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  */
29 struct 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 
47 struct partial_page {
48 	unsigned int offset;
49 	unsigned int len;
50 	unsigned long private;
51 };
52 
53 /*
54  * Passed to splice_to_pipe
55  */
56 struct 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 
65 typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
66 			   struct splice_desc *);
67 typedef int (splice_direct_actor)(struct pipe_inode_info *,
68 				  struct splice_desc *);
69 
70 extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
71 				loff_t *, size_t, unsigned int,
72 				splice_actor *);
73 extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
74 				  struct splice_desc *, splice_actor *);
75 extern ssize_t splice_to_pipe(struct pipe_inode_info *,
76 			      struct splice_pipe_desc *);
77 extern ssize_t add_to_pipe(struct pipe_inode_info *,
78 			      struct pipe_buffer *);
79 extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
80 				      splice_direct_actor *);
81 extern long do_splice(struct file *in, loff_t *off_in,
82 		      struct file *out, loff_t *off_out,
83 		      size_t len, unsigned int flags);
84 
85 extern long do_tee(struct file *in, struct file *out, size_t len,
86 		   unsigned int flags);
87 
88 /*
89  * for dynamic pipe sizing
90  */
91 extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
92 extern void splice_shrink_spd(struct splice_pipe_desc *);
93 
94 extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
95 extern const struct pipe_buf_operations default_pipe_buf_ops;
96 #endif
97