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 struct lib_ring_buffer;
  41
  42 int lib_ring_buffer_open(struct inode *inode, struct file *file,
  43                 struct lib_ring_buffer *buf);
  44 int lib_ring_buffer_release(struct inode *inode, struct file *file,
  45                 struct lib_ring_buffer *buf);
  46 unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait,
  47                 struct lib_ring_buffer *buf);
  48 ssize_t lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
  49                 struct pipe_inode_info *pipe, size_t len,
  50                 unsigned int flags, struct lib_ring_buffer *buf);
  51 int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma,
  52                 struct lib_ring_buffer *buf);
  53
  54 /* Ring Buffer ioctl() and ioctl numbers */
  55 long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
  56                 unsigned long arg, struct lib_ring_buffer *buf);
  57 #ifdef CONFIG_COMPAT
  58 long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
  59                 unsigned long arg, struct lib_ring_buffer *buf);
  60 #endif
  61
  62 ssize_t vfs_lib_ring_buffer_file_splice_read(struct file *in, loff_t *ppos,
  63                 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
  64 loff_t vfs_lib_ring_buffer_no_llseek(struct file *file, loff_t offset,
  65                 int origin);
  66 int vfs_lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma);
  67 ssize_t vfs_lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
  68                 struct pipe_inode_info *pipe, size_t len,
  69                 unsigned int flags);
  70
  71 /*
  72  * Use RING_BUFFER_GET_NEXT_SUBBUF / RING_BUFFER_PUT_NEXT_SUBBUF to read and
  73  * consume sub-buffers sequentially.
  74  *
  75  * Reading sub-buffers without consuming them can be performed with:
  76  *
  77  * RING_BUFFER_SNAPSHOT
  78  * RING_BUFFER_SNAPSHOT_GET_CONSUMED
  79  * RING_BUFFER_SNAPSHOT_GET_PRODUCED
  80  *
  81  * to get the offset range to consume, and then by passing each sub-buffer
  82  * offset to RING_BUFFER_GET_SUBBUF, read the sub-buffer, and then release it
  83  * with RING_BUFFER_PUT_SUBBUF.
  84  *
  85  * Note that the "snapshot" API can be used to read the sub-buffer in reverse
  86  * order, which is useful for flight recorder snapshots.
  87  */
  88
  89 /* Get a snapshot of the current ring buffer producer and consumer positions */
  90 #define RING_BUFFER_SNAPSHOT                    _IO(0xF6, 0x00)
  91 /* Get the consumer position (iteration start) */
  92 #define RING_BUFFER_SNAPSHOT_GET_CONSUMED       _IOR(0xF6, 0x01, unsigned long)
  93 /* Get the producer position (iteration end) */
  94 #define RING_BUFFER_SNAPSHOT_GET_PRODUCED       _IOR(0xF6, 0x02, unsigned long)
  95 /* Get exclusive read access to the specified sub-buffer position */
  96 #define RING_BUFFER_GET_SUBBUF                  _IOW(0xF6, 0x03, unsigned long)
  97 /* Release exclusive sub-buffer access */
  98 #define RING_BUFFER_PUT_SUBBUF                  _IO(0xF6, 0x04)
  99
 100 /* Get exclusive read access to the next sub-buffer that can be read. */
 101 #define RING_BUFFER_GET_NEXT_SUBBUF             _IO(0xF6, 0x05)
 102 /* Release exclusive sub-buffer access, move consumer forward. */
 103 #define RING_BUFFER_PUT_NEXT_SUBBUF             _IO(0xF6, 0x06)
 104 /* returns the size of the current sub-buffer, without padding (for mmap). */
 105 #define RING_BUFFER_GET_SUBBUF_SIZE             _IOR(0xF6, 0x07, unsigned long)
 106 /* returns the size of the current sub-buffer, with padding (for splice). */
 107 #define RING_BUFFER_GET_PADDED_SUBBUF_SIZE      _IOR(0xF6, 0x08, unsigned long)
 108 /* returns the maximum size for sub-buffers. */
 109 #define RING_BUFFER_GET_MAX_SUBBUF_SIZE         _IOR(0xF6, 0x09, unsigned long)
 110 /* returns the length to mmap. */
 111 #define RING_BUFFER_GET_MMAP_LEN                _IOR(0xF6, 0x0A, unsigned long)
 112 /* returns the offset of the subbuffer belonging to the mmap reader. */
 113 #define RING_BUFFER_GET_MMAP_READ_OFFSET        _IOR(0xF6, 0x0B, unsigned long)
 114 /* Flush the current sub-buffer, if non-empty. */
 115 #define RING_BUFFER_FLUSH                       _IO(0xF6, 0x0C)
 116 /* Get the current version of the metadata cache (after a get_next). */
 117 #define RING_BUFFER_GET_METADATA_VERSION        _IOR(0xF6, 0x0D, uint64_t)
 118 /*
 119  * Get a snapshot of the current ring buffer producer and consumer positions,
 120  * regardless of whether or not the two positions are contained within the same
 121  * sub-buffer.
