[ovs-dev] [Xen-devel] Re: [PATCH] ethtool: ETHTOOL_SFEATURES: remove NETIF_F_COMPAT return

Jesse Gross jesse at nicira.com
Sat May 28 17:31:03 UTC 2011


2011/5/28 Ian Campbell <Ian.Campbell at citrix.com>:
> On Sat, 2011-05-28 at 08:35 +0100, Michał Mirosław wrote:
>> On Sat, May 28, 2011 at 12:25:55AM +0100, Ben Hutchings wrote:
>> > On Fri, 2011-05-27 at 18:34 +0200, Michał Mirosław wrote:
>> > > On Fri, May 27, 2011 at 04:45:50PM +0100, Ben Hutchings wrote:
>> > > > On Fri, 2011-05-27 at 17:28 +0200, Michał Mirosław wrote:
>> > [...]
>> > > > >      (note: ETHTOOL_S{SG,...} are not ever going away)
>> > > > >    - causes NETIF_F_* to be an ABI
>> > > > If feature flag numbers are not stable then what is the point of
>> > > > /sys/class/net/<name>/features?  Also, I'm not aware that features have
>> > > > ever been renumbered in the past.
>> > > Since no NETIF_F_* were exported earlier, I assume /sys/class/net/*/features
>> > > is a debugging aid. What is it used for besides that?
>> > xen-api <https://github.com/xen-org/xen-api> uses it in
>> > scripts/InterfaceReconfigureVswitch.py.  Though it doesn't seem to be
>> > used for a particularly good reason...
>>
>> Look like it should use ETHTOOL_GFLAGS instead for netdev_has_vlan_accel().

ETHTOOL_GFLAGS didn't expose the vlan acceleration flags until 2.6.37,
which is why /sys/class/net was used instead.



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