can: sja1000: fix {pre,post}_irq() handling and IRQ handler return value

This patch fixes the issue that the sja1000_interrupt() function may have
returned IRQ_NONE without processing the optional pre_irq() and post_irq()
function before. Further the irq processing counter 'n' is moved to the end of
the while statement to return correct IRQ_[NONE|HANDLED] values at error
conditions.

Reported-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 7164a999f50ff37e176f9995f21cd04451f17043..f17c3018b7c7ffb3f7d75785c3ddd2218b0f3f79 100644 (file)
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -494,20 +494,20 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id)
        uint8_t isrc, status;
        int n = 0;
 
-       /* Shared interrupts and IRQ off? */
-       if (priv->read_reg(priv, SJA1000_IER) == IRQ_OFF)
-               return IRQ_NONE;
-
        if (priv->pre_irq)
                priv->pre_irq(priv);
 
+       /* Shared interrupts and IRQ off? */
+       if (priv->read_reg(priv, SJA1000_IER) == IRQ_OFF)
+               goto out;
+
        while ((isrc = priv->read_reg(priv, SJA1000_IR)) &&
               (n < SJA1000_MAX_IRQ)) {
-               n++;
+
                status = priv->read_reg(priv, SJA1000_SR);
                /* check for absent controller due to hw unplug */
                if (status == 0xFF && sja1000_is_absent(priv))
-                       return IRQ_NONE;
+                       goto out;
 
                if (isrc & IRQ_WUI)
                        netdev_warn(dev, "wakeup interrupt\n");
@@ -535,7 +535,7 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id)
                                status = priv->read_reg(priv, SJA1000_SR);
                                /* check for absent controller */
                                if (status == 0xFF && sja1000_is_absent(priv))
-                                       return IRQ_NONE;
+                                       goto out;
                        }
                }
                if (isrc & (IRQ_DOI | IRQ_EI | IRQ_BEI | IRQ_EPI | IRQ_ALI)) {
@@ -543,8 +543,9 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id)
                        if (sja1000_err(dev, isrc, status))
                                break;
                }
+               n++;
        }
-
+out:
        if (priv->post_irq)
                priv->post_irq(priv);