1 #ifndef _LINUX_RING_BUFFER_VATOMIC_H
2 #define _LINUX_RING_BUFFER_VATOMIC_H
5 * linux/ringbuffer/vatomic.h
7 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 * Dual LGPL v2.1/GPL v2 license.
12 #include <asm/atomic.h>
13 #include <asm/local.h>
16 * Same data type (long) accessed differently depending on configuration.
17 * v field is for non-atomic access (protected by mutual exclusion).
18 * In the fast-path, the ring_buffer_config structure is constant, so the
19 * compiler can statically select the appropriate branch.
20 * local_t is used for per-cpu and per-thread buffers.
21 * atomic_long_t is used for globally shared buffers.
30 long v_read(const struct lib_ring_buffer_config
*config
, union v_atomic
*v_a
)
32 if (config
->sync
== RING_BUFFER_SYNC_PER_CPU
)
33 return local_read(&v_a
->l
);
35 return atomic_long_read(&v_a
->a
);
39 void v_set(const struct lib_ring_buffer_config
*config
, union v_atomic
*v_a
,
42 if (config
->sync
== RING_BUFFER_SYNC_PER_CPU
)
43 local_set(&v_a
->l
, v
);
45 atomic_long_set(&v_a
->a
, v
);
49 void v_add(const struct lib_ring_buffer_config
*config
, long v
, union v_atomic
*v_a
)
51 if (config
->sync
== RING_BUFFER_SYNC_PER_CPU
)
52 local_add(v
, &v_a
->l
);
54 atomic_long_add(v
, &v_a
->a
);
58 void v_inc(const struct lib_ring_buffer_config
*config
, union v_atomic
*v_a
)
60 if (config
->sync
== RING_BUFFER_SYNC_PER_CPU
)
63 atomic_long_inc(&v_a
->a
);
67 * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer.
70 void _v_dec(const struct lib_ring_buffer_config
*config
, union v_atomic
*v_a
)
76 long v_cmpxchg(const struct lib_ring_buffer_config
*config
, union v_atomic
*v_a
,
79 if (config
->sync
== RING_BUFFER_SYNC_PER_CPU
)
80 return local_cmpxchg(&v_a
->l
, old
, _new
);
82 return atomic_long_cmpxchg(&v_a
->a
, old
, _new
);
85 #endif /* _LINUX_RING_BUFFER_VATOMIC_H */
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