Re: [dpdk-dev] [PATCH v1] net/failsafe: fix VLAN stripping configuration

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

On Wed, Nov 01, 2017 at 08:12:38PM +0000, Ophir Munk wrote:
> failsafe device has vlan stripping configured at startup however once
> a sub device is found as non-capable of vlan-stripping failsafe
> updates it configuration and removes vlan stripping from it.
> This update occurs only once at startup. Following a later plugin
> attempt and in case of vlan stripping mismatch between failsafe
> configuration and device capability - failsafe cannot recover and the
> device remains constantly in plug out state.
> 
> The sequence of events leading to this situation is described as
> follows:
> 1. Start testpmd with failsafe where mlx4 is a sub device (not capable
> of vlan stripping). Expected printout:
> PMD: net_failsafe: Disabling VLAN stripping offload
> 2. Execute:
> testpmd> port stop all
> testpmd> port config all max-pkt-len 2048
> testpmd> port start all
> 3. Do a plug out (e.g. disable sriov)
> 4. Do a plug in (e.g. enable sriov)
> 5. Expected result: failsafe successfully configures and starts its sub
> devices
> Actual result: failsafe is continuously failing with these messages:
> PMD: net_failsafe: VLAN stripping offload requested but not supported by
> sub_device 0
> PMD: net_failsafe: device already configured, cannot fix live
> configuration
> PMD: net_failsafe: Unable to synchronize sub device state
> 
> Root cause analysis: at startup failsafe removes vlan stripping from its
> configuration. After executing "port config all max-pkt-len 2048"
> testpmd marks failsafe in need for configuration update.
> After executing "port start all" testpmd overrides failsafe
> configuration with its own configuration which includes vlan stripping
> 

Have you tried launching testpmd with the option

"--disable-hw-vlan"

as your mlx4 port does not support it?

> During the plugin attempt failsafe refuses to update its configuration
> by removing vlan stripping since it has already updated its
> configuration at startup.
> 
> The fix is to remove the limitation of one time configuration at
> startup and allow it during plugin attempts.
> 
> Cc: stable@dpdk.org
> Fixes: bbc6a53dda44 ("net/failsafe: support Rx offload capabilities")
> 
> Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
> ---
> The commit message includes bug and fix descriptions
> ---
>  drivers/net/failsafe/failsafe_ops.c | 10 ----------
>  1 file changed, 10 deletions(-)
> 
> diff --git a/drivers/net/failsafe/failsafe_ops.c b/drivers/net/failsafe/failsafe_ops.c
> index f460551..953ee65 100644
> --- a/drivers/net/failsafe/failsafe_ops.c
> +++ b/drivers/net/failsafe/failsafe_ops.c
> @@ -187,16 +187,6 @@
>  			continue;
>  		DEBUG("Checking capabilities for sub_device %d", i);
>  		while ((capa_flag = fs_port_offload_validate(dev, sdev))) {
> -			/*
> -			 * Refuse to change configuration if multiple devices
> -			 * are present and we already have configured at least
> -			 * some of them.
> -			 */
> -			if (PRIV(dev)->state >= DEV_ACTIVE &&
> -			    PRIV(dev)->subs_tail > 1) {
> -				ERROR("device already configured, cannot fix live configuration");
> -				return -1;
> -			}
>  			ret = fs_port_disable_offload(&dev->data->dev_conf,
>  						      capa_flag);
>  			if (ret) {
> -- 
> 1.8.3.1
> 

-- 
Gaëtan Rivet
6WIND