maple_tree: reorder mas->store_type case statements

Move the unlikely case that mas->store_type is invalid to be the last
evaluated case and put liklier cases higher up.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Sidhartha Kumar <[e-mail]>
Suggested-by: Liam R. Howlett <[e-mail]>
Reviewed-by: Liam R. Howlett <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Wei Yang <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

lib/maple_tree.c

···
 	unsigned char new_end = mas_wr_new_end(wr_mas);
 
 	switch (mas->store_type) {
-	case wr_invalid:
-		MT_BUG_ON(mas->tree, 1);
-		return;
-	case wr_new_root:
-		mas_new_root(mas, wr_mas->entry);
-		break;
-	case wr_store_root:
-		mas_store_root(mas, wr_mas->entry);
-		break;
 	case wr_exact_fit:
 		rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry);
 		if (!!wr_mas->entry ^ !!wr_mas->content)
···
 	case wr_rebalance:
 		mas_wr_bnode(wr_mas);
 		break;
+	case wr_new_root:
+		mas_new_root(mas, wr_mas->entry);
+		break;
+	case wr_store_root:
+		mas_store_root(mas, wr_mas->entry);
+		break;
+	case wr_invalid:
+		MT_BUG_ON(mas->tree, 1);
 	}
 
 	return;
···
 	unsigned char delta = height - wr_mas->vacant_height;
 
 	switch (mas->store_type) {
-	case wr_invalid:
-		WARN_ON_ONCE(1);
-		break;
-	case wr_new_root:
-		ret = 1;
-		break;
-	case wr_store_root:
-		if (likely((mas->last != 0) || (mas->index != 0)))
-			ret = 1;
-		else if (((unsigned long) (entry) & 3) == 2)
-			ret = 1;
-		else
-			ret = 0;
+	case wr_exact_fit:
+	case wr_append:
+	case wr_slot_store:
+		ret = 0;
 		break;
 	case wr_spanning_store:
 		if (wr_mas->sufficient_height < wr_mas->vacant_height)
···
 	case wr_node_store:
 		ret = mt_in_rcu(mas->tree) ? 1 : 0;
 		break;
-	case wr_append:
-	case wr_exact_fit:
-	case wr_slot_store:
-		ret = 0;
+	case wr_new_root:
+		ret = 1;
+		break;
+	case wr_store_root:
+		if (likely((mas->last != 0) || (mas->index != 0)))
+			ret = 1;
+		else if (((unsigned long) (entry) & 3) == 2)
+			ret = 1;
+		else
+			ret = 0;
+		break;
+	case wr_invalid:
+		WARN_ON_ONCE(1);
 	}
 
 	return ret;