/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * 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 */

  #define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_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 */

  	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 add_to_pipe(struct pipe_inode_info *,
  			      struct pipe_buffer *);

  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 const struct pipe_buf_operations page_cache_pipe_buf_ops;

  extern const struct pipe_buf_operations default_pipe_buf_ops;

  #endif