Re: [PATCH v4] wifi: iwlwifi: pcie: optimize MSI-X interrupt affinity

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

Hi Adrián,

kernel test robot noticed the following build warnings:

[auto build test WARNING on wireless-next/main]
[also build test WARNING on wireless/main rust/rust-next linus/master v7.0-rc4 next-20260317]
[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/Adri-n-Garc-a-Casado/wifi-iwlwifi-pcie-optimize-MSI-X-interrupt-affinity/20260318-081834
base:   https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git main
patch link:    https://lore.kernel.org/r/20260317193252.13763-1-adriangarciacasado42%40gmail.com
patch subject: [PATCH v4] wifi: iwlwifi: pcie: optimize MSI-X interrupt affinity
config: x86_64-rhel-9.4-kunit (https://download.01.org/0day-ci/archive/20260318/202603182147.ECKLrJRf-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260318/202603182147.ECKLrJRf-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/202603182147.ECKLrJRf-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c: In function 'iwl_pcie_irq_set_affinity':
>> drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c:1675:37: warning: unused variable 'offset' [-Wunused-variable]
    1675 |         int iter_rx_q, i, ret, cpu, offset, last_cpu;
         |                                     ^~~~~~


vim +/offset +1675 drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c

  1670	
  1671	static void iwl_pcie_irq_set_affinity(struct iwl_trans *trans,
  1672					      struct iwl_trans_info *info)
  1673	{
  1674	#if defined(CONFIG_SMP)
> 1675		int iter_rx_q, i, ret, cpu, offset, last_cpu;
  1676		struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
  1677	
  1678		i = trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_FIRST_RSS ? 0 : 1;
  1679		iter_rx_q = info->num_rxqs - 1 + i;
  1680		last_cpu = -1;
  1681		for (; i < iter_rx_q ; i++) {
  1682			/*
  1683			 * Balanced distribution: skip CPU0 for high-rate RSS queues
  1684			 * to avoid contention with system housekeeping.
  1685			 */
  1686			cpu = cpumask_next(last_cpu, cpu_online_mask);
  1687			if (cpu >= nr_cpu_ids)
  1688				cpu = cpumask_first(cpu_online_mask);
  1689	
  1690			if (cpu == 0 && num_online_cpus() > 1) {
  1691				cpu = cpumask_next(0, cpu_online_mask);
  1692				if (cpu >= nr_cpu_ids)
  1693					cpu = cpumask_first(cpu_online_mask);
  1694			}
  1695			last_cpu = cpu;
  1696	
  1697			cpumask_set_cpu(cpu, &trans_pcie->affinity_mask[i]);
  1698			ret = irq_set_affinity_hint(trans_pcie->msix_entries[i].vector,
  1699						    &trans_pcie->affinity_mask[i]);
  1700			if (ret)
  1701				IWL_ERR(trans_pcie->trans,
  1702					"Failed to set affinity mask for IRQ %d\n",
  1703					trans_pcie->msix_entries[i].vector);
  1704		}
  1705	#endif
  1706	}
  1707	

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