Hi Christian, I love your patch! Perhaps something to improve: [auto build test WARNING on drm-misc/drm-misc-next] [also build test WARNING on media-tree/master drm-tip/drm-tip linus/master v6.2-rc5] [cannot apply to next-20230123] [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/Christian-K-nig/media-uvcvideo-expose-dma-heap-hint-to-userspace/20230123-213836 base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next patch link: https://lore.kernel.org/r/20230123123756.401692-3-christian.koenig%40amd.com patch subject: [PATCH 2/2] media: uvcvideo: expose dma-heap hint to userspace config: hexagon-randconfig-r032-20230123 (https://download.01.org/0day-ci/archive/20230124/202301240717.tim1ggHo-lkp@xxxxxxxxx/config) compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 4196ca3278f78c6e19246e54ab0ecb364e37d66a) 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/adc04dccd892eec7f84c6ec112b48df376172e48 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Christian-K-nig/media-uvcvideo-expose-dma-heap-hint-to-userspace/20230123-213836 git checkout adc04dccd892eec7f84c6ec112b48df376172e48 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/media/usb/uvc/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): In file included from drivers/media/usb/uvc/uvc_driver.c:10: >> include/linux/dma-heap.h:92:5: warning: no previous prototype for function 'dma_heap_create_device_link' [-Wmissing-prototypes] int dma_heap_create_device_link(struct device *dev, const char *heap) ^ include/linux/dma-heap.h:92:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int dma_heap_create_device_link(struct device *dev, const char *heap) ^ static >> include/linux/dma-heap.h:97:6: warning: no previous prototype for function 'dma_heap_remove_device_link' [-Wmissing-prototypes] void dma_heap_remove_device_link(struct device *dev) ^ include/linux/dma-heap.h:97:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void dma_heap_remove_device_link(struct device *dev) ^ static In file included from drivers/media/usb/uvc/uvc_driver.c:16: In file included from include/linux/usb.h:16: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from drivers/media/usb/uvc/uvc_driver.c:16: In file included from include/linux/usb.h:16: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from drivers/media/usb/uvc/uvc_driver.c:16: In file included from include/linux/usb.h:16: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ 8 warnings generated. vim +/dma_heap_create_device_link +92 include/linux/dma-heap.h 4ce5c5c0cf31f4 Christian König 2023-01-23 91 4ce5c5c0cf31f4 Christian König 2023-01-23 @92 int dma_heap_create_device_link(struct device *dev, const char *heap) 4ce5c5c0cf31f4 Christian König 2023-01-23 93 { 4ce5c5c0cf31f4 Christian König 2023-01-23 94 return 0; 4ce5c5c0cf31f4 Christian König 2023-01-23 95 } 4ce5c5c0cf31f4 Christian König 2023-01-23 96 4ce5c5c0cf31f4 Christian König 2023-01-23 @97 void dma_heap_remove_device_link(struct device *dev) 4ce5c5c0cf31f4 Christian König 2023-01-23 98 { 4ce5c5c0cf31f4 Christian König 2023-01-23 99 } 4ce5c5c0cf31f4 Christian König 2023-01-23 100 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests