From: Miaohe Lin <linmiaohe@huawei.com>
Date: Tue, 22 Mar 2022 21:39:25 +0000 (-0700)
Subject: mm/memremap: avoid calling kasan_remove_zero_shadow() for device private memory
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a74c6c00b1cb56386a98c2f2615f8966b3d1034d;p=linux.git

mm/memremap: avoid calling kasan_remove_zero_shadow() for device private memory

For device private memory, we do not create a linear mapping for the
memory because the device memory is un-accessible.  Thus we do not add
kasan zero shadow for it.  So it's unnecessary to do
kasan_remove_zero_shadow() for it.

Link: https://lkml.kernel.org/r/20220126092602.1425-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/memremap.c b/mm/memremap.c
index 6aa5f0c2d11fd..4d73533d8ca79 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -282,7 +282,8 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
 	return 0;
 
 err_add_memory:
-	kasan_remove_zero_shadow(__va(range->start), range_len(range));
+	if (!is_private)
+		kasan_remove_zero_shadow(__va(range->start), range_len(range));
 err_kasan:
 	untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range));
 err_pfn_remap: