Re: [PATCH net-next] mlx4: Better use of order-0 pages in RX path

Hi Eric,

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

url:    https://github.com/0day-ci/linux/commits/Eric-Dumazet/mlx4-Better-use-of-order-0-pages-in-RX-path/20170313-191100
config: x86_64-randconfig-s5-03131942 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   drivers/net/ethernet/mellanox/mlx4/en_rx.c:622:12: warning: 'struct iphdr' declared inside parameter list will not be visible outside of this definition or declaration
        struct iphdr *iph)
               ^~~~~
   In file included from include/linux/swab.h:4:0,
                    from include/uapi/linux/byteorder/little_endian.h:12,
                    from include/linux/byteorder/little_endian.h:4,
                    from arch/x86/include/uapi/asm/byteorder.h:4,
                    from include/asm-generic/bitops/le.h:5,
                    from arch/x86/include/asm/bitops.h:517,
                    from include/linux/bitops.h:36,
                    from include/linux/kernel.h:10,
                    from include/linux/list.h:8,
                    from include/linux/timer.h:4,
                    from include/linux/workqueue.h:8,
                    from include/linux/bpf.h:12,
                    from drivers/net/ethernet/mellanox/mlx4/en_rx.c:34:
   drivers/net/ethernet/mellanox/mlx4/en_rx.c: In function 'get_fixed_ipv4_csum':
   drivers/net/ethernet/mellanox/mlx4/en_rx.c:627:36: error: dereferencing pointer to incomplete type 'struct iphdr'
     length_for_csum = (be16_to_cpu(iph->tot_len) - (iph->ihl << 2));
                                       ^
   include/uapi/linux/swab.h:100:54: note: in definition of macro '__swab16'
    #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
                                                         ^

quoted

include/linux/byteorder/generic.h:96:21: note: in expansion of macro '__be16_to_cpu'

    #define be16_to_cpu __be16_to_cpu
                        ^~~~~~~~~~~~~

quoted

drivers/net/ethernet/mellanox/mlx4/en_rx.c:627:21: note: in expansion of macro 'be16_to_cpu'

     length_for_csum = (be16_to_cpu(iph->tot_len) - (iph->ihl << 2));
                        ^~~~~~~~~~~

vim +/be16_to_cpu +627 drivers/net/ethernet/mellanox/mlx4/en_rx.c

f8c6455b Shani Michaeli 2014-11-09  611  static inline __wsum get_fixed_vlan_csum(__wsum hw_checksum,
f8c6455b Shani Michaeli 2014-11-09  612  					 struct vlan_hdr *vlanh)
f8c6455b Shani Michaeli 2014-11-09  613  {
f8c6455b Shani Michaeli 2014-11-09  614  	return csum_add(hw_checksum, *(__wsum *)vlanh);
f8c6455b Shani Michaeli 2014-11-09  615  }
f8c6455b Shani Michaeli 2014-11-09  616  
f8c6455b Shani Michaeli 2014-11-09  617  /* Although the stack expects checksum which doesn't include the pseudo
f8c6455b Shani Michaeli 2014-11-09  618   * header, the HW adds it. To address that, we are subtracting the pseudo
f8c6455b Shani Michaeli 2014-11-09  619   * header checksum from the checksum value provided by the HW.
f8c6455b Shani Michaeli 2014-11-09  620   */
f8c6455b Shani Michaeli 2014-11-09  621  static void get_fixed_ipv4_csum(__wsum hw_checksum, struct sk_buff *skb,
f8c6455b Shani Michaeli 2014-11-09  622  				struct iphdr *iph)
f8c6455b Shani Michaeli 2014-11-09  623  {
f8c6455b Shani Michaeli 2014-11-09  624  	__u16 length_for_csum = 0;
f8c6455b Shani Michaeli 2014-11-09  625  	__wsum csum_pseudo_header = 0;
f8c6455b Shani Michaeli 2014-11-09  626  
f8c6455b Shani Michaeli 2014-11-09 @627  	length_for_csum = (be16_to_cpu(iph->tot_len) - (iph->ihl << 2));
f8c6455b Shani Michaeli 2014-11-09  628  	csum_pseudo_header = csum_tcpudp_nofold(iph->saddr, iph->daddr,
f8c6455b Shani Michaeli 2014-11-09  629  						length_for_csum, iph->protocol, 0);
f8c6455b Shani Michaeli 2014-11-09  630  	skb->csum = csum_sub(hw_checksum, csum_pseudo_header);
f8c6455b Shani Michaeli 2014-11-09  631  }
f8c6455b Shani Michaeli 2014-11-09  632  
f8c6455b Shani Michaeli 2014-11-09  633  #if IS_ENABLED(CONFIG_IPV6)
f8c6455b Shani Michaeli 2014-11-09  634  /* In IPv6 packets, besides subtracting the pseudo header checksum,
f8c6455b Shani Michaeli 2014-11-09  635   * we also compute/add the IP header checksum which

:::::: The code at line 627 was first introduced by commit
:::::: f8c6455bb04b944edb69e9b074e28efee2c56bdd net/mlx4_en: Extend checksum offloading by CHECKSUM COMPLETE

:::::: TO: Shani Michaeli [off-list ref]
:::::: CC: David S. Miller [off-list ref]

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