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