netdev - Re: [PATCH net-next 5/5] net: dsa: mv88e6xxx: do not purge a VTU entry

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Message-ID: <ae09e920-fcea-ac29-3b2d-51275e0fec56@gmail.com>
Date:   Wed, 7 Jun 2017 12:37:37 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
        netdev@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel@...oirfairelinux.com,
        "David S. Miller" <davem@...emloft.net>,
        Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH net-next 5/5] net: dsa: mv88e6xxx: do not purge a VTU
 entry

On 06/06/2017 01:56 PM, Vivien Didelot wrote:
> The mv88e6xxx driver currently tries to be smart and remove by itself a
> VLAN entry from the VTU when the driven switch sees no user ports as
> members of the VLAN.
> 
> This is bad in a multi-chip switch fabric, since a chip in between
> others may have no bridge port members, but still needs to be aware of
> the VID in order to correctly pass frames in the data path.
> 
> Remove the code purging a VTU entry when updating a port membership.

In that case the switch sitting between two other chips and passing
traffic would still have at least two of its DSA ports be part of a VTU
entry, right?

So could not we just do ....

> 
> Signed-off-by: Vivien Didelot <vivien.didelot@...oirfairelinux.com>
> ---
>  drivers/net/dsa/mv88e6xxx/chip.c | 15 +--------------
>  1 file changed, 1 insertion(+), 14 deletions(-)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index 522f023bb17e..64c0f88f9e79 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -1325,9 +1325,8 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
>  static int _mv88e6xxx_port_vlan_del(struct mv88e6xxx_chip *chip,
>  				    int port, u16 vid)
>  {
> -	struct dsa_switch *ds = chip->ds;
>  	struct mv88e6xxx_vtu_entry vlan;
> -	int i, err;
> +	int err;
>  
>  	err = mv88e6xxx_vtu_get(chip, vid, &vlan, false);
>  	if (err)
> @@ -1339,18 +1338,6 @@ static int _mv88e6xxx_port_vlan_del(struct mv88e6xxx_chip *chip,
>  
>  	vlan.member[port] = GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER;
>  
> -	/* keep the VLAN unless all ports are excluded */
> -	vlan.valid = false;
> -	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
> -		if (dsa_is_cpu_port(ds, i) || dsa_is_dsa_port(ds, i))
> -			continue;

... break the loop here?

> -
> -		if (vlan.member[i] != GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER) {
> -			vlan.valid = true;
> -			break;
> -		}
> -	}
> -
>  	err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
>  	if (err)
>  		return err;
> 


-- 
Florian