Re: [PATCH v7 08/10] blk-mq: use hk cpus only when isolcpus=io_queue is enabled

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

Hi Daniel,

kernel test robot noticed the following build errors:

[auto build test ERROR on 32f85e8468ce081d8e73ca3f0d588f1004013037]

url:    https://github.com/intel-lab-lkp/linux/commits/Daniel-Wagner/lib-group_cpus-Add-group_masks_cpus_evenly/20250703-003811
base:   32f85e8468ce081d8e73ca3f0d588f1004013037
patch link:    https://lore.kernel.org/r/20250702-isolcpus-io-queues-v7-8-557aa7eacce4%40kernel.org
patch subject: [PATCH v7 08/10] blk-mq: use hk cpus only when isolcpus=io_queue is enabled
config: arm-allnoconfig (https://download.01.org/0day-ci/archive/20250703/202507032238.AoTmQnGP-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f1a4bb62452d88a0edd9340b3ca7c9b11ad9193f)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250703/202507032238.AoTmQnGP-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/202507032238.AoTmQnGP-lkp@intel.com/

All errors (new ones prefixed by >>):

>> block/blk-mq-cpumap.c:155:16: error: array initializer must be an initializer list
     155 |         cpumask_var_t active_hctx __free(free_cpumask_var) = NULL;
         |                       ^
   block/blk-mq-cpumap.c:219:16: error: array initializer must be an initializer list
     219 |         cpumask_var_t active_hctx __free(free_cpumask_var) = NULL;
         |                       ^
   block/blk-mq-cpumap.c:220:16: error: array initializer must be an initializer list
     220 |         cpumask_var_t mask __free(free_cpumask_var) = NULL;
         |                       ^
   3 errors generated.


vim +155 block/blk-mq-cpumap.c

   144	
   145	/*
   146	 * blk_mq_map_hk_queues - Create housekeeping CPU to
   147	 *                        hardware queue mapping
   148	 * @qmap:	CPU to hardware queue map
   149	 *
   150	 * Create a housekeeping CPU to hardware queue mapping in @qmap. @qmap
   151	 * contains a valid configuration honoring the isolcpus configuration.
   152	 */
   153	static void blk_mq_map_hk_queues(struct blk_mq_queue_map *qmap)
   154	{
 > 155		cpumask_var_t active_hctx __free(free_cpumask_var) = NULL;
   156		struct cpumask *hk_masks __free(kfree) = NULL;
   157		const struct cpumask *mask;
   158		unsigned int queue, cpu, nr_masks;
   159	
   160		if (housekeeping_enabled(HK_TYPE_IO_QUEUE))
   161			mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE);
   162		else
   163			goto fallback;
   164	
   165		if (!zalloc_cpumask_var(&active_hctx, GFP_KERNEL))
   166			goto fallback;
   167	
   168		/* Map housekeeping CPUs to a hctx */
   169		hk_masks = group_mask_cpus_evenly(qmap->nr_queues, mask, &nr_masks);
   170		if (!hk_masks)
   171			goto fallback;
   172	
   173		for (queue = 0; queue < qmap->nr_queues; queue++) {
   174			unsigned int idx = (qmap->queue_offset + queue) % nr_masks;
   175	
   176			for_each_cpu(cpu, &hk_masks[idx]) {
   177				qmap->mq_map[cpu] = idx;
   178	
   179				if (cpu_online(cpu))
   180					cpumask_set_cpu(qmap->mq_map[cpu], active_hctx);
   181			}
   182		}
   183	
   184		/* Map isolcpus to hardware context */
   185		queue = cpumask_first(active_hctx);
   186		for_each_cpu_andnot(cpu, cpu_possible_mask, mask) {
   187			qmap->mq_map[cpu] = (qmap->queue_offset + queue) % nr_masks;
   188			queue = cpumask_next_wrap(queue, active_hctx);
   189		}
   190	
   191		if (!blk_mq_hk_validate(qmap, active_hctx))
   192			goto fallback;
   193	
   194		return;
   195	
   196	fallback:
   197		/*
   198		 * Map all CPUs to the first hctx to ensure at least one online
   199		 * housekeeping CPU is serving it.
   200		 */
   201		for_each_possible_cpu(cpu)
   202			qmap->mq_map[cpu] = 0;
   203	}
   204	

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