mm/swapfile.c: found_free could be represented by (tmp < max)

This is not necessary to use the variable found_free to record the status.
Just check tmp and max is enough.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200421213824.8099-1-richard.weiyang@gmail.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c

@@ -601,7 +601,6 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si,
 {
 	struct percpu_cluster *cluster;
 	struct swap_cluster_info *ci;
-	bool found_free;
 	unsigned long tmp, max;
 
 new_cluster:
@@ -623,8 +622,6 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si,
 			return false;
 	}
 
-	found_free = false;
-
 	/*
 	 * Other CPUs can use our cluster if they can't find a free cluster,
 	 * check if there is still free entry in the cluster
@@ -638,21 +635,19 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si,
 	}
 	ci = lock_cluster(si, tmp);
 	while (tmp < max) {
-		if (!si->swap_map[tmp]) {
-			found_free = true;
+		if (!si->swap_map[tmp])
 			break;
-		}
 		tmp++;
 	}
 	unlock_cluster(ci);
-	if (!found_free) {
+	if (tmp >= max) {
 		cluster_set_null(&cluster->index);
 		goto new_cluster;
 	}
 	cluster->next = tmp + 1;
 	*offset = tmp;
 	*scan_base = tmp;
-	return found_free;
+	return tmp < max;
 }
 
 static void __del_from_avail_list(struct swap_info_struct *p)