splice.h
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/*
* Function declerations and data structures related to the splice
* implementation.
*
* Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
*
*/
#ifndef SPLICE_H
#define SPLICE_H
#include <linux/pipe_fs_i.h>
/*
* Flags passed in from splice/tee/vmsplice
*/
#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
/* we may still block on the fd we splice */
/* from/to, of course */
#define SPLICE_F_MORE (0x04) /* expect more data */
#define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */
/*
* Passed to the actors
*/
struct splice_desc {
size_t total_len; /* remaining length */
unsigned int len; /* current length */
unsigned int flags; /* splice flags */
/*
* actor() private data
*/
union {
void __user *userptr; /* memory to write to */
struct file *file; /* file to read/write */
void *data; /* cookie */
} u;
loff_t pos; /* file position */
loff_t *opos; /* sendfile: output position */
size_t num_spliced; /* number of bytes already spliced */
bool need_wakeup; /* need to wake up writer */
};
struct partial_page {
unsigned int offset;
unsigned int len;
unsigned long private;
};
/*
* Passed to splice_to_pipe
*/
struct splice_pipe_desc {
struct page **pages; /* page map */
struct partial_page *partial; /* pages[] may not be contig */
int nr_pages; /* number of populated pages in map */
unsigned int nr_pages_max; /* pages[] & partial[] arrays size */
unsigned int flags; /* splice flags */
const struct pipe_buf_operations *ops;/* ops associated with output pipe */
void (*spd_release)(struct splice_pipe_desc *, unsigned int);
};
typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
struct splice_desc *);
typedef int (splice_direct_actor)(struct pipe_inode_info *,
struct splice_desc *);
extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
loff_t *, size_t, unsigned int,
splice_actor *);
extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
struct splice_desc *, splice_actor *);
extern ssize_t splice_to_pipe(struct pipe_inode_info *,
struct splice_pipe_desc *);
extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
splice_direct_actor *);
/*
* for dynamic pipe sizing
*/
extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
extern void splice_shrink_spd(struct splice_pipe_desc *);
extern void spd_release_page(struct splice_pipe_desc *, unsigned int);
extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
#endif