[PATCH v4 1/2] vhost-net: fix handle_rx buffer size

[PATCH v4 1/2] vhost-net: fix handle_rx buffer size

[Basil Gor]

Take vlan header length into account, when vlan id is stored as
vlan_tci. Otherwise tagged packets comming from macvtap will be
truncated.

Signed-off-by: Basil Gor <basil.gor@gmail.com>
---
 drivers/vhost/net.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1f21d2a..5c17010 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -24,6 +24,7 @@
 #include <linux/if_arp.h>
 #include <linux/if_tun.h>
 #include <linux/if_macvlan.h>
+#include <linux/if_vlan.h>
 
 #include <net/sock.h>
 
@@ -283,8 +284,12 @@ static int peek_head_len(struct sock *sk)
 
 	spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
 	head = skb_peek(&sk->sk_receive_queue);
-	if (likely(head))
+	if (likely(head)) {
 		len = head->len;
+		if (vlan_tx_tag_present(head))
+			len += VLAN_HLEN;
+	}
+
 	spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
 	return len;
 }
-- 
1.7.6.5

Re: [PATCH v4 1/2] vhost-net: fix handle_rx buffer size

[Michael S. Tsirkin]

On Fri, May 04, 2012 at 12:55:23PM +0400, Basil Gor wrote:
> Take vlan header length into account, when vlan id is stored as
> vlan_tci. Otherwise tagged packets comming from macvtap will be
> truncated.
> 
> Signed-off-by: Basil Gor <basil.gor@gmail.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

This doesn't fix packet socket backends but that can be
handled separately later.

Eric, ack?

> ---
>  drivers/vhost/net.c |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 1f21d2a..5c17010 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -24,6 +24,7 @@
>  #include <linux/if_arp.h>
>  #include <linux/if_tun.h>
>  #include <linux/if_macvlan.h>
> +#include <linux/if_vlan.h>
>  
>  #include <net/sock.h>
>  
> @@ -283,8 +284,12 @@ static int peek_head_len(struct sock *sk)
>  
>  	spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
>  	head = skb_peek(&sk->sk_receive_queue);
> -	if (likely(head))
> +	if (likely(head)) {
>  		len = head->len;
> +		if (vlan_tx_tag_present(head))
> +			len += VLAN_HLEN;
> +	}
> +
>  	spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
>  	return len;
>  }
> -- 
> 1.7.6.5

Re: [PATCH v4 1/2] vhost-net: fix handle_rx buffer size

[David Miller]

From: Basil Gor <basil.gor@gmail.com>
Date: Fri,  4 May 2012 12:55:23 +0400

> Take vlan header length into account, when vlan id is stored as
> vlan_tci. Otherwise tagged packets comming from macvtap will be
> truncated.
> 
> Signed-off-by: Basil Gor <basil.gor@gmail.com>

My patience with Eric B. to review this has run out, applied,
thanks Basil.

Re: [PATCH v4 1/2] vhost-net: fix handle_rx buffer size

[Eric W. Biederman]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Fri, May 04, 2012 at 12:55:23PM +0400, Basil Gor wrote:
>> Take vlan header length into account, when vlan id is stored as
>> vlan_tci. Otherwise tagged packets comming from macvtap will be
>> truncated.
>> 
>> Signed-off-by: Basil Gor <basil.gor@gmail.com>
>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>
> This doesn't fix packet socket backends but that can be
> handled separately later.

Yes that seems good enough.

Let me recommend just taking the packet out of the socket queue
instead of calling the recvmsg method.  Since vhost/net.c is
already munging with the queue directly that should make
it easy to avoid the peculiarities of pf_packet sockets
for reporting vlan information.

Eric