On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote:
> Use pipe_discard_from() explicitly in generic_file_read_iter(); don't bother
> with rather non-obvious use of iov_iter_advance() in there.
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> fs/splice.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/fs/splice.c b/fs/splice.c
> index 047b79db8eb5..6645b30ec990 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -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.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
