2023-11-23 16:37:50

by Sergey Shtylyov

[permalink] [raw]
Subject: Re: [PATCH 06/13] net: ravb: Let IP specific receive function to interrogate descriptors

On 11/20/23 11:45 AM, Claudiu wrote:

> From: Claudiu Beznea <[email protected]>
>
> ravb_poll() initial code used to interrogate the first descriptor of the
> RX queue in case gptp is false to know if ravb_rx() should be called.
> This is done for non GPTP IPs. For GPTP IPs the driver PTP specific

It's called gPTP, AFAIK.

> information was used to know if receive function should be called. As
> every IP has it's own receive function that interrogates the RX descriptor

Its own.

> list in the same way the ravb_poll() was doing there is no need to double
> check this in ravb_poll(). Removing the code form ravb_poll() and

From ravb_poll().

> adjusting ravb_rx_gbeth() leads to a cleaner code.
>
> Signed-off-by: Claudiu Beznea <[email protected]>
> ---
> drivers/net/ethernet/renesas/ravb_main.c | 18 ++++++------------
> 1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 588e3be692d3..0fc9810c5e78 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -771,12 +771,15 @@ static bool ravb_rx_gbeth(struct net_device *ndev, int *quota, int q)
> int limit;
>
> entry = priv->cur_rx[q] % priv->num_rx_ring[q];
> + desc = &priv->gbeth_rx_ring[entry];
> + if (desc->die_dt == DT_FEMPTY)
> + return false;
> +

I don't understand what this buys us, the following *while* loop will
be skipped anyway, and the *for* loop as well, I think... And ravb_rx_rcar()
doesn't have that anyway...

> @@ -1279,25 +1282,16 @@ static int ravb_poll(struct napi_struct *napi, int budget)
> struct net_device *ndev = napi->dev;
> struct ravb_private *priv = netdev_priv(ndev);
> const struct ravb_hw_info *info = priv->info;
> - bool gptp = info->gptp || info->ccc_gac;
> - struct ravb_rx_desc *desc;
> unsigned long flags;
> int q = napi - priv->napi;
> int mask = BIT(q);
> int quota = budget;
> - unsigned int entry;
>
> - if (!gptp) {
> - entry = priv->cur_rx[q] % priv->num_rx_ring[q];
> - desc = &priv->gbeth_rx_ring[entry];
> - }
> /* Processing RX Descriptor Ring */
> /* Clear RX interrupt */
> ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
> - if (gptp || desc->die_dt != DT_FEMPTY) {
> - if (ravb_rx(ndev, &quota, q))
> - goto out;
> - }

I don't really understand this code (despite I've AKCed it)...
Biju, could you explain this (well, you tried already but I don't
buy it anymore)?

> + if (ravb_rx(ndev, &quota, q))
> + goto out;

This restores the behavior before:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3d4e37df882b0f4f28b7223a42492650b71252c5

So does look correct. :-)

MBR, Sergey


2023-11-26 07:11:08

by claudiu beznea

[permalink] [raw]
Subject: Re: [PATCH 06/13] net: ravb: Let IP specific receive function to interrogate descriptors



On 23.11.2023 18:37, Sergey Shtylyov wrote:
> On 11/20/23 11:45 AM, Claudiu wrote:
>
>> From: Claudiu Beznea <[email protected]>
>>
>> ravb_poll() initial code used to interrogate the first descriptor of the
>> RX queue in case gptp is false to know if ravb_rx() should be called.
>> This is done for non GPTP IPs. For GPTP IPs the driver PTP specific
>
> It's called gPTP, AFAIK.
>
>> information was used to know if receive function should be called. As
>> every IP has it's own receive function that interrogates the RX descriptor
>
> Its own.
>
>> list in the same way the ravb_poll() was doing there is no need to double
>> check this in ravb_poll(). Removing the code form ravb_poll() and
>
> From ravb_poll().
>
>> adjusting ravb_rx_gbeth() leads to a cleaner code.
>>
>> Signed-off-by: Claudiu Beznea <[email protected]>
>> ---
>> drivers/net/ethernet/renesas/ravb_main.c | 18 ++++++------------
>> 1 file changed, 6 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>> index 588e3be692d3..0fc9810c5e78 100644
>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>> @@ -771,12 +771,15 @@ static bool ravb_rx_gbeth(struct net_device *ndev, int *quota, int q)
>> int limit;
>>
>> entry = priv->cur_rx[q] % priv->num_rx_ring[q];
>> + desc = &priv->gbeth_rx_ring[entry];
>> + if (desc->die_dt == DT_FEMPTY)
>> + return false;
>> +
>
> I don't understand what this buys us, the following *while* loop will
> be skipped anyway, and the *for* loop as well, I think... And ravb_rx_rcar()

Yes, I kept it because of the for loop and the update of the *quota.

As commit specifies the code has been moved in IP specific RX function
keeping the initial functionality.

> doesn't have that anyway...


>
>> @@ -1279,25 +1282,16 @@ static int ravb_poll(struct napi_struct *napi, int budget)
>> struct net_device *ndev = napi->dev;
>> struct ravb_private *priv = netdev_priv(ndev);
>> const struct ravb_hw_info *info = priv->info;
>> - bool gptp = info->gptp || info->ccc_gac;
>> - struct ravb_rx_desc *desc;
>> unsigned long flags;
>> int q = napi - priv->napi;
>> int mask = BIT(q);
>> int quota = budget;
>> - unsigned int entry;
>>
>> - if (!gptp) {
>> - entry = priv->cur_rx[q] % priv->num_rx_ring[q];
>> - desc = &priv->gbeth_rx_ring[entry];
>> - }
>> /* Processing RX Descriptor Ring */
>> /* Clear RX interrupt */
>> ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
>> - if (gptp || desc->die_dt != DT_FEMPTY) {
>> - if (ravb_rx(ndev, &quota, q))
>> - goto out;
>> - }
>
> I don't really understand this code (despite I've AKCed it)...
> Biju, could you explain this (well, you tried already but I don't
> buy it anymore)?
>
>> + if (ravb_rx(ndev, &quota, q))
>> + goto out;
>
> This restores the behavior before:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3d4e37df882b0f4f28b7223a42492650b71252c5
>
> So does look correct. :-)
>
> MBR, Sergey