[PATCH] mm/rmap.c: remove set but not used variable 'cstart'

[YueHaibing <yuehaibing@huawei.com>]

Fixes gcc '-Wunused-but-set-variable' warning:

mm/rmap.c: In function page_mkclean_one:
mm/rmap.c:906:17: warning: variable cstart set but not used [-Wunused-but-set-variable]

It is not used any more since
commit cdb07bdea28e ("mm/rmap.c: remove redundant variable cend")

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
 mm/rmap.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index ec1af8b..40e4def 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -903,10 +903,9 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
 	mmu_notifier_invalidate_range_start(&range);
 
 	while (page_vma_mapped_walk(&pvmw)) {
-		unsigned long cstart;
 		int ret = 0;
 
-		cstart = address = pvmw.address;
+		address = pvmw.address;
 		if (pvmw.pte) {
 			pte_t entry;
 			pte_t *pte = pvmw.pte;
@@ -933,7 +932,6 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
 			entry = pmd_wrprotect(entry);
 			entry = pmd_mkclean(entry);
 			set_pmd_at(vma->vm_mm, address, pmd, entry);
-			cstart &= PMD_MASK;
 			ret = 1;
 #else
 			/* unexpected pmd-mapped page? */
-- 
2.7.4