Re: [RFC PATCH 2/5] driver/net/tun: Added features for USO.

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

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Hi Andrew,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on net-next/master]
[also build test WARNING on net/master mst-vhost/linux-next linus/master v5.17-rc1 next-20220125]
[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]

url:    https://github.com/0day-ci/linux/commits/Andrew-Melnychenko/TUN-VirtioNet-USO-features-support/20220125-171057
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 6e667749271e58d34238cf700e543beabdbe6184
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20220125/202201252316.Wm0ucNBh-lkp(a)intel.com/config)
compiler: mips-linux-gcc (GCC) 11.2.0
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/3c1c2daa10c8eac3d9b546fa8caf99fcb5a40454
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Andrew-Melnychenko/TUN-VirtioNet-USO-features-support/20220125-171057
        git checkout 3c1c2daa10c8eac3d9b546fa8caf99fcb5a40454
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=mips SHELL=/bin/bash drivers/net/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/net/tap.c: In function 'set_offload':
>> drivers/net/tap.c:945:25: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
     945 |                 if (arg & (TUN_F_USO4 | TUN_F_USO6) == (TUN_F_USO4 | TUN_F_USO6))
         |                         ^
   drivers/net/tap.c:958:26: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
     958 |             feature_mask & (TUN_F_USO4 | TUN_F_USO6) == (TUN_F_USO4 | TUN_F_USO6))
         |                          ^


vim +945 drivers/net/tap.c

   919	
   920	static int set_offload(struct tap_queue *q, unsigned long arg)
   921	{
   922		struct tap_dev *tap;
   923		netdev_features_t features;
   924		netdev_features_t feature_mask = 0;
   925	
   926		tap = rtnl_dereference(q->tap);
   927		if (!tap)
   928			return -ENOLINK;
   929	
   930		features = tap->dev->features;
   931	
   932		if (arg & TUN_F_CSUM) {
   933			feature_mask = NETIF_F_HW_CSUM;
   934	
   935			if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
   936				if (arg & TUN_F_TSO_ECN)
   937					feature_mask |= NETIF_F_TSO_ECN;
   938				if (arg & TUN_F_TSO4)
   939					feature_mask |= NETIF_F_TSO;
   940				if (arg & TUN_F_TSO6)
   941					feature_mask |= NETIF_F_TSO6;
   942			}
   943	
   944			/* TODO: for now USO4 and USO6 should work simultaneously */
 > 945			if (arg & (TUN_F_USO4 | TUN_F_USO6) == (TUN_F_USO4 | TUN_F_USO6))
   946				features |= NETIF_F_GSO_UDP_L4;
   947		}
   948	
   949		/* tun/tap driver inverts the usage for TSO offloads, where
   950		 * setting the TSO bit means that the userspace wants to
   951		 * accept TSO frames and turning it off means that user space
   952		 * does not support TSO.
   953		 * For tap, we have to invert it to mean the same thing.
   954		 * When user space turns off TSO, we turn off GSO/LRO so that
   955		 * user-space will not receive TSO frames.
   956		 */
   957		if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6) ||
   958		    feature_mask & (TUN_F_USO4 | TUN_F_USO6) == (TUN_F_USO4 | TUN_F_USO6))
   959			features |= RX_OFFLOADS;
   960		else
   961			features &= ~RX_OFFLOADS;
   962	
   963		/* tap_features are the same as features on tun/tap and
   964		 * reflect user expectations.
   965		 */
   966		tap->tap_features = feature_mask;
   967		if (tap->update_features)
   968			tap->update_features(tap, features);
   969	
   970		return 0;
   971	}
   972	

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