net: phylink: disable PCS polling over major configuration

While we are performing a major configuration, there is no point having
the PCS polling timer running. Stop it before we begin preparing for
the configuration change, and restart it only once we've successfully
completed the change.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/phylink.c

@@ -758,6 +758,18 @@ static void phylink_resolve_flow(struct phylink_link_state *state)
 	}
 }
 
+static void phylink_pcs_poll_stop(struct phylink *pl)
+{
+	if (pl->cfg_link_an_mode == MLO_AN_INBAND)
+		del_timer(&pl->link_poll);
+}
+
+static void phylink_pcs_poll_start(struct phylink *pl)
+{
+	if (pl->pcs->poll && pl->cfg_link_an_mode == MLO_AN_INBAND)
+		mod_timer(&pl->link_poll, jiffies + HZ);
+}
+
 static void phylink_mac_config(struct phylink *pl,
 			       const struct phylink_link_state *state)
 {
@@ -789,6 +801,7 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 				  const struct phylink_link_state *state)
 {
 	struct phylink_pcs *pcs = NULL;
+	bool pcs_changed = false;
 	int err;
 
 	phylink_dbg(pl, "major config %s\n", phy_modes(state->interface));
@@ -801,8 +814,12 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 				    pcs);
 			return;
 		}
+
+		pcs_changed = pcs && pl->pcs != pcs;
 	}
 
+	phylink_pcs_poll_stop(pl);
+
 	if (pl->mac_ops->mac_prepare) {
 		err = pl->mac_ops->mac_prepare(pl->config, pl->cur_link_an_mode,
 					       state->interface);
@@ -816,18 +833,9 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 	/* If we have a new PCS, switch to the new PCS after preparing the MAC
 	 * for the change.
 	 */
-	if (pcs) {
+	if (pcs_changed)
 		pl->pcs = pcs;
 
-		if (!pl->phylink_disable_state &&
-		    pl->cfg_link_an_mode == MLO_AN_INBAND) {
-			if (pcs->poll)
-				mod_timer(&pl->link_poll, jiffies + HZ);
-			else
-				del_timer(&pl->link_poll);
-		}
-	}
-
 	phylink_mac_config(pl, state);
 
 	if (pl->pcs) {
@@ -852,6 +860,8 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 			phylink_err(pl, "mac_finish failed: %pe\n",
 				    ERR_PTR(err));
 	}
+
+	phylink_pcs_poll_start(pl);
 }
 
 /*