Comment 5 for bug 1748662

From the log it seems pretty different from upstream because we backported some cool stuff:
https://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-azure/log/drivers/hv/ring_buffer.c?h=master-next

Age Commit message (Expand)
Author
2 days UBUNTU: SAUCE: vmbus: fix performance regression
Stephen Hemminger
2 days UBUNTU: SAUCE: vmbus: simplify packet iterator
Stephen Hemminger
2 days UBUNTU: SAUCE: vmbus: don't need to check interrupt mask on read side
Stephen Hemminger

I think we can back out the changes in the three sauce items above and apply the patch cleanly. In the meantime when we sync up to 4.15 this should be easier to clean up.