From: Mugunthan V N <mugunthanvnm@ti•com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix•de>
Cc: <netdev@vger•kernel.org>, "David S. Miller" <davem@davemloft•net>,
<tglx@linutronix•de>
Subject: Re: [PATCH 3/5] net/cpsw: don't rely only on netif_running() to check which device is active
Date: Tue, 23 Apr 2013 23:11:29 +0530 [thread overview]
Message-ID: <5176C7C9.8020705@ti.com> (raw)
In-Reply-To: <1366738299-21285-4-git-send-email-bigeasy@linutronix.de>
On 4/23/2013 11:01 PM, Sebastian Andrzej Siewior wrote:
> netif_running() reports false before the ->ndo_stop() callback is
> called. That means if one executes "ifconfig down" and the system
> receives an interrupt before the interrupt source has been disabled we
> hang for always for two reasons:
> - we never disable the interrupt source because devices claim to be
> already inactive and don't feel responsible.
> - since the ISR always reports IRQ_HANDLED the line is never deactivated
> because it looks like the ISR feels responsible.
>
> This patch changes the logic in the ISR a little:
> - If none of the status registers reports an active source (RX or TX,
> misc is ignored because it is not actived) we leave with IRQ_NONE.
> - the interrupt is deactivated
> - The first active network device is taken and napi is scheduled. If
> none are active (a small race window between ndo_down() and the
> interrupt the) then we leave and should not come back because the
> source is off.
> There is no need to schedule the second NAPI because both share the
> same dma queue.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix•de>
> ---
> drivers/net/ethernet/ti/cpsw.c | 33 ++++++++++++++++++++++-----------
> 1 file changed, 22 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
> index 29700fb..13d4ed8 100644
> --- a/drivers/net/ethernet/ti/cpsw.c
> +++ b/drivers/net/ethernet/ti/cpsw.c
> @@ -510,20 +510,31 @@ void cpsw_rx_handler(void *token, int len, int status)
> static irqreturn_t cpsw_interrupt(int irq, void *dev_id)
> {
> struct cpsw_priv *priv = dev_id;
> + u32 rx, tx, rx_thresh;
>
> - if (likely(netif_running(priv->ndev))) {
> - cpsw_intr_disable(priv);
> - cpsw_disable_irq(priv);
> + rx_thresh = __raw_readl(&priv->wr_regs->rx_thresh_stat);
> + rx = __raw_readl(&priv->wr_regs->rx_stat);
> + tx = __raw_readl(&priv->wr_regs->tx_stat);
> + if (!rx_thresh && !rx && !tx)
> + return IRQ_NONE;
> +
> + cpsw_intr_disable(priv);
> + cpsw_disable_irq(priv);
> +
> + if (netif_running(priv->ndev)) {
> napi_schedule(&priv->napi);
> - } else {
> - priv = cpsw_get_slave_priv(priv, 1);
> - if (likely(priv) && likely(netif_running(priv->ndev))) {
> - cpsw_intr_disable(priv);
> - cpsw_disable_irq(priv);
> - napi_schedule(&priv->napi);
> - }
> + return IRQ_HANDLED;
> + }
> +
> + priv = cpsw_get_slave_priv(priv, 1);
> + if (!priv)
> + return IRQ_NONE;
> +
> + if (netif_running(priv->ndev)) {
> + napi_schedule(&priv->napi);
> + return IRQ_HANDLED;
> }
> - return IRQ_HANDLED;
> + return IRQ_NONE;
> }
>
> static int cpsw_poll(struct napi_struct *napi, int budget)
Acked-by: Mugunthan V N <mugunthanvnm@ti•com>
Regards
Mugunthan V N
next prev parent reply other threads:[~2013-04-23 17:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-23 17:31 cpsw queue, v2 Sebastian Andrzej Siewior
2013-04-23 17:31 ` [PATCH 1/5] net/davinci_cpdma: don't check for jiffies with interrupts Sebastian Andrzej Siewior
2013-04-23 17:31 ` [PATCH 2/5] net/cpsw: don't continue if we miss to allocate rx skbs Sebastian Andrzej Siewior
2013-04-23 17:41 ` Mugunthan V N
2013-04-23 17:31 ` [PATCH 3/5] net/cpsw: don't rely only on netif_running() to check which device is active Sebastian Andrzej Siewior
2013-04-23 17:41 ` Mugunthan V N [this message]
2013-04-23 17:31 ` [PATCH 4/5] net/davinci_cpdma: remove unused argument in cpdma_chan_submit() Sebastian Andrzej Siewior
2013-04-23 17:31 ` [PATCH 5/5] net/cpsw: redo rx skb allocation in rx path Sebastian Andrzej Siewior
2013-04-25 8:17 ` cpsw queue, v2 David Miller
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