linux-kernel - [PATCH linux-next v2] kernel/power: Use kmap_local

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Date: Tue, 19 Dec 2023 21:06:25 +0800
From: chenguanxi11234@....com
To: rafael@...nel.org
Cc: len.brown@...el.com,
	pavel@....cz,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Chen Haonan <chen.haonan2@....com.cn>
Subject: [PATCH linux-next v2] kernel/power: Use kmap_local_page() in snapshot.c

From: Chen Haonan <chen.haonan2@....com.cn>

kmap_atomic() has been deprecated in favor of kmap_local_page().

kmap_atomic() disables page-faults and preemption (the latter 
only for !PREEMPT_RT kernels).The code between the mapping and 
un-mapping in this patch does not depend on the above-mentioned 
side effects.So simply replaced kmap_atomic() with kmap_local_page().

Signed-off-by: Chen Haonan <chen.haonan2@....com.cn>
---
 kernel/power/snapshot.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index e3e8f1c6e75f..5c96ff067c64 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1487,11 +1487,11 @@ static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 	s_page = pfn_to_page(src_pfn);
 	d_page = pfn_to_page(dst_pfn);
 	if (PageHighMem(s_page)) {
-		src = kmap_atomic(s_page);
-		dst = kmap_atomic(d_page);
+		src = kmap_local_page(s_page);
+		dst = kmap_local_page(d_page);
 		zeros_only = do_copy_page(dst, src);
-		kunmap_atomic(dst);
-		kunmap_atomic(src);
+		kunmap_local(dst);
+		kunmap_local(src);
 	} else {
 		if (PageHighMem(d_page)) {
 			/*
@@ -1499,9 +1499,9 @@ static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 			 * data modified by kmap_atomic()
 			 */
 			zeros_only = safe_copy_page(buffer, s_page);
-			dst = kmap_atomic(d_page);
+			dst = kmap_local_page(d_page);
 			copy_page(dst, buffer);
-			kunmap_atomic(dst);
+			kunmap_local(dst);
 		} else {
 			zeros_only = safe_copy_page(page_address(d_page), s_page);
 		}
-- 
2.25.1