netdev - Re: [PATCH] forcedeth: Stay in NAPI as long as there's work

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Date:	Wed, 28 Apr 2010 10:54:11 -0700
From:	Joe Perches <joe@...ches.com>
To:	Tom Herbert <therbert@...gle.com>
Cc:	netdev@...r.kernel.org, aabdulla@...dia.com, davem@...emloft.net
Subject: Re: [PATCH] forcedeth: Stay in NAPI as long as there's work

On Tue, 2010-04-27 at 23:36 -0700, Tom Herbert wrote:
> Add loop in NAPI poll routine to keep processing RX and TX as long as
> there is more work to do.  This is similar to what tg3 and some other
> drivers do.
> Signed-off-by: Tom Herbert <therbert@...gle.com>
> ---
> diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
> index a1c0e7b..1e4de7b 100644
> --- a/drivers/net/forcedeth.c
> +++ b/drivers/net/forcedeth.c
> @@ -3736,6 +3736,23 @@ static irqreturn_t nv_nic_irq_tx(int foo, void *data)
>  }
>  
>  #ifdef CONFIG_FORCEDETH_NAPI
> +static inline int nv_has_work(struct fe_priv *np)
> +{
> +	if (nv_optimized(np)) {
> +		return (
> +		    ((np->get_rx.ex != np->put_rx.ex) &&
> +		     !(le32_to_cpu(np->get_rx.ex->flaglen) & NV_RX2_AVAIL)) ||
> +		    ((np->get_tx.ex != np->put_tx.ex) &&
> +		     !(le32_to_cpu(np->get_tx.ex->flaglen) & NV_TX_VALID)));
> +	} else {
> +		return (
> +		    ((np->get_rx.orig != np->put_rx.orig) &&
> +		     !(le32_to_cpu(np->get_rx.orig->flaglen) & NV_RX_AVAIL)) ||
> +		    ((np->get_tx.orig != np->put_tx.orig) &&
> +		     !(le32_to_cpu(np->get_tx.orig->flaglen) & NV_TX_VALID)));
> +	}
> +}

It might be better to test the comparisons using
a cpu_to_le32 of the constants.

static inline int nv_has_work(struct fe_priv *np)
{
	if (nv_optimized(np))
		return ((np->get_rx.ex != np->put_rx.ex) &&
			!(np->get_rx.ex->flaglen & cpu_to_le32(NV_RX2_AVAIL))) ||
		       ((np->get_tx.ex != np->put_tx.ex) &&
			!(np->get_tx.ex->flaglen & cpu_to_le32(NV_TX_VALID)));

	return ((np->get_rx.orig != np->put_rx.orig) &&
		!(np->get_rx.orig->flaglen & cpu_to_le32(NV_RX_AVAIL))) ||
	       ((np->get_tx.orig != np->put_tx.orig) &&
		!(np->get_tx.orig->flaglen & cpu_to_le32(NV_TX_VALID)));
}


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