Re: [PATCH] net/ena: Fix build warning in ena_xdp_set()

[David Miller]

From: Gavin Shan <gshan@xxxxxxxxxx>
Date: Fri, 24 Apr 2020 10:01:46 +1000

> This fixes the following build warning in ena_xdp_set()
> 
>    In file included from ./include/net/inet_sock.h:19,
>       from ./include/net/ip.h:27,
>       from drivers/net/ethernet/amazon/ena/ena_netdev.c:46:
>    drivers/net/ethernet/amazon/ena/ena_netdev.c: In function         \
>    ʽena_xdp_setʼ:                                                    \
>    drivers/net/ethernet/amazon/ena/ena_netdev.c:557:6: warning:      \
>    format ʽ%luʼ                                                      \
>    expects argument of type ʽlong unsigned intʼ, but argument 4      \
>    has type ʽintʼ                                                    \
>    [-Wformat=] "Failed to set xdp program, the current MTU (%d) is   \
>    larger than the maximum allowed MTU (%lu) while xdp is on",
> 
> Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>

The type of the argument is configuration dependent, this is because
sometimes one of the terms to define ENA_XDP_MAX_MTU is PAGE_SIZE and
sometimes it is SZ_16K.  And this determines whether it evaluates to
a long or not.

So your patch will just cause warnings in other configurations.

A better fix is therefore necessary.