCK_ATOMIC(t) *)lock; - - if (READ_LOCK_ATOMIC(dec_return)(count) >= 0) - return 1; - READ_LOCK_ATOMIC(inc)(count); - return 0; -} - -static inline int arch_write_trylock(arch_rwlock_t *lock) -{ - atomic_t *count = (atomic_t *)&lock->write; - - if (atomic_sub_and_test(WRITE_LOCK_CMP, count)) - return 1; - atomic_add(WRITE_LOCK_CMP, count); - return 0; -} - -static inline void arch_read_unlock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX READ_LOCK_SIZE(inc) " %0" - :"+m" (rw->lock) : : "memory"); -} - -static inline void arch_write_unlock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX WRITE_LOCK_ADD(%1) "%0" - : "+m" (rw->write) : "i" (RW_LOCK_BIAS) : "memory"); -} -#else #include -#endif /* CONFIG_QUEUE_RWLOCK */ #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) -#undef READ_LOCK_SIZE -#undef READ_LOCK_ATOMIC -#undef WRITE_LOCK_ADD -#undef WRITE_LOCK_SUB -#undef WRITE_LOCK_CMP - #define arch_spin_relax(lock) cpu_relax() #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index 73c4c007200f..5f9d7572d82b 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -34,10 +34,6 @@ typedef struct arch_spinlock { #define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } -#ifdef CONFIG_QUEUE_RWLOCK #include -#else -#include -#endif #endif /* _ASM_X86_SPINLOCK_TYPES_H */ -- 2.39.5