1 #ifndef _LINUX_RING_BUFFER_VFS_H
2 #define _LINUX_RING_BUFFER_VFS_H
5 * linux/ringbuffer/vfs.h
7 * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 * Wait-free ring buffer VFS file operations.
12 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
14 * Dual LGPL v2.1/GPL v2 license.
18 #include <linux/poll.h>
22 extern const struct file_operations lib_ring_buffer_file_operations
;
25 * Internal file operations.
28 int lib_ring_buffer_open(struct inode
*inode
, struct file
*file
);
29 int lib_ring_buffer_release(struct inode
*inode
, struct file
*file
);
30 unsigned int lib_ring_buffer_poll(struct file
*filp
, poll_table
*wait
);
31 ssize_t
lib_ring_buffer_splice_read(struct file
*in
, loff_t
*ppos
,
32 struct pipe_inode_info
*pipe
, size_t len
,
34 int lib_ring_buffer_mmap(struct file
*filp
, struct vm_area_struct
*vma
);
36 /* Ring Buffer ioctl() and ioctl numbers */
37 long lib_ring_buffer_ioctl(struct file
*filp
, unsigned int cmd
, unsigned long arg
);
39 long lib_ring_buffer_compat_ioctl(struct file
*filp
, unsigned int cmd
,
44 * Use RING_BUFFER_GET_NEXT_SUBBUF / RING_BUFFER_PUT_NEXT_SUBBUF to read and
45 * consume sub-buffers sequentially.
47 * Reading sub-buffers without consuming them can be performed with:
49 * RING_BUFFER_SNAPSHOT
50 * RING_BUFFER_SNAPSHOT_GET_CONSUMED
51 * RING_BUFFER_SNAPSHOT_GET_PRODUCED
53 * to get the offset range to consume, and then by passing each sub-buffer
54 * offset to RING_BUFFER_GET_SUBBUF, read the sub-buffer, and then release it
55 * with RING_BUFFER_PUT_SUBBUF.
57 * Note that the "snapshot" API can be used to read the sub-buffer in reverse
58 * order, which is useful for flight recorder snapshots.
61 /* Get a snapshot of the current ring buffer producer and consumer positions */
62 #define RING_BUFFER_SNAPSHOT _IO(0xF6, 0x00)
63 /* Get the consumer position (iteration start) */
64 #define RING_BUFFER_SNAPSHOT_GET_CONSUMED _IOR(0xF6, 0x01, unsigned long)
65 /* Get the producer position (iteration end) */
66 #define RING_BUFFER_SNAPSHOT_GET_PRODUCED _IOR(0xF6, 0x02, unsigned long)
67 /* Get exclusive read access to the specified sub-buffer position */
68 #define RING_BUFFER_GET_SUBBUF _IOW(0xF6, 0x03, unsigned long)
69 /* Release exclusive sub-buffer access */
70 #define RING_BUFFER_PUT_SUBBUF _IO(0xF6, 0x04)
72 /* Get exclusive read access to the next sub-buffer that can be read. */
73 #define RING_BUFFER_GET_NEXT_SUBBUF _IO(0xF6, 0x05)
74 /* Release exclusive sub-buffer access, move consumer forward. */
75 #define RING_BUFFER_PUT_NEXT_SUBBUF _IO(0xF6, 0x06)
76 /* returns the size of the current sub-buffer, without padding (for mmap). */
77 #define RING_BUFFER_GET_SUBBUF_SIZE _IOR(0xF6, 0x07, unsigned long)
78 /* returns the size of the current sub-buffer, with padding (for splice). */
79 #define RING_BUFFER_GET_PADDED_SUBBUF_SIZE _IOR(0xF6, 0x08, unsigned long)
80 /* returns the maximum size for sub-buffers. */
81 #define RING_BUFFER_GET_MAX_SUBBUF_SIZE _IOR(0xF6, 0x09, unsigned long)
82 /* returns the length to mmap. */
83 #define RING_BUFFER_GET_MMAP_LEN _IOR(0xF6, 0x0A, unsigned long)
84 /* returns the offset of the subbuffer belonging to the mmap reader. */
85 #define RING_BUFFER_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, unsigned long)
86 /* flush the current sub-buffer */
87 #define RING_BUFFER_FLUSH _IO(0xF6, 0x0C)
89 #endif /* _LINUX_RING_BUFFER_VFS_H */