libringbuffer/backend_types.h

   1 #ifndef _LINUX_RING_BUFFER_BACKEND_TYPES_H
   2 #define _LINUX_RING_BUFFER_BACKEND_TYPES_H
   3
   4 /*
   5  * linux/ringbuffer/backend_types.h
   6  *
   7  * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Ring buffer backend (types).
  10  *
  11  * Dual LGPL v2.1/GPL v2 license.
  12  */
  13
  14 struct lib_ring_buffer_backend_page {
  15         void *virt;                     /* page virtual address (cached) */
  16         struct page *page;              /* pointer to page structure */
  17 };
  18
  19 struct lib_ring_buffer_backend_pages {
  20         unsigned long mmap_offset;      /* offset of the subbuffer in mmap */
  21         union v_atomic records_commit;  /* current records committed count */
  22         union v_atomic records_unread;  /* records to read */
  23         unsigned long data_size;        /* Amount of data to read from subbuf */
  24         struct lib_ring_buffer_backend_page p[];
  25 };
  26
  27 struct lib_ring_buffer_backend_subbuffer {
  28         /* Identifier for subbuf backend pages. Exchanged atomically. */
  29         unsigned long id;               /* backend subbuffer identifier */
  30 };
  31
  32 /*
  33  * Forward declaration of frontend-specific channel and ring_buffer.
  34  */
  35 struct channel;
  36 struct lib_ring_buffer;
  37
  38 struct lib_ring_buffer_backend {
  39         /* Array of ring_buffer_backend_subbuffer for writer */
  40         struct lib_ring_buffer_backend_subbuffer *buf_wsb;
  41         /* ring_buffer_backend_subbuffer for reader */
  42         struct lib_ring_buffer_backend_subbuffer buf_rsb;
  43         /*
  44          * Pointer array of backend pages, for whole buffer.
  45          * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
  46          */
  47         struct lib_ring_buffer_backend_pages **array;
  48         unsigned int num_pages_per_subbuf;
  49
  50         struct channel *chan;           /* Associated channel */
  51         int cpu;                        /* This buffer's cpu. -1 if global. */
  52         union v_atomic records_read;    /* Number of records read */
  53         unsigned int allocated:1;       /* Bool: is buffer allocated ? */
  54 };
  55
  56 struct channel_backend {
  57         unsigned long buf_size;         /* Size of the buffer */
  58         unsigned long subbuf_size;      /* Sub-buffer size */
  59         unsigned int subbuf_size_order; /* Order of sub-buffer size */
  60         unsigned int num_subbuf_order;  /*
  61                                          * Order of number of sub-buffers/buffer
  62                                          * for writer.
  63                                          */
  64         unsigned int buf_size_order;    /* Order of buffer size */
  65         int extra_reader_sb:1;          /* Bool: has extra reader subbuffer */
  66         struct lib_ring_buffer *buf;    /* Channel per-cpu buffers */
  67
  68         unsigned long num_subbuf;       /* Number of sub-buffers for writer */
  69         u64 start_tsc;                  /* Channel creation TSC value */
  70         void *priv;                     /* Client-specific information */
  71         const struct lib_ring_buffer_config *config; /* Ring buffer configuration */
  72         char name[NAME_MAX];            /* Channel name */
  73 };
  74
  75 #endif /* _LINUX_RING_BUFFER_BACKEND_TYPES_H */