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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 * 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#define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_GIFT)
24
25/*
26 * Passed to the actors
27 */
28struct splice_desc {
29 size_t total_len; /* remaining length */
30 unsigned int len; /* current length */
31 unsigned int flags; /* splice flags */
32 /*
33 * actor() private data
34 */
35 union {
36 void __user *userptr; /* memory to write to */
37 struct file *file; /* file to read/write */
38 void *data; /* cookie */
39 } u;
40 loff_t pos; /* file position */
41 loff_t *opos; /* sendfile: output position */
42 size_t num_spliced; /* number of bytes already spliced */
43 bool need_wakeup; /* need to wake up writer */
44};
45
46struct partial_page {
47 unsigned int offset;
48 unsigned int len;
49 unsigned long private;
50};
51
52/*
53 * Passed to splice_to_pipe
54 */
55struct splice_pipe_desc {
56 struct page **pages; /* page map */
57 struct partial_page *partial; /* pages[] may not be contig */
58 int nr_pages; /* number of populated pages in map */
59 unsigned int nr_pages_max; /* pages[] & partial[] arrays size */
60 const struct pipe_buf_operations *ops;/* ops associated with output pipe */
61 void (*spd_release)(struct splice_pipe_desc *, unsigned int);
62};
63
64typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
65 struct splice_desc *);
66typedef int (splice_direct_actor)(struct pipe_inode_info *,
67 struct splice_desc *);
68
69extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
70 loff_t *, size_t, unsigned int,
71 splice_actor *);
72extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
73 struct splice_desc *, splice_actor *);
74extern ssize_t splice_to_pipe(struct pipe_inode_info *,
75 struct splice_pipe_desc *);
76extern ssize_t add_to_pipe(struct pipe_inode_info *,
77 struct pipe_buffer *);
78extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
79 splice_direct_actor *);
80
81/*
82 * for dynamic pipe sizing
83 */
84extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
85extern void splice_shrink_spd(struct splice_pipe_desc *);
86
87extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
88extern const struct pipe_buf_operations default_pipe_buf_ops;
89#endif