lib/ringbuffer/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 #include <linux/cpumask.h>
  15 #include <linux/types.h>
  16
  17 struct lib_ring_buffer_backend_page {
  18         void *virt;                     /* page virtual address (cached) */
  19         struct page *page;              /* pointer to page structure */
  20 };
  21
  22 struct lib_ring_buffer_backend_pages {
  23         unsigned long mmap_offset;      /* offset of the subbuffer in mmap */
  24         union v_atomic records_commit;  /* current records committed count */
  25         union v_atomic records_unread;  /* records to read */
  26         unsigned long data_size;        /* Amount of data to read from subbuf */
  27         struct lib_ring_buffer_backend_page p[];
  28 };
  29
  30 struct lib_ring_buffer_backend_subbuffer {
  31         /* Identifier for subbuf backend pages. Exchanged atomically. */
  32         unsigned long id;               /* backend subbuffer identifier */
  33 };
  34
  35 /*
  36  * Forward declaration of frontend-specific channel and ring_buffer.
  37  */
  38 struct channel;
  39 struct lib_ring_buffer;
  40
  41 struct lib_ring_buffer_backend {
  42         /* Array of ring_buffer_backend_subbuffer for writer */
  43         struct lib_ring_buffer_backend_subbuffer *buf_wsb;
  44         /* ring_buffer_backend_subbuffer for reader */
  45         struct lib_ring_buffer_backend_subbuffer buf_rsb;
  46         /*
  47          * Pointer array of backend pages, for whole buffer.
  48          * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
  49          */
  50         struct lib_ring_buffer_backend_pages **array;
  51         unsigned int num_pages_per_subbuf;
  52
  53         struct channel *chan;           /* Associated channel */
  54         int cpu;                        /* This buffer's cpu. -1 if global. */
  55         union v_atomic records_read;    /* Number of records read */
  56         unsigned int allocated:1;       /* is buffer allocated ? */
  57 };
  58
  59 struct channel_backend {
  60         unsigned long buf_size;         /* Size of the buffer */
  61         unsigned long subbuf_size;      /* Sub-buffer size */
  62         unsigned int subbuf_size_order; /* Order of sub-buffer size */
  63         unsigned int num_subbuf_order;  /*
  64                                          * Order of number of sub-buffers/buffer
  65                                          * for writer.
  66                                          */
  67         unsigned int buf_size_order;    /* Order of buffer size */
  68         unsigned int extra_reader_sb:1; /* has extra reader subbuffer ? */
  69         struct lib_ring_buffer *buf;    /* Channel per-cpu buffers */
  70
  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         struct notifier_block cpu_hp_notifier;   /* CPU hotplug notifier */
  75         /*
  76          * We need to copy config because the module containing the
  77          * source config can vanish before the last reference to this
  78          * channel's streams is released.
  79          */
  80         struct lib_ring_buffer_config config; /* Ring buffer configuration */
  81         cpumask_var_t cpumask;          /* Allocated per-cpu buffers cpumask */
  82         char name[NAME_MAX];            /* Channel name */
  83 };
  84
  85 #endif /* _LINUX_RING_BUFFER_BACKEND_TYPES_H */