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/*
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 populated pages in map */
55	unsigned int nr_pages_max;	/* pages[] & partial[] arrays size */
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/*
87 * for dynamic pipe sizing
88 */
89extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
90extern void splice_shrink_spd(struct splice_pipe_desc *);
91extern void spd_release_page(struct splice_pipe_desc *, unsigned int);
92
93extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
94#endif
95