Re: [PATCH v7] net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller

From	David Miller <davem@davemloft.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH v7] net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller
Date	2015-11-19 05:10 +0100
Message-ID	<qwoHL-4kt-11@gated-at.bofh.it> (permalink)
References	<qweIq-60C-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Mans Rullgard <mans@mansr.com>
Date: Wed, 18 Nov 2015 17:29:24 +0000

> +static int nb8800_poll(struct napi_struct *napi, int budget)
> +{
> +	struct net_device *dev = napi->dev;
> +	struct nb8800_priv *priv = netdev_priv(dev);
> +	struct nb8800_rx_desc *rxd;
> +	int work = 0;
> +	int last = priv->rx_eoc;
> +	int next;
 ...
> +		next = (last + 1) % RX_DESC_COUNT;

You should look at what the assembler looks like for these modulo
operations.

They will be much simpler (ie. one instruction) if you use unsigned
variables to hold the queue indices.

Please fix this in the entire driver.
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Re: [PATCH v7] net: ethernet: add driver for Aurora VLSI NB8800  Ethernet controller David Miller <davem@davemloft.net> - 2015-11-19 05:10 +0100

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