Commit | Line | Data |
---|---|---|
b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
9f36eaed | 2 | * |
24591303 | 3 | * ringbuffer/vatomic.h |
f3bc08c5 | 4 | * |
886d51a3 | 5 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 MD |
6 | */ |
7 | ||
9f36eaed MJ |
8 | #ifndef _LIB_RING_BUFFER_VATOMIC_H |
9 | #define _LIB_RING_BUFFER_VATOMIC_H | |
10 | ||
f3bc08c5 MD |
11 | #include <asm/atomic.h> |
12 | #include <asm/local.h> | |
13 | ||
14 | /* | |
15 | * Same data type (long) accessed differently depending on configuration. | |
16 | * v field is for non-atomic access (protected by mutual exclusion). | |
17 | * In the fast-path, the ring_buffer_config structure is constant, so the | |
18 | * compiler can statically select the appropriate branch. | |
19 | * local_t is used for per-cpu and per-thread buffers. | |
20 | * atomic_long_t is used for globally shared buffers. | |
21 | */ | |
22 | union v_atomic { | |
23 | local_t l; | |
24 | atomic_long_t a; | |
25 | long v; | |
26 | }; | |
27 | ||
28 | static inline | |
e20c0fec | 29 | long v_read(const struct lttng_kernel_ring_buffer_config *config, union v_atomic *v_a) |
f3bc08c5 MD |
30 | { |
31 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
32 | return local_read(&v_a->l); | |
33 | else | |
34 | return atomic_long_read(&v_a->a); | |
35 | } | |
36 | ||
37 | static inline | |
e20c0fec | 38 | void v_set(const struct lttng_kernel_ring_buffer_config *config, union v_atomic *v_a, |
f3bc08c5 MD |
39 | long v) |
40 | { | |
41 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
42 | local_set(&v_a->l, v); | |
43 | else | |
44 | atomic_long_set(&v_a->a, v); | |
45 | } | |
46 | ||
47 | static inline | |
e20c0fec | 48 | void v_add(const struct lttng_kernel_ring_buffer_config *config, long v, union v_atomic *v_a) |
f3bc08c5 MD |
49 | { |
50 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
51 | local_add(v, &v_a->l); | |
52 | else | |
53 | atomic_long_add(v, &v_a->a); | |
54 | } | |
55 | ||
56 | static inline | |
e20c0fec | 57 | void v_inc(const struct lttng_kernel_ring_buffer_config *config, union v_atomic *v_a) |
f3bc08c5 MD |
58 | { |
59 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
60 | local_inc(&v_a->l); | |
61 | else | |
62 | atomic_long_inc(&v_a->a); | |
63 | } | |
64 | ||
65 | /* | |
66 | * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer. | |
67 | */ | |
68 | static inline | |
e20c0fec | 69 | void _v_dec(const struct lttng_kernel_ring_buffer_config *config, union v_atomic *v_a) |
f3bc08c5 MD |
70 | { |
71 | --v_a->v; | |
72 | } | |
73 | ||
74 | static inline | |
e20c0fec | 75 | long v_cmpxchg(const struct lttng_kernel_ring_buffer_config *config, union v_atomic *v_a, |
f3bc08c5 MD |
76 | long old, long _new) |
77 | { | |
78 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
79 | return local_cmpxchg(&v_a->l, old, _new); | |
80 | else | |
81 | return atomic_long_cmpxchg(&v_a->a, old, _new); | |
82 | } | |
83 | ||
886d51a3 | 84 | #endif /* _LIB_RING_BUFFER_VATOMIC_H */ |