linux-kernel - [PATCH] LoongArch: Replace kmap_atomic() with kmap_local_page() in copy_user

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Message-Id: <20231007095229.235551-1-chenhuacai@loongson.cn>
Date:   Sat,  7 Oct 2023 17:52:29 +0800
From:   Huacai Chen <chenhuacai@...ngson.cn>
To:     Arnd Bergmann <arnd@...db.de>, Huacai Chen <chenhuacai@...nel.org>
Cc:     loongarch@...ts.linux.dev, linux-arch@...r.kernel.org,
        Xuefeng Li <lixuefeng@...ngson.cn>,
        Guo Ren <guoren@...nel.org>, Xuerui Wang <kernel@...0n.name>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        linux-kernel@...r.kernel.org, loongson-kernel@...ts.loongnix.cn,
        Huacai Chen <chenhuacai@...ngson.cn>,
        Deepak R Varma <drv@...lo.com>
Subject: [PATCH] LoongArch: Replace kmap_atomic() with kmap_local_page() in copy_user_highpage()

Replace kmap_atomic()/kunmap_atomic() calls with kmap_local_page()/
kunmap_local() in copy_user_highpage() which can be invoked from both
preemptible and atomic context [1].

[1] https://lore.kernel.org/all/20201029222652.302358281@linutronix.de/

Suggested-by: Deepak R Varma <drv@...lo.com>
Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
 arch/loongarch/mm/init.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index ddf1330c924c..4dd53427f657 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c
@@ -43,11 +43,11 @@ void copy_user_highpage(struct page *to, struct page *from,
 {
 	void *vfrom, *vto;
 
-	vto = kmap_atomic(to);
-	vfrom = kmap_atomic(from);
+	vfrom = kmap_local_page(from);
+	vto = kmap_local_page(to);
 	copy_page(vto, vfrom);
-	kunmap_atomic(vfrom);
-	kunmap_atomic(vto);
+	kunmap_local(vfrom);
+	kunmap_local(vto);
 	/* Make sure this page is cleared on other CPU's too before using it */
 	smp_wmb();
 }
-- 
2.39.3