Subject: Re: [PATCH net-next] nfp: VF rate limit support

From: Jakub Kicinski <[email-masked]>
Date: Fri, 29 Apr 2022 11:04:40 -0700

On Fri, 29 Apr 2022 11:03:47 -0700 Jakub Kicinski wrote:
> On Fri, 29 Apr 2022 08:54:53 +0000 Bin Chen wrote:
> > We agree with your suggestion, thanks. We plan to do this in two steps:
> > 1.The firmware that currently support this feature will reject the nonzero min_tx_rate configuration, so the check here will not step in.  We will remove the check from driver site and upstream the patch. 
> > 2.We will do more investigation jobs and add an appropriate check in the core.
> > What do you think?  
> 
> Sorry, I meant the second part of the condition only, basically
> something like:

I hit the wrong shortcut :) Here's the patch:

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 73f2cbc440c9..8de191cedaf7 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2368,6 +2368,19 @@ static int handle_vf_guid(struct net_device *dev, struct ifla_vf_guid *ivt, int
 	return handle_infiniband_guid(dev, ivt, guid_type);
 }
 
+static int rtnl_set_vf_rate(struct net_device *dev, int vf, int min_tx_rate,
+			    int max_tx_rate)
+{
+	int err;
+
+	if (!ops->ndo_set_vf_rate)
+		return -EOPNOTSUPP;
+	if (min_tx_rate > max_tx_rate)
+		return -EINVAL;
+
+	return ops->ndo_set_vf_rate(dev, vf, min_tx_rate, max_tx_rate);
+}
+
 static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
@@ -2443,11 +2456,8 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
 		if (err < 0)
 			return err;
 
-		err = -EOPNOTSUPP;
-		if (ops->ndo_set_vf_rate)
-			err = ops->ndo_set_vf_rate(dev, ivt->vf,
-						   ivf.min_tx_rate,
-						   ivt->rate);
+		err = rtnl_set_vf_rate(dev, ivt->vf,
+				       ivf.min_tx_rate, ivt->rate);
 		if (err < 0)
 			return err;
 	}
@@ -2457,11 +2467,8 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
 
 		if (ivt->vf >= INT_MAX)
 			return -EINVAL;
-		err = -EOPNOTSUPP;
-		if (ops->ndo_set_vf_rate)
-			err = ops->ndo_set_vf_rate(dev, ivt->vf,
-						   ivt->min_tx_rate,
-						   ivt->max_tx_rate);
+		err = rtnl_set_vf_rate(dev, ivt->vf,
+				       ivt->min_tx_rate, ivt->max_tx_rate);
 		if (err < 0)
 			return err;
 	}