Hi SeongJae,

I love your patch! Yet something to improve:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/SeongJae-Park/mm-page_reporting-replace-rcu_access_pointer-with-rcu_dereference_protected/20221228-093057
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20221228012902.1510901-1-sj%40kernel.org
patch subject: [PATCH v2] mm/page_reporting: replace rcu_access_pointer() with rcu_dereference_protected()
config: x86_64-randconfig-a002-20221226
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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/intel-lab-lkp/linux/commit/f7744809d7f12dccff86c60831ddf3c316ada60e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review SeongJae-Park/mm-page_reporting-replace-rcu_access_pointer-with-rcu_dereference_protected/20221228-093057
        git checkout f7744809d7f12dccff86c60831ddf3c316ada60e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

>> mm/page_reporting.c:360:5: error: member reference base type 'typeof (page_reporting_order)' (aka 'unsigned int') is not a structure or union
                                   lockdep_is_held(&page_reporting_order))) {
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/lockdep.h:286:52: note: expanded from macro 'lockdep_is_held'
   #define lockdep_is_held(lock)           lock_is_held(&(lock)->dep_map)
                                                               ^ ~~~~~~~
   include/linux/rcupdate.h:664:54: note: expanded from macro 'rcu_dereference_protected'
           __rcu_dereference_protected((p), __UNIQUE_ID(rcu), (c), __rcu)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~
   include/linux/rcupdate.h:460:21: note: expanded from macro '__rcu_dereference_protected'
           RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); \
           ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/rcupdate.h:381:8: note: expanded from macro 'RCU_LOCKDEP_WARN'
                   if ((c) && debug_lockdep_rcu_enabled() && !__warned) {  \
                        ^
   1 error generated.


vim +360 mm/page_reporting.c

   351	
   352	int page_reporting_register(struct page_reporting_dev_info *prdev)
   353	{
   354		int err = 0;
   355	
   356		mutex_lock(&page_reporting_mutex);
   357	
   358		/* nothing to do if already in use */
   359		if (rcu_dereference_protected(pr_dev_info,
 > 360					lockdep_is_held(&page_reporting_order))) {
   361			err = -EBUSY;
   362			goto err_out;
   363		}
   364	
   365		/*
   366		 * If the page_reporting_order value is not set, we check if
   367		 * an order is provided from the driver that is performing the
   368		 * registration. If that is not provided either, we default to
   369		 * pageblock_order.
   370		 */
   371	
   372		if (page_reporting_order == -1) {
   373			if (prdev->order > 0 && prdev->order <= MAX_ORDER)
   374				page_reporting_order = prdev->order;
   375			else
   376				page_reporting_order = pageblock_order;
   377		}
   378	
   379		/* initialize state and work structures */
   380		atomic_set(&prdev->state, PAGE_REPORTING_IDLE);
   381		INIT_DELAYED_WORK(&prdev->work, &page_reporting_process);
   382	
   383		/* Begin initial flush of zones */
   384		__page_reporting_request(prdev);
   385	
   386		/* Assign device to allow notifications */
   387		rcu_assign_pointer(pr_dev_info, prdev);
   388	
   389		/* enable page reporting notification */
   390		if (!static_key_enabled(&page_reporting_enabled)) {
   391			static_branch_enable(&page_reporting_enabled);
   392			pr_info("Free page reporting enabled\n");
   393		}
   394	err_out:
   395		mutex_unlock(&page_reporting_mutex);
   396	
   397		return err;
   398	}
   399	EXPORT_SYMBOL_GPL(page_reporting_register);
   400	

-- 
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