netdev - [PATCH net-next v3 12/18] net: stmmac: move priv->eee_enabled into stmmac_eee

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Message-Id: <E1tVCSO-007Y43-Fa@rmk-PC.armlinux.org.uk>
Date: Tue, 07 Jan 2025 16:29:28 +0000
From: "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>
To: Andrew Lunn <andrew@...n.ch>,
	Heiner Kallweit <hkallweit1@...il.com>
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Jose Abreu <joabreu@...opsys.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-stm32@...md-mailman.stormreply.com,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	netdev@...r.kernel.org,
	Paolo Abeni <pabeni@...hat.com>
Subject: [PATCH net-next v3 12/18] net: stmmac: move priv->eee_enabled into
 stmmac_eee_init()

All call sites for stmmac_eee_init() assign the return code to
priv->eee_enabled. Rather than having this coded at each call site,
move the assignment inside stmmac_eee_init().

Since stmmac_init_eee() takes priv->lock before checking the state of
priv->eee_enabled, move the assignment within the locked region. Also,
stmmac_suspend() checks the state of this member under the lock. While
two concurrent calls to stmmac_init_eee() aren't possible, there is
a possibility that stmmac_suspend() may run concurrently with a change
of priv->eee_enabled unless we modify it under the lock.

Reviewed-by: Andrew Lunn <andrew@...n.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c  | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 94bb6b07f96f..b7e0026c271b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -462,11 +462,13 @@ static void stmmac_eee_ctrl_timer(struct timer_list *t)
  *  can also manage EEE, this function enable the LPI state and start related
  *  timer.
  */
-static bool stmmac_eee_init(struct stmmac_priv *priv)
+static void stmmac_eee_init(struct stmmac_priv *priv)
 {
 	/* Check if MAC core supports the EEE feature. */
-	if (!priv->dma_cap.eee)
-		return false;
+	if (!priv->dma_cap.eee) {
+		priv->eee_enabled = false;
+		return;
+	}
 
 	mutex_lock(&priv->lock);
 
@@ -483,8 +485,9 @@ static bool stmmac_eee_init(struct stmmac_priv *priv)
 						priv->plat->mult_fact_100ns,
 						false);
 		}
+		priv->eee_enabled = false;
 		mutex_unlock(&priv->lock);
-		return false;
+		return;
 	}
 
 	if (priv->eee_active && !priv->eee_enabled) {
@@ -507,9 +510,10 @@ static bool stmmac_eee_init(struct stmmac_priv *priv)
 			  STMMAC_LPI_T(priv->tx_lpi_timer));
 	}
 
+	priv->eee_enabled = true;
+
 	mutex_unlock(&priv->lock);
 	netdev_dbg(priv->dev, "Energy-Efficient Ethernet initialized\n");
-	return true;
 }
 
 /* stmmac_get_tx_hwtstamp - get HW TX timestamps
@@ -967,7 +971,7 @@ static void stmmac_mac_link_down(struct phylink_config *config,
 
 	stmmac_mac_set(priv, priv->ioaddr, false);
 	priv->eee_active = false;
-	priv->eee_enabled = stmmac_eee_init(priv);
+	stmmac_eee_init(priv);
 	stmmac_set_eee_pls(priv, priv->hw, false);
 
 	if (stmmac_fpe_supported(priv))
@@ -1080,7 +1084,7 @@ static void stmmac_mac_link_up(struct phylink_config *config,
 					     STMMAC_FLAG_RX_CLK_RUNS_IN_LPI));
 		priv->tx_lpi_timer = phy->eee_cfg.tx_lpi_timer;
 		priv->eee_active = phy->enable_tx_lpi;
-		priv->eee_enabled = stmmac_eee_init(priv);
+		stmmac_eee_init(priv);
 		stmmac_set_eee_pls(priv, priv->hw, true);
 	}
 
-- 
2.30.2