Subject: Re: [PATCH net v2] bonding: disable arp and enable mii monitoring when bond change to no uses arp mode

From: Nikolay Aleksandrov <[email-masked]>
Date: Fri, 22 Nov 2013 14:55:19 +0100

On 11/22/2013 03:12 AM, Ding Tianhong wrote:
> Because the ARP monitoring is not support for 802.3ad, but I still
> could change the mode to 802.3ad from ab mode while ARP monitoring
> is running, it is incorrect.
> 
> So add a check for 802.3ad in bonding_store_mode to fix the problem,
> and make a new macro BOND_NO_USES_ARP() to simplify the code.
> 
> v2: according to the Dan Williams's suggestion, bond mode is the most
>     important bond option, it should override any of the other sub-options.
>     So when the mode is changed, the conficting values should be cleared
>     or reset, otherwise the user has to duplicate more operations to modify
>     the logic. I disable the arp and enable mii monitoring when the bond mode
>     is changed to AB, TB and 8023AD if the arp interval is true.
> 
> Suggested-by: Dan Williams <[email-masked]>
> Signed-off-by: Ding Tianhong <[email-masked]>
> ---
>  drivers/net/bonding/bond_options.c | 13 +++++++++----
>  drivers/net/bonding/bonding.h      |  5 +++++
>  2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
> index 9a5223c..04364f7a 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
> @@ -45,10 +45,15 @@ int bond_option_mode_set(struct bonding *bond, int mode)
>  		return -EPERM;
>  	}
>  
> -	if (BOND_MODE_IS_LB(mode) && bond->params.arp_interval) {
> -		pr_err("%s: %s mode is incompatible with arp monitoring.\n",
> -		       bond->dev->name, bond_mode_tbl[mode].modename);
> -		return -EINVAL;
> +	if (BOND_NO_USES_ARP(mode) && bond->params.arp_interval) {
> +		pr_info("%s: %s mode is incompatible with arp monitoring, start mii monitoring\n",
> +			bond->dev->name, bond_mode_tbl[mode].modename);
> +		/* disable arp monitoring */
> +		bond->params.arp_interval = 0;
> +		/* set miimon to default value */
> +		bond->params.miimon = 100;
> +		pr_info("%s: Setting MII monitoring interval to %d.\n",
> +			bond->dev->name, bond->params.miimon);
>  	}
>  
Maybe define the "default" miimon value somewhere ? A value of 100 for miimon is
used repeatedly in bond_check_params() as well, it'd be nice to give it a name,
e.g. I had to grep around to see why you chose 100 to be that value.

>  	/* don't cache arp_validate between modes */
> diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
> index ca31286..a310fb5 100644
> --- a/drivers/net/bonding/bonding.h
> +++ b/drivers/net/bonding/bonding.h
> @@ -55,6 +55,11 @@
>  		 ((mode) == BOND_MODE_TLB)          ||	\
>  		 ((mode) == BOND_MODE_ALB))
>  
> +#define BOND_NO_USES_ARP(mode)				\
> +		(((mode) == BOND_MODE_8023AD)	||	\
> +		 ((mode) == BOND_MODE_TLB)	||	\
> +		 ((mode) == BOND_MODE_ALB))
> +
>  #define TX_QUEUE_OVERRIDE(mode)				\
>  			(((mode) == BOND_MODE_ACTIVEBACKUP) ||	\
>  			 ((mode) == BOND_MODE_ROUNDROBIN))
> 
One small note, you can save a few lines in bond_sysfs.c if you switch
the check in bonding_store_arp_interval() to the new macro BOND_NO_USES_ARP()
as it's identical.

Cheers,
 Nik