[PATCH v2] vfio/pci: Propagate ACPI notifications to user-space via eventfd

[kernel test robot]

Hi Grzegorz,

kernel test robot noticed the following build warnings:

[auto build test WARNING on awilliam-vfio/for-linus]
[also build test WARNING on linus/master v6.3 next-20230424]
[cannot apply to awilliam-vfio/next]
[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/Grzegorz-Jaszczyk/vfio-pci-Propagate-ACPI-notifications-to-user-space-via-eventfd/20230425-002935
base:   https://github.com/awilliam/linux-vfio.git for-linus
patch link:    https://lore.kernel.org/r/20230424162748.2711945-1-jaz%40semihalf.com
patch subject: [PATCH v2] vfio/pci: Propagate ACPI notifications to user-space via eventfd
config: x86_64-randconfig-a012 (https://download.01.org/0day-ci/archive/20230425/202304250702.Jn8hOwUl-lkp@intel.com/config)
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/62d759059cd5e6dab70052027e1b69c5d5cdc0f2
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Grzegorz-Jaszczyk/vfio-pci-Propagate-ACPI-notifications-to-user-space-via-eventfd/20230425-002935
        git checkout 62d759059cd5e6dab70052027e1b69c5d5cdc0f2
        # 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 drivers/vfio/pci/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp at intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304250702.Jn8hOwUl-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/vfio/pci/vfio_pci_core.c:709:6: warning: no previous prototype for function 'vfio_pci_acpi_notify_close_device' [-Wmissing-prototypes]
   void vfio_pci_acpi_notify_close_device(struct vfio_pci_core_device *vdev)
        ^
   drivers/vfio/pci/vfio_pci_core.c:709:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void vfio_pci_acpi_notify_close_device(struct vfio_pci_core_device *vdev)
   ^
   static 
>> drivers/vfio/pci/vfio_pci_core.c:1029:11: warning: variable 'events' set but not used [-Wunused-but-set-variable]
           __poll_t events;
                    ^
   2 warnings generated.


vim +/vfio_pci_acpi_notify_close_device +709 drivers/vfio/pci/vfio_pci_core.c

   708	
 > 709	void vfio_pci_acpi_notify_close_device(struct vfio_pci_core_device *vdev)
   710	{
   711		struct vfio_acpi_notification *acpi_notify = vdev->acpi_notification;
   712		struct pci_dev *pdev = vdev->pdev;
   713		struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
   714		struct notification_queue *entry, *entry_tmp;
   715		u64 cnt;
   716	
   717		if (!acpi_notify || !acpi_notify->acpi_notify_trigger)
   718			return;
   719	
   720		acpi_remove_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
   721					   vfio_pci_core_acpi_notify);
   722	
   723		eventfd_ctx_remove_wait_queue(acpi_notify->acpi_notify_trigger,
   724					      &acpi_notify->wait, &cnt);
   725	
   726		flush_work(&acpi_notify->acpi_notification_work);
   727	
   728		mutex_lock(&acpi_notify->notification_list_lock);
   729		list_for_each_entry_safe(entry, entry_tmp,
   730					 &acpi_notify->notification_list,
   731					 notify_val_next) {
   732			list_del(&entry->notify_val_next);
   733			kfree(entry);
   734		}
   735		mutex_unlock(&acpi_notify->notification_list_lock);
   736	
   737		eventfd_ctx_put(acpi_notify->acpi_notify_trigger);
   738	
   739		kfree(acpi_notify);
   740	
   741		vdev->acpi_notification = NULL;
   742	}
   743	#else
   744	void vfio_pci_acpi_notify_close_device(struct vfio_pci_core_device *vdev) {}
   745	#endif /* CONFIG_ACPI */
   746	

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https://github.com/intel/lkp-tests