Re: [PATCH] uio: Replace mutex info_lock with percpu_ref

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

Hi Guixin,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on linux/master linus/master v5.18-rc6]
[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/Guixin-Liu/uio-Replace-mutex-info_lock-with-percpu_ref/20220510-135202
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git 33a1c6618677fe33f8e84cb7bedc45abbce89a50
config: s390-randconfig-s031-20220509 (https://download.01.org/0day-ci/archive/20220510/202205101914.ZJmSORCV-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 11.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/intel-lab-lkp/linux/commit/4d3e70c70de7bcf57d176790db79b8cbee990171
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Guixin-Liu/uio-Replace-mutex-info_lock-with-percpu_ref/20220510-135202
        git checkout 4d3e70c70de7bcf57d176790db79b8cbee990171
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=s390 SHELL=/bin/bash

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


sparse warnings: (new ones prefixed by >>)
>> drivers/uio/uio.c:564:24: sparse: sparse: incorrect type in return expression (different base types) @@     expected restricted __poll_t @@     got int @@
   drivers/uio/uio.c:564:24: sparse:     expected restricted __poll_t
   drivers/uio/uio.c:564:24: sparse:     got int
   drivers/uio/uio.c:567:21: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted __poll_t [usertype] ret @@     got int @@
   drivers/uio/uio.c:567:21: sparse:     expected restricted __poll_t [usertype] ret
   drivers/uio/uio.c:567:21: sparse:     got int

vim +564 drivers/uio/uio.c

   556	
   557	static __poll_t uio_poll(struct file *filep, poll_table *wait)
   558	{
   559		struct uio_listener *listener = filep->private_data;
   560		struct uio_device *idev = listener->dev;
   561		__poll_t ret = 0;
   562	
   563		if (!percpu_ref_tryget_live(&idev->info_ref))
 > 564			return -EIO;
   565	
   566		if (!idev->info || !idev->info->irq)
   567			ret = -EIO;
   568		percpu_ref_put(&idev->info_ref);
   569	
   570		if (ret)
   571			return ret;
   572	
   573		poll_wait(filep, &idev->wait, wait);
   574		if (listener->event_count != atomic_read(&idev->event))
   575			return EPOLLIN | EPOLLRDNORM;
   576		return 0;
   577	}
   578	

-- 
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