[PATCHv2] mm/migrate: clean up useless code in migrate_vma_collect_pmd()

[Pingfan Liu <kernelfans@gmail.com>]

Clean up useless 'pfn' variable.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jan Kara <jack@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/migrate.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 8992741..d483a55 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2225,17 +2225,15 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 		pte_t pte;
 
 		pte = *ptep;
-		pfn = pte_pfn(pte);
 
 		if (pte_none(pte)) {
 			mpfn = MIGRATE_PFN_MIGRATE;
 			migrate->cpages++;
-			pfn = 0;
 			goto next;
 		}
 
 		if (!pte_present(pte)) {
-			mpfn = pfn = 0;
+			mpfn = 0;
 
 			/*
 			 * Only care about unaddressable device page special
@@ -2252,10 +2250,10 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 			if (is_write_device_private_entry(entry))
 				mpfn |= MIGRATE_PFN_WRITE;
 		} else {
+			pfn = pte_pfn(pte);
 			if (is_zero_pfn(pfn)) {
 				mpfn = MIGRATE_PFN_MIGRATE;
 				migrate->cpages++;
-				pfn = 0;
 				goto next;
 			}
 			page = vm_normal_page(migrate->vma, addr, pte);
@@ -2265,10 +2263,9 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 		/* FIXME support THP */
 		if (!page || !page->mapping || PageTransCompound(page)) {
-			mpfn = pfn = 0;
+			mpfn = 0;
 			goto next;
 		}
-		pfn = page_to_pfn(page);
 
 		/*
 		 * By getting a reference on the page we pin it and that blocks
-- 
2.7.5