include/ringbuffer/vfs.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
   2  *
   3  * ringbuffer/vfs.h
   4  *
   5  * Wait-free ring buffer VFS file operations.
   6  *
   7  * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #ifndef _LIB_RING_BUFFER_VFS_H
  11 #define _LIB_RING_BUFFER_VFS_H
  12
  13 #include <linux/fs.h>
  14 #include <linux/poll.h>
  15
  16 /* VFS API */
  17
  18 extern const struct file_operations lib_ring_buffer_file_operations;
  19
  20 /*
  21  * Internal file operations.
  22  */
  23
  24 struct lib_ring_buffer;
  25
  26 int lib_ring_buffer_open(struct inode *inode, struct file *file,
  27                 struct lib_ring_buffer *buf);
  28 int lib_ring_buffer_release(struct inode *inode, struct file *file,
  29                 struct lib_ring_buffer *buf);
  30 unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait,
  31                 struct lib_ring_buffer *buf);
  32 ssize_t lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
  33                 struct pipe_inode_info *pipe, size_t len,
  34                 unsigned int flags, struct lib_ring_buffer *buf);
  35 int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma,
  36                 struct lib_ring_buffer *buf);
  37
  38 /* Ring Buffer ioctl() and ioctl numbers */
  39 long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
  40                 unsigned long arg, struct lib_ring_buffer *buf);
  41 #ifdef CONFIG_COMPAT
  42 long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
  43                 unsigned long arg, struct lib_ring_buffer *buf);
  44 #endif
  45
  46 ssize_t vfs_lib_ring_buffer_file_splice_read(struct file *in, loff_t *ppos,
  47                 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
  48 loff_t vfs_lib_ring_buffer_no_llseek(struct file *file, loff_t offset,
  49                 int origin);
  50 int vfs_lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma);
  51 ssize_t vfs_lib_ring_buffer_splice_read(struct file *in, loff_t *ppos,
  52                 struct pipe_inode_info *pipe, size_t len,
  53                 unsigned int flags);
  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, if non-empty. */
  99 #define RING_BUFFER_FLUSH                       _IO(0xF6, 0x0C)
 100 /* Get the current version of the metadata cache (after a get_next). */
 101 #define RING_BUFFER_GET_METADATA_VERSION        _IOR(0xF6, 0x0D, uint64_t)
 102 /*
 103  * Get a snapshot of the current ring buffer producer and consumer positions,
 104  * regardless of whether or not the two positions are contained within the same
 105  * sub-buffer.
 106  */
 107 #define RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS   _IO(0xF6, 0x0E)
 108 /* Flush the current sub-buffer, even if empty. */
 109 #define RING_BUFFER_FLUSH_EMPTY                 _IO(0xF6, 0x0F)
 110 /*
 111  * Reset the position of what has been consumed from the metadata cache to 0
 112  * so it can be read again.
 113  */
 114 #define RING_BUFFER_METADATA_CACHE_DUMP         _IO(0xF6, 0x10)
 115 /* Clear ring buffer content. */
 116 #define RING_BUFFER_CLEAR                       _IO(0xF6, 0x11)
 117
 118 #ifdef CONFIG_COMPAT
 119 /* Get a snapshot of the current ring buffer producer and consumer positions */
 120 #define RING_BUFFER_COMPAT_SNAPSHOT             RING_BUFFER_SNAPSHOT
 121 /* Get the consumer position (iteration start) */
 122 #define RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED \
 123         _IOR(0xF6, 0x01, compat_ulong_t)
 124 /* Get the producer position (iteration end) */
 125 #define RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED \
 126         _IOR(0xF6, 0x02, compat_ulong_t)
 127 /* Get exclusive read access to the specified sub-buffer position */
 128 #define RING_BUFFER_COMPAT_GET_SUBBUF           _IOW(0xF6, 0x03, compat_ulong_t)
 129 /* Release exclusive sub-buffer access */
 130 #define RING_BUFFER_COMPAT_PUT_SUBBUF           RING_BUFFER_PUT_SUBBUF
 131
 132 /* Get exclusive read access to the next sub-buffer that can be read. */
 133 #define RING_BUFFER_COMPAT_GET_NEXT_SUBBUF      RING_BUFFER_GET_NEXT_SUBBUF
 134 /* Release exclusive sub-buffer access, move consumer forward. */
 135 #define RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF      RING_BUFFER_PUT_NEXT_SUBBUF
 136 /* returns the size of the current sub-buffer, without padding (for mmap). */
 137 #define RING_BUFFER_COMPAT_GET_SUBBUF_SIZE      _IOR(0xF6, 0x07, compat_ulong_t)
 138 /* returns the size of the current sub-buffer, with padding (for splice). */
 139 #define RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE \
 140         _IOR(0xF6, 0x08, compat_ulong_t)
 141 /* returns the maximum size for sub-buffers. */
 142 #define RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE  _IOR(0xF6, 0x09, compat_ulong_t)
 143 /* returns the length to mmap. */
 144 #define RING_BUFFER_COMPAT_GET_MMAP_LEN         _IOR(0xF6, 0x0A, compat_ulong_t)
 145 /* returns the offset of the subbuffer belonging to the mmap reader. */
 146 #define RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, compat_ulong_t)
 147 /* Flush the current sub-buffer, if non-empty. */
 148 #define RING_BUFFER_COMPAT_FLUSH                RING_BUFFER_FLUSH
 149 /* Get the current version of the metadata cache (after a get_next). */
 150 #define RING_BUFFER_COMPAT_GET_METADATA_VERSION RING_BUFFER_GET_METADATA_VERSION
 151 /*
 152  * Get a snapshot of the current ring buffer producer and consumer positions,
 153  * regardless of whether or not the two positions are contained within the same
 154  * sub-buffer.
 155  */
 156 #define RING_BUFFER_COMPAT_SNAPSHOT_SAMPLE_POSITIONS    \
 157         RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS
 158 /* Flush the current sub-buffer, even if empty. */
 159 #define RING_BUFFER_COMPAT_FLUSH_EMPTY                  \
 160         RING_BUFFER_FLUSH_EMPTY
 161 /* Clear ring buffer content. */
 162 #define RING_BUFFER_COMPAT_CLEAR                        \
 163         RING_BUFFER_CLEAR
 164 #endif /* CONFIG_COMPAT */
 165
 166 #endif /* _LIB_RING_BUFFER_VFS_H */