[PATCH] mm/mprotect: fix compilation warning because of unused 'mm' varaible

[Mike Rapoport <rppt@linux.ibm.com>]

Since commit 0cbe3e26abe0 ("mm: update ptep_modify_prot_start/commit to
take vm_area_struct as arg") the only place that uses the local 'mm'
variable in change_pte_range() is the call to set_pte_at().

Many architectures define set_pte_at() as macro that does not use the 'mm'
parameter, which generates the following compilation warning:

 CC      mm/mprotect.o
mm/mprotect.c: In function 'change_pte_range':
mm/mprotect.c:42:20: warning: unused variable 'mm' [-Wunused-variable]
  struct mm_struct *mm = vma->vm_mm;
                    ^~

Fix it by passing vma->mm to set_pte_at() and dropping the local 'mm'
variable in change_pte_range().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
 mm/mprotect.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 028c724..61bfe24 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -39,7 +39,6 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 		unsigned long addr, unsigned long end, pgprot_t newprot,
 		int dirty_accountable, int prot_numa)
 {
-	struct mm_struct *mm = vma->vm_mm;
 	pte_t *pte, oldpte;
 	spinlock_t *ptl;
 	unsigned long pages = 0;
@@ -136,7 +135,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 				newpte = swp_entry_to_pte(entry);
 				if (pte_swp_soft_dirty(oldpte))
 					newpte = pte_swp_mksoft_dirty(newpte);
-				set_pte_at(mm, addr, pte, newpte);
+				set_pte_at(vma->mm, addr, pte, newpte);
 
 				pages++;
 			}
-- 
2.7.4