zsmalloc: remove obj_tagged()

obj_tagged() is not needed at this point, because objects can only have
one tag: OBJ_ALLOCATED_TAG.  We needed obj_tagged() for the zsmalloc LRU
implementation, which has now been removed.  Simplify zsmalloc code and
revert to the previous implementation that was in place before the
zsmalloc LRU series.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Acked-by: Nhat Pham <[email protected]>
Cc: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

mm/zsmalloc.c

@@ -795,8 +795,8 @@ static unsigned long handle_to_obj(unsigned long handle)
 	return *(unsigned long *)handle;
 }
 
-static bool obj_tagged(struct page *page, void *obj, unsigned long *phandle,
-		int tag)
+static inline bool obj_allocated(struct page *page, void *obj,
+				 unsigned long *phandle)
 {
 	unsigned long handle;
 	struct zspage *zspage = get_zspage(page);
@@ -807,19 +807,14 @@ static bool obj_tagged(struct page *page, void *obj, unsigned long *phandle,
 	} else
 		handle = *(unsigned long *)obj;
 
-	if (!(handle & tag))
+	if (!(handle & OBJ_ALLOCATED_TAG))
 		return false;
 
 	/* Clear all tags before returning the handle */
 	*phandle = handle & ~OBJ_TAG_MASK;
 	return true;
 }
 
-static inline bool obj_allocated(struct page *page, void *obj, unsigned long *phandle)
-{
-	return obj_tagged(page, obj, phandle, OBJ_ALLOCATED_TAG);
-}
-
 static void reset_page(struct page *page)
 {
 	__ClearPageMovable(page);
@@ -1551,11 +1546,11 @@ static void zs_object_copy(struct size_class *class, unsigned long dst,
 }
 
 /*
- * Find object with a certain tag in zspage from index object and
+ * Find alloced object in zspage from index object and
  * return handle.
  */
-static unsigned long find_tagged_obj(struct size_class *class,
-					struct page *page, int *obj_idx, int tag)
+static unsigned long find_alloced_obj(struct size_class *class,
+				      struct page *page, int *obj_idx)
 {
 	unsigned int offset;
 	int index = *obj_idx;
@@ -1566,7 +1561,7 @@ static unsigned long find_tagged_obj(struct size_class *class,
 	offset += class->size * index;
 
 	while (offset < PAGE_SIZE) {
-		if (obj_tagged(page, addr + offset, &handle, tag))
+		if (obj_allocated(page, addr + offset, &handle))
 			break;
 
 		offset += class->size;
@@ -1580,16 +1575,6 @@ static unsigned long find_tagged_obj(struct size_class *class,
 	return handle;
 }
 
-/*
- * Find alloced object in zspage from index object and
- * return handle.
- */
-static unsigned long find_alloced_obj(struct size_class *class,
-					struct page *page, int *obj_idx)
-{
-	return find_tagged_obj(class, page, obj_idx, OBJ_ALLOCATED_TAG);
-}
-
 static void migrate_zspage(struct zs_pool *pool, struct zspage *src_zspage,
 			   struct zspage *dst_zspage)
 {