netdev - Re: [net-next, PATCH 2/2] net: netsec: remove loops in napi Rx process

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Date:   Wed, 19 Jun 2019 11:41:30 +0200
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Ilias Apalodimas <ilias.apalodimas@...aro.org>
Cc:     Jaswinder Singh <jaswinder.singh@...aro.org>,
        "<netdev@...r.kernel.org>" <netdev@...r.kernel.org>,
        Masahisa Kojima <masahisa.kojima@...aro.org>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [net-next, PATCH 2/2] net: netsec: remove loops in napi Rx process

On Wed, 19 Jun 2019 at 09:57, Ilias Apalodimas
<ilias.apalodimas@...aro.org> wrote:
>
> netsec_process_rx was running in a loop trying to process as many packets
> as possible before re-enabling interrupts. With the recent DMA changes
> this is not needed anymore as we manage to consume all the budget without
> looping over the function.
> Since it has no performance penalty let's remove that and simplify the Rx
> path a bit
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@...aro.org>

Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>

> ---
>  drivers/net/ethernet/socionext/netsec.c | 11 ++---------
>  1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> index a10ef700f16d..48fd7448b513 100644
> --- a/drivers/net/ethernet/socionext/netsec.c
> +++ b/drivers/net/ethernet/socionext/netsec.c
> @@ -820,19 +820,12 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
>  static int netsec_napi_poll(struct napi_struct *napi, int budget)
>  {
>         struct netsec_priv *priv;
> -       int rx, done, todo;
> +       int done;
>
>         priv = container_of(napi, struct netsec_priv, napi);
>
>         netsec_process_tx(priv);
> -
> -       todo = budget;
> -       do {
> -               rx = netsec_process_rx(priv, todo);
> -               todo -= rx;
> -       } while (rx);
> -
> -       done = budget - todo;
> +       done = netsec_process_rx(priv, budget);
>
>         if (done < budget && napi_complete_done(napi, done)) {
>                 unsigned long flags;
> --
> 2.20.1
>