[PATCH 03/10] mm/hugetlb: Protect follow_huge_(pud|pgd) functions from race

[kbuild test robot]

Hi Anshuman,

[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.6-rc2 next-20160407]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Anshuman-Khandual/Enable-HugeTLB-page-migration-on-POWER/20160407-165841
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: s390-allyesconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=s390 

All errors (new ones prefixed by >>):

   mm/hugetlb.c: In function 'follow_huge_pud':
>> mm/hugetlb.c:4360:3: error: implicit declaration of function 'pud_page' [-Werror=implicit-function-declaration]
      page = pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
      ^
   mm/hugetlb.c:4360:8: warning: assignment makes pointer from integer without a cast
      page = pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
           ^
   mm/hugetlb.c: In function 'follow_huge_pgd':
   mm/hugetlb.c:4395:3: error: implicit declaration of function 'pgd_page' [-Werror=implicit-function-declaration]
      page = pgd_page(*pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
      ^
   mm/hugetlb.c:4395:8: warning: assignment makes pointer from integer without a cast
      page = pgd_page(*pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
           ^
   cc1: some warnings being treated as errors

vim +/pud_page +4360 mm/hugetlb.c

  4354		 * make sure that the address range covered by this pud is not
  4355		 * unmapped from other threads.
  4356		 */
  4357		if (!pud_huge(*pud))
  4358			goto out;
  4359		if (pud_present(*pud)) {
> 4360			page = pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
  4361			if (flags & FOLL_GET)
  4362				get_page(page);
  4363		} else {

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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