Xen devel - Oct 2011 - [PATCH] netback: disable features not supported by netfront

From: pbonzini@redhat.com

# HG changeset patch
# User Paolo Bonzini <pbonzini@redhat.com>
# Date 1318837036 -7200
# Node ID eb896361fc70b60b9a257d0c82e19633a11b9d41
# Parent  3c900d6a5f6a51ff1547f21fef30ab8b92feccc9
netback: disable features not supported by netfront

Netback works by first setting all possible features, and then
resetting some after connection, if the front-end didn''t negotiate
them.
Except that in the old 2.6.18 tree the "resetting" part was missing.
In the pvops tree, this should work correctly through the fix_features
mechanism.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/drivers/xen/netback/interface.c b/drivers/xen/netback/interface.c
--- a/drivers/xen/netback/interface.c
+++ b/drivers/xen/netback/interface.c
@@ -98,8 +98,9 @@ static int netbk_change_mtu(struct net_d
 void netif_set_features(netif_t *netif)
 {
 	struct net_device *dev = netif->dev;
-	int features = dev->features;
+	int features;
 
+	features = dev->features & ~(NETIF_F_SG|NETIF_F_TSO|NETIF_F_IP_CSUM);
 	if (netif->can_sg)
 		features |= NETIF_F_SG;
 	if (netif->gso)



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>>> On 17.10.11 at 09:41, Paolo Bonzini <pbonzini@redhat.com>
wrote:
> From: pbonzini@redhat.com 
> 
> # HG changeset patch
> # User Paolo Bonzini <pbonzini@redhat.com>
> # Date 1318837036 -7200
> # Node ID eb896361fc70b60b9a257d0c82e19633a11b9d41
> # Parent  3c900d6a5f6a51ff1547f21fef30ab8b92feccc9
> netback: disable features not supported by netfront
> 
> Netback works by first setting all possible features, and then
> resetting some after connection, if the front-end didn''t negotiate
them.
> Except that in the old 2.6.18 tree the "resetting" part was
missing.
Indeed - I always wondered about that. Applied, thanks!

Jan
> In the pvops tree, this should work correctly through the fix_features
> mechanism.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> diff --git a/drivers/xen/netback/interface.c
b/drivers/xen/netback/interface.c
> --- a/drivers/xen/netback/interface.c
> +++ b/drivers/xen/netback/interface.c
> @@ -98,8 +98,9 @@ static int netbk_change_mtu(struct net_d
>  void netif_set_features(netif_t *netif)
>  {
>  	struct net_device *dev = netif->dev;
> -	int features = dev->features;
> +	int features;
>  
> +	features = dev->features &
~(NETIF_F_SG|NETIF_F_TSO|NETIF_F_IP_CSUM);
>  	if (netif->can_sg)
>  		features |= NETIF_F_SG;
>  	if (netif->gso)
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com 
> http://lists.xensource.com/xen-devel 



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