splice: Remove generic_file_splice_read()

Remove generic_file_splice_read() as it has been replaced with calls to
filemap_splice_read() and copy_splice_read().

With this, ITER_PIPE is no longer used.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Steve French <smfrench@gmail.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-30-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: dhowells

fs/splice.c

@@ -386,49 +386,6 @@ ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 }
 EXPORT_SYMBOL(copy_splice_read);
 
-/**
- * generic_file_splice_read - splice data from file to a pipe
- * @in:		file to splice from
- * @ppos:	position in @in
- * @pipe:	pipe to splice to
- * @len:	number of bytes to splice
- * @flags:	splice modifier flags
- *
- * Description:
- *    Will read pages from given file and fill them into a pipe. Can be
- *    used as long as it has more or less sane ->read_iter().
- *
- */
-ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
-				 struct pipe_inode_info *pipe, size_t len,
-				 unsigned int flags)
-{
-	struct iov_iter to;
-	struct kiocb kiocb;
-	int ret;
-
-	iov_iter_pipe(&to, ITER_DEST, pipe, len);
-	init_sync_kiocb(&kiocb, in);
-	kiocb.ki_pos = *ppos;
-	ret = call_read_iter(in, &kiocb, &to);
-	if (ret > 0) {
-		*ppos = kiocb.ki_pos;
-		file_accessed(in);
-	} else if (ret < 0) {
-		/* free what was emitted */
-		pipe_discard_from(pipe, to.start_head);
-		/*
-		 * callers of ->splice_read() expect -EAGAIN on
-		 * "can't put anything in there", rather than -EFAULT.
-		 */
-		if (ret == -EFAULT)
-			ret = -EAGAIN;
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL(generic_file_splice_read);
-
 const struct pipe_buf_operations default_pipe_buf_ops = {
 	.release	= generic_pipe_buf_release,
 	.try_steal	= generic_pipe_buf_try_steal,

include/linux/fs.h

@@ -2755,8 +2755,6 @@ ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
 ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 			 struct pipe_inode_info *pipe,
 			 size_t len, unsigned int flags);
-extern ssize_t generic_file_splice_read(struct file *, loff_t *,
-		struct pipe_inode_info *, size_t, unsigned int);
 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
 		struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,