RE: [patch v1, kernel version 3.2.1] rtnetlink workaround around the skb buff size issue

On Tue, 2012-02-07 at 00:13 +0000, Rose, Gregory V wrote:

quoted

-----Original Message-----
From: Ben Hutchings [mailto:bhutchings@solarflare.com]
Sent: Monday, February 06, 2012 3:51 PM
To: Rose, Gregory V
Cc: David Miller; steweg@ynet.sk; linux-kernel@vger.kernel.org;
netdev@vger.kernel.org
Subject: RE: [patch v1, kernel version 3.2.1] rtnetlink workaround around
the skb buff size issue

On Mon, 2012-02-06 at 04:41 +0000, Rose, Gregory V wrote:
[...]

quoted

quoted

This is not how we're going to fix this.  I already stated the desired
way to fix this, which is to make the existing dump request have a way
for the requestor to enable extended parts of the device dump.

This is just like netlink diag socket dumps, where the dump request
specifies what the user wants to see.

In this case we'd add a netlink attribute to the dump request which
is just a u32 bitmask or similar.

The Intel engineer who added the VF dump support said he would work on
this fix so why don't you just wait patiently for him to do the work?

The patch below is what I've got so far.  Right now the bit mask array
is global so if you enable display of VF (n) on one interface it will
enable display of the same VF on other interfaces.  I intend to move
the bit mask array into the net_device structure so we can set the
display mask for each interface independently.

I don't think this can work.  Using an application that requests VF
information and uses large buffers (e.g. the updated 'ip') will break
another application that doesn't (e.g. current Network Manager), won't
it?

It's my understanding that the problem isn't with the application
buffer size but with the kernel buffer size, which is limited to a
page.

[...]

Then it's no wonder you're going about this the wrong way.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.