PATCH] via-rhine.c: don't reference skb after passing it to netif_rx

PATCH] via-rhine.c: don't reference skb after passing it to netif_rx

[Arnaldo Carvalho de Melo]

humm, almost finishing... 8)

Em Mon, Feb 26, 2001 at 08:33:59PM -0300, Arnaldo Carvalho de Melo escreveu:
Hi,

	I've just read davem's post at netdev about the brokeness of
referencing skbs after passing it to netif_rx, so please consider applying
this patch. Ah, this was just added to the Janitor's TODO list at
http://bazar.conectiva.com.br/~acme/TODO and I'm doing a quick audit in the
net drivers searching for this, maybe some more patches will follow.

- Arnaldo

--- linux-2.4.2/drivers/net/via-rhine.c	Mon Dec 11 19:38:29 2000
+++ linux-2.4.2.acme/drivers/net/via-rhine.c	Mon Feb 26 22:36:18 2001
@@ -1147,9 +1147,9 @@
 								 np->rx_buf_sz, PCI_DMA_FROMDEVICE);
 			}
 			skb->protocol = eth_type_trans(skb, dev);
+			np->stats.rx_bytes += skb->len;
 			netif_rx(skb);
 			dev->last_rx = jiffies;
-			np->stats.rx_bytes += skb->len;
 			np->stats.rx_packets++;
 		}
 		entry = (++np->cur_rx) % RX_RING_SIZE;

Re: PATCH] via-rhine.c: don't reference skb after passing it to netif_rx

[Donald Becker]

On Mon, 26 Feb 2001, Arnaldo Carvalho de Melo wrote:

> Em Mon, Feb 26, 2001 at 08:33:59PM -0300, Arnaldo Carvalho de Melo escreveu:
> 	I've just read davem's post at netdev about the brokeness of
> referencing skbs after passing it to netif_rx, so please consider applying
> this patch. Ah, this was just added to the Janitor's TODO list at

> --- linux-2.4.2/drivers/net/via-rhine.c	Mon Dec 11 19:38:29 2000
> +++ linux-2.4.2.acme/drivers/net/via-rhine.c	Mon Feb 26 22:36:18 2001
> @@ -1147,9 +1147,9 @@
>  								 np->rx_buf_sz, PCI_DMA_FROMDEVICE);
>  			}
>  			skb->protocol = eth_type_trans(skb, dev);
> +			np->stats.rx_bytes += skb->len;
>  			netif_rx(skb);
>  			dev->last_rx = jiffies;
> -			np->stats.rx_bytes += skb->len;
>  			np->stats.rx_packets++;
>  		}

Easier fix: 
-			np->stats.rx_bytes += skb->len;
+			np->stats.rx_bytes += pkt_len;

Grouping the writes to np->stats results in better cache usage.


Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993

Re: PATCH] via-rhine.c: don't reference skb after passing it to netif_rx

[Arnaldo Carvalho de Melo]

Em Mon, Feb 26, 2001 at 08:52:39PM -0500, Donald Becker escreveu:
> On Mon, 26 Feb 2001, Arnaldo Carvalho de Melo wrote:
> 
> > Em Mon, Feb 26, 2001 at 08:33:59PM -0300, Arnaldo Carvalho de Melo escreveu:
> > 	I've just read davem's post at netdev about the brokeness of
> > referencing skbs after passing it to netif_rx, so please consider applying
> > this patch. Ah, this was just added to the Janitor's TODO list at
> 
> > --- linux-2.4.2/drivers/net/via-rhine.c	Mon Dec 11 19:38:29 2000
> > +++ linux-2.4.2.acme/drivers/net/via-rhine.c	Mon Feb 26 22:36:18 2001
> > @@ -1147,9 +1147,9 @@
> >  								 np->rx_buf_sz, PCI_DMA_FROMDEVICE);
> >  			}
> >  			skb->protocol = eth_type_trans(skb, dev);
> > +			np->stats.rx_bytes += skb->len;
> >  			netif_rx(skb);
> >  			dev->last_rx = jiffies;
> > -			np->stats.rx_bytes += skb->len;
> >  			np->stats.rx_packets++;
> >  		}
> 
> Easier fix: 
> -			np->stats.rx_bytes += skb->len;
> +			np->stats.rx_bytes += pkt_len;
> 
> Grouping the writes to np->stats results in better cache usage.

thanks, I'll take that into account for the remaining ones and this should
be checked by the driver authors for the ones I've already sent.

- Arnaldo

Re: PATCH] via-rhine.c: don't reference skb after passing it to netif_rx

[Urban Widmark]

On Mon, 26 Feb 2001, Arnaldo Carvalho de Melo wrote:

> thanks, I'll take that into account for the remaining ones and this should
> be checked by the driver authors for the ones I've already sent.

The pkt_len variant is already in 2.4.1-ac15 and probably before that
(changed by Manfred Spraul back in ac4?).

Perhaps you should run through the drivers in -acX instead/also?
(too late now I guess :)

/Urban

Re: PATCH] via-rhine.c: don't reference skb after passing it tonetif_rx

[Jeff Garzik]

Urban Widmark wrote:
> 
> On Mon, 26 Feb 2001, Arnaldo Carvalho de Melo wrote:
> 
> > thanks, I'll take that into account for the remaining ones and this should
> > be checked by the driver authors for the ones I've already sent.
> 
> The pkt_len variant is already in 2.4.1-ac15 and probably before that
> (changed by Manfred Spraul back in ac4?).
> 
> Perhaps you should run through the drivers in -acX instead/also?
> (too late now I guess :)

FWIW I sync up all my network driver patches (include most of the
last_rx/etc changes) with Alan first, and then ship them to Linus as
they are proven stable.

	Jeff


-- 
Jeff Garzik       | "You see, in this world there's two kinds of
Building 1024     |  people, my friend: Those with loaded guns
MandrakeSoft      |  and those who dig. You dig."  --Blondie

Re: PATCH] via-rhine.c: don't reference skb after passing it to netif_rx

[Arnaldo Carvalho de Melo]

Em Tue, Feb 27, 2001 at 10:07:07AM +0100, Urban Widmark escreveu:
> On Mon, 26 Feb 2001, Arnaldo Carvalho de Melo wrote:
> 
> > thanks, I'll take that into account for the remaining ones and this should
> > be checked by the driver authors for the ones I've already sent.
> 
> The pkt_len variant is already in 2.4.1-ac15 and probably before that
> (changed by Manfred Spraul back in ac4?).
> 
> Perhaps you should run through the drivers in -acX instead/also?
> (too late now I guess :)

well, I think that some of the patches will apply cleanly to both 2.4.2
stock and 2.4.2-acLATEST, or at least sound as a hint to driver
maintainers. I'll wait for the next ac patch and look again.

- Arnaldo