net: mvmdio: fix interrupt timeout handling

This version corrects the whitespace issue.

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@freebox.fr>
Signed-off-by: Leigh Brown <leigh@solinno.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/marvell/mvmdio.c b/drivers/net/ethernet/marvell/mvmdio.c
index 7354960..c4eeb69 100644 (file)
--- 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);