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Subject[PATCH V2 3/8] mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page()
Date
From: Ira Weiny <ira.weiny@intel.com>

3 more common kmap patterns are kmap/memcpy/kunmap, kmap/memmove/kunmap.
and kmap/memset/kunmap.

Add helper functions for those patterns which use kmap_local_page().

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
New for V2
---
include/linux/highmem.h | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index c17a175fe5fe..0b5d89621cb9 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -276,6 +276,39 @@ static inline void copy_highpage(struct page *to, struct page *from)

#endif

+static inline void memcpy_page(struct page *dst_page, size_t dst_off,
+ struct page *src_page, size_t src_off,
+ size_t len)
+{
+ char *dst = kmap_local_page(dst_page);
+ char *src = kmap_local_page(src_page);
+
+ memcpy(dst + dst_off, src + src_off, len);
+ kunmap_local(src);
+ kunmap_local(dst);
+}
+
+static inline void memmove_page(struct page *dst_page, size_t dst_off,
+ struct page *src_page, size_t src_off,
+ size_t len)
+{
+ char *dst = kmap_local_page(dst_page);
+ char *src = kmap_local_page(src_page);
+
+ memmove(dst + dst_off, src + src_off, len);
+ kunmap_local(src);
+ kunmap_local(dst);
+}
+
+static inline void memset_page(struct page *page, size_t offset, int val,
+ size_t len)
+{
+ char *addr = kmap_local_page(page);
+
+ memset(addr + offset, val, len);
+ kunmap_local(addr);
+}
+
static inline void memcpy_from_page(char *to, struct page *page,
size_t offset, size_t len)
{
--
2.28.0.rc0.12.gb6a658bd00c9
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