[PATCH 06/18] netvsc: allow more flexible setting of number of channels

[Stephen Hemminger <stephen@networkplumber.org>]

This allows for number of channels to be managed in a manner similar
to existing hardware drivers. It also removes the restriction of
maximum 8 channels and allows as many as the host will allow.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
---
 drivers/net/hyperv/hyperv_net.h |   1 +
 drivers/net/hyperv/netvsc_drv.c | 128 +++++++++++++++-------------------------
 2 files changed, 50 insertions(+), 79 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 5bf21418bbe5..5a652eb8a619 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -628,6 +628,7 @@ struct nvsp_message {
 
 #define VRSS_SEND_TAB_SIZE 16
 #define VRSS_CHANNEL_MAX 64
+#define VRSS_CHANNEL_DEFAULT 8
 
 #define RNDIS_MAX_PKT_DEFAULT 8
 #define RNDIS_PKT_ALIGN_DEFAULT 8
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 40a88387a8f5..ead472150742 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -47,8 +47,6 @@ static int ring_size = 128;
 module_param(ring_size, int, S_IRUGO);
 MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
 
-static int max_num_vrss_chns = 8;
-
 static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
 				NETIF_MSG_LINK | NETIF_MSG_IFUP |
 				NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR |
@@ -709,102 +707,76 @@ static void netvsc_get_channels(struct net_device *net,
 	}
 }
 
+static int netvsc_set_queues(struct net_device *net, struct hv_device *dev,
+			     u32 num_chn)
+{
+	struct netvsc_device_info device_info;
+	int ret;
+
+	memset(&device_info, 0, sizeof(device_info));
+	device_info.num_chn = num_chn;
+	device_info.ring_size = ring_size;
+	device_info.max_num_vrss_chns = num_chn;
+
+	ret = rndis_filter_device_add(dev, &device_info);
+	if (ret)
+		return ret;
+
+	ret = netif_set_real_num_tx_queues(net, num_chn);
+	if (ret)
+		return ret;
+
+	ret = netif_set_real_num_rx_queues(net, num_chn);
+
+	return ret;
+}
+
 static int netvsc_set_channels(struct net_device *net,
 			       struct ethtool_channels *channels)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(net);
 	struct hv_device *dev = net_device_ctx->device_ctx;
 	struct netvsc_device *nvdev = net_device_ctx->nvdev;
-	struct netvsc_device_info device_info;
-	u32 num_chn;
-	u32 max_chn;
-	int ret = 0;
-	bool recovering = false;
+	unsigned int count = channels->combined_count;
+	int ret;
+
+	/* We do not support separate count for rx, tx, or other */
+	if (count == 0 ||
+	    channels->rx_count || channels->tx_count || channels->other_count)
+		return -EINVAL;
+
+	if (count > net->num_tx_queues || count > net->num_rx_queues)
+		return -EINVAL;
 
 	if (net_device_ctx->start_remove || !nvdev || nvdev->destroy)
 		return -ENODEV;
 
-	num_chn = nvdev->num_chn;
-	max_chn = min_t(u32, nvdev->max_chn, num_online_cpus());
-
-	if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
-		pr_info("vRSS unsupported before NVSP Version 5\n");
+	if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5)
 		return -EINVAL;
-	}
 
-	/* We do not support rx, tx, or other */
-	if (!channels ||
-	    channels->rx_count ||
-	    channels->tx_count ||
-	    channels->other_count ||
-	    (channels->combined_count < 1))
+	if (count > nvdev->max_chn)
 		return -EINVAL;
 
-	if (channels->combined_count > max_chn) {
-		pr_info("combined channels too high, using %d\n", max_chn);
-		channels->combined_count = max_chn;
-	}
-
 	ret = netvsc_close(net);
 	if (ret)
-		goto out;
+		return ret;
 
- do_set:
 	net_device_ctx->start_remove = true;
 	rndis_filter_device_remove(dev);
 
