Re: [PATCH] net/mlx4: Treat VFs fair when handling comm_channel_events

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

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Hi Hans,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on rdma/for-next]
[also build test WARNING on linus/master v5.12-rc7 next-20210414]
[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/Hans-Westgaard-Ry/net-mlx4-Treat-VFs-fair-when-handling-comm_channel_events/20210415-194619
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next
config: arc-allyesconfig (attached as .config)
compiler: arceb-elf-gcc (GCC) 9.3.0
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/9de686423c117ccefb2c09e57ab16f84f0434c68
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Hans-Westgaard-Ry/net-mlx4-Treat-VFs-fair-when-handling-comm_channel_events/20210415-194619
        git checkout 9de686423c117ccefb2c09e57ab16f84f0434c68
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arc 

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/ethernet/mellanox/mlx4/cmd.c: In function 'mlx4_master_comm_channel':
>> drivers/net/ethernet/mellanox/mlx4/cmd.c:2251:6: warning: variable 'prev_slave' set but not used [-Wunused-but-set-variable]
    2251 |  u32 prev_slave;
         |      ^~~~~~~~~~


vim +/prev_slave +2251 drivers/net/ethernet/mellanox/mlx4/cmd.c

  2230	
  2231	/* master command processing */
  2232	void mlx4_master_comm_channel(struct work_struct *work)
  2233	{
  2234		struct mlx4_mfunc_master_ctx *master =
  2235			container_of(work,
  2236				     struct mlx4_mfunc_master_ctx,
  2237				     comm_work);
  2238		struct mlx4_mfunc *mfunc =
  2239			container_of(master, struct mlx4_mfunc, master);
  2240		struct mlx4_priv *priv =
  2241			container_of(mfunc, struct mlx4_priv, mfunc);
  2242		struct mlx4_dev *dev = &priv->dev;
  2243		u32 comm_cmd;
  2244		int i, slave;
  2245		int toggle;
  2246		int served = 0;
  2247		int reported = 0;
  2248		u32 slt;
  2249		u32 lbit_vec[COMM_CHANNEL_BIT_ARRAY_SIZE];
  2250		u32 nmbr_bits;
> 2251		u32 prev_slave;
  2252		bool first = true;
  2253	
  2254		for (i = 0; i < COMM_CHANNEL_BIT_ARRAY_SIZE; i++)
  2255			lbit_vec[i] = be32_to_cpu(master->comm_arm_bit_vector[i]);
  2256		nmbr_bits = dev->persist->num_vfs + 1;
  2257		if (++priv->next_slave >= nmbr_bits)
  2258			priv->next_slave = 0;
  2259		slave = priv->next_slave;
  2260		while (true) {
  2261			slave = find_next_bit((const unsigned long *)&lbit_vec, nmbr_bits, slave);
  2262			if  (!first && slave >= priv->next_slave) {
  2263				break;
  2264			} else if (slave == nmbr_bits) {
  2265				if (!first)
  2266					break;
  2267				first = false;
  2268				slave = 0;
  2269				continue;
  2270			}
  2271			++reported;
  2272			comm_cmd = swab32(readl(&mfunc->comm[slave].slave_write));
  2273			slt = swab32(readl(&mfunc->comm[slave].slave_read)) >> 31;
  2274			toggle = comm_cmd >> 31;
  2275			if (toggle != slt) {
  2276				if (master->slave_state[slave].comm_toggle
  2277				    != slt) {
  2278					pr_info("slave %d out of sync. read toggle %d, state toggle %d. Resynching.\n",
  2279						slave, slt,
  2280						master->slave_state[slave].comm_toggle);
  2281					master->slave_state[slave].comm_toggle =
  2282						slt;
  2283				}
  2284				mlx4_master_do_cmd(dev, slave,
  2285						   comm_cmd >> 16 & 0xff,
  2286						   comm_cmd & 0xffff, toggle);
  2287				++served;
  2288			}
  2289			prev_slave = slave++;
  2290		}
  2291	
  2292		if (reported && reported != served)
  2293			mlx4_warn(dev, "Got command event with bitmask from %d slaves but %d were served %x %d\n",
  2294				  reported, served, lbit_vec[0], priv->next_slave);
  2295	
  2296		if (mlx4_ARM_COMM_CHANNEL(dev))
  2297			mlx4_warn(dev, "Failed to arm comm channel events\n");
  2298	}
  2299	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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