[patch 099/100] skge: fix occasional BUG during MTU change

Chris Wright
2009-04-23T08:01:24Z

[-- Attachment #1: skge-fix-occasional-bug-during-mtu-change.patch --]
[-- Type: text/plain, Size: 1835 bytes --]

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Michal Schmidt <mschmidt@redhat.com>

upstream commit: d119b3927994e3d620d6adb0dd1ea6bf24427875

The BUG_ON(skge->tx_ring.to_use != skge->tx_ring.to_clean) in skge_up()
was sometimes observed when setting MTU.

skge_down() disables the TX queue, but then reenables it by mistake via
skge_tx_clean().
Fix it by moving the waking of the queue from skge_tx_clean() to the
other caller. And to make sure start_xmit is not in progress on another
CPU, skge_down() should call netif_tx_disable().

The bug was reported to me by Jiri Jilek whose Debian system sometimes
failed to boot. He tested the patch and the bug did not happen anymore.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
drivers/net/skge.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -2674,7 +2674,7 @@ static int skge_down(struct net_device *
if (netif_msg_ifdown(skge))
printk(KERN_INFO PFX "%s: disabling interface\n", dev->name);

- netif_stop_queue(dev);
+ netif_tx_disable(dev);

if (hw->chip_id == CHIP_ID_GENESIS && hw->phy_type == SK_PHY_XMAC)
del_timer_sync(&skge->link_timer);
@@ -2881,7 +2881,6 @@ static void skge_tx_clean(struct net_dev
}

skge->tx_ring.to_clean = e;
- netif_wake_queue(dev);
}

static void skge_tx_timeout(struct net_device *dev)
@@ -2893,6 +2892,7 @@ static void skge_tx_timeout(struct net_d

skge_write8(skge->hw, Q_ADDR(txqaddr[skge->port], Q_CSR), CSR_STOP);
skge_tx_clean(dev);
+ netif_wake_queue(dev);
}

static int skge_change_mtu(struct net_device *dev, int new_mtu)