net: bonding: Fix transmit load balancing in balance-alb mode

balance-alb mode used to have transmit dynamic load balancing feature
enabled by default.  However, transmit dynamic load balancing no longer
works in balance-alb after commit 8b426dc54cf4 ("bonding: remove
hardcoded value").

Both balance-tlb and balance-alb use the function bond_do_alb_xmit() to
send packets.  This function uses the parameter tlb_dynamic_lb.
tlb_dynamic_lb used to have the default value of 1 for balance-alb, but
now the value is set to 0 except in balance-tlb.

Re-enable transmit dyanmic load balancing by initializing tlb_dynamic_lb
for balance-alb similar to balance-tlb.

Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
Cc: stable@vger.kernel.org
---
 drivers/net/bonding/bond_main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

On Thu, Jul 20, 2017 at 1:20 AM, Kosuke Tatsukawa <tatsu@ab.jp.nec.com> wrote:
> balance-alb mode used to have transmit dynamic load balancing feature
> enabled by default.  However, transmit dynamic load balancing no longer
> works in balance-alb after commit 8b426dc54cf4 ("bonding: remove
> hardcoded value").
>
> Both balance-tlb and balance-alb use the function bond_do_alb_xmit() to
> send packets.  This function uses the parameter tlb_dynamic_lb.
> tlb_dynamic_lb used to have the default value of 1 for balance-alb, but
> now the value is set to 0 except in balance-tlb.
>
> Re-enable transmit dyanmic load balancing by initializing tlb_dynamic_lb
> for balance-alb similar to balance-tlb.
>
> Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
> Cc: stable@vger.kernel.org

You probably should add:

Fixes: 8b426dc54cf4 ("bonding: remove hardcoded value").

Otherwise this looks reasonable to me.

Acked-by: Andy Gospodarek <andy@greyhouse.net>


> ---
>  drivers/net/bonding/bond_main.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 14ff622..181839d 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -4596,7 +4596,7 @@ static int bond_check_params(struct bond_params *params)
>         }
>         ad_user_port_key = valptr->value;
>
> -       if (bond_mode == BOND_MODE_TLB) {
> +       if ((bond_mode == BOND_MODE_TLB) || (bond_mode == BOND_MODE_ALB)) {
>                 bond_opt_initstr(&newval, "default");
>                 valptr = bond_opt_parse(bond_opt_get(BOND_OPT_TLB_DYNAMIC_LB),
>                                         &newval);
>

From: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
Date: Thu, 20 Jul 2017 05:20:40 +0000

> balance-alb mode used to have transmit dynamic load balancing feature
> enabled by default.  However, transmit dynamic load balancing no longer
> works in balance-alb after commit 8b426dc54cf4 ("bonding: remove
> hardcoded value").
> 
> Both balance-tlb and balance-alb use the function bond_do_alb_xmit() to
> send packets.  This function uses the parameter tlb_dynamic_lb.
> tlb_dynamic_lb used to have the default value of 1 for balance-alb, but
> now the value is set to 0 except in balance-tlb.
> 
> Re-enable transmit dyanmic load balancing by initializing tlb_dynamic_lb
> for balance-alb similar to balance-tlb.
> 
> Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>

Applied and queued up for -stable, thanks.

Andy, thanks for the Fixes: tag.

Reinis Rozitis reported that tlb_dynamic_lb was still 0 in balance-alb
mode even when using linux-4.12.10 kernels, which includes this patch.

It turned out that my previous patch only fixed the case when
balance-alb mode was specified as bonding module parameter, and not when
balance-alb mode was set using /sys/class/net/*/bonding/mode (the most
common usage).  In the latter case, tlb_dynamic_lb was set up according
to the default mode of the bonding interface, which happens to be
balance-rr.

I'll send another patch to address this case.

In the meantime, a workaround for this issue is to specify balance-tlb
mode as a module parameter for bonding.  This will change the value of
tlb_balance_lb to 1, and make balance-alb work like pre-4.12 kernels.

Best regards.


> balance-alb mode used to have transmit dynamic load balancing feature
> enabled by default.  However, transmit dynamic load balancing no longer
> works in balance-alb after commit 8b426dc54cf4 ("bonding: remove
> hardcoded value").
> 
> Both balance-tlb and balance-alb use the function bond_do_alb_xmit() to
> send packets.  This function uses the parameter tlb_dynamic_lb.
> tlb_dynamic_lb used to have the default value of 1 for balance-alb, but
> now the value is set to 0 except in balance-tlb.
> 
> Re-enable transmit dyanmic load balancing by initializing tlb_dynamic_lb
> for balance-alb similar to balance-tlb.
> 
> Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/net/bonding/bond_main.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 14ff622..181839d 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -4596,7 +4596,7 @@ static int bond_check_params(struct bond_params *params)
>  	}
>  	ad_user_port_key = valptr->value;
>  
> -	if (bond_mode == BOND_MODE_TLB) {
> +	if ((bond_mode == BOND_MODE_TLB) || (bond_mode == BOND_MODE_ALB)) {
>  		bond_opt_initstr(&newval, "default");
>  		valptr = bond_opt_parse(bond_opt_get(BOND_OPT_TLB_DYNAMIC_LB),
>  					&newval);
---
Kosuke TATSUKAWA  | 1st Platform Software Division
                  | NEC Solution Innovators
                  | tatsu@ab.jp.nec.com