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 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 loff_t *opos; /* sendfile: output position */ 39 size_t num_spliced; /* number of bytes already spliced */ 40 bool need_wakeup; /* need to wake up writer */ 41 }; 42 43 struct partial_page { 44 unsigned int offset; 45 unsigned int len; 46 unsigned long private; 47 }; 48 49 /* 50 * Passed to splice_to_pipe 51 */ 52 struct splice_pipe_desc { 53 struct page **pages; /* page map */ 54 struct partial_page *partial; /* pages[] may not be contig */ 55 int nr_pages; /* number of populated pages in map */ 56 unsigned int nr_pages_max; /* pages[] & partial[] arrays size */ 57 unsigned int flags; /* splice flags */ 58 const struct pipe_buf_operations *ops;/* ops associated with output pipe */ 59 void (*spd_release)(struct splice_pipe_desc *, unsigned int); 60 }; 61 62 typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, 63 struct splice_desc *); 64 typedef int (splice_direct_actor)(struct pipe_inode_info *, 65 struct splice_desc *); 66 67 extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *, 68 loff_t *, size_t, unsigned int, 69 splice_actor *); 70 extern ssize_t __splice_from_pipe(struct pipe_inode_info *, 71 struct splice_desc *, splice_actor *); 72 extern int splice_from_pipe_feed(struct pipe_inode_info *, struct splice_desc *, 73 splice_actor *); 74 extern int splice_from_pipe_next(struct pipe_inode_info *, 75 struct splice_desc *); 76 extern void splice_from_pipe_begin(struct splice_desc *); 77 extern void splice_from_pipe_end(struct pipe_inode_info *, 78 struct splice_desc *); 79 extern int pipe_to_file(struct pipe_inode_info *, struct pipe_buffer *, 80 struct splice_desc *); 81 82 extern ssize_t splice_to_pipe(struct pipe_inode_info *, 83 struct splice_pipe_desc *); 84 extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *, 85 splice_direct_actor *); 86 87 /* 88 * for dynamic pipe sizing 89 */ 90 extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *); 91 extern void splice_shrink_spd(struct splice_pipe_desc *); 92 extern void spd_release_page(struct splice_pipe_desc *, unsigned int); 93 94 extern const struct pipe_buf_operations page_cache_pipe_buf_ops; 95 #endif 96