[PATCH 4.19 232/267] e1000e: Disable TSO for buffer overrun workaround

Greg Kroah-Hartman
2020-06-19T16:16:37Z

From: Kai-Heng Feng <kai.heng.feng@canonical.com>

commit f29801030ac67bf98b7a65d3aea67b30769d4f7c upstream.

Commit b10effb92e27 ("e1000e: fix buffer overrun while the I219 is
processing DMA transactions") imposes roughly 30% performance penalty.

The commit log states that "Disabling TSO eliminates performance loss
for TCP traffic without a noticeable impact on CPU performance", so
let's disable TSO by default to regain the loss.

CC: stable <stable@vger.kernel.org>
Fixes: b10effb92e27 ("e1000e: fix buffer overrun while the I219 is processing DMA transactions")
BugLink: https://bugs.launchpad.net/bugs/1802691
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5251,6 +5251,10 @@ static void e1000_watchdog_task(struct w
/* oops */
break;
}
+ if (hw->mac.type == e1000_pch_spt) {
+ netdev->features &= ~NETIF_F_TSO;
+ netdev->features &= ~NETIF_F_TSO6;
+ }
}

/* enable transmits in the hardware, need to do this