Hi Wang,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on v4.19]
[also build test WARNING on next-20181019]
[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/Wang-Hai/Change-judgment-len-position/20181025-010812
config: i386-randconfig-x002-201842 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   In file included from include/linux/compiler_types.h:64:0,
                    from <command-line>:0:
   net/ipv4/tcp.c: In function 'do_tcp_getsockopt':
>> include/linux/compiler-gcc.h:82:45: warning: 'len' is used uninitialized in this function [-Wuninitialized]
    #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
                                                ^~~~~~~~~~~~
   net/ipv4/tcp.c:3302:11: note: 'len' was declared here
     int val, len;
              ^~~
--
   In file included from include/linux/compiler_types.h:64:0,
                    from <command-line>:0:
   net//ipv4/tcp.c: In function 'do_tcp_getsockopt':
>> include/linux/compiler-gcc.h:82:45: warning: 'len' is used uninitialized in this function [-Wuninitialized]
    #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
                                                ^~~~~~~~~~~~
   net//ipv4/tcp.c:3302:11: note: 'len' was declared here
     int val, len;
              ^~~

vim +/len +82 include/linux/compiler-gcc.h

87358710 David Woodhouse 2018-02-19  81  
cb984d10 Joe Perches     2015-06-25 @82  #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
cb984d10 Joe Perches     2015-06-25  83  

:::::: The code at line 82 was first introduced by commit
:::::: cb984d101b30eb7478d32df56a0023e4603cba7f compiler-gcc: integrate the various compiler-gcc[345].h files

:::::: TO: Joe Perches <joe@perches.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation