[rcu:willy-maple 178/202] mm/mempolicy.c:807:25: warning: variable 'next' set but not used

From: kernel test robot
Date: Tue Feb 02 2021 - 18:51:33 EST

tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git willy-maple
head: 7e346d2845b4bd77663394f39fa70456e0084c86
commit: adcfbd7698558a279b852cb3a644557dc021b557 [178/202] mm/mempolicy: Use maple tree iterators instead of vma linked list
config: x86_64-randconfig-s021-20210202 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.3-215-g0fb77bb6-dirty
# https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?id=adcfbd7698558a279b852cb3a644557dc021b557
git remote add rcu https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
git fetch --no-tags rcu willy-maple
git checkout adcfbd7698558a279b852cb3a644557dc021b557
# save the attached .config to linux build tree
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

mm/mempolicy.c: In function 'mbind_range':
>> mm/mempolicy.c:807:25: warning: variable 'next' set but not used [-Wunused-but-set-variable]
807 | struct vm_area_struct *next;
| ^~~~


vim +/next +807 mm/mempolicy.c

8d34694c1abf29 KOSAKI Motohiro 2012-10-08 802
^1da177e4c3f41 Linus Torvalds 2005-04-16 803 /* Step 2: apply policy to a range and do splits. */
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 804 static int mbind_range(struct mm_struct *mm, unsigned long start,
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 805 unsigned long end, struct mempolicy *new_pol)
^1da177e4c3f41 Linus Torvalds 2005-04-16 806 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 @807 struct vm_area_struct *next;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 808 struct vm_area_struct *prev;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 809 struct vm_area_struct *vma;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 810 int err = 0;
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 811 pgoff_t pgoff;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 812 unsigned long vmstart;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 813 unsigned long vmend;
adcfbd7698558a Liam R. Howlett 2021-01-04 814 MA_STATE(mas, &mm->mm_mt, start, start);
^1da177e4c3f41 Linus Torvalds 2005-04-16 815
adcfbd7698558a Liam R. Howlett 2021-01-04 816 vma = mas_find(&mas, ULONG_MAX);
f18da660c095e3 Li Xinhai 2019-11-30 817 VM_BUG_ON(!vma);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 818
adcfbd7698558a Liam R. Howlett 2021-01-04 819 prev = vma_mas_prev(&mas);
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 820 if (start > vma->vm_start)
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 821 prev = vma;
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 822
adcfbd7698558a Liam R. Howlett 2021-01-04 823 mas_for_each(&mas, vma, end - 1) {
adcfbd7698558a Liam R. Howlett 2021-01-04 824 next = vma_next(mm, vma);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 825 vmstart = max(start, vma->vm_start);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 826 vmend = min(end, vma->vm_end);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 827
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 828 if (mpol_equal(vma_policy(vma), new_pol))
adcfbd7698558a Liam R. Howlett 2021-01-04 829 goto next;
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 830
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 831 pgoff = vma->vm_pgoff +
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 832 ((vmstart - vma->vm_start) >> PAGE_SHIFT);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 833 prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
e26a51148f3ebd KOSAKI Motohiro 2011-12-28 834 vma->anon_vma, vma->vm_file, pgoff,
19a809afe2fe08 Andrea Arcangeli 2015-09-04 835 new_pol, vma->vm_userfaultfd_ctx);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 836 if (prev) {
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 837 vma = prev;
adcfbd7698558a Liam R. Howlett 2021-01-04 838 next = vma_next(mm, vma);
3964acd0dbec12 Oleg Nesterov 2013-07-31 839 if (mpol_equal(vma_policy(vma), new_pol))
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 840 continue;
3964acd0dbec12 Oleg Nesterov 2013-07-31 841 /* vma_merge() joined vma && vma->next, case 8 */
3964acd0dbec12 Oleg Nesterov 2013-07-31 842 goto replace;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 843 }
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 844 if (vma->vm_start != vmstart) {
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 845 err = split_vma(vma->vm_mm, vma, vmstart, 1);
^1da177e4c3f41 Linus Torvalds 2005-04-16 846 if (err)
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 847 goto out;
^1da177e4c3f41 Linus Torvalds 2005-04-16 848 }
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 849 if (vma->vm_end != vmend) {
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 850 err = split_vma(vma->vm_mm, vma, vmend, 0);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 851 if (err)
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 852 goto out;
adcfbd7698558a Liam R. Howlett 2021-01-04 853 mas_pause(&mas);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 854 }
3964acd0dbec12 Oleg Nesterov 2013-07-31 855 replace:
869833f2c5c6e4 KOSAKI Motohiro 2012-10-08 856 err = vma_replace_policy(vma, new_pol);
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 857 if (err)
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 858 goto out;
adcfbd7698558a Liam R. Howlett 2021-01-04 859 next:
adcfbd7698558a Liam R. Howlett 2021-01-04 860 prev = vma;
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 861 }
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 862
9d8cebd4bcd7c3 KOSAKI Motohiro 2010-03-05 863 out:
^1da177e4c3f41 Linus Torvalds 2005-04-16 864 return err;
^1da177e4c3f41 Linus Torvalds 2005-04-16 865 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 866

:::::: The code at line 807 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

:::::: TO: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx>

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Attachment: .config.gz
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