Re: [PATCH V3 04/21] dax: Add dax_operations for use by fs-dax on fsdev dax

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

Hi John,

kernel test robot noticed the following build errors:

[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on linus/master v6.19-rc4 next-20260108]
[cannot apply to mszeredi-fuse/for-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/John-Groves/dax-add-fsdev-c-driver-for-fs-dax-on-character-dax/20260108-013232
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link:    https://lore.kernel.org/r/20260107153332.64727-5-john%40groves.net
patch subject: [PATCH V3 04/21] dax: Add dax_operations for use by fs-dax on fsdev dax
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20260108/202601081822.Ww7CSgov-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260108/202601081822.Ww7CSgov-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202601081822.Ww7CSgov-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/dax/fsdev.c:97:9: error: call to undeclared function '_copy_from_iter_flushcache'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
      97 |         return _copy_from_iter_flushcache(addr, bytes, i);
         |                ^
   drivers/dax/fsdev.c:97:9: note: did you mean '__copy_from_user_flushcache'?
   arch/x86/include/asm/uaccess_64.h:166:1: note: '__copy_from_user_flushcache' declared here
     166 | __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
         | ^
   1 error generated.


vim +/_copy_from_iter_flushcache +97 drivers/dax/fsdev.c

    93	
    94	static size_t fsdev_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
    95			void *addr, size_t bytes, struct iov_iter *i)
    96	{
  > 97		return _copy_from_iter_flushcache(addr, bytes, i);
    98	}
    99	

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