Subject: Re: [PATCH bpf-next v1 1/2] xdp: recycle Page Pool backed skbs built from XDP frames

From: kernel test robot <[email-masked]>
Date: Thu, 2 Mar 2023 03:18:49 +0800

Hi Alexander,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Alexander-Lobakin/xdp-recycle-Page-Pool-backed-skbs-built-from-XDP-frames/20230302-000635
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230301160315.1022488-2-aleksander.lobakin%40intel.com
patch subject: [PATCH bpf-next v1 1/2] xdp: recycle Page Pool backed skbs built from XDP frames
config: x86_64-randconfig-a014 (https://download.01.org/0day-ci/archive/20230302/[email-masked]/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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/intel-lab-lkp/linux/commit/a5ca5578e9bd35220be091fd02df96d492120ee3
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Alexander-Lobakin/xdp-recycle-Page-Pool-backed-skbs-built-from-XDP-frames/20230302-000635
        git checkout a5ca5578e9bd35220be091fd02df96d492120ee3
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email-masked]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

All errors (new ones prefixed by >>):

>> net/core/xdp.c:662:3: error: implicit declaration of function 'skb_mark_for_recycle' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                   skb_mark_for_recycle(skb);
                   ^
   1 error generated.

vim +/skb_mark_for_recycle +662 net/core/xdp.c

   614	
   615	struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
   616						   struct sk_buff *skb,
   617						   struct net_device *dev)
   618	{
   619		struct skb_shared_info *sinfo = xdp_get_shared_info_from_frame(xdpf);
   620		unsigned int headroom, frame_size;
   621		void *hard_start;
   622		u8 nr_frags;
   623	
   624		/* xdp frags frame */
   625		if (unlikely(xdp_frame_has_frags(xdpf)))
   626			nr_frags = sinfo->nr_frags;
   627	
   628		/* Part of headroom was reserved to xdpf */
   629		headroom = sizeof(*xdpf) + xdpf->headroom;
   630	
   631		/* Memory size backing xdp_frame data already have reserved
   632		 * room for build_skb to place skb_shared_info in tailroom.
   633		 */
   634		frame_size = xdpf->frame_sz;
   635	
   636		hard_start = xdpf->data - headroom;
   637		skb = build_skb_around(skb, hard_start, frame_size);
   638		if (unlikely(!skb))
   639			return NULL;
   640	
   641		skb_reserve(skb, headroom);
   642		__skb_put(skb, xdpf->len);
   643		if (xdpf->metasize)
   644			skb_metadata_set(skb, xdpf->metasize);
   645	
   646		if (unlikely(xdp_frame_has_frags(xdpf)))
   647			xdp_update_skb_shared_info(skb, nr_frags,
   648						   sinfo->xdp_frags_size,
   649						   nr_frags * xdpf->frame_sz,
   650						   xdp_frame_is_frag_pfmemalloc(xdpf));
   651	
   652		/* Essential SKB info: protocol and skb->dev */
   653		skb->protocol = eth_type_trans(skb, dev);
   654	
   655		/* Optional SKB info, currently missing:
   656		 * - HW checksum info		(skb->ip_summed)
   657		 * - HW RX hash			(skb_set_hash)
   658		 * - RX ring dev queue index	(skb_record_rx_queue)
   659		 */
   660	
   661		if (xdpf->mem.type == MEM_TYPE_PAGE_POOL)
 > 662			skb_mark_for_recycle(skb);
   663	
   664		/* Allow SKB to reuse area used by xdp_frame */
   665		xdp_scrub_frame(xdpf);
   666	
   667		return skb;
   668	}
   669	EXPORT_SYMBOL_GPL(__xdp_build_skb_from_frame);
   670	

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