mm/zswap.c: improve a size determination in zswap_frontswap_init()

Replace the specification of a data structure by a pointer dereference
as the parameter for the operator "sizeof" to make the corresponding
size determination a bit safer according to the Linux coding style
convention.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Markus Elfring <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: Seth Jennings <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

mm/zswap.c

@@ -1235,7 +1235,7 @@ static void zswap_frontswap_init(unsigned type)
 {
 	struct zswap_tree *tree;
 
-	tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL);
+	tree = kzalloc(sizeof(*tree), GFP_KERNEL);
 	if (!tree) {
 		pr_err("alloc failed, zswap disabled for swap type %d\n", type);
 		return;