Re: [PATCH net-next 1/2] rds: refactor zcopy code into rds_message_zcopy_from_user

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

On Tue, Mar 6, 2018 at 10:22 AM, Sowmini Varadhan
<sowmini.varadhan@oracle.com> wrote:
> Move the large block of code predicated on zcopy from
> rds_message_copy_from_user into a new function,
> rds_message_zcopy_from_user()
>
> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>

Acked-by: Willem de Bruijn <willemb@google.com>

> +int rds_message_copy_from_user(struct rds_message *rm, struct iov_iter *from,
> +                              bool zcopy)
> +{
> +       unsigned long to_copy, nbytes;
> +       unsigned long sg_off;
> +       struct scatterlist *sg;
> +       int ret = 0;
> +
> +       rm->m_inc.i_hdr.h_len = cpu_to_be32(iov_iter_count(from));
> +
> +       /* now allocate and copy in the data payload.  */
> +       sg = rm->data.op_sg;
> +       sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */

The above lines appear both here and in rds_message_zcopy_from_user.
Not strictly necessary, but not buggy, so no need to revise just for that.