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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __TOOLS_ASM_GENERIC_ATOMIC_H3#define __TOOLS_ASM_GENERIC_ATOMIC_H4 5#include <linux/compiler.h>6#include <linux/types.h>7#include <linux/bitops.h>8 9/*10 * Atomic operations that C can't guarantee us. Useful for11 * resource counting etc..12 *13 * Excerpts obtained from the Linux kernel sources.14 */15 16#define ATOMIC_INIT(i) { (i) }17 18/**19 * atomic_read - read atomic variable20 * @v: pointer of type atomic_t21 *22 * Atomically reads the value of @v.23 */24static inline int atomic_read(const atomic_t *v)25{26 return READ_ONCE((v)->counter);27}28 29/**30 * atomic_set - set atomic variable31 * @v: pointer of type atomic_t32 * @i: required value33 *34 * Atomically sets the value of @v to @i.35 */36static inline void atomic_set(atomic_t *v, int i)37{38 v->counter = i;39}40 41/**42 * atomic_inc - increment atomic variable43 * @v: pointer of type atomic_t44 *45 * Atomically increments @v by 1.46 */47static inline void atomic_inc(atomic_t *v)48{49 __sync_add_and_fetch(&v->counter, 1);50}51 52/**53 * atomic_dec_and_test - decrement and test54 * @v: pointer of type atomic_t55 *56 * Atomically decrements @v by 1 and57 * returns true if the result is 0, or false for all other58 * cases.59 */60static inline int atomic_dec_and_test(atomic_t *v)61{62 return __sync_sub_and_fetch(&v->counter, 1) == 0;63}64 65#define cmpxchg(ptr, oldval, newval) \66 __sync_val_compare_and_swap(ptr, oldval, newval)67 68static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval)69{70 return cmpxchg(&(v)->counter, oldval, newval);71}72 73static inline int test_and_set_bit(long nr, unsigned long *addr)74{75 unsigned long mask = BIT_MASK(nr);76 long old;77 78 addr += BIT_WORD(nr);79 80 old = __sync_fetch_and_or(addr, mask);81 return !!(old & mask);82}83 84static inline int test_and_clear_bit(long nr, unsigned long *addr)85{86 unsigned long mask = BIT_MASK(nr);87 long old;88 89 addr += BIT_WORD(nr);90 91 old = __sync_fetch_and_and(addr, ~mask);92 return !!(old & mask);93}94 95#endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */96