net: phy: avoid clearing PHY interrupts twice in irq handler

[ Upstream commit 249bc9744e165abe74ae326f43e9d70bad54c3b7 ]

On all PHY drivers that implement did_interrupt() reading the interrupt
status bits clears them. This means we may loose an interrupt that
is triggered between calling did_interrupt() and phy_clear_interrupt().
As part of the fix make it a requirement that did_interrupt() clears
the interrupt.

The Fixes tag refers to the first commit where the patch applies
cleanly.

Fixes: 49644e68f472 ("net: phy: add callback for custom interrupt handler to struct phy_driver")
Reported-by: Michael Walle <michael@walle.cc>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 105d389..ea890d8 100644 (file)
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -761,7 +761,8 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)
                phy_trigger_machine(phydev);
        }
 
-       if (phy_clear_interrupt(phydev))
+       /* did_interrupt() may have cleared the interrupt already */
+       if (!phydev->drv->did_interrupt && phy_clear_interrupt(phydev))
                goto phy_err;
        return IRQ_HANDLED;
 

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 3d5d533..bf87c59 100644 (file)
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -524,6 +524,7 @@ struct phy_driver {
        /*
         * Checks if the PHY generated an interrupt.
         * For multi-PHY devices with shared PHY interrupt pin
+        * Set interrupt bits have to be cleared.
         */
        int (*did_interrupt)(struct phy_device *phydev);