Commit 6a0996db authored by Ira Weiny's avatar Ira Weiny Committed by David Sterba
Browse files

mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page() 



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>
Reviewed-by: default avatarChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarIra Weiny <ira.weiny@intel.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 61b205f5

include/linux/highmem.h

+33 −0
Original line number Diff line number Diff line
@@ -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)

{