scsiback_release_cmd() must not dereference se_cmd->se_tmr_req
because that memory is freed by target_free_cmd_mem() before
scsiback_release_cmd() is called. Fix this use-after-free by
inlining struct scsiback_tmr into struct vscsibk_pend.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: David Disseldorp <ddiss@suse.de> Cc: xen-devel@lists.xenproject.org Cc: <stable@vger.kernel.org> # 3.18+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>