netdev - [PATCH net 1/2] net: phy: don't use locking in phy_is

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Date:   Wed, 13 Feb 2019 20:11:40 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        David Miller <davem@...emloft.net>
Cc:     Russell King - ARM Linux <linux@...linux.org.uk>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net 1/2] net: phy: don't use locking in phy_is_started

Russell suggested to remove the locking from phy_is_started() because
the read is atomic anyway and actually the locking may be more
misleading.

Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Suggested-by: Russell King - ARM Linux admin <linux@...linux.org.uk>
Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/phy/phy.c | 11 +++++------
 include/linux/phy.h   | 15 +--------------
 2 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index ca5e0c0f018c..602816d70281 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -553,7 +553,7 @@ int phy_start_aneg(struct phy_device *phydev)
 	if (err < 0)
 		goto out_unlock;
 
-	if (__phy_is_started(phydev)) {
+	if (phy_is_started(phydev)) {
 		if (phydev->autoneg == AUTONEG_ENABLE) {
 			err = phy_check_link_status(phydev);
 		} else {
@@ -709,7 +709,7 @@ void phy_stop_machine(struct phy_device *phydev)
 	cancel_delayed_work_sync(&phydev->state_queue);
 
 	mutex_lock(&phydev->lock);
-	if (__phy_is_started(phydev))
+	if (phy_is_started(phydev))
 		phydev->state = PHY_UP;
 	mutex_unlock(&phydev->lock);
 }
@@ -839,15 +839,14 @@ EXPORT_SYMBOL(phy_stop_interrupts);
  */
 void phy_stop(struct phy_device *phydev)
 {
-	mutex_lock(&phydev->lock);
-
-	if (!__phy_is_started(phydev)) {
+	if (!phy_is_started(phydev)) {
 		WARN(1, "called from state %s\n",
 		     phy_state_to_str(phydev->state));
-		mutex_unlock(&phydev->lock);
 		return;
 	}
 
+	mutex_lock(&phydev->lock);
+
 	if (phy_interrupt_is_valid(phydev))
 		phy_disable_interrupts(phydev);
 
diff --git a/include/linux/phy.h b/include/linux/phy.h
index ef20aeea10cc..127fcc9c3778 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -674,26 +674,13 @@ phy_lookup_setting(int speed, int duplex, const unsigned long *mask,
 size_t phy_speeds(unsigned int *speeds, size_t size,
 		  unsigned long *mask);
 
-static inline bool __phy_is_started(struct phy_device *phydev)
-{
-	WARN_ON(!mutex_is_locked(&phydev->lock));
-
-	return phydev->state >= PHY_UP;
-}
-
 /**
  * phy_is_started - Convenience function to check whether PHY is started
  * @phydev: The phy_device struct
  */
 static inline bool phy_is_started(struct phy_device *phydev)
 {
-	bool started;
-
-	mutex_lock(&phydev->lock);
-	started = __phy_is_started(phydev);
-	mutex_unlock(&phydev->lock);
-
-	return started;
+	return phydev->state >= PHY_UP;
 }
 
 void phy_resolve_aneg_linkmode(struct phy_device *phydev);
-- 
2.20.1