Currently, the maximum amount of RAM that scsi_debug can allocate is
4GB. This patch increases it to 2TB; scsi_debug can allocates 2TB
memory and export it as if it were 2TB scsi disk.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Douglas Gilbert <dougg@torque.net> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>