linux-kernel - Re: [PATCH v5] net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 11 Nov 2015 00:34:48 +0100
From:	Francois Romieu <romieu@...zoreil.com>
To:	Mans Rullgard <mans@...sr.com>
Cc:	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	slash.tmp@...e.fr
Subject: Re: [PATCH v5] net: ethernet: add driver for Aurora VLSI NB8800
 Ethernet controller

Mans Rullgard <mans@...sr.com> :
> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c
> new file mode 100644
> index 0000000..11cd389
> --- /dev/null
> +++ b/drivers/net/ethernet/aurora/nb8800.c
[...]
> +static int nb8800_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
[...]
> +
> +	netdev_sent_queue(dev, skb->len);
> +
> +	smp_mb__before_spinlock();
> +	spin_lock_irqsave(&priv->tx_lock, flags);

At some point you may consider performing both Tx and Rx from napi context
and thus replacing priv->tx_lock with netif_tx_lock.

> +
> +	if (!skb->xmit_more) {
> +		priv->tx_chain->ready = true;
> +		priv->tx_chain = NULL;
> +		nb8800_tx_dma_start(dev);
> +	}
> +
> +	spin_unlock_irqrestore(&priv->tx_lock, flags);
> +
> +	priv->tx_next = next;

Are there strong reasons why nb8800_tx_done could not kick between
spin_unlock_irqrestore and the non-local update of priv->tx_next ?

[...]
> +static irqreturn_t nb8800_irq(int irq, void *dev_id)
> +{
> +	struct net_device *dev = dev_id;
> +	struct nb8800_priv *priv = netdev_priv(dev);
> +	u32 val;
> +
> +	/* tx interrupt */
> +	val = nb8800_readl(priv, NB8800_TXC_SR);
> +	if (val) {
[...]
> +	}
> +
> +	/* rx interrupt */
> +	val = nb8800_readl(priv, NB8800_RXC_SR);
> +	if (val) {
[...]
> +	}
> +
> +	return IRQ_HANDLED;

Returning IRQ_HANDLED is fine if one of those hold:
1. you're sure that at least one of the "if" branch is used
2. you'll be able to quickly figure out what's happening whenever 1. stops
   being true.

-- 
Ueimor
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/