Re: [PATCH] pktgen: Clone skb to avoid corruption of skbs in ndo_start_xmit methods

Neil Horman
2011-07-20T15:18:47Z

On Wed, Jul 20, 2011 at 06:24:15AM +0200, Eric Dumazet wrote:
> Le mardi 19 juillet 2011 à 22:07 -0400, Neil Horman a écrit :
> > >
> > I think this is a good idea. It lets pktgen dynamically make the clone/share
> > decision dynamically and only impacts performance for those systems.
> >
>
> Just let pktgen refuse to use clone_skb command for these devices.
>
copy that, This is by no means final, but what do you think of this? If its
agreeable to you, Ben, et al. I can add this to my local tree and start auditing
all the drivers that may need to have the flag set.

Regards
Neil

diff --git a/include/linux/if.h b/include/linux/if.h
index 3bc63e6..ae904fe 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -76,6 +76,7 @@
#define IFF_BRIDGE_PORT 0x4000 /* device used as bridge port */
#define IFF_OVS_DATAPATH 0x8000 /* device used as Open vSwitch
* datapath port */
+#define IFF_CANT_SHARE_SKB 0x10000 /* Device can't share skbs in tx path */

#define IF_GET_IFACE 0x0001 /* for querying only */
#define IF_GET_PROTO 0x0002
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f76079c..bf6d88d 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -1071,6 +1071,9 @@ static ssize_t pktgen_if_write(struct file *file,
if (len < 0)
return len;

+ if (pkt_dev->priv_flags & IFF_CANT_SHARE_SKB)
+ return -EOPNOTSUPP;
+
i += len;
pkt_dev->clone_skb = value;