iscsi update

This is a resend of the last iscsi patches I sent yesterday
http://marc.theaimsgroup.com/?l=linux-scsi&m=113712848705512&w=2
but they address Christoph's comments, fix the mutex usage, and some are rediffed so that they apply cleanly or are dropped becuase of how we handled Christoph's comments.

This patchset was made against scsi-misc and fixes xfs and jfs support, xfs or st or sg with 4k stacks, highmem support, reworks the transport class to allow HW iscsi to hook in and fixes several refcount bugs.