LXR linux/include/linux/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        loff_t pos;                     /* file position */
  42        loff_t *opos;                   /* sendfile: output position */
  43        size_t num_spliced;             /* number of bytes already spliced */
  44        bool need_wakeup;               /* need to wake up writer */
  45};
  46
  47struct partial_page {
  48        unsigned int offset;
  49        unsigned int len;
  50        unsigned long private;
  51};
  52
  53/*
  54 * Passed to splice_to_pipe
  55 */
  56struct splice_pipe_desc {
  57        struct page **pages;            /* page map */
  58        struct partial_page *partial;   /* pages[] may not be contig */
  59        int nr_pages;                   /* number of populated pages in map */
  60        unsigned int nr_pages_max;      /* pages[] & partial[] arrays size */
  61        const struct pipe_buf_operations *ops;/* ops associated with output pipe */
  62        void (*spd_release)(struct splice_pipe_desc *, unsigned int);
  63};
  64
  65typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
  66                           struct splice_desc *);
  67typedef int (splice_direct_actor)(struct pipe_inode_info *,
  68                                  struct splice_desc *);
  69
  70extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
  71                                loff_t *, size_t, unsigned int,
  72                                splice_actor *);
  73extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
  74                                  struct splice_desc *, splice_actor *);
  75extern ssize_t splice_to_pipe(struct pipe_inode_info *,
  76                              struct splice_pipe_desc *);
  77extern ssize_t add_to_pipe(struct pipe_inode_info *,
  78                              struct pipe_buffer *);
  79extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
  80                                      splice_direct_actor *);
  81extern long do_splice(struct file *in, loff_t *off_in,
  82                      struct file *out, loff_t *off_out,
  83                      size_t len, unsigned int flags);
  84
  85extern long do_tee(struct file *in, struct file *out, size_t len,
  86                   unsigned int flags);
  87
  88/*
  89 * for dynamic pipe sizing
  90 */
  91extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
  92extern void splice_shrink_spd(struct splice_pipe_desc *);
  93
  94extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
  95extern const struct pipe_buf_operations default_pipe_buf_ops;
  96#endif
  97