The following patches were made over Linus's tree and also apply over the mst vhost branch. They reduce the memory use for vhost-scsi. For a simple device with 1 queue and 128 cmds we use around 25 MB. These patches allow us to reduce that to 8.2 MB when supporting up to 128 8 MB IOs (the current passthrough max size). For a more complex device with 16 queues we use around 2.5 GB. These patches allow us to reduce that to 77.1 MB when supporting 1024 8 MB IOs. v2 - Rebase against current trees/branches. - Fix email threading.
