netdev - [PATCH net-next 3/9] netvsc: change max channel calculation

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Date:   Wed, 22 Mar 2017 14:50:59 -0700
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     kys@...rosoft.com, davem@...emloft.net
Cc:     netdev@...r.kernel.org, haiyangz@...rosoft.com,
        Stephen Hemminger <sthemmin@...rosoft.com>
Subject: [PATCH net-next 3/9] netvsc: change max channel calculation

The default number of maximum channels should be limited to the
number of cpus available on the numa node of the primary channel.
This also makes sure maximum channels <= num_online_cpus

Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
---
 drivers/net/hyperv/netvsc_drv.c   |  3 +--
 drivers/net/hyperv/rndis_filter.c | 25 ++++++++++---------------
 2 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index b3a7f508434b..2f9de2e9f38e 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1503,8 +1503,7 @@ 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 = min_t(u32, VRSS_CHANNEL_DEFAULT,
-					      num_online_cpus());
+	device_info.num_chn = VRSS_CHANNEL_DEFAULT;
 	ret = rndis_filter_device_add(dev, &device_info);
 	if (ret != 0) {
 		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 382b9a62e3c4..d193d549cec6 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1181,33 +1181,28 @@ int rndis_filter_device_add(struct hv_device *dev,
 	if (ret || rsscap.num_recv_que < 2)
 		goto out;
 
-	net_device->max_chn = min_t(u32, VRSS_CHANNEL_MAX, rsscap.num_recv_que);
-
-	num_rss_qs = min(device_info->max_num_vrss_chns, net_device->max_chn);
-
 	/*
 	 * We will limit the VRSS channels to the number CPUs in the NUMA node
 	 * the primary channel is currently bound to.
+	 *
+	 * This also guarantees that num_possible_rss_qs <= num_online_cpus
 	 */
 	node_cpu_mask = cpumask_of_node(cpu_to_node(dev->channel->target_cpu));
-	num_possible_rss_qs = cpumask_weight(node_cpu_mask);
+	num_possible_rss_qs = min_t(u32, cpumask_weight(node_cpu_mask),
+				    rsscap.num_recv_que);
 
-	/* We will use the given number of channels if available. */
-	if (device_info->num_chn && device_info->num_chn < net_device->max_chn)
-		net_device->num_chn = device_info->num_chn;
-	else
-		net_device->num_chn = min(num_possible_rss_qs, num_rss_qs);
+	net_device->max_chn = min_t(u32, VRSS_CHANNEL_MAX, num_possible_rss_qs);
 
-	num_rss_qs = net_device->num_chn - 1;
+	/* We will use the given number of channels if available. */
+	net_device->num_chn = min(net_device->max_chn, device_info->num_chn);
 
 	for (i = 0; i < ITAB_NUM; i++)
 		rndis_device->ind_table[i] = ethtool_rxfh_indir_default(i,
 							net_device->num_chn);
 
-	net_device->num_sc_offered = num_rss_qs;
-
-	if (net_device->num_chn == 1)
-		goto out;
+	num_rss_qs = net_device->num_chn - 1;
+	if (num_rss_qs == 0)
+		return 0;
 
 	vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);
 
-- 
2.11.0