Merge branch 'nfp-mtu-buffer-reconfig'

Merge branch 'nfp-mtu-buffer-reconfig'

Jakub Kicinski says:

====================
MTU/buffer reconfig changes

I re-discussed MPLS/MTU internally, dropped it from the patch 1,
re-tested everything, found out I forgot about debugfs pointers,
fixed that as well.

v5:
 - don't reserve space in RX buffers for MPLS label stack
   (patch 1);
 - fix debugfs pointers to ring structures (patch 5).
v4:
 - cut down on unrelated patches;
 - don't "close" the device on error path.

--- v4 cover letter

Previous series included some not entirely related patches,
this one is cut down.  Main issue I'm trying to solve here
is that .ndo_change_mtu() in nfpvf driver is doing full
close/open to reallocate buffers - which if open fails
can result in device being basically closed even though
the interface is started.  As suggested by you I try to move
towards a paradigm where the resources are allocated first
and the MTU change is only done once I'm certain (almost)
nothing can fail.  Almost because I need to communicate
with FW and that can always time out.

Patch 1 fixes small issue.  Next 10 patches reorganize things
so that I can easily allocate new rings and sets of buffers
while the device is running.  Patches 13 and 15 reshape the
.ndo_change_mtu() and ethtool's ring-resize operation into
desired form.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>