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