[PATCH] mm/migrate_device: fix cache flush when replacing huge zero PMD

[Hui Su <sh_def@163.com>]

migrate_vma_insert_huge_pmd_page() calls flush_cache_page() before
replacing an existing huge zero PMD. However, the third argument to
flush_cache_page() is a PFN, while addr + HPAGE_PMD_SIZE is an end
virtual address.

More importantly, the mapping being invalidated is PMD-sized rather
than PAGE_SIZE-sized. Flush the whole PMD range with
flush_cache_range(), matching other huge PMD invalidation paths.

Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
Signed-off-by: Hui Su <sh_def@163.com>
---
 mm/migrate_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 908d2d4ec43a..098c04c1b124 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -872,7 +872,7 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate,
 
 	if (flush) {
 		pte_free(vma->vm_mm, pgtable);
-		flush_cache_page(vma, addr, addr + HPAGE_PMD_SIZE);
+		flush_cache_range(vma, addr, addr + HPAGE_PMD_SIZE);
 		pmdp_invalidate(vma, addr, pmdp);
 	} else {
 		pgtable_trans_huge_deposit(vma->vm_mm, pmdp, pgtable);
-- 
2.54.0