Commit 0d964934 authored by Al Viro's avatar Al Viro
Browse files

splice: stop abusing iov_iter_advance() to flush a pipe 



Use pipe_discard_from() explicitly in generic_file_read_iter(); don't bother
with rather non-obvious use of iov_iter_advance() in there.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 3e20a751

fs/splice.c

+2 −5
Original line number Diff line number Diff line
@@ -301,11 +301,9 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 
{

	struct iov_iter to;

	struct kiocb kiocb;

	unsigned int i_head;

	int ret;



	iov_iter_pipe(&to, READ, pipe, len);

	i_head = to.head;

	init_sync_kiocb(&kiocb, in);

	kiocb.ki_pos = *ppos;

	ret = call_read_iter(in, &kiocb, &to);
@@ -313,9 +311,8 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 
		*ppos = kiocb.ki_pos;

		file_accessed(in);

	} else if (ret < 0) {

		to.head = i_head;

		to.iov_offset = 0;

		iov_iter_advance(&to, 0); /* to free what was emitted */

		/* 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.