Hi Umesh, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on drm-intel/for-linux-next] [also build test WARNING on drm-tip/drm-tip v5.8-rc5 next-20200716] [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/0day-ci/linux/commits/Umesh-Nerlige-Ramappa/drm-i915-p... base: git://anongit.freedesktop.org/drm-intel for-linux-next config: x86_64-allyesconfig (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project ed6b578040a85977026c93bf4188f996148f3218) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): int i915_perf_mmap(struct file *file, struct vm_area_struct *vma) ^ drivers/gpu/drm/i915/i915_perf.c:1642:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int i915_perf_mmap(struct file *file, struct vm_area_struct *vma) ^ static 1 warning generated. vim +/i915_perf_mmap +1642 drivers/gpu/drm/i915/i915_perf.c 1641 1643 { 1644 struct i915_perf_stream *stream = file->private_data; 1645 1646 if (vma->vm_end < vma->vm_start) 1647 return -EINVAL; 1648 1649 if ((vma->vm_end - vma->vm_start) > OA_BUFFER_SIZE) 1650 return -EINVAL; 1651 1652 if (vma->vm_flags & VM_WRITE) 1653 return -EINVAL; 1654 1655 if (vma->vm_pgoff != I915_PERF_OA_BUFFER_MMAP_OFFSET) 1656 return -EINVAL; 1657 1658 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC | VM_MAYSHARE); 1659 vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 1660 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 1661 vma->vm_private_data = stream; 1662 vma->vm_ops = &vm_ops_oa; 1663 1664 return 0; 1665 } 1666 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org