[RFC PATCH v3 06/21] mm/zsmalloc: convert __zs_{map,unmap}_object() to use zsdesc

[Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>]

These two functions take pointer to an array of struct page. Introduce
zsdesc_kmap_atomic() and make __zs_{map,unmap}_object() take pointer
to an array of zsdesc instead of page.

Add silly type casting when calling them. Casting will be removed
in the next patch.

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
---
 mm/zsmalloc.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 91fccc67185b..be3b8734bdf2 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -322,6 +322,11 @@ static inline void wait_on_zsdesc_locked(struct zsdesc *zsdesc)
 	wait_on_page_locked(zsdesc_page(zsdesc));
 }
 
+static inline void *zsdesc_kmap_atomic(struct zsdesc *zsdesc)
+{
+	return kmap_atomic(zsdesc_page(zsdesc));
+}
+
 struct zspage {
 	struct {
 		unsigned int huge:HUGE_BITS;
@@ -1155,7 +1160,7 @@ static inline void __zs_cpu_down(struct mapping_area *area)
 }
 
 static void *__zs_map_object(struct mapping_area *area,
-			struct page *pages[2], int off, int size)
+			struct zsdesc *zsdescs[2], int off, int size)
 {
 	int sizes[2];
 	void *addr;
@@ -1172,10 +1177,10 @@ static void *__zs_map_object(struct mapping_area *area,
 	sizes[1] = size - sizes[0];
 
 	/* copy object to per-cpu buffer */
-	addr = kmap_atomic(pages[0]);
+	addr = zsdesc_kmap_atomic(zsdescs[0]);
 	memcpy(buf, addr + off, sizes[0]);
 	kunmap_atomic(addr);
-	addr = kmap_atomic(pages[1]);
+	addr = zsdesc_kmap_atomic(zsdescs[1]);
 	memcpy(buf + sizes[0], addr, sizes[1]);
 	kunmap_atomic(addr);
 out:
@@ -1183,7 +1188,7 @@ static void *__zs_map_object(struct mapping_area *area,
 }
 
 static void __zs_unmap_object(struct mapping_area *area,
-			struct page *pages[2], int off, int size)
+			struct zsdesc *zsdescs[2], int off, int size)
 {
 	int sizes[2];
 	void *addr;
@@ -1202,10 +1207,10 @@ static void __zs_unmap_object(struct mapping_area *area,
 	sizes[1] = size - sizes[0];
 
 	/* copy per-cpu buffer to object */
-	addr = kmap_atomic(pages[0]);
+	addr = zsdesc_kmap_atomic(zsdescs[0]);
 	memcpy(addr + off, buf, sizes[0]);
 	kunmap_atomic(addr);
-	addr = kmap_atomic(pages[1]);
+	addr = zsdesc_kmap_atomic(zsdescs[1]);
 	memcpy(addr, buf + sizes[0], sizes[1]);
 	kunmap_atomic(addr);
 
@@ -1346,7 +1351,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 	pages[1] = get_next_page(page);
 	BUG_ON(!pages[1]);
 
-	ret = __zs_map_object(area, pages, off, class->size);
+	ret = __zs_map_object(area, (struct zsdesc **)pages, off, class->size);
 out:
 	if (likely(!ZsHugePage(zspage)))
 		ret += ZS_HANDLE_SIZE;
@@ -1381,7 +1386,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 		pages[1] = get_next_page(page);
 		BUG_ON(!pages[1]);
 
-		__zs_unmap_object(area, pages, off, class->size);
+		__zs_unmap_object(area, (struct zsdesc **)pages, off, class->size);
 	}
 	local_unlock(&zs_map_area.lock);
 
-- 
2.39.3