devlink: append split port number to the port name

Instead of doing sprintf twice in case the port is split or not, append
the split port suffix in case the port is split.
Signed-off-by: NJiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20210527104819.789840-1-jiri@resnulli.usSigned-off-by: NJakub Kicinski <kuba@kernel.org>

net/core/devlink.c

@@ -8632,12 +8632,10 @@ static int __devlink_port_phys_port_name_get(struct devlink_port *devlink_port,
 	switch (attrs->flavour) {
 	case DEVLINK_PORT_FLAVOUR_PHYSICAL:
 	case DEVLINK_PORT_FLAVOUR_VIRTUAL:
-		if (!attrs->split)
-			n = snprintf(name, len, "p%u", attrs->phys.port_number);
-		else
-			n = snprintf(name, len, "p%us%u",
-				     attrs->phys.port_number,
-				     attrs->phys.split_subport_number);
+		n = snprintf(name, len, "p%u", attrs->phys.port_number);
+		if (n < len && attrs->split)
+			n += snprintf(name + n, len - n, "s%u",
+				      attrs->phys.split_subport_number);
 		break;
 	case DEVLINK_PORT_FLAVOUR_CPU:
 	case DEVLINK_PORT_FLAVOUR_DSA: