From: Eric Dumazet <redacted>
Date: Tue, 26 Apr 2011 08:33:17 +0200

Le lundi 25 avril 2011 à 15:01 -0700, Greg Rose a écrit :

quoted

The message size allocated for rtnl info dumps was limited to a single page.
This is not enough for additional interface info available with devices
that support SR-IOV.  Check that the amount of data allocated is sufficient
for the amount of data requested.

Signed-off-by: Greg Rose <redacted>
---

 include/linux/rtnetlink.h |    1 +
 net/core/rtnetlink.c      |    6 ++++++
 net/netlink/af_netlink.c  |   37 +++++++++++++++++++++++++++++++------
 3 files changed, 38 insertions(+), 6 deletions(-)

Hmm, thats a hack, because netlink_dump() is generic and you add
something very specific.

You also can't do this without breaking applications.

We've trained every single netlink library out there about this message size
formula, so they know that if you allocate at least 8192 bytes for a recvmsg()
call they can receive fully any single netlink message.

And they must be able to make assumptions like this, otherwise they
cannot know how to reliably be able to receive a netlink message in
it's entirety in a generic fashion.

So one must not attack this problem from this angle.

It is absolutely necessary to find some way to report the VF
information, out of band, instead of trying to make the message
larger.

Needing more than 8K to get a dump of a single device over netlink is
absolutely rediculious, this VF stuff was poorly designed.  If has to
be fixed and the current stuff marked deprecated.