1 #ifndef _LINUX_RING_BUFFER_BACKEND_TYPES_H
2 #define _LINUX_RING_BUFFER_BACKEND_TYPES_H
5 * linux/ringbuffer/backend_types.h
7 * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 * Ring buffer backend (types).
11 * Dual LGPL v2.1/GPL v2 license.
14 #include "shm_internal.h"
16 struct lib_ring_buffer_backend_pages
{
17 unsigned long mmap_offset
; /* offset of the subbuffer in mmap */
18 union v_atomic records_commit
; /* current records committed count */
19 union v_atomic records_unread
; /* records to read */
20 unsigned long data_size
; /* Amount of data to read from subbuf */
21 DECLARE_SHMP(char, p
); /* Backing memory map */
24 struct lib_ring_buffer_backend_subbuffer
{
25 /* Identifier for subbuf backend pages. Exchanged atomically. */
26 unsigned long id
; /* backend subbuffer identifier */
30 * Forward declaration of frontend-specific channel and ring_buffer.
33 struct lib_ring_buffer
;
35 struct lib_ring_buffer_backend_pages_shmp
{
36 DECLARE_SHMP(struct lib_ring_buffer_backend_pages
, shmp
);
39 struct lib_ring_buffer_backend
{
40 /* Array of ring_buffer_backend_subbuffer for writer */
41 DECLARE_SHMP(struct lib_ring_buffer_backend_subbuffer
, buf_wsb
);
42 /* ring_buffer_backend_subbuffer for reader */
43 struct lib_ring_buffer_backend_subbuffer buf_rsb
;
45 * Pointer array of backend pages, for whole buffer.
46 * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
48 DECLARE_SHMP(struct lib_ring_buffer_backend_pages_shmp
, array
);
49 DECLARE_SHMP(char, memory_map
); /* memory mapping */
51 DECLARE_SHMP(struct channel
, chan
); /* Associated channel */
52 int cpu
; /* This buffer's cpu. -1 if global. */
53 union v_atomic records_read
; /* Number of records read */
54 unsigned int allocated
:1; /* Bool: is buffer allocated ? */
57 struct lib_ring_buffer_shmp
{
58 DECLARE_SHMP(struct lib_ring_buffer
, shmp
); /* Channel per-cpu buffers */
61 struct channel_backend
{
62 unsigned long buf_size
; /* Size of the buffer */
63 unsigned long subbuf_size
; /* Sub-buffer size */
64 unsigned int subbuf_size_order
; /* Order of sub-buffer size */
65 unsigned int num_subbuf_order
; /*
66 * Order of number of sub-buffers/buffer
69 unsigned int buf_size_order
; /* Order of buffer size */
70 int extra_reader_sb
:1; /* Bool: has extra reader subbuffer */
71 unsigned long num_subbuf
; /* Number of sub-buffers for writer */
72 u64 start_tsc
; /* Channel creation TSC value */
73 void *priv
; /* Client-specific information */
74 const struct lib_ring_buffer_config
*config
; /* Ring buffer configuration */
75 char name
[NAME_MAX
]; /* Channel name */
76 struct lib_ring_buffer_shmp buf
[];
79 #endif /* _LINUX_RING_BUFFER_BACKEND_TYPES_H */