Merge branch 'Two-phylink-pause-fixes'

Russell King says:

====================
Two phylink pause fixes

While testing, I discovered two issues with ethtool -A with phylink.
First, if there is a PHY bound to the network device, we hit a
deadlock when phylib tries to notify us of the link changing as a
result of triggering a renegotiation.

Second, when we are manually forcing the pause settings, and there
is no renegotiation triggered, we do not update the MAC via the new
mac_link_up approach.

These two patches solve both problems, and will need to be backported
to v5.7; they do not apply cleanly there due to the introduction of
PCS in the v5.8 merge window.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phylink.c

@@ -1463,6 +1463,8 @@ int phylink_ethtool_set_pauseparam(struct phylink *pl,
 				   struct ethtool_pauseparam *pause)
 {
 	struct phylink_link_state *config = &pl->link_config;
+	bool manual_changed;
+	int pause_state;
 
 	ASSERT_RTNL();
 
@@ -1477,15 +1479,15 @@ int phylink_ethtool_set_pauseparam(struct phylink *pl,
 	    !pause->autoneg && pause->rx_pause != pause->tx_pause)
 		return -EINVAL;
 
-	mutex_lock(&pl->state_mutex);
-	config->pause = 0;
+	pause_state = 0;
 	if (pause->autoneg)
-		config->pause |= MLO_PAUSE_AN;
+		pause_state |= MLO_PAUSE_AN;
 	if (pause->rx_pause)
-		config->pause |= MLO_PAUSE_RX;
+		pause_state |= MLO_PAUSE_RX;
 	if (pause->tx_pause)
-		config->pause |= MLO_PAUSE_TX;
+		pause_state |= MLO_PAUSE_TX;
 
+	mutex_lock(&pl->state_mutex);
 	/*
 	 * See the comments for linkmode_set_pause(), wrt the deficiencies
 	 * with the current implementation.  A solution to this issue would
@@ -1502,18 +1504,35 @@ int phylink_ethtool_set_pauseparam(struct phylink *pl,
 	linkmode_set_pause(config->advertising, pause->tx_pause,
 			   pause->rx_pause);
 
-	/* If we have a PHY, phylib will call our link state function if the
-	 * mode has changed, which will trigger a resolve and update the MAC
-	 * configuration.
+	manual_changed = (config->pause ^ pause_state) & MLO_PAUSE_AN ||
+			 (!(pause_state & MLO_PAUSE_AN) &&
+			   (config->pause ^ pause_state) & MLO_PAUSE_TXRX_MASK);
+
+	config->pause = pause_state;
+
+	if (!pl->phydev && !test_bit(PHYLINK_DISABLE_STOPPED,
+				     &pl->phylink_disable_state))
+		phylink_pcs_config(pl, true, &pl->link_config);
+
+	mutex_unlock(&pl->state_mutex);
+
+	/* If we have a PHY, a change of the pause frame advertisement will
+	 * cause phylib to renegotiate (if AN is enabled) which will in turn
+	 * call our phylink_phy_change() and trigger a resolve.  Note that
+	 * we can't hold our state mutex while calling phy_set_asym_pause().
 	 */
-	if (pl->phydev) {
+	if (pl->phydev)
 		phy_set_asym_pause(pl->phydev, pause->rx_pause,
 				   pause->tx_pause);
-	} else if (!test_bit(PHYLINK_DISABLE_STOPPED,
-			     &pl->phylink_disable_state)) {
-		phylink_pcs_config(pl, true, &pl->link_config);
+
+	/* If the manual pause settings changed, make sure we trigger a
+	 * resolve to update their state; we can not guarantee that the
+	 * link will cycle.
+	 */
+	if (manual_changed) {
+		pl->mac_link_dropped = true;
+		phylink_run_resolve(pl);
 	}
-	mutex_unlock(&pl->state_mutex);
 
 	return 0;
 }