linux-kernel - [PATCH 2/3] mm/highmem: Convert memzero_page() to kmap_local

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Date:   Tue,  9 Mar 2021 13:21:36 -0800
From:   ira.weiny@...el.com
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Ira Weiny <ira.weiny@...el.com>,
        Chaitanya Kulkarni <chaitanya.kulkarni@....com>,
        David Sterba <dsterba@...e.com>, Chris Mason <clm@...com>,
        Josef Bacik <josef@...icpanda.com>,
        linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] mm/highmem: Convert memzero_page() to kmap_local_page()

From: Ira Weiny <ira.weiny@...el.com>

The memset() does not need to be performed atomically.  Use
kmap_local_page() which will improved performance for this call.

Cc: Chaitanya Kulkarni <chaitanya.kulkarni@....com>
Cc: David Sterba <dsterba@...e.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
 include/linux/highmem.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 832b49b50c7b..0dc0451cf1d1 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -334,9 +334,9 @@ static inline void memcpy_to_page(struct page *page, size_t offset,
 
 static inline void memzero_page(struct page *page, size_t offset, size_t len)
 {
-	char *addr = kmap_atomic(page);
+	char *addr = kmap_local_page(page);
 	memset(addr + offset, 0, len);
-	kunmap_atomic(addr);
+	kunmap_local(addr);
 }
 
 #endif /* _LINUX_HIGHMEM_H */
-- 
2.28.0.rc0.12.gb6a658bd00c9