linux-kernel - [PATCH V2 2/8] mm/highmem: Convert memcpy_[to|from]_page() to kmap_local

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Message-Id: <20210210062221.3023586-3-ira.weiny@intel.com>
Date:   Tue,  9 Feb 2021 22:22:15 -0800
From:   ira.weiny@...el.com
To:     Andrew Morton <akpm@...ux-foundation.org>,
        David Sterba <dsterba@...e.cz>
Cc:     Ira Weiny <ira.weiny@...el.com>,
        Christoph Hellwig <hch@...radead.org>, clm@...com,
        josef@...icpanda.com, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org
Subject: [PATCH V2 2/8] mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page()

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

kmap_local_page() is more efficient and is well suited for these calls.
Convert the kmap() to kmap_local_page()

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Christoph Hellwig <hch@...radead.org>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
New for V2
---
 include/linux/highmem.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 736b6a9f144d..c17a175fe5fe 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -279,19 +279,19 @@ static inline void copy_highpage(struct page *to, struct page *from)
 static inline void memcpy_from_page(char *to, struct page *page,
 				    size_t offset, size_t len)
 {
-	char *from = kmap_atomic(page);
+	char *from = kmap_local_page(page);
 
 	memcpy(to, from + offset, len);
-	kunmap_atomic(from);
+	kunmap_local(from);
 }
 
 static inline void memcpy_to_page(struct page *page, size_t offset,
 				  const char *from, size_t len)
 {
-	char *to = kmap_atomic(page);
+	char *to = kmap_local_page(page);
 
 	memcpy(to + offset, from, len);
-	kunmap_atomic(to);
+	kunmap_local(to);
 }
 
 #endif /* _LINUX_HIGHMEM_H */
-- 
2.28.0.rc0.12.gb6a658bd00c9