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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 | /* | |
24 | * Passed to the actors | |
25 | */ | |
26 | struct 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 | ||
44 | struct partial_page { | |
45 | unsigned int offset; | |
46 | unsigned int len; | |
47 | unsigned long private; | |
48 | }; | |
49 | ||
50 | /* | |
51 | * Passed to splice_to_pipe | |
52 | */ | |
53 | struct 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 | ||
63 | typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, | |
64 | struct splice_desc *); | |
65 | typedef int (splice_direct_actor)(struct pipe_inode_info *, | |
66 | struct splice_desc *); | |
67 | ||
68 | extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *, | |
69 | loff_t *, size_t, unsigned int, | |
70 | splice_actor *); | |
71 | extern ssize_t __splice_from_pipe(struct pipe_inode_info *, | |
72 | struct splice_desc *, splice_actor *); | |
73 | extern ssize_t splice_to_pipe(struct pipe_inode_info *, | |
74 | struct splice_pipe_desc *); | |
75 | extern ssize_t add_to_pipe(struct pipe_inode_info *, | |
76 | struct pipe_buffer *); | |
77 | extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *, | |
78 | splice_direct_actor *); | |
79 | ||
80 | /* | |
81 | * for dynamic pipe sizing | |
82 | */ | |
83 | extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *); | |
84 | extern void splice_shrink_spd(struct splice_pipe_desc *); | |
85 | extern void spd_release_page(struct splice_pipe_desc *, unsigned int); | |
86 | ||
87 | extern const struct pipe_buf_operations page_cache_pipe_buf_ops; | |
88 | extern const struct pipe_buf_operations default_pipe_buf_ops; | |
89 | #endif |