Linux kernel mirror (for testing)
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1#ifndef _LINUX_PIPE_FS_I_H
2#define _LINUX_PIPE_FS_I_H
3
4#define PIPEFS_MAGIC 0x50495045
5
6#define PIPE_BUFFERS (16)
7
8#define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */
9#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
10#define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */
11
12struct pipe_buffer {
13 struct page *page;
14 unsigned int offset, len;
15 struct pipe_buf_operations *ops;
16 unsigned int flags;
17};
18
19/*
20 * Note on the nesting of these functions:
21 *
22 * ->pin()
23 * ->steal()
24 * ...
25 * ->map()
26 * ...
27 * ->unmap()
28 *
29 * That is, ->map() must be called on a pinned buffer, same goes for ->steal().
30 */
31struct pipe_buf_operations {
32 int can_merge;
33 void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int);
34 void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *);
35 int (*pin)(struct pipe_inode_info *, struct pipe_buffer *);
36 void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
37 int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
38 void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
39};
40
41struct pipe_inode_info {
42 wait_queue_head_t wait;
43 unsigned int nrbufs, curbuf;
44 struct pipe_buffer bufs[PIPE_BUFFERS];
45 struct page *tmp_page;
46 unsigned int start;
47 unsigned int readers;
48 unsigned int writers;
49 unsigned int waiting_writers;
50 unsigned int r_counter;
51 unsigned int w_counter;
52 struct fasync_struct *fasync_readers;
53 struct fasync_struct *fasync_writers;
54 struct inode *inode;
55};
56
57/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
58 memory allocation, whereas PIPE_BUF makes atomicity guarantees. */
59#define PIPE_SIZE PAGE_SIZE
60
61/* Drop the inode semaphore and wait for a pipe event, atomically */
62void pipe_wait(struct pipe_inode_info *pipe);
63
64struct pipe_inode_info * alloc_pipe_info(struct inode * inode);
65void free_pipe_info(struct inode * inode);
66void __free_pipe_info(struct pipe_inode_info *);
67
68/* Generic pipe buffer ops functions */
69void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int);
70void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *);
71void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
72int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
73int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
74
75/*
76 * splice is tied to pipes as a transport (at least for now), so we'll just
77 * add the splice flags here.
78 */
79#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
80#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
81 /* we may still block on the fd we splice */
82 /* from/to, of course */
83#define SPLICE_F_MORE (0x04) /* expect more data */
84#define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */
85
86/*
87 * Passed to the actors
88 */
89struct splice_desc {
90 unsigned int len, total_len; /* current and remaining length */
91 unsigned int flags; /* splice flags */
92 struct file *file; /* file to read/write */
93 loff_t pos; /* file position */
94};
95
96typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
97 struct splice_desc *);
98
99extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
100 loff_t *, size_t, unsigned int,
101 splice_actor *);
102
103#endif