[PATCH V2 1/1] brd: use memcpy_to|from_page() in copy_to|from_brd()

[Chaitanya Kulkarni <kch@xxxxxxxxxx>]

"kmap_atomic - Atomically map a page for temporary usage - Deprecated!"

Use memcpy_from_page() helper does the same job of mapping and copying
except it uses non deprecated kmap_local_page() and kunmap_local()
in copy_from_brd().

Use memcpy_to_page() helper does the same job of mapping and copying
except it uses non deprecated kmap_local_page() and kunmap_local()
in copy_to_brd().

Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
---
 drivers/block/brd.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 34177f1bd97d..c1251159bd13 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -189,7 +189,6 @@ static void copy_to_brd(struct brd_device *brd, const void *src,
 			sector_t sector, size_t n)
 {
 	struct page *page;
-	void *dst;
 	unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT;
 	size_t copy;
 
@@ -197,9 +196,7 @@ static void copy_to_brd(struct brd_device *brd, const void *src,
 	page = brd_lookup_page(brd, sector);
 	BUG_ON(!page);
 
-	dst = kmap_atomic(page);
-	memcpy(dst + offset, src, copy);
-	kunmap_atomic(dst);
+	memcpy_to_page(page, offset, src, copy);
 
 	if (copy < n) {
 		src += copy;
@@ -208,9 +205,7 @@ static void copy_to_brd(struct brd_device *brd, const void *src,
 		page = brd_lookup_page(brd, sector);
 		BUG_ON(!page);
 
-		dst = kmap_atomic(page);
-		memcpy(dst, src, copy);
-		kunmap_atomic(dst);
+		memcpy_to_page(page, 0, src, copy);
 	}
 }
 
@@ -221,17 +216,14 @@ static void copy_from_brd(void *dst, struct brd_device *brd,
 			sector_t sector, size_t n)
 {
 	struct page *page;
-	void *src;
 	unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT;
 	size_t copy;
 
 	copy = min_t(size_t, n, PAGE_SIZE - offset);
 	page = brd_lookup_page(brd, sector);
-	if (page) {
-		src = kmap_atomic(page);
-		memcpy(dst, src + offset, copy);
-		kunmap_atomic(src);
-	} else
+	if (page)
+		memcpy_from_page(dst, page, offset, copy);
+	else
 		memset(dst, 0, copy);
 
 	if (copy < n) {
@@ -239,11 +231,9 @@ static void copy_from_brd(void *dst, struct brd_device *brd,
 		sector += copy >> SECTOR_SHIFT;
 		copy = n - copy;
 		page = brd_lookup_page(brd, sector);
-		if (page) {
-			src = kmap_atomic(page);
-			memcpy(dst, src, copy);
-			kunmap_atomic(src);
-		} else
+		if (page)
+			memcpy_from_page(dst, page, 0, copy);
+		else
 			memset(dst, 0, copy);
 	}
 }
-- 
2.29.0