Thread (11 messages) 11 messages, 4 authors, 2020-09-29

Re: [PATCH net v2] virtio-net: don't disable guest csum when disable LRO

From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: 2020-09-29 07:29:45
Also in: virtualization

On Tue, Sep 29, 2020 at 9:23 AM Michael S. Tsirkin [off-list ref] wrote:
On Tue, Sep 29, 2020 at 02:59:03PM +0800, Tonghao Zhang wrote:
quoted
On Tue, Sep 29, 2020 at 2:23 PM Michael S. Tsirkin [off-list ref] wrote:
quoted
On Tue, Sep 29, 2020 at 09:58:06AM +0800, xiangxia.m.yue@gmail.com wrote:
quoted
From: Tonghao Zhang <redacted>

Open vSwitch and Linux bridge will disable LRO of the interface
when this interface added to them. Now when disable the LRO, the
virtio-net csum is disable too. That drops the forwarding performance.

Fixes: a02e8964eaf9 ("virtio-net: ethtool configurable LRO")
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Tonghao Zhang <redacted>
---
v2:
* change the fix-tag
---
 drivers/net/virtio_net.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7145c83c6c8c..21b71148c532 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -63,6 +63,11 @@ static const unsigned long guest_offloads[] = {
      VIRTIO_NET_F_GUEST_CSUM
 };

+#define GUEST_OFFLOAD_LRO_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
+                             (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
+                             (1ULL << VIRTIO_NET_F_GUEST_ECN)  | \
+                             (1ULL << VIRTIO_NET_F_GUEST_UFO))
+
I think I'd rather we open-coded this, the macro is only
used in one place ...
Yes, in this patch, it is used only in one place. But in next patch
[1], we use it twice and that make the code look a bit nicer.
Would we open-coded this in this patch ?

[1] - http://patchwork.ozlabs.org/project/netdev/patch/20200928033915.82810-2-xiangxia.m.yue@gmail.com/
OK then maybe keep this in a series like you did with v1.
If this is a fix it has to target net, unlike the other patch.
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