Re: [PATCH v3 6/7] s390x/css: Refactor the css_queue_crw() routine

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 17 Apr 2020 04:34:39 +0200
Eric Farman <farman@linux.ibm.com> wrote:

> We have a use case (vfio-ccw) where a CRW is already built and
> ready to use.  Rather than teasing out the components just to
> reassemble it later, let's rework this code so we can queue a
> fully-qualified CRW directly.
> 
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> ---
>  hw/s390x/css.c         | 44 ++++++++++++++++++++++++++++--------------
>  include/hw/s390x/css.h |  1 +
>  2 files changed, 30 insertions(+), 15 deletions(-)
> 
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index a44faa3549..a72c09adbe 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -2170,30 +2170,23 @@ void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
>      }
>  }
>  
> -void css_queue_crw(uint8_t rsc, uint8_t erc, int solicited,
> -                   int chain, uint16_t rsid)
> +void css_queue_crw_cont(CRW crw)

Don't really like this name, as it makes me think of 'continuation'
instead of 'container'.

css_queue_crw_container?
css_crw_add_to_queue?

Naming is hard :(

>  {
>      CrwContainer *crw_cont;
>  
> -    trace_css_crw(rsc, erc, rsid, chain ? "(chained)" : "");
> +    trace_css_crw((crw.flags & CRW_FLAGS_MASK_RSC) >> 8,
> +                  crw.flags & CRW_FLAGS_MASK_ERC,
> +                  crw.rsid,
> +                  (crw.flags & CRW_FLAGS_MASK_C) ? "(chained)" : "");
> +
>      /* TODO: Maybe use a static crw pool? */
>      crw_cont = g_try_new0(CrwContainer, 1);
>      if (!crw_cont) {
>          channel_subsys.crws_lost = true;
>          return;

Now that we actually pass something in, do we want to inform the caller
whether the crw was queued or not?

>      }
> -    crw_cont->crw.flags = (rsc << 8) | erc;
> -    if (solicited) {
> -        crw_cont->crw.flags |= CRW_FLAGS_MASK_S;
> -    }
> -    if (chain) {
> -        crw_cont->crw.flags |= CRW_FLAGS_MASK_C;
> -    }
> -    crw_cont->crw.rsid = rsid;
> -    if (channel_subsys.crws_lost) {
> -        crw_cont->crw.flags |= CRW_FLAGS_MASK_R;
> -        channel_subsys.crws_lost = false;
> -    }
> +
> +    crw_cont->crw = crw;
>  
>      QTAILQ_INSERT_TAIL(&channel_subsys.pending_crws, crw_cont, sibling);
>  

Generally, looks sane to me.