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6a3f30b8bd
Rename do_splice_to() to vfs_splice_read() and export it so that it can be used as a helper when calling down to a lower layer filesystem as it performs all the necessary checks[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christian Brauner <brauner@kernel.org> cc: Miklos Szeredi <miklos@szeredi.hu> cc: Jens Axboe <axboe@kernel.dk> cc: Al Viro <viro@zeniv.linux.org.uk> cc: John Hubbard <jhubbard@nvidia.com> cc: David Hildenbrand <david@redhat.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-unionfs@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/CAJfpeguGksS3sCigmRi9hJdUec8qtM9f+_9jC1rJhsXT+dV01w@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/20230522135018.2742245-6-dhowells@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
99 lines
3.1 KiB
C
99 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Function declerations and data structures related to the splice
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* implementation.
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*
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* Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
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*
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*/
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#ifndef SPLICE_H
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#define SPLICE_H
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#include <linux/pipe_fs_i.h>
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/*
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* Flags passed in from splice/tee/vmsplice
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*/
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#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
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#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
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/* we may still block on the fd we splice */
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/* from/to, of course */
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#define SPLICE_F_MORE (0x04) /* expect more data */
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#define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */
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#define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_GIFT)
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/*
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* Passed to the actors
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*/
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struct splice_desc {
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size_t total_len; /* remaining length */
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unsigned int len; /* current length */
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unsigned int flags; /* splice flags */
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/*
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* actor() private data
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*/
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union {
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void __user *userptr; /* memory to write to */
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struct file *file; /* file to read/write */
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void *data; /* cookie */
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} u;
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loff_t pos; /* file position */
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loff_t *opos; /* sendfile: output position */
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size_t num_spliced; /* number of bytes already spliced */
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bool need_wakeup; /* need to wake up writer */
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};
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struct partial_page {
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unsigned int offset;
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unsigned int len;
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unsigned long private;
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};
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/*
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* Passed to splice_to_pipe
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*/
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struct splice_pipe_desc {
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struct page **pages; /* page map */
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struct partial_page *partial; /* pages[] may not be contig */
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int nr_pages; /* number of populated pages in map */
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unsigned int nr_pages_max; /* pages[] & partial[] arrays size */
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const struct pipe_buf_operations *ops;/* ops associated with output pipe */
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void (*spd_release)(struct splice_pipe_desc *, unsigned int);
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};
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typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
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struct splice_desc *);
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typedef int (splice_direct_actor)(struct pipe_inode_info *,
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struct splice_desc *);
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extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
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loff_t *, size_t, unsigned int,
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splice_actor *);
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extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
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struct splice_desc *, splice_actor *);
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extern ssize_t splice_to_pipe(struct pipe_inode_info *,
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struct splice_pipe_desc *);
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extern ssize_t add_to_pipe(struct pipe_inode_info *,
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struct pipe_buffer *);
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long vfs_splice_read(struct file *in, loff_t *ppos,
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struct pipe_inode_info *pipe, size_t len,
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unsigned int flags);
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extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
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splice_direct_actor *);
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extern long do_splice(struct file *in, loff_t *off_in,
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struct file *out, loff_t *off_out,
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size_t len, unsigned int flags);
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extern long do_tee(struct file *in, struct file *out, size_t len,
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unsigned int flags);
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/*
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* for dynamic pipe sizing
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*/
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extern int splice_grow_spd(const struct pipe_inode_info *, struct splice_pipe_desc *);
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extern void splice_shrink_spd(struct splice_pipe_desc *);
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extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
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extern const struct pipe_buf_operations default_pipe_buf_ops;
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#endif
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