netdevsim: add ability to change channel count

For testing visibility of mq/mqprio default children.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netdevsim/ethtool.c

@@ -81,6 +81,30 @@ static int nsim_set_ringparam(struct net_device *dev,
 	return 0;
 }
 
+static void
+nsim_get_channels(struct net_device *dev, struct ethtool_channels *ch)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	ch->max_combined = ns->nsim_bus_dev->num_queues;
+	ch->combined_count = ns->ethtool.channels;
+}
+
+static int
+nsim_set_channels(struct net_device *dev, struct ethtool_channels *ch)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+	int err;
+
+	err = netif_set_real_num_queues(dev, ch->combined_count,
+					ch->combined_count);
+	if (err)
+		return err;
+
+	ns->ethtool.channels = ch->combined_count;
+	return 0;
+}
+
 static int
 nsim_get_fecparam(struct net_device *dev, struct ethtool_fecparam *fecparam)
 {
@@ -118,6 +142,8 @@ static const struct ethtool_ops nsim_ethtool_ops = {
 	.get_coalesce			= nsim_get_coalesce,
 	.get_ringparam			= nsim_get_ringparam,
 	.set_ringparam			= nsim_set_ringparam,
+	.get_channels			= nsim_get_channels,
+	.set_channels			= nsim_set_channels,
 	.get_fecparam			= nsim_get_fecparam,
 	.set_fecparam			= nsim_set_fecparam,
 };
@@ -141,6 +167,8 @@ void nsim_ethtool_init(struct netdevsim *ns)
 	ns->ethtool.fec.fec = ETHTOOL_FEC_NONE;
 	ns->ethtool.fec.active_fec = ETHTOOL_FEC_NONE;
 
+	ns->ethtool.channels = ns->nsim_bus_dev->num_queues;
+
 	ethtool = debugfs_create_dir("ethtool", ns->nsim_dev_port->ddir);
 
 	debugfs_create_u32("get_err", 0600, ethtool, &ns->ethtool.get_err);

drivers/net/netdevsim/netdevsim.h

@@ -62,6 +62,7 @@ struct nsim_ethtool_pauseparam {
 struct nsim_ethtool {
 	u32 get_err;
 	u32 set_err;
+	u32 channels;
 	struct nsim_ethtool_pauseparam pauseparam;
 	struct ethtool_coalesce coalesce;
 	struct ethtool_ringparam ring;