mm/migrate.c: clean up useless code in migrate_vma_collect_pmd()

Remove unused 'pfn' variable.

Link: http://lkml.kernel.org/r/1565167272-21453-1-git-send-email-kernelfans@gmail.com
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 6 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 374ef2fcb722..73d476d690b1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2218,17 +2218,15 @@ again:
                 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
@@ -2245,10 +2243,10 @@ again:
                         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);
@@ -2258,10 +2256,9 @@ again:
 
                 /* 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