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1 | /* SPDX-License-Identifier: GPL-2.0 */ | |
2 | #ifndef _ASM_GENERIC_LOCAL_H | |
3 | #define _ASM_GENERIC_LOCAL_H | |
4 | ||
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 is | |
14 | * rather pointless. The whole point behind local_t is that some processors | |
15 | * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs | |
16 | * 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. */ | |
22 | typedef struct | |
23 | { | |
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_xchg(l, n) atomic_long_xchg((&(l)->a), (n)) | |
46 | #define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u)) | |
47 | #define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a) | |
48 | ||
49 | /* Non-atomic variants, ie. preemption disabled and won't be touched | |
50 | * in interrupt, etc. Some archs can optimize this case well. */ | |
51 | #define __local_inc(l) local_set((l), local_read(l) + 1) | |
52 | #define __local_dec(l) local_set((l), local_read(l) - 1) | |
53 | #define __local_add(i,l) local_set((l), local_read(l) + (i)) | |
54 | #define __local_sub(i,l) local_set((l), local_read(l) - (i)) | |
55 | ||
56 | #endif /* _ASM_GENERIC_LOCAL_H */ |