Hi Michal,
Am Sa., 6. Juni 2020 um 15:43 Uhr schrieb Michal Kubecek <mkube...@suse.cz>:
>
> On Sat, Jun 06, 2020 at 03:24:22PM +0200, Heiko Thiery wrote:
> > Hi Michael et all,
> >
> > I'm digging in the reason for a failure when building ethtool with
> > buildroot [1].
> >
> > I see the following error:
> > ---
> > data/buildroot/buildroot-test/instance-0/output/host/bin/i686-linux-gcc
> > -DHAVE_CONFIG_H -I. -I./uapi -D_LARGEFILE_SOURCE
> > -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Wall -D_LARGEFILE_SOURCE
> > -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -static -c -o
> > netlink/desc-rtnl.o netlink/desc-rtnl.c
> > In file included from ./uapi/linux/ethtool_netlink.h:12,
> > from netlink/desc-ethtool.c:7:
> > ./uapi/linux/ethtool.h:1294:19: warning: implicit declaration of
> > function '__KERNEL_DIV_ROUND_UP' [-Wimplicit-function-declaration]
> > __u32 queue_mask[__KERNEL_DIV_ROUND_UP(MAX_NUM_QUEUE, 32)];
> > ^~~~~~~~~~~~~~~~~~~~~
> > ./uapi/linux/ethtool.h:1294:8: error: variably modified 'queue_mask'
> > at file scope
> > __u32 queue_mask[__KERNEL_DIV_ROUND_UP(MAX_NUM_QUEUE, 32)];
> > ^~~~~~~~~~
> > ---
>
> Thank you for the report. This is fixed by first part of this patch:
>
>
> https://patchwork.ozlabs.org/project/netdev/patch/bb60cbfe99071fca4b0ea9e62d67a2341d8dd652.1590707335.git.mkube...@suse.cz/
>
> I'm going to apply it (with the rest of the series) this weekend.
I will try to apply this patch and check if the failure is gone.
>
> > The problems seems to be injected by the "warning: implicit
> > declaration of function".
> >
> > When I move the __KERNEL_DIV_ROUND_UP macro right beside usage in
> > "uapi/linux/ethtool.h" the failure is gone.
> >
> > ---
> > diff --git a/uapi/linux/ethtool.h b/uapi/linux/ethtool.h
> > index d3dcb45..6710fa0 100644
> > --- a/uapi/linux/ethtool.h
> > +++ b/uapi/linux/ethtool.h
> > @@ -1288,6 +1288,11 @@ enum ethtool_sfeatures_retval_bits {
> > * @queue_mask: Bitmap of the queues which sub command apply to
> > * @data: A complete command structure following for each of the
> > queues addressed
> > */
> > +/* ethtool.h epxects __KERNEL_DIV_ROUND_UP to be defined by
> > <linux/kernel.h> */
> > +#include <linux/kernel.h>
> > +#ifndef __KERNEL_DIV_ROUND_UP
> > +#define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
> > +#endif
> > struct ethtool_per_queue_op {
> > __u32 cmd;
> > __u32 sub_command;
> > ---
>
> This would fix the warning and error too but uapi/linux/ethtool.h is
> a sanitized copy of a kernel header which we import and do not apply
> further changes. Moreover, there is no need to have multiple definitions
> of the same macro and there is already one in internal.h.
I saw that the definition is already done in internal.h. I just did a
quick hackaround to check if the failure is gone.
Thanks!
--
Heiko
