Re: [PATCH net-next v3 23/27] virtio_net: xsk: rx: support recv merge mode

[kernel test robot <lkp@intel.com>]

Hi Xuan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on mst-vhost/linux-next]
[cannot apply to net-next/main linus/master horms-ipvs/master v6.7-rc7 next-20231222]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Xuan-Zhuo/virtio_net-rename-free_old_xmit_skbs-to-free_old_xmit/20231229-155253
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
patch link:    https://lore.kernel.org/r/20231229073108.57778-24-xuanzhuo%40linux.alibaba.com
patch subject: [PATCH net-next v3 23/27] virtio_net: xsk: rx: support recv merge mode
config: arm64-defconfig (https://download.01.org/0day-ci/archive/20231230/202312300808.efv5HGcd-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231230/202312300808.efv5HGcd-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/202312300808.efv5HGcd-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/net/virtio/main.c: In function 'virtnet_receive':
>> drivers/net/virtio/main.c:1895:27: warning: variable 'pctx' set but not used [-Wunused-but-set-variable]
    1895 |         void *buf, *ctx, *pctx = NULL;
         |                           ^~~~


vim +/pctx +1895 drivers/net/virtio/main.c

  1889	
  1890	static int virtnet_receive(struct virtnet_rq *rq, int budget,
  1891				   unsigned int *xdp_xmit)
  1892	{
  1893		struct virtnet_info *vi = rq->vq->vdev->priv;
  1894		struct virtnet_rq_stats stats = {};
> 1895		void *buf, *ctx, *pctx = NULL;
  1896		unsigned int len;
  1897		int packets = 0;
  1898		int i;
  1899	
  1900		if (rq->xsk.pool) {
  1901			struct sk_buff *skb;
  1902	
  1903			while (packets < budget) {
  1904				buf = virtqueue_get_buf(rq->vq, &len);
  1905				if (!buf)
  1906					break;
  1907	
  1908				skb = virtnet_receive_xsk_buf(vi, rq, buf, len, xdp_xmit, &stats);
  1909				if (skb)
  1910					virtnet_receive_done(vi, rq, skb);
  1911	
  1912				packets++;
  1913			}
  1914		} else {
  1915			if (!vi->big_packets || vi->mergeable_rx_bufs)
  1916				pctx = &ctx;
  1917			else
  1918				ctx = NULL;
  1919	
  1920			while (packets < budget) {
  1921				buf = virtnet_rq_get_buf(rq, &len, &ctx);
  1922				if (!buf)
  1923					break;
  1924	
  1925				receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &stats);
  1926				packets++;
  1927			}
  1928		}
  1929	
  1930		if (rq->vq->num_free > min((unsigned int)budget, virtqueue_get_vring_size(rq->vq)) / 2) {
  1931			if (!try_fill_recv(vi, rq, GFP_ATOMIC)) {
  1932				spin_lock(&vi->refill_lock);
  1933				if (vi->refill_enabled)
  1934					schedule_delayed_work(&vi->refill, 0);
  1935				spin_unlock(&vi->refill_lock);
  1936			}
  1937		}
  1938	
  1939		u64_stats_set(&stats.packets, packets);
  1940		u64_stats_update_begin(&rq->stats.syncp);
  1941		for (i = 0; i < VIRTNET_RQ_STATS_LEN; i++) {
  1942			size_t offset = virtnet_rq_stats_desc[i].offset;
  1943			u64_stats_t *item, *src;
  1944	
  1945			item = (u64_stats_t *)((u8 *)&rq->stats + offset);
  1946			src = (u64_stats_t *)((u8 *)&stats + offset);
  1947			u64_stats_add(item, u64_stats_read(src));
  1948		}
  1949		u64_stats_update_end(&rq->stats.syncp);
  1950	
  1951		return packets;
  1952	}
  1953	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki