netdev - [PATCH RfC 1/2] net: phy: core: remove now uneeded disabling of interrupts

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Message-ID: <0f24f12a-2e1d-dd79-b425-77bd16db21e8@gmail.com>
Date:   Sun, 12 Nov 2017 22:08:22 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        David Miller <davem@...emloft.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH RfC 1/2] net: phy: core: remove now uneeded disabling of
 interrupts

After commits c974bdbc3e "net: phy: Use threaded IRQ, to allow IRQ from
sleeping devices" and 664fcf123a30 "net: phy: Threaded interrupts allow
some simplification" all relevant code pieces run in process context
anyway and I don't think we need the disabling of interrupts any longer.

Interestingly enough, latter commit already removed the comment
explaining why interrupts need to be temporarily disabled.

On my system phy interrupt mode works fine with this patch.
However I may miss something, especially in the context of shared phy
interrupts, therefore I'd appreciate if more people could test this.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/phy/phy.c | 26 ++------------------------
 include/linux/phy.h   |  1 -
 2 files changed, 2 insertions(+), 25 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 2b1e67bc1..b3784c9a2 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -629,9 +629,6 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)
 	if (PHY_HALTED == phydev->state)
 		return IRQ_NONE;		/* It can't be ours.  */
 
-	disable_irq_nosync(irq);
-	atomic_inc(&phydev->irq_disable);
-
 	phy_change(phydev);
 
 	return IRQ_HANDLED;
@@ -689,7 +686,6 @@ static int phy_disable_interrupts(struct phy_device *phydev)
  */
 int phy_start_interrupts(struct phy_device *phydev)
 {
-	atomic_set(&phydev->irq_disable, 0);
 	if (request_threaded_irq(phydev->irq, NULL, phy_interrupt,
 				 IRQF_ONESHOT | IRQF_SHARED,
 				 phydev_name(phydev), phydev) < 0) {
@@ -716,13 +712,6 @@ int phy_stop_interrupts(struct phy_device *phydev)
 
 	free_irq(phydev->irq, phydev);
 
-	/* If work indeed has been cancelled, disable_irq() will have
-	 * been left unbalanced from phy_interrupt() and enable_irq()
-	 * has to be called so that other devices on the line work.
-	 */
-	while (atomic_dec_return(&phydev->irq_disable) >= 0)
-		enable_irq(phydev->irq);
-
 	return err;
 }
 EXPORT_SYMBOL(phy_stop_interrupts);
@@ -736,7 +725,7 @@ void phy_change(struct phy_device *phydev)
 	if (phy_interrupt_is_valid(phydev)) {
 		if (phydev->drv->did_interrupt &&
 		    !phydev->drv->did_interrupt(phydev))
-			goto ignore;
+			return;
 
 		if (phy_disable_interrupts(phydev))
 			goto phy_err;
@@ -748,27 +737,16 @@ void phy_change(struct phy_device *phydev)
 	mutex_unlock(&phydev->lock);
 
 	if (phy_interrupt_is_valid(phydev)) {
-		atomic_dec(&phydev->irq_disable);
-		enable_irq(phydev->irq);
-
 		/* Reenable interrupts */
 		if (PHY_HALTED != phydev->state &&
 		    phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED))
-			goto irq_enable_err;
+			goto phy_err;
 	}
 
 	/* reschedule state queue work to run as soon as possible */
 	phy_trigger_machine(phydev, true);
 	return;
 
-ignore:
-	atomic_dec(&phydev->irq_disable);
-	enable_irq(phydev->irq);
-	return;
-
-irq_enable_err:
-	disable_irq(phydev->irq);
-	atomic_inc(&phydev->irq_disable);
 phy_err:
 	phy_error(phydev);
 }
diff --git a/include/linux/phy.h b/include/linux/phy.h
index dc82a07cb..8a87e441f 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -468,7 +468,6 @@ struct phy_device {
 	/* Interrupt and Polling infrastructure */
 	struct work_struct phy_queue;
 	struct delayed_work state_queue;
-	atomic_t irq_disable;
 
 	struct mutex lock;
 
-- 
2.15.0