Hi John,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on rdma/for-next]
[cannot apply to v5.4 next-20191122]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/John-Hubbard/pin_user_pages-reduced-risk-series-for-Linux-5-5/20191125-125637
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next
config: arm-randconfig-a001-20191125 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=arm 

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

All errors (new ones prefixed by >>):

   mm/gup.o: In function `pin_user_pages_remote':
>> mm/gup.c:2528: undefined reference to `get_user_pages_remote'

vim +2528 mm/gup.c

  2507	
  2508	/**
  2509	 * pin_user_pages_remote() - pin pages of a remote process (task != current)
  2510	 *
  2511	 * For now, this is a placeholder function, until various call sites are
  2512	 * converted to use the correct get_user_pages*() or pin_user_pages*() API. So,
  2513	 * this is identical to get_user_pages_remote().
  2514	 *
  2515	 * This is intended for Case 1 (DIO) in Documentation/vm/pin_user_pages.rst. It
  2516	 * is NOT intended for Case 2 (RDMA: long-term pins).
  2517	 */
  2518	long pin_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
  2519				   unsigned long start, unsigned long nr_pages,
  2520				   unsigned int gup_flags, struct page **pages,
  2521				   struct vm_area_struct **vmas, int *locked)
  2522	{
  2523		/*
  2524		 * This is a placeholder, until the pin functionality is activated.
  2525		 * Until then, just behave like the corresponding get_user_pages*()
  2526		 * routine.
  2527		 */
> 2528		return get_user_pages_remote(tsk, mm, start, nr_pages, gup_flags, pages,
  2529					     vmas, locked);
  2530	}
  2531	EXPORT_SYMBOL(pin_user_pages_remote);
  2532	

---
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