Hi wenxu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net/master]
[also build test WARNING on v5.0-rc4 next-20190222]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/wenxu-ucloud-cn/ip_tunnel-Add-ip-tunnel-tunnel_info-dst_cache-in-ip_tunnel_xmit/20190224-065214
config: x86_64-randconfig-x016-201908 (attached as .config)
compiler: gcc-8 (Debian 8.2.0-20) 8.2.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   In file included from net/ipv4/ip_tunnel.c:48:
   net/ipv4/ip_tunnel.c: In function 'ip_tunnel_xmit':
>> include/net/ip_tunnels.h:207:15: warning: 'tun_info' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (info->key.tun_flags & TUNNEL_NOCACHE)
         ~~~~~~~~~^~~~~~~~~~
   net/ipv4/ip_tunnel.c:640:25: note: 'tun_info' was declared here
     struct ip_tunnel_info *tun_info;
                            ^~~~~~~~
   net/ipv4/ip_tunnel.c:734:5: warning: 'rt' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (!rt) {
        ^
--
   In file included from net//ipv4/ip_tunnel.c:48:
   net//ipv4/ip_tunnel.c: In function 'ip_tunnel_xmit':
>> include/net/ip_tunnels.h:207:15: warning: 'tun_info' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (info->key.tun_flags & TUNNEL_NOCACHE)
         ~~~~~~~~~^~~~~~~~~~
   net//ipv4/ip_tunnel.c:640:25: note: 'tun_info' was declared here
     struct ip_tunnel_info *tun_info;
                            ^~~~~~~~
   net//ipv4/ip_tunnel.c:734:5: warning: 'rt' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (!rt) {
        ^

vim +/tun_info +207 include/net/ip_tunnels.h

1d8fff90 Thomas Graf     2015-07-21  198  
db3c6139 Daniel Borkmann 2016-03-04  199  static inline bool
db3c6139 Daniel Borkmann 2016-03-04  200  ip_tunnel_dst_cache_usable(const struct sk_buff *skb,
db3c6139 Daniel Borkmann 2016-03-04  201  			   const struct ip_tunnel_info *info)
db3c6139 Daniel Borkmann 2016-03-04  202  {
db3c6139 Daniel Borkmann 2016-03-04  203  	if (skb->mark)
db3c6139 Daniel Borkmann 2016-03-04  204  		return false;
db3c6139 Daniel Borkmann 2016-03-04  205  	if (!info)
db3c6139 Daniel Borkmann 2016-03-04  206  		return true;
db3c6139 Daniel Borkmann 2016-03-04 @207  	if (info->key.tun_flags & TUNNEL_NOCACHE)
db3c6139 Daniel Borkmann 2016-03-04  208  		return false;
db3c6139 Daniel Borkmann 2016-03-04  209  
db3c6139 Daniel Borkmann 2016-03-04  210  	return true;
db3c6139 Daniel Borkmann 2016-03-04  211  }
db3c6139 Daniel Borkmann 2016-03-04  212  

:::::: The code at line 207 was first introduced by commit
:::::: db3c6139e6ead91b42e7c2ad044ed8beaee884e6 bpf, vxlan, geneve, gre: fix usage of dst_cache on xmit

:::::: TO: Daniel Borkmann <daniel@iogearbox.net>
:::::: CC: David S. Miller <davem@davemloft.net>

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