-	nvdev->num_chn = channels->combined_count;
-
-	memset(&device_info, 0, sizeof(device_info));
-	device_info.num_chn = nvdev->num_chn; /* passed to RNDIS */
-	device_info.ring_size = ring_size;
-	device_info.max_num_vrss_chns = max_num_vrss_chns;
-
-	ret = rndis_filter_device_add(dev, &device_info);
-	if (ret) {
-		if (recovering) {
-			netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
-			return ret;
-		}
-		goto recover;
-	}
-
-	nvdev = net_device_ctx->nvdev;
-
-	ret = netif_set_real_num_tx_queues(net, nvdev->num_chn);
-	if (ret) {
-		if (recovering) {
-			netdev_err(net, "could not set tx queue count (ret %d)\n", ret);
-			return ret;
-		}
-		goto recover;
-	}
-
-	ret = netif_set_real_num_rx_queues(net, nvdev->num_chn);
-	if (ret) {
-		if (recovering) {
-			netdev_err(net, "could not set rx queue count (ret %d)\n", ret);
-			return ret;
-		}
-		goto recover;
-	}
+	ret = netvsc_set_queues(net, dev, count);
+	if (ret == 0)
+		nvdev->num_chn = count;
+	else
+		netvsc_set_queues(net, dev, nvdev->num_chn);
 
- out:
 	netvsc_open(net);
 	net_device_ctx->start_remove = false;
+
 	/* We may have missed link change notifications */
 	schedule_delayed_work(&net_device_ctx->dwork, 0);
 
 	return ret;
-
- recover:
-	/* If the above failed, we attempt to recover through the same
-	 * process but with the original number of channels.
-	 */
-	netdev_err(net, "could not set channels, recovering\n");
-	recovering = true;
-	channels->combined_count = num_chn;
-	goto do_set;
 }
 
 static bool netvsc_validate_ethtool_ss_cmd(const struct ethtool_cmd *cmd)
@@ -865,8 +837,7 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 	struct netvsc_device *nvdev = ndevctx->nvdev;
 	struct hv_device *hdev = ndevctx->device_ctx;
 	struct netvsc_device_info device_info;
-	u32 num_chn;
-	int ret = 0;
+	int ret;
 
 	if (ndevctx->start_remove || !nvdev || nvdev->destroy)
 		return -ENODEV;
@@ -875,8 +846,6 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 	if (ret)
 		goto out;
 
-	num_chn = nvdev->num_chn;
-
 	ndevctx->start_remove = true;
 	rndis_filter_device_remove(hdev);
 
@@ -884,8 +853,8 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 
 	memset(&device_info, 0, sizeof(device_info));
 	device_info.ring_size = ring_size;
-	device_info.num_chn = num_chn;
-	device_info.max_num_vrss_chns = max_num_vrss_chns;
+	device_info.num_chn = nvdev->num_chn;
+	device_info.max_num_vrss_chns = nvdev->num_chn;
 	rndis_filter_device_add(hdev, &device_info);
 
 out:
@@ -1410,7 +1379,7 @@ static int netvsc_probe(struct hv_device *dev,
 	int ret;
 
 	net = alloc_etherdev_mq(sizeof(struct net_device_context),
-				num_online_cpus());
+				VRSS_CHANNEL_MAX);
 	if (!net)
 		return -ENOMEM;
 
@@ -1457,7 +1426,8 @@ static int netvsc_probe(struct hv_device *dev,
 	/* Notify the netvsc driver of the new device */
 	memset(&device_info, 0, sizeof(device_info));
 	device_info.ring_size = ring_size;
-	device_info.max_num_vrss_chns = max_num_vrss_chns;
+	device_info.max_num_vrss_chns = min_t(u32, VRSS_CHANNEL_DEFAULT,
+					      num_online_cpus());
 	ret = rndis_filter_device_add(dev, &device_info);
 	if (ret != 0) {
 		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
-- 
2.11.0