Re: [PATCH V3 1/2] md: don't unregister sync_thread with reconfig_mutex held

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

Hi Guoqing,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on song-md/md-next]
[also build test WARNING on v5.18-rc5 next-20220505]
[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/intel-lab-lkp/linux/commits/Guoqing-Jiang/two-fixes-for-md/20220505-162202
base:   git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git md-next
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20220505/202205052148.TTOFRBQx-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 11.3.0
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/intel-lab-lkp/linux/commit/e8e9c97eb79c337a89a98a92106cfa6139a7c9e0
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Guoqing-Jiang/two-fixes-for-md/20220505-162202
        git checkout e8e9c97eb79c337a89a98a92106cfa6139a7c9e0
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash drivers/md/

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/md/md.c: In function 'md_reap_sync_thread':
>> drivers/md/md.c:9448:17: warning: ignoring return value of 'mddev_lock' declared with attribute 'warn_unused_result' [-Wunused-result]
    9448 |                 mddev_lock(mddev);
         |                 ^~~~~~~~~~~~~~~~~


vim +9448 drivers/md/md.c

  9434	
  9435	void md_reap_sync_thread(struct mddev *mddev)
  9436	{
  9437		struct md_rdev *rdev;
  9438		sector_t old_dev_sectors = mddev->dev_sectors;
  9439		bool is_reshaped = false, is_locked = false;
  9440	
  9441		if (mddev_is_locked(mddev)) {
  9442			is_locked = true;
  9443			mddev_unlock(mddev);
  9444		}
  9445		/* resync has finished, collect result */
  9446		md_unregister_thread(&mddev->sync_thread);
  9447		if (is_locked)
> 9448			mddev_lock(mddev);
  9449	
  9450		if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
  9451		    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
  9452		    mddev->degraded != mddev->raid_disks) {
  9453			/* success...*/
  9454			/* activate any spares */
  9455			if (mddev->pers->spare_active(mddev)) {
  9456				sysfs_notify_dirent_safe(mddev->sysfs_degraded);
  9457				set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
  9458			}
  9459		}
  9460		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
  9461		    mddev->pers->finish_reshape) {
  9462			mddev->pers->finish_reshape(mddev);
  9463			if (mddev_is_clustered(mddev))
  9464				is_reshaped = true;
  9465		}
  9466	
  9467		/* If array is no-longer degraded, then any saved_raid_disk
  9468		 * information must be scrapped.
  9469		 */
  9470		if (!mddev->degraded)
  9471			rdev_for_each(rdev, mddev)
  9472				rdev->saved_raid_disk = -1;
  9473	
  9474		md_update_sb(mddev, 1);
  9475		/* MD_SB_CHANGE_PENDING should be cleared by md_update_sb, so we can
  9476		 * call resync_finish here if MD_CLUSTER_RESYNC_LOCKED is set by
  9477		 * clustered raid */
  9478		if (test_and_clear_bit(MD_CLUSTER_RESYNC_LOCKED, &mddev->flags))
  9479			md_cluster_ops->resync_finish(mddev);
  9480		clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
  9481		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
  9482		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
  9483		clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
  9484		clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
  9485		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
  9486		/*
  9487		 * We call md_cluster_ops->update_size here because sync_size could
  9488		 * be changed by md_update_sb, and MD_RECOVERY_RESHAPE is cleared,
  9489		 * so it is time to update size across cluster.
  9490		 */
  9491		if (mddev_is_clustered(mddev) && is_reshaped
  9492					      && !test_bit(MD_CLOSING, &mddev->flags))
  9493			md_cluster_ops->update_size(mddev, old_dev_sectors);
  9494		wake_up(&resync_wait);
  9495		/* flag recovery needed just to double check */
  9496		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
  9497		sysfs_notify_dirent_safe(mddev->sysfs_action);
  9498		md_new_event();
  9499		if (mddev->event_work.func)
  9500			queue_work(md_misc_wq, &mddev->event_work);
  9501	}
  9502	EXPORT_SYMBOL(md_reap_sync_thread);
  9503	

-- 
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