[PATCH net v3 1/1] ethtool: netlink: do not return SQI value if link is down

[PATCH net v3 1/1] ethtool: netlink: do not return SQI value if link is down

[Oleksij Rempel]

Do not attach SQI value if link is down. "SQI values are only valid if
link-up condition is present" per OpenAlliance specification of
100Base-T1 Interoperability Test suite [1]. The same rule would apply
for other link types.

[1] https://opensig.org/automotive-ethernet-specifications/#

Fixes: 806602191592 ("ethtool: provide UAPI for PHY Signal Quality Index (SQI)")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
changes v3:
- add (data->sqi <= data->sqi_max) validation
changes v2:
- add and reuse helper functions linkstate_sqi_critical_error() and
  linkstate_sqi_valid()
- make sure we set sqi and sqi_max vals only if both are valid
---
 net/ethtool/linkstate.c | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/net/ethtool/linkstate.c b/net/ethtool/linkstate.c
index b2de2108b356a..34d76e87847d0 100644
--- a/net/ethtool/linkstate.c
+++ b/net/ethtool/linkstate.c
@@ -37,6 +37,8 @@ static int linkstate_get_sqi(struct net_device *dev)
 	mutex_lock(&phydev->lock);
 	if (!phydev->drv || !phydev->drv->get_sqi)
 		ret = -EOPNOTSUPP;
+	else if (!phydev->link)
+		ret = -ENETDOWN;
 	else
 		ret = phydev->drv->get_sqi(phydev);
 	mutex_unlock(&phydev->lock);
@@ -55,6 +57,8 @@ static int linkstate_get_sqi_max(struct net_device *dev)
 	mutex_lock(&phydev->lock);
 	if (!phydev->drv || !phydev->drv->get_sqi_max)
 		ret = -EOPNOTSUPP;
+	else if (!phydev->link)
+		ret = -ENETDOWN;
 	else
 		ret = phydev->drv->get_sqi_max(phydev);
 	mutex_unlock(&phydev->lock);
@@ -62,6 +66,17 @@ static int linkstate_get_sqi_max(struct net_device *dev)
 	return ret;
 };
 
+static bool linkstate_sqi_critical_error(int sqi)
+{
+	return sqi < 0 && sqi != -EOPNOTSUPP && sqi != -ENETDOWN;
+}
+
+static bool linkstate_sqi_valid(struct linkstate_reply_data *data)
+{
+	return data->sqi >= 0 && data->sqi_max >= 0 &&
+	       data->sqi <= data->sqi_max;
+}
+
 static int linkstate_get_link_ext_state(struct net_device *dev,
 					struct linkstate_reply_data *data)
 {
@@ -93,12 +108,12 @@ static int linkstate_prepare_data(const struct ethnl_req_info *req_base,
 	data->link = __ethtool_get_link(dev);
 
 	ret = linkstate_get_sqi(dev);
-	if (ret < 0 && ret != -EOPNOTSUPP)
+	if (linkstate_sqi_critical_error(ret))
 		goto out;
 	data->sqi = ret;
 
 	ret = linkstate_get_sqi_max(dev);
-	if (ret < 0 && ret != -EOPNOTSUPP)
+	if (linkstate_sqi_critical_error(ret))
 		goto out;
 	data->sqi_max = ret;
 
@@ -136,11 +151,10 @@ static int linkstate_reply_size(const struct ethnl_req_info *req_base,
 	len = nla_total_size(sizeof(u8)) /* LINKSTATE_LINK */
 		+ 0;
 
-	if (data->sqi != -EOPNOTSUPP)
-		len += nla_total_size(sizeof(u32));
-
-	if (data->sqi_max != -EOPNOTSUPP)
-		len += nla_total_size(sizeof(u32));
+	if (linkstate_sqi_valid(data)) {
+		len += nla_total_size(sizeof(u32)); /* LINKSTATE_SQI */
+		len += nla_total_size(sizeof(u32)); /* LINKSTATE_SQI_MAX */
+	}
 
 	if (data->link_ext_state_provided)
 		len += nla_total_size(sizeof(u8)); /* LINKSTATE_EXT_STATE */
@@ -164,13 +178,14 @@ static int linkstate_fill_reply(struct sk_buff *skb,
 	    nla_put_u8(skb, ETHTOOL_A_LINKSTATE_LINK, !!data->link))
 		return -EMSGSIZE;
 
-	if (data->sqi != -EOPNOTSUPP &&
-	    nla_put_u32(skb, ETHTOOL_A_LINKSTATE_SQI, data->sqi))
-		return -EMSGSIZE;
+	if (linkstate_sqi_valid(data)) {
+		if (nla_put_u32(skb, ETHTOOL_A_LINKSTATE_SQI, data->sqi))
+			return -EMSGSIZE;
 
-	if (data->sqi_max != -EOPNOTSUPP &&
-	    nla_put_u32(skb, ETHTOOL_A_LINKSTATE_SQI_MAX, data->sqi_max))
-		return -EMSGSIZE;
+		if (nla_put_u32(skb, ETHTOOL_A_LINKSTATE_SQI_MAX,
+				data->sqi_max))
+			return -EMSGSIZE;
+	}
 
 	if (data->link_ext_state_provided) {
 		if (nla_put_u8(skb, ETHTOOL_A_LINKSTATE_EXT_STATE,
-- 
2.39.2

RE: [PATCH net v3 1/1] ethtool: netlink: do not return SQI value if link is down

[Woojung.Huh]

> -----Original Message-----
> From: Oleksij Rempel <o.rempel@pengutronix.de>
> Sent: Tuesday, July 9, 2024 2:20 AM
> To: Michal Kubecek <mkubecek@suse.cz>; David S. Miller <davem@davemloft.net>;
> Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>; Jiri Pirko <jiri@resnulli.us>; Vladimir Oltean
> <vladimir.oltean@nxp.com>; Andrew Lunn <andrew@lunn.ch>; Arun Ramadoss -
> I17769 <Arun.Ramadoss@microchip.com>; Woojung Huh - C21699
> <Woojung.Huh@microchip.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>; kernel@pengutronix.de;
> netdev@vger.kernel.org; UNGLinuxDriver <UNGLinuxDriver@microchip.com>;
> linux-kernel@vger.kernel.org
> Subject: [PATCH net v3 1/1] ethtool: netlink: do not return SQI value if
> link is down
> 
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> 
> Do not attach SQI value if link is down. "SQI values are only valid if
> link-up condition is present" per OpenAlliance specification of
> 100Base-T1 Interoperability Test suite [1]. The same rule would apply
> for other link types.
> 
> [1] https://opensig.org/automotive-ethernet-specifications/#
> 
> Fixes: 806602191592 ("ethtool: provide UAPI for PHY Signal Quality Index
> (SQI)")
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> ---

Reviewed-by: Woojung Huh <woojung.huh@microchip.com>

Thanks.
Woojung

Re: [PATCH net v3 1/1] ethtool: netlink: do not return SQI value if link is down

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Tue,  9 Jul 2024 08:19:43 +0200 you wrote:
> Do not attach SQI value if link is down. "SQI values are only valid if
> link-up condition is present" per OpenAlliance specification of
> 100Base-T1 Interoperability Test suite [1]. The same rule would apply
> for other link types.
> 
> [1] https://opensig.org/automotive-ethernet-specifications/#
> 
> [...]

Here is the summary with links:
  - [net,v3,1/1] ethtool: netlink: do not return SQI value if link is down
    https://git.kernel.org/netdev/net/c/c184cf94e73b

You are awesome, thank you!
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