linux-kernel - [PATCH -next] lib/test_hmm: check page after calling xa_untag

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Message-ID: <20210526140522.2535643-1-yangyingliang@huawei.com>
Date:   Wed, 26 May 2021 22:05:22 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
CC:     <jglisse@...hat.com>, <apopple@...dia.com>, <sfr@...b.auug.org.au>
Subject: [PATCH -next] lib/test_hmm: check page after calling xa_untag_pointer()

Check page after calling xa_untag_pointer() to fix compile warning:
  lib/test_hmm.c:631:16: warning: variable ‘page’ set but not used [-Wunused-but-set-variable]
  631 |   struct page *page;
      |                ^~~~

Fixes: 8b2a105c3794 ("mm: selftests for exclusive device memory")
Reported-by: Hulk Robot <hulkci@...wei.com>
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
 lib/test_hmm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 74d69f87691e..87db37e51d7b 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -632,7 +632,7 @@ static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start,
 
 		entry = xa_load(&dmirror->pt, pfn);
 		page = xa_untag_pointer(entry);
-		if (xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC)
+		if (!page || xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC)
 			return -EPERM;
 	}
 
-- 
2.25.1