Re: [PATCH v3 net-next] net: advance skb_defer_disable_key check in napi_consume_skb

Re: [PATCH v3 net-next] net: advance skb_defer_disable_key check in napi_consume_skb

[kernel test robot]

Hi Jason,

kernel test robot noticed the following build errors:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Jason-Xing/net-advance-skb_defer_disable_key-check-in-napi_consume_skb/20260403-115110
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260401033211.44463-1-kerneljasonxing%40gmail.com
patch subject: [PATCH v3 net-next] net: advance skb_defer_disable_key check in napi_consume_skb
config: x86_64-buildonly-randconfig-005-20260403 (https://download.01.org/0day-ci/archive/20260403/202604031607.o753ScQ1-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260403/202604031607.o753ScQ1-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/202604031607.o753ScQ1-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/core/skbuff.c:1522:31: error: use of undeclared identifier 'skb_defer_disable_key'
    1522 |         if (!static_branch_unlikely(&skb_defer_disable_key) &&
         |                                      ^
>> net/core/skbuff.c:1522:31: error: use of undeclared identifier 'skb_defer_disable_key'
>> net/core/skbuff.c:1522:31: error: use of undeclared identifier 'skb_defer_disable_key'
>> net/core/skbuff.c:1522:31: error: use of undeclared identifier 'skb_defer_disable_key'
   4 errors generated.


vim +/skb_defer_disable_key +1522 net/core/skbuff.c

  1500	
  1501	/**
  1502	 * napi_consume_skb() - consume skb in NAPI context, try to feed skb cache
  1503	 * @skb: buffer to free
  1504	 * @budget: NAPI budget
  1505	 *
  1506	 * Non-zero @budget must come from the @budget argument passed by the core
  1507	 * to a NAPI poll function. Note that core may pass budget of 0 to NAPI poll
  1508	 * for example when polling for netpoll / netconsole.
  1509	 *
  1510	 * Passing @budget of 0 is safe from any context, it turns this function
  1511	 * into dev_consume_skb_any().
  1512	 */
  1513	void napi_consume_skb(struct sk_buff *skb, int budget)
  1514	{
  1515		if (unlikely(!budget || !skb)) {
  1516			dev_consume_skb_any(skb);
  1517			return;
  1518		}
  1519	
  1520		DEBUG_NET_WARN_ON_ONCE(!in_softirq());
  1521	
> 1522		if (!static_branch_unlikely(&skb_defer_disable_key) &&
  1523		    skb->alloc_cpu != smp_processor_id() && !skb_shared(skb)) {
  1524			skb_release_head_state(skb);
  1525			return skb_attempt_defer_free(skb);
  1526		}
  1527	
  1528		if (!skb_unref(skb))
  1529			return;
  1530	
  1531		/* if reaching here SKB is ready to free */
  1532		trace_consume_skb(skb, __builtin_return_address(0));
  1533	
  1534		/* if SKB is a clone, don't handle this case */
  1535		if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
  1536			__kfree_skb(skb);
  1537			return;
  1538		}
  1539	
  1540		skb_release_all(skb, SKB_CONSUMED);
  1541		napi_skb_cache_put(skb);
  1542	}
  1543	EXPORT_SYMBOL(napi_consume_skb);
  1544	

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