netdev - [PATCH net-next 4/5] net: stmmac: remove unnecessary netif_carrier

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Message-Id: <E1sBvK1-00EHyi-4l@rmk-PC.armlinux.org.uk>
Date: Tue, 28 May 2024 12:48:53 +0100
From: "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>
To: Serge Semin <fancer.lancer@...il.com>
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Jose Abreu <joabreu@...opsys.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	netdev@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org
Subject: [PATCH net-next 4/5] net: stmmac: remove unnecessary
 netif_carrier_off()

It is incorrect to call netif_carrier_off(), or in fact any driver
teardown, before unregister_netdev() has been called.

unregister_netdev() unpublishes the network device from userspace, and
takes the interface down if it was up prior to returning. Therefore,
once the call has returned, we are guaranteed that .ndo_stop() will
have been called for an interface that was up. Phylink will take the
carrier down via phylink_stop(), making any manipulation of the carrier
in the remove path unnecessary.

In the stmmac_release() path, the netif_carrier_off() call follows the
call to phylink_stop(), so this call is redundant.

Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index e01340034d50..6e427ed7af05 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4097,8 +4097,6 @@ static int stmmac_release(struct net_device *dev)
 	if (priv->plat->serdes_powerdown)
 		priv->plat->serdes_powerdown(dev, priv->plat->bsp_priv);
 
-	netif_carrier_off(dev);
-
 	stmmac_release_ptp(priv);
 
 	pm_runtime_put(priv->device);
@@ -7821,7 +7819,6 @@ void stmmac_dvr_remove(struct device *dev)
 
 	stmmac_stop_all_dma(priv);
 	stmmac_mac_set(priv, priv->ioaddr, false);
-	netif_carrier_off(ndev);
 	unregister_netdev(ndev);
 
 #ifdef CONFIG_DEBUG_FS
-- 
2.30.2