@@ -642,12 +642,17 @@ static struct page *follow_pmd_mask(stru
}
retry:
if (!pmd_present(pmdval)) {
+ /*
+ * Should never reach here, if thp migration is not supported;
+ * Otherwise, it must be a thp migration entry.
+ */
+ VM_BUG_ON(!thp_migration_supported() ||
+ !is_pmd_migration_entry(pmdval));
+
if (likely(!(flags & FOLL_MIGRATION)))
return no_page_table(vma, flags);
- VM_BUG_ON(thp_migration_supported() &&
- !is_pmd_migration_entry(pmdval));
- if (is_pmd_migration_entry(pmdval))
- pmd_migration_entry_wait(mm, pmd);
+
+ pmd_migration_entry_wait(mm, pmd);
pmdval = READ_ONCE(*pmd);
/*
* MADV_DONTNEED may convert the pmd to null because