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	size_t total_len;		/* remaining length */
28	unsigned int len;		/* current 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	loff_t *opos;			/* sendfile: output position */
40	size_t num_spliced;		/* number of bytes already spliced */
41	bool need_wakeup;		/* need to wake up writer */
42};
43
44struct partial_page {
45	unsigned int offset;
46	unsigned int len;
47	unsigned long private;
48};
49
50/*
51 * Passed to splice_to_pipe
52 */
53struct splice_pipe_desc {
54	struct page **pages;		/* page map */
55	struct partial_page *partial;	/* pages[] may not be contig */
56	int nr_pages;			/* number of populated pages in map */
57	unsigned int nr_pages_max;	/* pages[] & partial[] arrays size */
58	unsigned int flags;		/* splice flags */
59	const struct pipe_buf_operations *ops;/* ops associated with output pipe */
60	void (*spd_release)(struct splice_pipe_desc *, unsigned int);
61};
62
63typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
64			   struct splice_desc *);
65typedef int (splice_direct_actor)(struct pipe_inode_info *,
66				  struct splice_desc *);
67
68extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
69				loff_t *, size_t, unsigned int,
70				splice_actor *);
71extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
72				  struct splice_desc *, splice_actor *);
73extern ssize_t splice_to_pipe(struct pipe_inode_info *,
74			      struct splice_pipe_desc *);
75extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
76				      splice_direct_actor *);
77
78/*
79 * for dynamic pipe sizing
80 */
81extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
82extern void splice_shrink_spd(struct splice_pipe_desc *);
83extern void spd_release_page(struct splice_pipe_desc *, unsigned int);
84
85extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
86#endif
87