Re: drivers/media/pci/intel/ipu3/ipu3-cio2.h:22:28: warning: conversion from 'long unsigned int' to 'u16' {aka 'short unsigned int'} changes value from '131072' to '0'

From: Andy Shevchenko
Date: Tue Dec 29 2020 - 10:20:37 EST


On Tue, Dec 29, 2020 at 12:42:08PM +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: dea8dcf2a9fa8cc540136a6cd885c3beece16ec3
> commit: 7b285f41f7376dc37e7fad1e803995fd39f42848 media: ipu3-cio2: Introduce CIO2_LOP_ENTRIES constant
> date: 4 months ago
> config: ia64-randconfig-r014-20201221 (attached as .config)
> compiler: ia64-linux-gcc (GCC) 9.3.0
> 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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7b285f41f7376dc37e7fad1e803995fd39f42848
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 7b285f41f7376dc37e7fad1e803995fd39f42848
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> All warnings (new ones prefixed by >>):
>
> In file included from drivers/media/pci/intel/ipu3/ipu3-cio2.c:29:
> drivers/media/pci/intel/ipu3/ipu3-cio2.c: In function 'cio2_fbpt_entry_init_dummy':
> >> drivers/media/pci/intel/ipu3/ipu3-cio2.h:22:28: warning: conversion from 'long unsigned int' to 'u16' {aka 'short unsigned int'} changes value from '131072' to '0' [-Woverflow]
> 22 | #define CIO2_LOP_ENTRIES (PAGE_SIZE / sizeof(u32))
> | ^
> drivers/media/pci/intel/ipu3/ipu3-cio2.c:163:39: note: in expansion of macro 'CIO2_LOP_ENTRIES'
> 163 | entry[1].second_entry.num_of_pages = CIO2_LOP_ENTRIES * CIO2_MAX_LOPS;
> | ^~~~~~~~~~~~~~~~

Patch is available https://lore.kernel.org/linux-media/20201214152832.39463-1-andriy.shevchenko@xxxxxxxxxxxxxxx/

--
With Best Regards,
Andy Shevchenko