Re: [net-next PATCH 11/11] net: ravb: Add VLAN checksum support

[kernel test robot <lkp@intel.com>]

Hi Paul,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Paul-Barker/net-ravb-Factor-out-checksum-offload-enable-bits/20241001-001351
base:   net-next/main
patch link:    https://lore.kernel.org/r/20240930160845.8520-12-paul%40pbarker.dev
patch subject: [net-next PATCH 11/11] net: ravb: Add VLAN checksum support
config: arc-randconfig-r123-20241001 (https://download.01.org/0day-ci/archive/20241002/202410020057.Z9KJHqVt-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 13.2.0
reproduce: (https://download.01.org/0day-ci/archive/20241002/202410020057.Z9KJHqVt-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410020057.Z9KJHqVt-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/net/ethernet/renesas/ravb_main.c:2076:17: sparse: sparse: restricted __be16 degrades to integer
   drivers/net/ethernet/renesas/ravb_main.c: note: in included file (through include/linux/mutex.h, include/linux/notifier.h, include/linux/clk.h):
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true

vim +2076 drivers/net/ethernet/renesas/ravb_main.c

  2063	
  2064	static bool ravb_can_tx_csum_gbeth(struct sk_buff *skb)
  2065	{
  2066		u16 net_protocol = ntohs(skb->protocol);
  2067	
  2068		/* GbEth IP can calculate the checksum if:
  2069		 * - there are zero or one VLAN headers with TPID=0x8100
  2070		 * - the network protocol is IPv4 or IPv6
  2071		 * - the transport protocol is TCP, UDP or ICMP
  2072		 * - the packet is not fragmented
  2073		 */
  2074	
  2075		if (skb_vlan_tag_present(skb) &&
> 2076		    (skb->vlan_proto != ETH_P_8021Q || net_protocol == ETH_P_8021Q))
  2077			return false;
  2078	
  2079		if (net_protocol == ETH_P_8021Q) {
  2080			struct vlan_hdr vhdr, *vh;
  2081	
  2082			vh = skb_header_pointer(skb, ETH_HLEN, sizeof(vhdr), &vhdr);
  2083			if (!vh)
  2084				return false;
  2085	
  2086			net_protocol = ntohs(vh->h_vlan_encapsulated_proto);
  2087		}
  2088	
  2089		switch (net_protocol) {
  2090		case ETH_P_IP:
  2091			switch (ip_hdr(skb)->protocol) {
  2092			case IPPROTO_TCP:
  2093			case IPPROTO_UDP:
  2094			case IPPROTO_ICMP:
  2095				return true;
  2096			}
  2097			break;
  2098	
  2099		case ETH_P_IPV6:
  2100			switch (ipv6_hdr(skb)->nexthdr) {
  2101			case IPPROTO_TCP:
  2102			case IPPROTO_UDP:
  2103			case IPPROTO_ICMPV6:
  2104				return true;
  2105			}
  2106		}
  2107	
  2108		return false;
  2109	}
  2110	

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