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[14/19] mm/migrate: remove unnecessary is_zone_device_page() check

Message ID 20200904233604.NcA1bsFWe%akpm@linux-foundation.org
State New
Headers show
Series [01/19] memcg: fix use-after-free in uncharge_batch | expand

Commit Message

Andrew Morton Sept. 4, 2020, 11:36 p.m. UTC
From: Ralph Campbell <rcampbell@nvidia.com>
Subject: mm/migrate: remove unnecessary is_zone_device_page() check

Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()".

I happened to notice this from code inspection after seeing Alistair
Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes").


This patch (of 2):

The check for is_zone_device_page() and is_device_private_page() is
unnecessary since the latter is sufficient to determine if the page is a
device private page.  Simplify the code for easier reading.

Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |   12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)
diff mbox series

Patch

--- a/mm/migrate.c~mm-migrate-remove-unnecessary-is_zone_device_page-check
+++ a/mm/migrate.c
@@ -246,13 +246,11 @@  static bool remove_migration_pte(struct
 		else if (pte_swp_uffd_wp(*pvmw.pte))
 			pte = pte_mkuffd_wp(pte);
 
-		if (unlikely(is_zone_device_page(new))) {
-			if (is_device_private_page(new)) {
-				entry = make_device_private_entry(new, pte_write(pte));
-				pte = swp_entry_to_pte(entry);
-				if (pte_swp_uffd_wp(*pvmw.pte))
-					pte = pte_swp_mkuffd_wp(pte);
-			}
+		if (unlikely(is_device_private_page(new))) {
+			entry = make_device_private_entry(new, pte_write(pte));
+			pte = swp_entry_to_pte(entry);
+			if (pte_swp_uffd_wp(*pvmw.pte))
+				pte = pte_swp_mkuffd_wp(pte);
 		}
 
 #ifdef CONFIG_HUGETLB_PAGE