projects/linux·blob v2.6.39 · refs

92 lines · 2.8 KiB

1/*
2 * Function declerations and data structures related to the splice
3 * implementation.
4 *
5 * Copyright (C) 2007 Jens Axboe <[email protected]>
6 *
7 */
8#ifndef SPLICE_H
9#define SPLICE_H
10
11#include <linux/pipe_fs_i.h>
12
13/*
14 * Flags passed in from splice/tee/vmsplice
15 */
16#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
17#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
18 /* we may still block on the fd we splice */
19 /* from/to, of course */
20#define SPLICE_F_MORE (0x04) /* expect more data */
21#define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */
22
23/*
24 * Passed to the actors
25 */
26struct splice_desc {
27 unsigned int len, total_len; /* current and remaining length */
28 unsigned int flags; /* splice flags */
29 /*
30 * actor() private data
31 */
32 union {
33 void __user *userptr; /* memory to write to */
34 struct file *file; /* file to read/write */
35 void *data; /* cookie */
36 } u;
37 loff_t pos; /* file position */
38 size_t num_spliced; /* number of bytes already spliced */
39 bool need_wakeup; /* need to wake up writer */
40};
41
42struct partial_page {
43 unsigned int offset;
44 unsigned int len;
45 unsigned long private;
46};
47
48/*
49 * Passed to splice_to_pipe
50 */
51struct splice_pipe_desc {
52 struct page **pages; /* page map */
53 struct partial_page *partial; /* pages[] may not be contig */
54 int nr_pages; /* number of pages in map */
55 unsigned int flags; /* splice flags */
56 const struct pipe_buf_operations *ops;/* ops associated with output pipe */
57 void (*spd_release)(struct splice_pipe_desc *, unsigned int);
58};
59
60typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
61 struct splice_desc *);
62typedef int (splice_direct_actor)(struct pipe_inode_info *,
63 struct splice_desc *);
64
65extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
66 loff_t *, size_t, unsigned int,
67 splice_actor *);
68extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
69 struct splice_desc *, splice_actor *);
70extern int splice_from_pipe_feed(struct pipe_inode_info *, struct splice_desc *,
71 splice_actor *);
72extern int splice_from_pipe_next(struct pipe_inode_info *,
73 struct splice_desc *);
74extern void splice_from_pipe_begin(struct splice_desc *);
75extern void splice_from_pipe_end(struct pipe_inode_info *,
76 struct splice_desc *);
77extern int pipe_to_file(struct pipe_inode_info *, struct pipe_buffer *,
78 struct splice_desc *);
79
80extern ssize_t splice_to_pipe(struct pipe_inode_info *,
81 struct splice_pipe_desc *);
82extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
83 splice_direct_actor *);
84
85/*
86 * for dynamic pipe sizing
87 */
88extern int splice_grow_spd(struct pipe_inode_info *, struct splice_pipe_desc *);
89extern void splice_shrink_spd(struct pipe_inode_info *,
90 struct splice_pipe_desc *);
91
92#endif