[2/6] fm10k: fix "failed to kill vid" message for VF

From: Ngai-Mint Kwan <ngai-mint.kwan@intel.com>

When a VF is under PF VLAN assignment:

ip link set <pf> vf <#> vlan <vid>

This will remove all previous entries in the VLAN table including those
generated by VLAN interfaces created on the VF. The issue arises when
the VF is under PF VLAN assignment and one or more of these VLAN
interfaces of the VF are deleted. When deleting these VLAN interfaces,
the following message will be generated in "dmesg":

failed to kill vid 0081/<vid> for device <vf>

This is due to the fact that "ndo_vlan_rx_kill_vid" exits with an error.
The handler for this ndo is "fm10k_update_vid". Any calls to this
function while under PF VLAN management will exit prematurely and, thus,
it will generate the failure message.

Additionally, since "fm10k_update_vid" exits prematurely, none of the
VLAN update is performed. So, even though the actual VLAN interfaces of
the VF will be deleted, the active_vlans bitmask is not cleared. When
the VF is no longer under PF VLAN assignment, the driver mistakenly
restores the previous entries of the VLAN table based on an
unsynchronized list of active VLANs.

The solution to this issue involves checking the VLAN update action type
before exiting "fm10k_update_vid". If the VLAN update action type is to
"add", this action will not be permitted while the VF is under PF VLAN
assignment and the VLAN update is abandoned like before.

However, if the VLAN update action type is to "kill", then we need to
also clear the active_vlans bitmask. However, we don't need to actually
queue any messages to the PF, because the MAC and VLAN tables have
already been cleared, and the PF would silently ignore these requests
anyways.

Signed-off-by: Ngai-Mint Kwan <ngai-mint.kwan@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
---
 drivers/net/ethernet/intel/fm10k/fm10k_netdev.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On Behalf
> Of Jacob Keller
> Sent: Friday, December 1, 2017 11:00 AM
> To: Intel Wired LAN <intel-wired-lan@lists.osuosl.org>
> Cc: Kwan, Ngai-mint <ngai-mint.kwan@intel.com>
> Subject: [Intel-wired-lan] [PATCH 2/6] fm10k: fix "failed to kill vid" message for
> VF
> 
> From: Ngai-Mint Kwan <ngai-mint.kwan@intel.com>
> 
> When a VF is under PF VLAN assignment:
> 
> ip link set <pf> vf <#> vlan <vid>
> 
> This will remove all previous entries in the VLAN table including those
> generated by VLAN interfaces created on the VF. The issue arises when
> the VF is under PF VLAN assignment and one or more of these VLAN
> interfaces of the VF are deleted. When deleting these VLAN interfaces,
> the following message will be generated in "dmesg":
> 
> failed to kill vid 0081/<vid> for device <vf>
> 
> This is due to the fact that "ndo_vlan_rx_kill_vid" exits with an error.
> The handler for this ndo is "fm10k_update_vid". Any calls to this
> function while under PF VLAN management will exit prematurely and, thus,
> it will generate the failure message.
> 
> Additionally, since "fm10k_update_vid" exits prematurely, none of the
> VLAN update is performed. So, even though the actual VLAN interfaces of
> the VF will be deleted, the active_vlans bitmask is not cleared. When
> the VF is no longer under PF VLAN assignment, the driver mistakenly
> restores the previous entries of the VLAN table based on an
> unsynchronized list of active VLANs.
> 
> The solution to this issue involves checking the VLAN update action type
> before exiting "fm10k_update_vid". If the VLAN update action type is to
> "add", this action will not be permitted while the VF is under PF VLAN
> assignment and the VLAN update is abandoned like before.
> 
> However, if the VLAN update action type is to "kill", then we need to
> also clear the active_vlans bitmask. However, we don't need to actually
> queue any messages to the PF, because the MAC and VLAN tables have
> already been cleared, and the PF would silently ignore these requests
> anyways.
> 
> Signed-off-by: Ngai-Mint Kwan <ngai-mint.kwan@intel.com>
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> ---
>  drivers/net/ethernet/intel/fm10k/fm10k_netdev.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
> b/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
> index 4b5272f13d40..f8e2d1804a17 100644
> --- a/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
> +++ b/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
> @@ -934,8 +934,12 @@ static int fm10k_update_vid(struct net_device
> *netdev, u16 vid, bool set)
>  	if (vid >= VLAN_N_VID)
>  		return -EINVAL;
> 
> -	/* Verify we have permission to add VLANs */
> -	if (hw->mac.vlan_override)
> +	/* Verify that we have permission to add VLANs. If this is a request
> +	 * to remove a VLAN, we still want to allow the user to remove the
> +	 * VLAN device. In that case, we need to clear the bit in the
> +	 * active_vlans bitmask.
> +	 */
> +	if (set && hw->mac.vlan_override)
>  		return -EACCES;
> 
>  	/* update active_vlans bitmask */
> @@ -954,6 +958,12 @@ static int fm10k_update_vid(struct net_device
> *netdev, u16 vid, bool set)
>  			rx_ring->vid &= ~FM10K_VLAN_CLEAR;
>  	}
> 
> +	/* If our VLAN has been overridden, there is no reason to send VLAN
> +	 * removal requests as they will be silently ignored.
> +	 */
> +	if (hw->mac.vlan_override)
> +		return 0;
> +
>  	/* Do not remove default VLAN ID related entries from VLAN and MAC
>  	 * tables
>  	 */
> --
> 2.15.0
> 
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Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>