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 splice_direct_to_actor(struct file *, struct splice_desc *, 76 splice_direct_actor *); 77 78 /* 79 * for dynamic pipe sizing 80 */ 81 extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *); 82 extern void splice_shrink_spd(struct splice_pipe_desc *); 83 extern void spd_release_page(struct splice_pipe_desc *, unsigned int); 84 85 extern const struct pipe_buf_operations page_cache_pipe_buf_ops; 86 #endif 87