[net-next,1/1] net: fec: clear receive interrupts before processing a packet

From: Russell King <rmk+kernel@arm.linux.org.uk>

The patch just to re-submit the patch "db3421c114cfa6326" because the
patch "4d494cdc92b3b9a0" remove the change.

Clear any pending receive interrupt before we process a pending packet.
This helps to avoid any spurious interrupts being raised after we have
fully cleaned the receive ring, while still allowing an interrupt to be
raised if we receive another packet.

The position of this is critical: we must do this prior to reading the
next packet status to avoid potentially dropping an interrupt when a
packet is still pending.

Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 drivers/net/ethernet/freescale/fec_main.c | 1 +
 1 file changed, 1 insertion(+)

On Wed, Sep 02, 2015 at 05:24:14PM +0800, Fugang Duan wrote:
> From: Russell King <rmk+kernel@arm.linux.org.uk>
> 
> The patch just to re-submit the patch "db3421c114cfa6326" because the
> patch "4d494cdc92b3b9a0" remove the change.

I think you should mention also the titles of the commits.

And maybe send it also to stable.
> 
> Clear any pending receive interrupt before we process a pending packet.
> This helps to avoid any spurious interrupts being raised after we have
> fully cleaned the receive ring, while still allowing an interrupt to be
> raised if we receive another packet.
> 
> The position of this is critical: we must do this prior to reading the
> next packet status to avoid potentially dropping an interrupt when a
> packet is still pending.
> 
> Acked-by: Fugang Duan <B38611@freescale.com>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 1f89c59..6bed0ff 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1400,6 +1400,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
>  		if ((status & BD_ENET_RX_LAST) == 0)
>  			netdev_err(ndev, "rcv is not +last\n");
>  
Could a comment be added here to avoid another future removal ?

> +		writel(FEC_ENET_RXF, fep->hwp + FEC_IEVENT);
>  
>  		/* Check for errors. */
>  		if (status & (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
> -- 
> 1.9.1

Philippe
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On Wed, Sep 02, 2015 at 11:40:15AM +0200, Philippe De Muyter wrote:
> On Wed, Sep 02, 2015 at 05:24:14PM +0800, Fugang Duan wrote:
> > From: Russell King <rmk+kernel@arm.linux.org.uk>
> > 
> > The patch just to re-submit the patch "db3421c114cfa6326" because the
> > patch "4d494cdc92b3b9a0" remove the change.
> 
> I think you should mention also the titles of the commits.

Yes, that's standard kernel procedure.  Also, 12 characters of commit ID
is the recommended length.

> Could a comment be added here to avoid another future removal ?

I think reading the commit messages introducing the code would also help,
but a comment wouldn't hurt.

From: Fugang Duan <b38611@freescale.com>
Date: Wed, 2 Sep 2015 17:24:14 +0800

> From: Russell King <rmk+kernel@arm.linux.org.uk>
> 
> The patch just to re-submit the patch "db3421c114cfa6326" because the
> patch "4d494cdc92b3b9a0" remove the change.
> 
> Clear any pending receive interrupt before we process a pending packet.
> This helps to avoid any spurious interrupts being raised after we have
> fully cleaned the receive ring, while still allowing an interrupt to be
> raised if we receive another packet.
> 
> The position of this is critical: we must do this prior to reading the
> next packet status to avoid potentially dropping an interrupt when a
> packet is still pending.
> 
> Acked-by: Fugang Duan <B38611@freescale.com>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Applied and queued up for -stable, thanks.
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Hi Andy,

can you resubmit it, adding also my

Reported-by: Philippe De Muyter <phdm@macqel.be>

and explaining that it also prevents a complete rx blockage failure ?

