tree cd107aeab2fb6b1e6e1debc868ef8773bb777710
parent e8de56b5e76ab7ed2a4aa3476649fe3fa85de1d7
author Nicholas Bellinger <nab@linux-iscsi.org> 1422249298 -0800
committer Nicholas Bellinger <nab@linux-iscsi.org> 1423076137 -0800

vhost/scsi: Add ANY_LAYOUT support in vhost_scsi_handle_vq

This patch adds ANY_LAYOUT compatible support within the existing
vhost_scsi_handle_vq() ->handle_kick() callback.

It calculates data_direction + exp_data_len for the new tcm_vhost_cmd
descriptor by walking both outgoing + incoming iovecs using iov_iter,
assuming the layout of outgoing request header + T10_PI + Data payload
comes first.

It also uses copy_from_iter() to copy leading virtio-scsi request header
that may or may not include SCSI CDB, that returns a re-calculated iovec
to start of T10_PI or Data SGL memory.

Also, go ahead and drop the legacy pre virtio v1.0 !ANY_LAYOUT logic.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>