splice.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Function declerations and data structures related to the splice
  4 * implementation.
  5 *
  6 * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
  7 *
  8 */
  9#ifndef SPLICE_H
 10#define SPLICE_H
 11
 12#include <linux/pipe_fs_i.h>
 13
 14/*
 15 * Flags passed in from splice/tee/vmsplice
 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#define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_GIFT)
 25
 26/*
 27 * Passed to the actors
 28 */
 29struct splice_desc {
 30	size_t total_len;		/* remaining length */
 31	unsigned int len;		/* current length */
 32	unsigned int flags;		/* splice flags */
 33	/*
 34	 * actor() private data
 35	 */
 36	union {
 37		void __user *userptr;	/* memory to write to */
 38		struct file *file;	/* file to read/write */
 39		void *data;		/* cookie */
 40	} u;
 41	void (*splice_eof)(struct splice_desc *sd); /* Unexpected EOF handler */
 42	loff_t pos;			/* file position */
 43	loff_t *opos;			/* sendfile: output position */
 44	size_t num_spliced;		/* number of bytes already spliced */
 45	bool need_wakeup;		/* need to wake up writer */
 46};
 47
 48struct partial_page {
 49	unsigned int offset;
 50	unsigned int len;
 51	unsigned long private;
 52};
 53
 54/*
 55 * Passed to splice_to_pipe
 56 */
 57struct splice_pipe_desc {
 58	struct page **pages;		/* page map */
 59	struct partial_page *partial;	/* pages[] may not be contig */
 60	int nr_pages;			/* number of populated pages in map */
 61	unsigned int nr_pages_max;	/* pages[] & partial[] arrays size */
 62	const struct pipe_buf_operations *ops;/* ops associated with output pipe */
 63	void (*spd_release)(struct splice_pipe_desc *, unsigned int);
 64};
 65
 66typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
 67			   struct splice_desc *);
 68typedef int (splice_direct_actor)(struct pipe_inode_info *,
 69				  struct splice_desc *);
 70
 71ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
 72			 loff_t *ppos, size_t len, unsigned int flags,
 73			 splice_actor *actor);
 74ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
 75			   struct splice_desc *sd, splice_actor *actor);
 76ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 77			      struct splice_pipe_desc *spd);
 78ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf);
 79ssize_t vfs_splice_read(struct file *in, loff_t *ppos,
 80			struct pipe_inode_info *pipe, size_t len,
 81			unsigned int flags);
 82ssize_t splice_direct_to_actor(struct file *file, struct splice_desc *sd,
 83			       splice_direct_actor *actor);
 84ssize_t do_splice(struct file *in, loff_t *off_in, struct file *out,
 85		  loff_t *off_out, size_t len, unsigned int flags);
 86ssize_t do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 87			 loff_t *opos, size_t len, unsigned int flags);
 88ssize_t splice_file_range(struct file *in, loff_t *ppos, struct file *out,
 89			  loff_t *opos, size_t len);
 90
 91static inline long splice_copy_file_range(struct file *in, loff_t pos_in,
 92					  struct file *out, loff_t pos_out,
 93					  size_t len)
 94{
 95	return splice_file_range(in, &pos_in, out, &pos_out, len);
 96}
 97
 98ssize_t do_tee(struct file *in, struct file *out, size_t len,
 99	       unsigned int flags);
100ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out,
101			 loff_t *ppos, size_t len, unsigned int flags);
102
103/*
104 * for dynamic pipe sizing
105 */
106extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
107extern void splice_shrink_spd(struct splice_pipe_desc *);
108
109extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
110extern const struct pipe_buf_operations default_pipe_buf_ops;
111#endif