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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _ASM_GENERIC_LOCAL_H3#define _ASM_GENERIC_LOCAL_H4 5#include <linux/percpu.h>6#include <linux/atomic.h>7#include <asm/types.h>8 9/*10 * A signed long type for operations which are atomic for a single CPU.11 * Usually used in combination with per-cpu variables.12 *13 * This is the default implementation, which uses atomic_long_t. Which is14 * rather pointless. The whole point behind local_t is that some processors15 * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs16 * running on this CPU. local_t allows exploitation of such capabilities.17 */18 19/* Implement in terms of atomics. */20 21/* Don't use typedef: don't want them to be mixed with atomic_t's. */22typedef struct23{24 atomic_long_t a;25} local_t;26 27#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }28 29#define local_read(l) atomic_long_read(&(l)->a)30#define local_set(l,i) atomic_long_set((&(l)->a),(i))31#define local_inc(l) atomic_long_inc(&(l)->a)32#define local_dec(l) atomic_long_dec(&(l)->a)33#define local_add(i,l) atomic_long_add((i),(&(l)->a))34#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))35 36#define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a))37#define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a)38#define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a)39#define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a))40#define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a))41#define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a))42#define local_inc_return(l) atomic_long_inc_return(&(l)->a)43 44#define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n))45#define local_try_cmpxchg(l, po, n) atomic_long_try_cmpxchg((&(l)->a), (po), (n))46#define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n))47#define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u))48#define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a)49 50/* Non-atomic variants, ie. preemption disabled and won't be touched51 * in interrupt, etc. Some archs can optimize this case well. */52#define __local_inc(l) local_set((l), local_read(l) + 1)53#define __local_dec(l) local_set((l), local_read(l) - 1)54#define __local_add(i,l) local_set((l), local_read(l) + (i))55#define __local_sub(i,l) local_set((l), local_read(l) - (i))56 57#endif /* _ASM_GENERIC_LOCAL_H */58