 122  */
 123 #define RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS   _IO(0xF6, 0x0E)
 124 /* Flush the current sub-buffer, even if empty. */
 125 #define RING_BUFFER_FLUSH_EMPTY                 _IO(0xF6, 0x0F)
 126 /*
 127  * Reset the position of what has been consumed from the metadata cache to 0
 128  * so it can be read again.
 129  */
 130 #define RING_BUFFER_METADATA_CACHE_DUMP         _IO(0xF6, 0x10)
 131
 132 #ifdef CONFIG_COMPAT
 133 /* Get a snapshot of the current ring buffer producer and consumer positions */
 134 #define RING_BUFFER_COMPAT_SNAPSHOT             RING_BUFFER_SNAPSHOT
 135 /* Get the consumer position (iteration start) */
 136 #define RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED \
 137         _IOR(0xF6, 0x01, compat_ulong_t)
 138 /* Get the producer position (iteration end) */
 139 #define RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED \
 140         _IOR(0xF6, 0x02, compat_ulong_t)
 141 /* Get exclusive read access to the specified sub-buffer position */
 142 #define RING_BUFFER_COMPAT_GET_SUBBUF           _IOW(0xF6, 0x03, compat_ulong_t)
 143 /* Release exclusive sub-buffer access */
 144 #define RING_BUFFER_COMPAT_PUT_SUBBUF           RING_BUFFER_PUT_SUBBUF
 145
 146 /* Get exclusive read access to the next sub-buffer that can be read. */
 147 #define RING_BUFFER_COMPAT_GET_NEXT_SUBBUF      RING_BUFFER_GET_NEXT_SUBBUF
 148 /* Release exclusive sub-buffer access, move consumer forward. */
 149 #define RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF      RING_BUFFER_PUT_NEXT_SUBBUF
 150 /* returns the size of the current sub-buffer, without padding (for mmap). */
 151 #define RING_BUFFER_COMPAT_GET_SUBBUF_SIZE      _IOR(0xF6, 0x07, compat_ulong_t)
 152 /* returns the size of the current sub-buffer, with padding (for splice). */
 153 #define RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE \
 154         _IOR(0xF6, 0x08, compat_ulong_t)
 155 /* returns the maximum size for sub-buffers. */
 156 #define RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE  _IOR(0xF6, 0x09, compat_ulong_t)
 157 /* returns the length to mmap. */
 158 #define RING_BUFFER_COMPAT_GET_MMAP_LEN         _IOR(0xF6, 0x0A, compat_ulong_t)
 159 /* returns the offset of the subbuffer belonging to the mmap reader. */
 160 #define RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, compat_ulong_t)
 161 /* Flush the current sub-buffer, if non-empty. */
 162 #define RING_BUFFER_COMPAT_FLUSH                RING_BUFFER_FLUSH
 163 /* Get the current version of the metadata cache (after a get_next). */
 164 #define RING_BUFFER_COMPAT_GET_METADATA_VERSION RING_BUFFER_GET_METADATA_VERSION
 165 /*
 166  * Get a snapshot of the current ring buffer producer and consumer positions,
 167  * regardless of whether or not the two positions are contained within the same
 168  * sub-buffer.
 169  */
 170 #define RING_BUFFER_COMPAT_SNAPSHOT_SAMPLE_POSITIONS    \
 171         RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS
 172 /* Flush the current sub-buffer, even if empty. */
 173 #define RING_BUFFER_COMPAT_FLUSH_EMPTY                  \
 174         RING_BUFFER_FLUSH_EMPTY
 175 #endif /* CONFIG_COMPAT */
 176
 177 #endif /* _LIB_RING_BUFFER_VFS_H */