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852c2936 MD |
1 | #ifndef _LINUX_RING_BUFFER_VFS_H |
2 | #define _LINUX_RING_BUFFER_VFS_H | |
3 | ||
4 | /* | |
5 | * linux/ringbuffer/vfs.h | |
6 | * | |
7 | * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
9 | * Wait-free ring buffer VFS file operations. | |
10 | * | |
11 | * Author: | |
12 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
13 | * | |
14 | * Dual LGPL v2.1/GPL v2 license. | |
15 | */ | |
16 | ||
852c2936 MD |
17 | /* VFS API */ |
18 | ||
19 | extern const struct file_operations lib_ring_buffer_file_operations; | |
20 | ||
21 | /* | |
22 | * Internal file operations. | |
23 | */ | |
24 | ||
25 | int lib_ring_buffer_open(struct inode *inode, struct file *file); | |
26 | int lib_ring_buffer_release(struct inode *inode, struct file *file); | |
27 | unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait); | |
28 | ssize_t lib_ring_buffer_splice_read(struct file *in, loff_t *ppos, | |
29 | struct pipe_inode_info *pipe, size_t len, | |
30 | unsigned int flags); | |
31 | int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma); | |
32 | ||
33 | /* Ring Buffer ioctl() and ioctl numbers */ | |
34 | long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg); | |
35 | #ifdef CONFIG_COMPAT | |
36 | long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
37 | unsigned long arg); | |
38 | #endif | |
39 | ||
40 | /* | |
41 | * Use RING_BUFFER_GET_NEXT_SUBBUF / RING_BUFFER_PUT_NEXT_SUBBUF to read and | |
42 | * consume sub-buffers sequentially. | |
43 | * | |
44 | * Reading sub-buffers without consuming them can be performed with: | |
45 | * | |
46 | * RING_BUFFER_SNAPSHOT | |
47 | * RING_BUFFER_SNAPSHOT_GET_CONSUMED | |
48 | * RING_BUFFER_SNAPSHOT_GET_PRODUCED | |
49 | * | |
50 | * to get the offset range to consume, and then by passing each sub-buffer | |
51 | * offset to RING_BUFFER_GET_SUBBUF, read the sub-buffer, and then release it | |
52 | * with RING_BUFFER_PUT_SUBBUF. | |
53 | * | |
54 | * Note that the "snapshot" API can be used to read the sub-buffer in reverse | |
55 | * order, which is useful for flight recorder snapshots. | |
56 | */ | |
57 | ||
58 | /* Get a snapshot of the current ring buffer producer and consumer positions */ | |
59 | #define RING_BUFFER_SNAPSHOT _IO(0xF6, 0x00) | |
60 | /* Get the consumer position (iteration start) */ | |
61 | #define RING_BUFFER_SNAPSHOT_GET_CONSUMED _IOR(0xF6, 0x01, unsigned long) | |
62 | /* Get the producer position (iteration end) */ | |
63 | #define RING_BUFFER_SNAPSHOT_GET_PRODUCED _IOR(0xF6, 0x02, unsigned long) | |
64 | /* Get exclusive read access to the specified sub-buffer position */ | |
65 | #define RING_BUFFER_GET_SUBBUF _IOW(0xF6, 0x03, unsigned long) | |
66 | /* Release exclusive sub-buffer access */ | |
67 | #define RING_BUFFER_PUT_SUBBUF _IO(0xF6, 0x04) | |
68 | ||
69 | /* Get exclusive read access to the next sub-buffer that can be read. */ | |
70 | #define RING_BUFFER_GET_NEXT_SUBBUF _IO(0xF6, 0x05) | |
71 | /* Release exclusive sub-buffer access, move consumer forward. */ | |
72 | #define RING_BUFFER_PUT_NEXT_SUBBUF _IO(0xF6, 0x06) | |
73 | /* returns the size of the current sub-buffer, without padding (for mmap). */ | |
74 | #define RING_BUFFER_GET_SUBBUF_SIZE _IOR(0xF6, 0x07, unsigned long) | |
75 | /* returns the size of the current sub-buffer, with padding (for splice). */ | |
76 | #define RING_BUFFER_GET_PADDED_SUBBUF_SIZE _IOR(0xF6, 0x08, unsigned long) | |
77 | /* returns the maximum size for sub-buffers. */ | |
78 | #define RING_BUFFER_GET_MAX_SUBBUF_SIZE _IOR(0xF6, 0x09, unsigned long) | |
79 | /* returns the length to mmap. */ | |
80 | #define RING_BUFFER_GET_MMAP_LEN _IOR(0xF6, 0x0A, unsigned long) | |
81 | /* returns the offset of the subbuffer belonging to the mmap reader. */ | |
82 | #define RING_BUFFER_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, unsigned long) | |
83 | ||
84 | #endif /* _LINUX_RING_BUFFER_VFS_H */ |