lib/ringbuffer/vfs.h

   1 #ifndef _LIB_RING_BUFFER_VFS_H
   2 #define _LIB_RING_BUFFER_VFS_H
   3
   4 /*
   5  * lib/ringbuffer/vfs.h
   6  *
   7  * Wait-free ring buffer VFS file operations.
   8  *
   9  * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; only
  14  * version 2.1 of the License.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  *
  25  * Author:
  26  *      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  27  */
  28
  29 #include <linux/fs.h>
  30 #include <linux/poll.h>
  31
  32 /* VFS API */
  33
  34 extern const struct file_operations lib_ring_buffer_file_operations;
  35
  36 /*
  37  * Internal file operations.
  38  */
  39
  40 int lib_ring_buffer_open(struct inode *inode, struct file *file);
  41 int lib_ring_buffer_release(struct inode *inode, struct file *file);
  42 unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait);
  43 ssize_t lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
  44                                     struct pipe_inode_info *pipe, size_t len,
  45                                     unsigned int flags);
  46 int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma);
  47
  48 /* Ring Buffer ioctl() and ioctl numbers */
  49 long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
  50 #ifdef CONFIG_COMPAT
  51 long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
  52                                   unsigned long arg);
  53 #endif
  54
  55 /*
  56  * Use RING_BUFFER_GET_NEXT_SUBBUF / RING_BUFFER_PUT_NEXT_SUBBUF to read and
  57  * consume sub-buffers sequentially.
  58  *
  59  * Reading sub-buffers without consuming them can be performed with:
  60  *
  61  * RING_BUFFER_SNAPSHOT
  62  * RING_BUFFER_SNAPSHOT_GET_CONSUMED
  63  * RING_BUFFER_SNAPSHOT_GET_PRODUCED
  64  *
  65  * to get the offset range to consume, and then by passing each sub-buffer
  66  * offset to RING_BUFFER_GET_SUBBUF, read the sub-buffer, and then release it
  67  * with RING_BUFFER_PUT_SUBBUF.
  68  *
  69  * Note that the "snapshot" API can be used to read the sub-buffer in reverse
  70  * order, which is useful for flight recorder snapshots.
  71  */
  72
  73 /* Get a snapshot of the current ring buffer producer and consumer positions */
  74 #define RING_BUFFER_SNAPSHOT                    _IO(0xF6, 0x00)
  75 /* Get the consumer position (iteration start) */
  76 #define RING_BUFFER_SNAPSHOT_GET_CONSUMED       _IOR(0xF6, 0x01, unsigned long)
  77 /* Get the producer position (iteration end) */
  78 #define RING_BUFFER_SNAPSHOT_GET_PRODUCED       _IOR(0xF6, 0x02, unsigned long)
  79 /* Get exclusive read access to the specified sub-buffer position */
  80 #define RING_BUFFER_GET_SUBBUF                  _IOW(0xF6, 0x03, unsigned long)
  81 /* Release exclusive sub-buffer access */
  82 #define RING_BUFFER_PUT_SUBBUF                  _IO(0xF6, 0x04)
  83
  84 /* Get exclusive read access to the next sub-buffer that can be read. */
  85 #define RING_BUFFER_GET_NEXT_SUBBUF             _IO(0xF6, 0x05)
  86 /* Release exclusive sub-buffer access, move consumer forward. */
  87 #define RING_BUFFER_PUT_NEXT_SUBBUF             _IO(0xF6, 0x06)
  88 /* returns the size of the current sub-buffer, without padding (for mmap). */
  89 #define RING_BUFFER_GET_SUBBUF_SIZE             _IOR(0xF6, 0x07, unsigned long)
  90 /* returns the size of the current sub-buffer, with padding (for splice). */
  91 #define RING_BUFFER_GET_PADDED_SUBBUF_SIZE      _IOR(0xF6, 0x08, unsigned long)
  92 /* returns the maximum size for sub-buffers. */
  93 #define RING_BUFFER_GET_MAX_SUBBUF_SIZE         _IOR(0xF6, 0x09, unsigned long)
  94 /* returns the length to mmap. */
  95 #define RING_BUFFER_GET_MMAP_LEN                _IOR(0xF6, 0x0A, unsigned long)
  96 /* returns the offset of the subbuffer belonging to the mmap reader. */
  97 #define RING_BUFFER_GET_MMAP_READ_OFFSET        _IOR(0xF6, 0x0B, unsigned long)
  98 /* flush the current sub-buffer */
  99 #define RING_BUFFER_FLUSH                       _IO(0xF6, 0x0C)
 100
 101 #ifdef CONFIG_COMPAT
 102 /* Get a snapshot of the current ring buffer producer and consumer positions */
 103 #define RING_BUFFER_COMPAT_SNAPSHOT             RING_BUFFER_SNAPSHOT
 104 /* Get the consumer position (iteration start) */
 105 #define RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED \
 106         _IOR(0xF6, 0x01, compat_ulong_t)
 107 /* Get the producer position (iteration end) */
 108 #define RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED \
 109         _IOR(0xF6, 0x02, compat_ulong_t)
 110 /* Get exclusive read access to the specified sub-buffer position */
 111 #define RING_BUFFER_COMPAT_GET_SUBBUF           _IOW(0xF6, 0x03, compat_ulong_t)
 112 /* Release exclusive sub-buffer access */
 113 #define RING_BUFFER_COMPAT_PUT_SUBBUF           RING_BUFFER_PUT_SUBBUF
 114
 115 /* Get exclusive read access to the next sub-buffer that can be read. */
 116 #define RING_BUFFER_COMPAT_GET_NEXT_SUBBUF      RING_BUFFER_GET_NEXT_SUBBUF
 117 /* Release exclusive sub-buffer access, move consumer forward. */
 118 #define RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF      RING_BUFFER_PUT_NEXT_SUBBUF
 119 /* returns the size of the current sub-buffer, without padding (for mmap). */
 120 #define RING_BUFFER_COMPAT_GET_SUBBUF_SIZE      _IOR(0xF6, 0x07, compat_ulong_t)
 121 /* returns the size of the current sub-buffer, with padding (for splice). */
 122 #define RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE \
 123         _IOR(0xF6, 0x08, compat_ulong_t)
 124 /* returns the maximum size for sub-buffers. */
 125 #define RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE  _IOR(0xF6, 0x09, compat_ulong_t)
 126 /* returns the length to mmap. */
 127 #define RING_BUFFER_COMPAT_GET_MMAP_LEN         _IOR(0xF6, 0x0A, compat_ulong_t)
 128 /* returns the offset of the subbuffer belonging to the mmap reader. */
 129 #define RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, compat_ulong_t)
 130 /* flush the current sub-buffer */
 131 #define RING_BUFFER_COMPAT_FLUSH                RING_BUFFER_FLUSH
 132 #endif /* CONFIG_COMPAT */
 133
 134 #endif /* _LIB_RING_BUFFER_VFS_H */