From b5ca88eb335580dc48ef5ebb3b86719bdb5a4113 Mon Sep 17 00:00:00 2001
From: Jesse Brandeburg <jesse.brandeburg@intel.com>
Date: Tue, 8 Jul 2008 15:51:42 -0700
Subject: [PATCH] ixgb: fix race on rx_buffer_len in mtu change
some random coverage testing found that when changing mtu
under heavy traffic load, NAPI would use the rx_buffer_len variable
after it had been changed by change_mtu.
Similar to e1000 bugs found long ago.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---
drivers/net/ixgb/ixgb_main.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 4bf6bbc658225..c3234c4510438 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1573,14 +1573,18 @@ ixgb_change_mtu(struct net_device *netdev, int new_mtu)
return -EINVAL;
}
+ if (old_max_frame == max_frame)
+ return 0;
+
+ if (netif_running(netdev))
+ ixgb_down(adapter, true);
+
adapter->rx_buffer_len = max_frame + 8; /* + 8 for errata */
netdev->mtu = new_mtu;
- if ((old_max_frame != max_frame) && netif_running(netdev)) {
- ixgb_down(adapter, true);
+ if (netif_running(netdev))
ixgb_up(adapter);
- }
return 0;
}
--
2.30.2