Re: [PATCH v2 16/53] migration/rdma: Fix or document problematic uses of errno

[Juan Quintela]

Markus Armbruster <armbru@redhat.com> wrote:
> We use errno after calling Libibverbs functions that are not
> documented to set errno (manual page does not mention errno), or where
> the documentation is unclear ("returns [...] the value of errno on
> failure").  While this could be read as "sets errno and returns it",
> a glance at the source code[*] kills that hope:
>
>     static inline int ibv_post_send(struct ibv_qp *qp, struct ibv_send_wr *wr,
>                                     struct ibv_send_wr **bad_wr)
>     {
>             return qp->context->ops.post_send(qp, wr, bad_wr);
>     }
>
> The callback can be
>
>     static int mana_post_send(struct ibv_qp *ibqp, struct ibv_send_wr *wr,
>                               struct ibv_send_wr **bad)
>     {
>             /* This version of driver supports RAW QP only.
>              * Posting WR is done directly in the application.
>              */
>             return EOPNOTSUPP;
>     }
>
> Neither of them touches errno.
>
> One of these errno uses is easy to fix, so do that now.  Several more
> will go away later in the series; add temporary FIXME commments.
> Three will remain; add TODO comments.  TODO, not FIXME, because the
> bug might be in Libibverbs documentation.
>
> [*] https://github.com/linux-rdma/rdma-core.git
>     commit 55fa316b4b18f258d8ac1ceb4aa5a7a35b094dcf
>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

And here I am, re-merging from this patch O:-)