mm/zswap.c: get swapper address_space by using macro

There is a proper macro to get the corresponding swapper address space
from a swap entry.  Instead of directly accessing "swapper_spaces" array,
use the "swap_address_space" macro.
Signed-off-by: NSunghan Suh <sunghan.suh@samsung.com>
Reviewed-by: NBob Liu <bob.liu@oracle.com>
Reviewed-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: NSeth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/zswap.c

@@ -409,7 +409,7 @@ static int zswap_get_swap_cache_page(swp_entry_t entry,
 				struct page **retpage)
 {
 	struct page *found_page, *new_page = NULL;
-	struct address_space *swapper_space = &swapper_spaces[swp_type(entry)];
+	struct address_space *swapper_space = swap_address_space(entry);
 	int err;
 
 	*retpage = NULL;