Re: [PATCH v3 net-next 08/15] net: dsa: sja1105: prepare tagger for handling DSA tags and VLAN simultaneously

From: Vladimir Oltean <olteanv@gmail.com>
To: kbuild test robot <lkp@intel.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	kbuild-all@lists.01.org, "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Jiri Pirko <jiri@mellanox.com>,
	Ido Schimmel <idosch@idosch.org>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	netdev <netdev@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 net-next 08/15] net: dsa: sja1105: prepare tagger for handling DSA tags and VLAN simultaneously
Date: Wed, 13 May 2020 03:08:01 +0300	[thread overview]
Message-ID: <CA+h21hq_p=q7L_LFeu3mn3utAXSdA6FUNYFB=4qQ1LJ1J=BTVg@mail.gmail.com> (raw)
In-Reply-To: <202005130724.KFjVH0Y9%lkp@intel.com>

On Wed, 13 May 2020 at 03:02, kbuild test robot <lkp@intel.com> wrote:
>
> Hi Vladimir,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on net-next/master]
> [also build test WARNING on next-20200512]
> [cannot apply to linus/master v5.7-rc5]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system. BTW, we also suggest to use '--base' option to specify the
> base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
>
> url:    https://github.com/0day-ci/linux/commits/Vladimir-Oltean/Traffic-support-for-dsa_8021q-in-vlan_filtering-1-mode/20200513-012422
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 3242956bd610af40e884b530b6c6f76f5bf85f3b
> reproduce:
>         # apt-get install sparse
>         # sparse version: v0.6.1-191-gc51a0382-dirty
>         make ARCH=x86_64 allmodconfig
>         make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kbuild test robot <lkp@intel.com>
>
>
> sparse warnings: (new ones prefixed by >>)
>
> >> net/dsa/tag_sja1105.c:76:34: sparse: sparse: cast to restricted __be16
> >> net/dsa/tag_sja1105.c:76:34: sparse: sparse: cast to restricted __be16
> >> net/dsa/tag_sja1105.c:76:34: sparse: sparse: cast to restricted __be16
> >> net/dsa/tag_sja1105.c:76:34: sparse: sparse: cast to restricted __be16
> >> net/dsa/tag_sja1105.c:76:16: sparse: sparse: restricted __be16 degrades to integer
>    net/dsa/tag_sja1105.c:79:34: sparse: sparse: cast to restricted __be16
>    net/dsa/tag_sja1105.c:79:34: sparse: sparse: cast to restricted __be16
>    net/dsa/tag_sja1105.c:79:34: sparse: sparse: cast to restricted __be16
>    net/dsa/tag_sja1105.c:79:34: sparse: sparse: cast to restricted __be16
>    net/dsa/tag_sja1105.c:79:16: sparse: sparse: restricted __be16 degrades to integer
>
> vim +76 net/dsa/tag_sja1105.c
>
>     71
>     72  static bool sja1105_can_use_vlan_as_tags(const struct sk_buff *skb)
>     73  {
>     74          struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
>     75
>   > 76          if (hdr->h_vlan_proto == ntohs(ETH_P_SJA1105))
>     77                  return true;

Oh my, I really suck at this...
I think it's complaining because I should have called htons instead of ntohs?

>     78
>     79          if (hdr->h_vlan_proto != ntohs(ETH_P_8021Q))
>     80                  return false;
>     81
>     82          return vid_is_dsa_8021q(ntohs(hdr->h_vlan_TCI) & VLAN_VID_MASK);
>     83  }
>     84
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org