From 560cb12a4080a48b84da8b96878cafbd193c4d64 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 23 Apr 2014 16:12:30 +0200 Subject: [PATCH] locking,arch: Rewrite generic atomic support Rewrite generic atomic support to only require cmpxchg(), generate all other primitives from that. Furthermore reduce the endless repetition for all these primitives to a few CPP macros. This way we get more for less lines. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20140508135852.940119622@infradead.org Cc: Arnd Bergmann Cc: David Howells Cc: Paul E. McKenney Cc: David S. Miller Cc: Linus Torvalds Cc: linux-arch@vger.kernel.org Signed-off-by: Ingo Molnar --- include/asm-generic/atomic.h | 192 ++++++++++++++++----------------- include/asm-generic/atomic64.h | 20 +++- lib/atomic64.c | 83 +++++++------- 3 files changed, 148 insertions(+), 147 deletions(-) diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h index 9c79e7603459..56d4d36e1531 100644 --- a/include/asm-generic/atomic.h +++ b/include/asm-generic/atomic.h @@ -18,14 +18,100 @@ #include #include +/* + * atomic_$op() - $op integer to atomic variable + * @i: integer value to $op + * @v: pointer to the atomic variable + * + * Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use + * smp_mb__{before,after}_atomic(). + */ + +/* + * atomic_$op_return() - $op interer to atomic variable and returns the result + * @i: integer value to $op + * @v: pointer to the atomic variable + * + * Atomically $ops @i to @v. Does imply a full memory barrier. + */ + #ifdef CONFIG_SMP -/* Force people to define core atomics */ -# if !defined(atomic_add_return) || !defined(atomic_sub_return) || \ - !defined(atomic_clear_mask) || !defined(atomic_set_mask) -# error "SMP requires a little arch-specific magic" -# endif + +/* we can build all atomic primitives from cmpxchg */ + +#define ATOMIC_OP(op, c_op) \ +static inline void atomic_##op(int i, atomic_t *v) \ +{ \ + int c, old; \ + \ + c = v->counter; \ + while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ + c = old; \ +} + +#define ATOMIC_OP_RETURN(op, c_op) \ +static inline int atomic_##op##_return(int i, atomic_t *v) \ +{ \ + int c, old; \ + \ + c = v->counter; \ + while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ + c = old; \ + \ + return c c_op i; \ +} + +#else + +#include + +#define ATOMIC_OP(op, c_op) \ +static inline void atomic_##op(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + \ + raw_local_irq_save(flags); \ + v->counter = v->counter c_op i; \ + raw_local_irq_restore(flags); \ +} + +#define ATOMIC_OP_RETURN(op, c_op) \ +static inline int atomic_##op##_return(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + int ret; \ + \ + raw_local_irq_save(flags); \ + ret = (v->counter = v->counter c_op i); \ + raw_local_irq_restore(flags); \ + \ + return ret; \ +} + +#endif /* CONFIG_SMP */ + +#ifndef atomic_add_return +ATOMIC_OP_RETURN(add, +) +#endif + +#ifndef atomic_sub_return +ATOMIC_OP_RETURN(sub, -) +#endif + +#ifndef atomic_clear_mask +ATOMIC_OP(and, &) +#define atomic_clear_mask(i, v) atomic_and(~(i), (v)) #endif +#ifndef atomic_set_mask +#define CONFIG_ARCH_HAS_ATOMIC_OR +ATOMIC_OP(or, |) +#define atomic_set_mask(i, v) atomic_or((i), (v)) +#endif + +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + /* * Atomic operations that C can't guarantee us. Useful for * resource counting etc.. @@ -33,8 +119,6 @@ #define ATOMIC_INIT(i) { (i) } -#ifdef __KERNEL__ - /** * atomic_read - read atomic variable * @v: pointer of type atomic_t @@ -56,52 +140,6 @@ #include -/** - * atomic_add_return - add integer to atomic variable - * @i: integer value to add - * @v: pointer of type atomic_t - * - * Atomically adds @i to @v and returns the result - */ -#ifndef atomic_add_return -static inline int atomic_add_return(int i, atomic_t *v) -{ - unsigned long flags; - int temp; - - raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ - temp = v->counter; - temp += i; - v->counter = temp; - raw_local_irq_restore(flags); - - return temp; -} -#endif - -/** - * atomic_sub_return - subtract integer from atomic variable - * @i: integer value to subtract - * @v: pointer of type atomic_t - * - * Atomically subtracts @i from @v and returns the result - */ -#ifndef atomic_sub_return -static inline int atomic_sub_return(int i, atomic_t *v) -{ - unsigned long flags; - int temp; - - raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ - temp = v->counter; - temp -= i; - v->counter = temp; - raw_local_irq_restore(flags); - - return temp; -} -#endif - static inline int atomic_add_negative(int i, atomic_t *v) { return atomic_add_return(i, v) < 0; @@ -139,49 +177,11 @@ static inline void atomic_dec(atomic_t *v) static inline int __atomic_add_unless(atomic_t *v, int a, int u) { - int c, old; - c = atomic_read(v); - while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) - c = old; - return c; -} - -/** - * atomic_clear_mask - Atomically clear bits in atomic variable - * @mask: Mask of the bits to be cleared - * @v: pointer of type atomic_t - * - * Atomically clears the bits set in @mask from @v - */ -#ifndef atomic_clear_mask -static inline void atomic_clear_mask(unsigned long mask, atomic_t *v) -{ - unsigned long flags; - - mask = ~mask; - raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ - v->counter &= mask; - raw_local_irq_restore(flags); + int c, old; + c = atomic_read(v); + while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) + c = old; + return c; } -#endif - -/** - * atomic_set_mask - Atomically set bits in atomic variable - * @mask: Mask of the bits to be set - * @v: pointer of type atomic_t - * - * Atomically sets the bits set in @mask in @v - */ -#ifndef atomic_set_mask -static inline void atomic_set_mask(unsigned int mask, atomic_t *v) -{ - unsigned long flags; - - raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ - v->counter |= mask; - raw_local_irq_restore(flags); -} -#endif -#endif /* __KERNEL__ */ #endif /* __ASM_GENERIC_ATOMIC_H */ diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h index b18ce4f9ee3d..30ad9c86cebb 100644 --- a/include/asm-generic/atomic64.h +++ b/include/asm-generic/atomic64.h @@ -20,10 +20,22 @@ typedef struct { extern long long atomic64_read(const atomic64_t *v); extern void atomic64_set(atomic64_t *v, long long i); -extern void atomic64_add(long long a, atomic64_t *v); -extern long long atomic64_add_return(long long a, atomic64_t *v); -extern void atomic64_sub(long long a, atomic64_t *v); -extern long long atomic64_sub_return(long long a, atomic64_t *v); + +#define ATOMIC64_OP(op) \ +extern void atomic64_##op(long long a, atomic64_t *v); + +#define ATOMIC64_OP_RETURN(op) \ +extern long long atomic64_##op##_return(long long a, atomic64_t *v); + +#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) + +ATOMIC64_OPS(add) +ATOMIC64_OPS(sub) + +#undef ATOMIC64_OPS +#undef ATOMIC64_OP_RETURN +#undef ATOMIC64_OP + extern long long atomic64_dec_if_positive(atomic64_t *v); extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n); extern long long atomic64_xchg(atomic64_t *v, long long new); diff --git a/lib/atomic64.c b/lib/atomic64.c index 08a4f068e61e..1298c05ef528 100644 --- a/lib/atomic64.c +++ b/lib/atomic64.c @@ -70,53 +70,42 @@ void atomic64_set(atomic64_t *v, long long i) } EXPORT_SYMBOL(atomic64_set); -void atomic64_add(long long a, atomic64_t *v) -{ - unsigned long flags; - raw_spinlock_t *lock = lock_addr(v); - - raw_spin_lock_irqsave(lock, flags); - v->counter += a; - raw_spin_unlock_irqrestore(lock, flags); -} -EXPORT_SYMBOL(atomic64_add); - -long long atomic64_add_return(long long a, atomic64_t *v) -{ - unsigned long flags; - raw_spinlock_t *lock = lock_addr(v); - long long val; - - raw_spin_lock_irqsave(lock, flags); - val = v->counter += a; - raw_spin_unlock_irqrestore(lock, flags); - return val; -} -EXPORT_SYMBOL(atomic64_add_return); - -void atomic64_sub(long long a, atomic64_t *v) -{ - unsigned long flags; - raw_spinlock_t *lock = lock_addr(v); - - raw_spin_lock_irqsave(lock, flags); - v->counter -= a; - raw_spin_unlock_irqrestore(lock, flags); -} -EXPORT_SYMBOL(atomic64_sub); - -long long atomic64_sub_return(long long a, atomic64_t *v) -{ - unsigned long flags; - raw_spinlock_t *lock = lock_addr(v); - long long val; - - raw_spin_lock_irqsave(lock, flags); - val = v->counter -= a; - raw_spin_unlock_irqrestore(lock, flags); - return val; -} -EXPORT_SYMBOL(atomic64_sub_return); +#define ATOMIC64_OP(op, c_op) \ +void atomic64_##op(long long a, atomic64_t *v) \ +{ \ + unsigned long flags; \ + raw_spinlock_t *lock = lock_addr(v); \ + \ + raw_spin_lock_irqsave(lock, flags); \ + v->counter c_op a; \ + raw_spin_unlock_irqrestore(lock, flags); \ +} \ +EXPORT_SYMBOL(atomic64_##op); + +#define ATOMIC64_OP_RETURN(op, c_op) \ +long long atomic64_##op##_return(long long a, atomic64_t *v) \ +{ \ + unsigned long flags; \ + raw_spinlock_t *lock = lock_addr(v); \ + long long val; \ + \ + raw_spin_lock_irqsave(lock, flags); \ + val = (v->counter c_op a); \ + raw_spin_unlock_irqrestore(lock, flags); \ + return val; \ +} \ +EXPORT_SYMBOL(atomic64_##op##_return); + +#define ATOMIC64_OPS(op, c_op) \ + ATOMIC64_OP(op, c_op) \ + ATOMIC64_OP_RETURN(op, c_op) + +ATOMIC64_OPS(add, +=) +ATOMIC64_OPS(sub, -=) + +#undef ATOMIC64_OPS +#undef ATOMIC64_OP_RETURN +#undef ATOMIC64_OP long long atomic64_dec_if_positive(atomic64_t *v) { -- 2.39.5