Re: [dpdk-dev] [PATCH BUG 335 3/3] net/virtio: fix compilation error with 0 headroom

[Thomas Monjalon <thomas@monjalon.net>]

05/08/2019 15:07, Maxime Coquelin:
> On 8/1/19 10:09 AM, Hemant Agrawal wrote:
> >> On 7/26/19 2:25 PM, Olivier Matz wrote:
> >>> On Thu, Jul 25, 2019 at 04:36:45PM +0530, Hemant Agrawal wrote:
> >>>> When using RTE_PKTMBUF_HEADROOM as 0, virito ethdev driver throws
> >>>> compilation error
> >>>> virtio_ethdev.c:1851:2: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
> >>>> RTE_BUILD_BUG_ON(RTE_PKTMBUF_HEADROOM
> >>>> 	< sizeof(struct virtio_net_hdr_mrg_rxbuf));
> >>>>
> >>>> This patch change it into run-time check.
[...]
> >>>>
> >>>> Fixes: 198ab33677c9 ("net/virtio: move device initialization in a
> >>>> function")
> >>>
> >>> I think the proper commit is:
> >>> Fixes: dec08c28c0b3 ("virtio: check packet headroom at compile time")
> >>
> >> Indeed.
> >>
> >>> It looks this patch more or less reverts this old commit.
> >>> +CC Stephen
> >>
> >> I wonder whether we could have a warning at build time so that the one who
> >> builds DPDK is aware some driver may not be usable, in addition to the
> >> below patch that fails virtio-net init.
> > 
> > [Hemant] I will also prefer compile time check instead of run-time check for any non-default configs.
> > If someone is modifying the config, he can very well disable the drivers, which don't like those settings. 
> > 
> > However, earlier discussion w.r.t this bug moved in other direction to make DPDK compliable for all cases and allow regress testing.
> 
> Ok, I don't have a strong opinion on this, so feel free to apply this
> patch as is. We can add a build-ime warning later if we find it useful.
> 
> Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Series applied, thanks.

I think the right fix should be a check in meson.