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1 | #ifndef _LIB_RING_BUFFER_VATOMIC_H |
2 | #define _LIB_RING_BUFFER_VATOMIC_H | |
f3bc08c5 MD |
3 | |
4 | /* | |
886d51a3 | 5 | * lib/ringbuffer/vatomic.h |
f3bc08c5 | 6 | * |
886d51a3 | 7 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 | 8 | * |
886d51a3 MD |
9 | * This library is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; only | |
12 | * version 2.1 of the License. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
f3bc08c5 MD |
22 | */ |
23 | ||
24 | #include <asm/atomic.h> | |
25 | #include <asm/local.h> | |
26 | ||
27 | /* | |
28 | * Same data type (long) accessed differently depending on configuration. | |
29 | * v field is for non-atomic access (protected by mutual exclusion). | |
30 | * In the fast-path, the ring_buffer_config structure is constant, so the | |
31 | * compiler can statically select the appropriate branch. | |
32 | * local_t is used for per-cpu and per-thread buffers. | |
33 | * atomic_long_t is used for globally shared buffers. | |
34 | */ | |
35 | union v_atomic { | |
36 | local_t l; | |
37 | atomic_long_t a; | |
38 | long v; | |
39 | }; | |
40 | ||
41 | static inline | |
42 | long v_read(const struct lib_ring_buffer_config *config, union v_atomic *v_a) | |
43 | { | |
44 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
45 | return local_read(&v_a->l); | |
46 | else | |
47 | return atomic_long_read(&v_a->a); | |
48 | } | |
49 | ||
50 | static inline | |
51 | void v_set(const struct lib_ring_buffer_config *config, union v_atomic *v_a, | |
52 | long v) | |
53 | { | |
54 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
55 | local_set(&v_a->l, v); | |
56 | else | |
57 | atomic_long_set(&v_a->a, v); | |
58 | } | |
59 | ||
60 | static inline | |
61 | void v_add(const struct lib_ring_buffer_config *config, long v, union v_atomic *v_a) | |
62 | { | |
63 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
64 | local_add(v, &v_a->l); | |
65 | else | |
66 | atomic_long_add(v, &v_a->a); | |
67 | } | |
68 | ||
69 | static inline | |
70 | void v_inc(const struct lib_ring_buffer_config *config, union v_atomic *v_a) | |
71 | { | |
72 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
73 | local_inc(&v_a->l); | |
74 | else | |
75 | atomic_long_inc(&v_a->a); | |
76 | } | |
77 | ||
78 | /* | |
79 | * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer. | |
80 | */ | |
81 | static inline | |
82 | void _v_dec(const struct lib_ring_buffer_config *config, union v_atomic *v_a) | |
83 | { | |
84 | --v_a->v; | |
85 | } | |
86 | ||
87 | static inline | |
88 | long v_cmpxchg(const struct lib_ring_buffer_config *config, union v_atomic *v_a, | |
89 | long old, long _new) | |
90 | { | |
91 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
92 | return local_cmpxchg(&v_a->l, old, _new); | |
93 | else | |
94 | return atomic_long_cmpxchg(&v_a->a, old, _new); | |
95 | } | |
96 | ||
886d51a3 | 97 | #endif /* _LIB_RING_BUFFER_VATOMIC_H */ |