Subject: tap/bridge: Dropping NETIF_F_GSO/NETIF_F_SG

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 4 May 2011 21:18:14 +0300

BTW, I just noticed that net-next spits out
many of the following when I run any VMs:

tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Features changed: 0x401b4849 -> 0x40004040
device msttap0 entered promiscuous mode
br0: Dropping NETIF_F_GSO since no SG feature.
br0: port 1(msttap0) entering forwarding state
br0: port 1(msttap0) entering forwarding state
tap0: Features changed: 0x40004040 -> 0x40024849
tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Features changed: 0x40024849 -> 0x40004040
br0: Dropping NETIF_F_GSO since no SG feature.
tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Features changed: 0x40004040 -> 0x401b4849
tap0: Dropping NETIF_F_SG since no checksum feature.
tap0: Dropping NETIF_F_GSO since no SG feature.
tap0: Features changed: 0x401b4849 -> 0x40004040
br0: Dropping NETIF_F_GSO since no SG feature.

My problem is not primarily with warnings:

will that linearize all packets and disable GSO
for tap and bridge? If yes it can't be good
for performance...

-- 
MST