On 8/15/19 10:19 AM, Jerome Glisse wrote:
On Wed, Aug 07, 2019 at 04:41:12PM +0800, Pingfan Liu wrote:
Clean up useless 'pfn' variable.
NAK there is a bug see below:
Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
To: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
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);
You can not remove that one ! Otherwise it will break the device
private case.
I don't understand. The only use of "pfn" I see is in the "else"
clause above where it is set just before using it.
