net: Avoid extra wakeups of threads blocked in wait_for_packet()
[linux-2.6.git] / include / linux / splice.h
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  * splice is tied to pipes as a transport (at least for now), so we'll just
15  * add the splice flags here.
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 /*
25  * Passed to the actors
26  */
27 struct splice_desc {
28         unsigned int len, total_len;    /* current and remaining 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 };
40
41 struct partial_page {
42         unsigned int offset;
43         unsigned int len;
44         unsigned long private;
45 };
46
47 /*
48  * Passed to splice_to_pipe
49  */
50 struct splice_pipe_desc {
51         struct page **pages;            /* page map */
52         struct partial_page *partial;   /* pages[] may not be contig */
53         int nr_pages;                   /* number of pages in map */
54         unsigned int flags;             /* splice flags */
55         const struct pipe_buf_operations *ops;/* ops associated with output pipe */
56         void (*spd_release)(struct splice_pipe_desc *, unsigned int);
57 };
58
59 typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
60                            struct splice_desc *);
61 typedef int (splice_direct_actor)(struct pipe_inode_info *,
62                                   struct splice_desc *);
63
64 extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
65                                 loff_t *, size_t, unsigned int,
66                                 splice_actor *);
67 extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
68                                   struct splice_desc *, splice_actor *);
69 extern ssize_t splice_to_pipe(struct pipe_inode_info *,
70                               struct splice_pipe_desc *);
71 extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
72                                       splice_direct_actor *);
73
74 #endif