netdev - tap/bridge: Dropping NETIF_F_GSO/NETIF_F

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Message-ID: <20110504181813.GA17547@redhat.com>
Date:	Wed, 4 May 2011 21:18:14 +0300
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:	netdev@...r.kernel.org, Ben Hutchings <bhutchings@...arflare.com>,
	herbert@...dor.hengli.com.au
Subject: tap/bridge: Dropping NETIF_F_GSO/NETIF_F_SG

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
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