The KM_BIO_SRC_IRQ kmap slot must be taken with local irqs disabled.  Add a
check into scsi for this.

Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>