Philippe

On Wed, Sep 02, 2015 at 11:40:15AM +0200, Philippe De Muyter wrote:
> On Wed, Sep 02, 2015 at 05:24:14PM +0800, Fugang Duan wrote:
> > From: Russell King <rmk+kernel@arm.linux.org.uk>
> > 
> > The patch just to re-submit the patch "db3421c114cfa6326" because the
> > patch "4d494cdc92b3b9a0" remove the change.
> 
> I think you should mention also the titles of the commits.
> 
> And maybe send it also to stable.
> > 
> > Clear any pending receive interrupt before we process a pending packet.
> > This helps to avoid any spurious interrupts being raised after we have
> > fully cleaned the receive ring, while still allowing an interrupt to be
> > raised if we receive another packet.
> > 
> > The position of this is critical: we must do this prior to reading the
> > next packet status to avoid potentially dropping an interrupt when a
> > packet is still pending.
> > 
> > Acked-by: Fugang Duan <B38611@freescale.com>
> > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> > ---
> >  drivers/net/ethernet/freescale/fec_main.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> > index 1f89c59..6bed0ff 100644
> > --- a/drivers/net/ethernet/freescale/fec_main.c
> > +++ b/drivers/net/ethernet/freescale/fec_main.c
> > @@ -1400,6 +1400,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
> >  		if ((status & BD_ENET_RX_LAST) == 0)
> >  			netdev_err(ndev, "rcv is not +last\n");
> >  
> Could a comment be added here to avoid another future removal ?
> 
> > +		writel(FEC_ENET_RXF, fep->hwp + FEC_IEVENT);
> >  
> >  		/* Check for errors. */
> >  		if (status & (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
> > -- 
> > 1.9.1
> 
> Philippe

From: Philippe De Muyter <phdm@macq.eu> Sent: Thursday, September 03, 2015 4:00 PM
> To: Duan Fugang-B38611
> Cc: davem@davemloft.net; netdev@vger.kernel.org; linux@arm.linux.org.uk
> Subject: Re: [PATCH net-next 1/1] net: fec: clear receive interrupts
> before processing a packet
> 
> Hi Andy,
> 
> can you resubmit it, adding also my
> 
> Reported-by: Philippe De Muyter <phdm@macqel.be>
> 
> and explaining that it also prevents a complete rx blockage failure ?
> 
> Philippe
> 
Sorry, consider the patch was submitted/reviewed/applied, so I just re-submited it with keeping the original author/commit log/sign-in information.

> On Wed, Sep 02, 2015 at 11:40:15AM +0200, Philippe De Muyter wrote:
> > On Wed, Sep 02, 2015 at 05:24:14PM +0800, Fugang Duan wrote:
> > > From: Russell King <rmk+kernel@arm.linux.org.uk>
> > >
> > > The patch just to re-submit the patch "db3421c114cfa6326" because
> > > the patch "4d494cdc92b3b9a0" remove the change.
> >
> > I think you should mention also the titles of the commits.
> >
> > And maybe send it also to stable.
> > >
> > > Clear any pending receive interrupt before we process a pending
> packet.
> > > This helps to avoid any spurious interrupts being raised after we
> > > have fully cleaned the receive ring, while still allowing an
> > > interrupt to be raised if we receive another packet.
> > >
> > > The position of this is critical: we must do this prior to reading
> > > the next packet status to avoid potentially dropping an interrupt
> > > when a packet is still pending.
> > >
> > > Acked-by: Fugang Duan <B38611@freescale.com>
> > > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> > > ---
> > >  drivers/net/ethernet/freescale/fec_main.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/net/ethernet/freescale/fec_main.c
> > > b/drivers/net/ethernet/freescale/fec_main.c
> > > index 1f89c59..6bed0ff 100644
> > > --- a/drivers/net/ethernet/freescale/fec_main.c
> > > +++ b/drivers/net/ethernet/freescale/fec_main.c
> > > @@ -1400,6 +1400,7 @@ fec_enet_rx_queue(struct net_device *ndev, int
> budget, u16 queue_id)
> > >  		if ((status & BD_ENET_RX_LAST) == 0)
> > >  			netdev_err(ndev, "rcv is not +last\n");
> > >
> > Could a comment be added here to avoid another future removal ?
> >
> > > +		writel(FEC_ENET_RXF, fep->hwp + FEC_IEVENT);
> > >
> > >  		/* Check for errors. */
> > >  		if (status & (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
> > > --
> > > 1.9.1
> >
> > Philippe
> 
> --
> Philippe De Muyter +32 2 6101532 Macq SA rue de l'Aeronef 2 B-1140
> Bruxelles
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