From edb726666b26bcec63ef9cba7f8417a9c6fedd28 Mon Sep 17 00:00:00 2001
From: Izabela Bakollari <ibakolla@redhat.com>
Date: Tue, 7 Nov 2023 16:38:48 +0100
Subject: [PATCH] net: transfer rtnl_lock() requirement from
 ethtool_set_ethtool_phy_ops() to caller

JIRA: https://issues.redhat.com/browse/RHEL-946

commit 70ef7d87f62a86674c21a99341dabc175c19681a
Author: Vladimir Oltean <vladimir.oltean@nxp.com>
Date:   Tue Aug 1 17:28:22 2023 +0300

    net: transfer rtnl_lock() requirement from ethtool_set_ethtool_phy_ops() to caller

    phy_init() and phy_exit() will have to do more stuff under rtnl_lock()
    in a future change. Since rtnl_unlock() -> netdev_run_todo() does a lot
    of stuff under the hood, it's a pity to lock and unlock the rtnetlink
    mutex twice in a row.

    Change the calling convention such that the only caller of
    ethtool_set_ethtool_phy_ops(), phy_device.c, provides a context where
    the rtnl_mutex is already acquired.

    Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
    Link: https://lore.kernel.org/r/20230801142824.1772134-11-vladimir.oltean@nxp.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Izabela Bakollari <ibakolla@redhat.com>
---
 drivers/net/phy/phy_device.c | 7 +++++++
 net/ethtool/common.c         | 3 +--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index c7cf61fe41cf..19794ff25530 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -30,6 +30,7 @@
 #include <linux/phy_led_triggers.h>
 #include <linux/pse-pd/pse.h>
 #include <linux/property.h>
+#include <linux/rtnetlink.h>
 #include <linux/sfp.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
@@ -3442,7 +3443,9 @@ static int __init phy_init(void)
 {
 	int rc;
 
+	rtnl_lock();
 	ethtool_set_ethtool_phy_ops(&phy_ethtool_phy_ops);
+	rtnl_unlock();
 
 	rc = mdio_bus_init();
 	if (rc)
@@ -3465,7 +3468,9 @@ err_c45:
 err_mdio_bus:
 	mdio_bus_exit();
 err_ethtool_phy_ops:
+	rtnl_lock();
 	ethtool_set_ethtool_phy_ops(NULL);
+	rtnl_unlock();
 
 	return rc;
 }
@@ -3475,7 +3480,9 @@ static void __exit phy_exit(void)
 	phy_driver_unregister(&genphy_c45_driver);
 	phy_driver_unregister(&genphy_driver);
 	mdio_bus_exit();
+	rtnl_lock();
 	ethtool_set_ethtool_phy_ops(NULL);
+	rtnl_unlock();
 }
 
 subsys_initcall(phy_init);
diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index c586db0c5e68..47fe5e3cc231 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -664,9 +664,8 @@ const struct ethtool_phy_ops *ethtool_phy_ops;
 
 void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops)
 {
-	rtnl_lock();
+	ASSERT_RTNL();
 	ethtool_phy_ops = ops;
-	rtnl_unlock();
 }
 EXPORT_SYMBOL_GPL(ethtool_set_ethtool_phy_ops);