netdev - [PATCH RFC net-next 09/13] net: phylink: simplify fixed-link case for ksettings

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Message-Id: <E1jqHG9-0006Pj-2J@rmk-PC.armlinux.org.uk>
Date:   Tue, 30 Jun 2020 15:29:17 +0100
From:   Russell King <rmk+kernel@...linux.org.uk>
To:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Ioana Ciornei <ioana.ciornei@....com>
Cc:     Vladimir Oltean <vladimir.oltean@....com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Alexandru Marginean <alexandru.marginean@....com>,
        "michael@...le.cc" <michael@...le.cc>,
        "olteanv@...il.com" <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH RFC net-next 09/13] net: phylink: simplify fixed-link case for
 ksettings_set method

For fixed links, we only allow the current settings, so this should be
a matter of merely rejecting an attempt to change the settings.  If the
settings agree, then there is nothing more we need to do.

Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
---
 drivers/net/phy/phylink.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 967c068d16c8..b91151062cdc 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1360,22 +1360,31 @@ int phylink_ethtool_ksettings_set(struct phylink *pl,
 		if (!s)
 			return -EINVAL;
 
-		/* If we have a fixed link (as specified by firmware), refuse
-		 * to change link parameters.
+		/* If we have a fixed link, refuse to change link parameters.
+		 * If the link parameters match, accept them but do nothing.
 		 */
-		if (pl->cur_link_an_mode == MLO_AN_FIXED &&
-		    (s->speed != pl->link_config.speed ||
-		     s->duplex != pl->link_config.duplex))
-			return -EINVAL;
+		if (pl->cur_link_an_mode == MLO_AN_FIXED) {
+			if (s->speed != pl->link_config.speed ||
+			    s->duplex != pl->link_config.duplex)
+				return -EINVAL;
+			return 0;
+		}
 
 		config.speed = s->speed;
 		config.duplex = s->duplex;
 		break;
 
 	case AUTONEG_ENABLE:
-		/* If we have a fixed link, refuse to enable autonegotiation */
-		if (pl->cur_link_an_mode == MLO_AN_FIXED)
-			return -EINVAL;
+		/* If we have a fixed link, allow autonegotiation (since that
+		 * is our default case) but do not allow the advertisement to
+		 * be changed. If the advertisement matches, simply return.
+		 */
+		if (pl->cur_link_an_mode == MLO_AN_FIXED) {
+			if (!linkmode_equal(config.advertising,
+					    pl->link_config.advertising))
+				return -EINVAL;
+			return 0;
+		}
 
 		config.speed = SPEED_UNKNOWN;
 		config.duplex = DUPLEX_UNKNOWN;
@@ -1385,8 +1394,8 @@ int phylink_ethtool_ksettings_set(struct phylink *pl,
 		return -EINVAL;
 	}
 
-	/* For a fixed link, this isn't able to change any parameters,
-	 * which just leaves inband mode.
+	/* We have ruled out the case with a PHY attached, and the
+	 * fixed-link cases.  All that is left are in-band links.
 	 */
 	if (phylink_validate(pl, support, &config))
 		return -EINVAL;
-- 
2.20.1