[PATCH v5] Block backend checks for insane ring entries.

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

These patches were posted in the past (v2?) and at which point Jan
Beulich suggested to use a different macro. Unfortunatly after a
more exhaustive testing it was found that said macro is not
appropiate and would needlessly hang up the connection.

Hence re-introducing the new macro which will allow to detect
the producer and consumer indexes being greater than the ring size:

 [v5 1/2] xen/ring: Add a new macro to detect whether there is an

And the patch which will now use it:
 [v5 2/2] xen/blkback: Check for insane amounts of request on the ring


 drivers/block/xen-blkback/blkback.c | 12 +++++++++++-
 drivers/block/xen-blkback/common.h  |  2 ++
 drivers/block/xen-blkback/xenbus.c  |  2 ++
 include/xen/interface/io/ring.h     |  6 ++++++
 4 files changed, 21 insertions(+), 1 deletion(-)

Konrad Rzeszutek Wilk (2):
      xen/ring: Add a new macro to detect whether there is an overflow in requests and response.
      xen/blkback: Check for insane amounts of request on the ring (v5).