[PATCH net] bnxt: do not busy-poll when link is down

[PATCH net] bnxt: do not busy-poll when link is down

[Andy Gospodarek]

When busy polling while a link is down (during a link-flap test), TX
timeouts were observed as well as the following messages in the ring
buffer:

bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free tx failed. rc:-1
bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free rx failed. rc:-1

These were resolved by checking for link status and returning if link
was not up.

Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Tested-by: Rob Miller <rob.miller@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index e18635b..013e373 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -1811,6 +1811,9 @@ static int bnxt_busy_poll(struct napi_struct *napi)
 	if (atomic_read(&bp->intr_sem) != 0)
 		return LL_FLUSH_FAILED;
 
+	if (!bp->link_info.link_up)
+		return LL_FLUSH_FAILED;
+
 	if (!bnxt_lock_poll(bnapi))
 		return LL_FLUSH_BUSY;
 
-- 
2.1.0

Re: [PATCH net] bnxt: do not busy-poll when link is down

[Eric Dumazet]

On Tue, 2016-11-22 at 13:14 -0500, Andy Gospodarek wrote:
> When busy polling while a link is down (during a link-flap test), TX
> timeouts were observed as well as the following messages in the ring
> buffer:
> 
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free tx failed. rc:-1
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free rx failed. rc:-1
> 
> These were resolved by checking for link status and returning if link
> was not up.
> 
> Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
> Signed-off-by: Michael Chan <michael.chan@broadcom.com>
> Tested-by: Rob Miller <rob.miller@broadcom.com>
> ---
>  drivers/net/ethernet/broadcom/bnxt/bnxt.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> index e18635b..013e373 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> @@ -1811,6 +1811,9 @@ static int bnxt_busy_poll(struct napi_struct *napi)
>  	if (atomic_read(&bp->intr_sem) != 0)
>  		return LL_FLUSH_FAILED;
>  
> +	if (!bp->link_info.link_up)
> +		return LL_FLUSH_FAILED;
> +
>  	if (!bnxt_lock_poll(bnapi))
>  		return LL_FLUSH_BUSY;
>  


Any plans removing this busy polling stuff, now it is done in core
networking stack ?

This would remove bnxt_lock_napi() extra overhead in normal path ( napi
poll )

I could do this but I do not have the hardware to do the tests.

Re: [PATCH net] bnxt: do not busy-poll when link is down

[Michael Chan]

On Tue, Nov 22, 2016 at 10:38 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Tue, 2016-11-22 at 13:14 -0500, Andy Gospodarek wrote:
>> When busy polling while a link is down (during a link-flap test), TX
>> timeouts were observed as well as the following messages in the ring
>> buffer:
>>
>> bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
>> bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free tx failed. rc:-1
>> bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
>> bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free rx failed. rc:-1
>>
>> These were resolved by checking for link status and returning if link
>> was not up.
>>
>> Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
>> Signed-off-by: Michael Chan <michael.chan@broadcom.com>
>> Tested-by: Rob Miller <rob.miller@broadcom.com>
>> ---
>>  drivers/net/ethernet/broadcom/bnxt/bnxt.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
>> index e18635b..013e373 100644
>> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
>> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
>> @@ -1811,6 +1811,9 @@ static int bnxt_busy_poll(struct napi_struct *napi)
>>       if (atomic_read(&bp->intr_sem) != 0)
>>               return LL_FLUSH_FAILED;
>>
>> +     if (!bp->link_info.link_up)
>> +             return LL_FLUSH_FAILED;
>> +
>>       if (!bnxt_lock_poll(bnapi))
>>               return LL_FLUSH_BUSY;
>>
>
>
> Any plans removing this busy polling stuff, now it is done in core
> networking stack ?
>
> This would remove bnxt_lock_napi() extra overhead in normal path ( napi
> poll )
>
> I could do this but I do not have the hardware to do the tests.
>
It's on my list of many TODO things.  Probably in the next few weeks.

Re: [PATCH net] bnxt: do not busy-poll when link is down

[Eric Dumazet]

On Tue, 2016-11-22 at 10:55 -0800, Michael Chan wrote:
> On Tue, Nov 22, 2016 at 10:38 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:

> >
> > Any plans removing this busy polling stuff, now it is done in core
> > networking stack ?
> >
> > This would remove bnxt_lock_napi() extra overhead in normal path ( napi
> > poll )
> >
> > I could do this but I do not have the hardware to do the tests.
> >
> It's on my list of many TODO things.  Probably in the next few weeks.

Awesome, thanks !

Re: [PATCH net] bnxt: do not busy-poll when link is down

[David Miller]

From: Andy Gospodarek <gospo@broadcom.com>
Date: Tue, 22 Nov 2016 13:14:08 -0500

> When busy polling while a link is down (during a link-flap test), TX
> timeouts were observed as well as the following messages in the ring
> buffer:
> 
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free tx failed. rc:-1
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: Resp cmpl intr err msg: 0x51
> bnxt_en 0008:01:00.2 enP8p1s0f2d2: hwrm_ring_free rx failed. rc:-1
> 
> These were resolved by checking for link status and returning if link
> was not up.
> 
> Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
> Signed-off-by: Michael Chan <michael.chan@broadcom.com>
> Tested-by: Rob Miller <rob.miller@broadcom.com>

Applied.