/* 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;
        void (*splice_eof)(struct splice_desc *sd); /* Unexpected EOF handler */
        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 *);

ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
                         loff_t *ppos, size_t len, unsigned int flags,
                         splice_actor *actor);
ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
                           struct splice_desc *sd, splice_actor *actor);
ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
                              struct splice_pipe_desc *spd);
ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf);
ssize_t vfs_splice_read(struct file *in, loff_t *ppos,
                        struct pipe_inode_info *pipe, size_t len,
                        unsigned int flags);
ssize_t splice_direct_to_actor(struct file *file, struct splice_desc *sd,
                               splice_direct_actor *actor);
ssize_t do_splice(struct file *in, loff_t *off_in, struct file *out,
                  loff_t *off_out, size_t len, unsigned int flags);
ssize_t do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
                         loff_t *opos, size_t len, unsigned int flags);
ssize_t splice_file_range(struct file *in, loff_t *ppos, struct file *out,
                          loff_t *opos, size_t len);

static inline long splice_copy_file_range(struct file *in, loff_t pos_in,
                                          struct file *out, loff_t pos_out,
                                          size_t len)
{
        return splice_file_range(in, &pos_in, out, &pos_out, len);
}

ssize_t do_tee(struct file *in, struct file *out, size_t len,
               unsigned int flags);
ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out,
                         loff_t *ppos, size_t len, unsigned int flags);

/*
 * 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