[PATCH] net: mvmdio: fix interrupt timeout handling

From: Leigh Brown
Date: Thu Dec 19 2013 - 06:13:26 EST


orion_mdio_wait_ready uses wait_event_timeout to wait for the
SMI interrupt to fire. wait_event_timeout waits for between
"timeout - 1" and "timeout" jiffies. In this case a 1ms timeout
when HZ is 1000 results in a wait of 0 to 1 jiffies, causing
premature timeouts.

This fix ensures a minimum timeout of 2 jiffies, ensuring
wait_event_timeout will always wait at least 1 jiffie.

Issue reported by Nicolas Schichan.

Tested-by: Nicolas Schichan <nschichan@xxxxxxxxxx>
Signed-off-by: Leigh Brown <leigh@xxxxxxxxxxxxx>
---
drivers/net/ethernet/marvell/mvmdio.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/marvell/mvmdio.c b/drivers/net/ethernet/marvell/mvmdio.c
index 7354960..a42a750 100644
--- a/drivers/net/ethernet/marvell/mvmdio.c
+++ b/drivers/net/ethernet/marvell/mvmdio.c
@@ -92,6 +92,12 @@ static int orion_mdio_wait_ready(struct mii_bus *bus)
if (time_is_before_jiffies(end))
++timedout;
} else {
+ /* wait_event_timeout does not guarantee a delay of at
+ * least one whole jiffie, so timeout must be no less
+ * than two.
+ */
+ if (timeout < 2)
+ timeout = 2;
wait_event_timeout(dev->smi_busy_wait,
orion_mdio_smi_is_done(dev),
timeout);
--
1.8.5.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/