Hi Jeremy,

I love your patch! Perhaps something to improve:

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

url:    https://github.com/0day-ci/linux/commits/Jeremy-Kerr/mctp-Return-new-key-from-mctp_alloc_local_tag/20211028-142024
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 5a48585d7ec1d0e1e83539d56846c1e513ef66ea
config: hexagon-randconfig-r005-20211027 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 5db7568a6a1fcb408eb8988abdaff2a225a8eb72)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/587328c0d21081a26183368afcf4874a210889c3
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Jeremy-Kerr/mctp-Return-new-key-from-mctp_alloc_local_tag/20211028-142024
        git checkout 587328c0d21081a26183368afcf4874a210889c3
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=hexagon 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

quoted

net/core/skbuff.c:6572:5: warning: 'CONFIG_MCTP_FLOWS' is not defined, evaluates to 0 [-Wundef]

   #if CONFIG_MCTP_FLOWS
       ^
   1 warning generated.


vim +/CONFIG_MCTP_FLOWS +6572 net/core/skbuff.c

  6556	
  6557	void __skb_ext_put(struct skb_ext *ext)
  6558	{
  6559		/* If this is last clone, nothing can increment
  6560		 * it after check passes.  Avoids one atomic op.
  6561		 */
  6562		if (refcount_read(&ext->refcnt) == 1)
  6563			goto free_now;
  6564	
  6565		if (!refcount_dec_and_test(&ext->refcnt))
  6566			return;
  6567	free_now:
  6568	#ifdef CONFIG_XFRM
  6569		if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH))
  6570			skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH));
  6571	#endif

6572	#if CONFIG_MCTP_FLOWS

---
0-DAY CI Kernel Test Service, Intel Corporation
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