ACK: [PATCH 1/1][SRU][B][E][F][G][OEM-OSP1-B][OEM-5.6] e1000e: Disable TSO for buffer overrun workaround

[Kleber Souza]

On 2020-05-27 10:52, AceLan Kao wrote:
> From: Kai-Heng Feng <kai.heng.feng at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1802691
> 
> 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 at 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 at canonical.com>
> Tested-by: Aaron Brown <aaron.f.brown at intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher at intel.com>
> (cherry picked from commit f29801030ac67bf98b7a65d3aea67b30769d4f7c linux-next)
> Signed-off-by: AceLan Kao <acelan.kao at canonical.com>

Good test results, fix accepted upstream.

Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>

> ---
>  drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index d65f3ed32b7d0..cefac84648953 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -5255,6 +5255,10 @@ static void e1000_watchdog_task(struct work_struct *work)
>  					/* 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
>