netdev - [RFC PATCH net-next 6/9] net: phylink: Make fixed link notifier calls edge-triggered

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Date:   Thu, 23 May 2019 01:20:41 +0000
From:   Ioana Ciornei <ioana.ciornei@....com>
To:     "linux@...linux.org.uk" <linux@...linux.org.uk>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "andrew@...n.ch" <andrew@...n.ch>,
        "hkallweit1@...il.com" <hkallweit1@...il.com>,
        "maxime.chevallier@...tlin.com" <maxime.chevallier@...tlin.com>,
        "olteanv@...il.com" <olteanv@...il.com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        Ioana Ciornei <ioana.ciornei@....com>
Subject: [RFC PATCH net-next 6/9] net: phylink: Make fixed link notifier calls
 edge-triggered

Otherwise .mac_link_up and .mac_link_down on fixed-link interfaces are
called every second.

On a raw phylink instance we cannot call netdev_carrier_ok for an
indication of the last state of the link, so keep track and update this
in a new field of the phylink structure.

Signed-off-by: Ioana Ciornei <ioana.ciornei@....com>
---
 drivers/net/phy/phylink.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 7b6b233c1a07..3bc91b249990 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -44,6 +44,7 @@ struct phylink {
 	const struct phylink_mac_ops *ops;
 	struct notifier_block *nb;
 	struct blocking_notifier_head notifier_chain;
+	unsigned int old_link_state:1;
 
 	unsigned long phylink_disable_state; /* bitmask of disables */
 	struct phy_device *phydev;
@@ -499,6 +500,7 @@ static void phylink_resolve(struct work_struct *w)
 	struct phylink *pl = container_of(w, struct phylink, resolve);
 	struct phylink_link_state link_state;
 	struct net_device *ndev = pl->netdev;
+	int link_changed;
 
 	mutex_lock(&pl->state_mutex);
 	if (pl->phylink_disable_state) {
@@ -548,10 +550,13 @@ static void phylink_resolve(struct work_struct *w)
 		}
 	}
 
-	/* Take the branch without checking the carrier status
-	 * if there is no netdevice.
-	 */
-	if (!pl->ops || link_state.link != netif_carrier_ok(ndev)) {
+	if (pl->ops)
+		link_changed = (link_state.link != netif_carrier_ok(ndev));
+	else
+		link_changed = (link_state.link != pl->old_link_state);
+
+	if (link_changed) {
+		pl->old_link_state = link_state.link;
 		if (!link_state.link)
 			phylink_mac_link_down(pl);
 		else
-- 
2.21.0