From: Hongchen Zhang <zhanghongchen@loongson.cn>
Date: Tue, 10 May 2022 01:20:53 +0000 (-0700)
Subject: mm/swapops: make is_pmd_migration_entry more strict
X-Git-Tag: v5.19-rc1~138^2~186
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b304c6f0d39d927a87e72a8ac6c89b96ac25f355;p=thirdparty%2Fkernel%2Flinux.git

mm/swapops: make is_pmd_migration_entry more strict

A pmd migration entry should first be a swap pmd,so use is_swap_pmd(pmd)
instead of !pmd_present(pmd).

On the other hand, some architecture (MIPS for example) may misjudge a
pmd_none entry as a pmd migration entry.

Link: https://lkml.kernel.org/r/1651131333-6386-1-git-send-email-zhanghongchen@loongson.cn
Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index d1b728904d4ed..82265b055a0d1 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -331,7 +331,7 @@ static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
 
 static inline int is_pmd_migration_entry(pmd_t pmd)
 {
-	return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
+	return is_swap_pmd(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
 }
 #else
 static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,