Re: [PATCH v2 net-next] net: hsr: Disable promiscuous mode in offload mode

[Jakub Kicinski]

On Wed, 14 Jun 2023 17:17:10 +0530 Ravi Gunasekaran wrote:
> When port-to-port forwarding for interfaces in HSR node is enabled,
> disable promiscuous mode since L2 frame forward happens at the
> offloaded hardware.
> 
> Signed-off-by: Ravi Gunasekaran <r-gunasekaran@xxxxxx>
> Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>

Bridge folks any thoughts on this? Is this the behavior bridge has 
and if not should we try to align the two?

> Changes from v1:
> ===============
> * Changed the data type of "fwd_offloaded" from "unsigned int" to "bool"
>   and moved it below "net_id" struct member as per Paolo's comment.
> * Collected Reviewed-by tag from v1 patch.
> 
> v1: https://lore.kernel.org/all/20230612093933.13267-1-r-gunasekaran@xxxxxx/
> 
>  net/hsr/hsr_device.c |  5 +++++
>  net/hsr/hsr_main.h   |  1 +
>  net/hsr/hsr_slave.c  | 15 +++++++++++----
>  3 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
> index 5a236aae2366..306f942c3b28 100644
> --- a/net/hsr/hsr_device.c
> +++ b/net/hsr/hsr_device.c
> @@ -531,6 +531,11 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
>  	if (res)
>  		goto err_add_master;
>  
> +	/* HSR forwarding offload supported in lower device? */
> +	if ((slave[0]->features & NETIF_F_HW_HSR_FWD) &&
> +	    (slave[1]->features & NETIF_F_HW_HSR_FWD))
> +		hsr->fwd_offloaded = true;
> +
>  	res = register_netdevice(hsr_dev);
>  	if (res)
>  		goto err_unregister;
> diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
> index 5584c80a5c79..6851e33df7d1 100644
> --- a/net/hsr/hsr_main.h
> +++ b/net/hsr/hsr_main.h
> @@ -208,6 +208,7 @@ struct hsr_priv {
>  	u8 net_id;		/* for PRP, it occupies most significant 3 bits
>  				 * of lan_id
>  				 */
> +	bool fwd_offloaded;	/* Forwarding offloaded to HW */
>  	unsigned char		sup_multicast_addr[ETH_ALEN] __aligned(sizeof(u16));
>  				/* Align to u16 boundary to avoid unaligned access
>  				 * in ether_addr_equal
> diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c
> index b70e6bbf6021..e5742f2a2d52 100644
> --- a/net/hsr/hsr_slave.c
> +++ b/net/hsr/hsr_slave.c
> @@ -131,9 +131,14 @@ static int hsr_portdev_setup(struct hsr_priv *hsr, struct net_device *dev,
>  	struct hsr_port *master;
>  	int res;
>  
> -	res = dev_set_promiscuity(dev, 1);
> -	if (res)
> -		return res;
> +	/* Don't use promiscuous mode for offload since L2 frame forward
> +	 * happens at the offloaded hardware.
> +	 */
> +	if (!port->hsr->fwd_offloaded) {
> +		res = dev_set_promiscuity(dev, 1);
> +		if (res)
> +			return res;
> +	}
>  
>  	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
>  	hsr_dev = master->dev;
> @@ -152,7 +157,9 @@ static int hsr_portdev_setup(struct hsr_priv *hsr, struct net_device *dev,
>  fail_rx_handler:
>  	netdev_upper_dev_unlink(dev, hsr_dev);
>  fail_upper_dev_link:
> -	dev_set_promiscuity(dev, -1);
> +	if (!port->hsr->fwd_offloaded)
> +		dev_set_promiscuity(dev, -1);
> +
>  	return res;
>  }
>