Commit 6a3f30b8 authored by David Howells's avatar David Howells Committed by Jens Axboe
Browse files

splice: Make do_splice_to() generic and export it 



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: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarChristian 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: default avatarJens Axboe <axboe@kernel.dk>
parent e69f37bc

fs/splice.c

+20 −7
Original line number Diff line number Diff line
@@ -867,10 +867,22 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out, 
	return out->f_op->splice_write(pipe, out, ppos, len, flags);

}



/*

 * Attempt to initiate a splice from a file to a pipe.

/**

 * vfs_splice_read - Read data from a file and splice it into a pipe

 * @in:		File to splice from

 * @ppos:	Input file offset

 * @pipe:	Pipe to splice to

 * @len:	Number of bytes to splice

 * @flags:	Splice modifier flags (SPLICE_F_*)

 *

 * Splice the requested amount of data from the input file to the pipe.  This

 * is synchronous as the caller must hold the pipe lock across the entire

 * operation.

 *

 * If successful, it returns the amount of data spliced, 0 if it hit the EOF or

 * a hole and a negative error code otherwise.

 */

static long do_splice_to(struct file *in, loff_t *ppos,

long vfs_splice_read(struct file *in, loff_t *ppos,

		     struct pipe_inode_info *pipe, size_t len,

		     unsigned int flags)

{
@@ -895,6 +907,7 @@ static long do_splice_to(struct file *in, loff_t *ppos, 
		return warn_unsupported(in, "read");

	return in->f_op->splice_read(in, ppos, pipe, len, flags);

}

EXPORT_SYMBOL_GPL(vfs_splice_read);



/**

 * splice_direct_to_actor - splices data directly between two non-pipes
@@ -964,7 +977,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, 
		size_t read_len;

		loff_t pos = sd->pos, prev_pos = pos;



		ret = do_splice_to(in, &pos, pipe, len, flags);

		ret = vfs_splice_read(in, &pos, pipe, len, flags);

		if (unlikely(ret <= 0))

			goto out_release;
@@ -1112,7 +1125,7 @@ long splice_file_to_pipe(struct file *in, 
	pipe_lock(opipe);

	ret = wait_for_space(opipe, flags);

	if (!ret)

		ret = do_splice_to(in, offset, opipe, len, flags);

		ret = vfs_splice_read(in, offset, opipe, len, flags);

	pipe_unlock(opipe);

	if (ret > 0)

		wakeup_pipe_readers(opipe);

include/linux/splice.h

+3 −0
Original line number Diff line number Diff line
@@ -76,6 +76,9 @@ 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 *);

long vfs_splice_read(struct file *in, loff_t *ppos,

		     struct pipe_inode_info *pipe, size_t len,

		     unsigned int flags);

extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,

				      splice_direct_actor *);

extern long do_splice(struct file *in, loff_t *off_in,