1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Function declerations and data structures related to the splice
4 * implementation.
5 *
6 * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
7 *
8 */
9#ifndef SPLICE_H
10#define SPLICE_H
11
12#include <linux/pipe_fs_i.h>
13
14/*
15 * Flags passed in from splice/tee/vmsplice
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#define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_GIFT)
25
26/*
27 * Passed to the actors
28 */
29struct splice_desc {
30 size_t total_len; /* remaining length */
31 unsigned int len; /* current length */
32 unsigned int flags; /* splice flags */
33 /*
34 * actor() private data
35 */
36 union {
37 void __user *userptr; /* memory to write to */
38 struct file *file; /* file to read/write */
39 void *data; /* cookie */
40 } u;
41 loff_t pos; /* file position */
42 loff_t *opos; /* sendfile: output position */
43 size_t num_spliced; /* number of bytes already spliced */
44 bool need_wakeup; /* need to wake up writer */
45};
46
47struct partial_page {
48 unsigned int offset;
49 unsigned int len;
50 unsigned long private;
51};
52
53/*
54 * Passed to splice_to_pipe
55 */
56struct splice_pipe_desc {
57 struct page **pages; /* page map */
58 struct partial_page *partial; /* pages[] may not be contig */
59 int nr_pages; /* number of populated pages in map */
60 unsigned int nr_pages_max; /* pages[] & partial[] arrays size */
61 const struct pipe_buf_operations *ops;/* ops associated with output pipe */
62 void (*spd_release)(struct splice_pipe_desc *, unsigned int);
63};
64
65typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
66 struct splice_desc *);
67typedef int (splice_direct_actor)(struct pipe_inode_info *,
68 struct splice_desc *);
69
70extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
71 loff_t *, size_t, unsigned int,
72 splice_actor *);
73extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
74 struct splice_desc *, splice_actor *);
75extern ssize_t splice_to_pipe(struct pipe_inode_info *,
76 struct splice_pipe_desc *);
77extern ssize_t add_to_pipe(struct pipe_inode_info *,
78 struct pipe_buffer *);
79extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
80 splice_direct_actor *);
81
82/*
83 * for dynamic pipe sizing
84 */
85extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
86extern void splice_shrink_spd(struct splice_pipe_desc *);
87
88extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
89extern const struct pipe_buf_operations default_pipe_buf_ops;
90#endif
91