ps3rom does:
scsi_for_each_sg(cmd, sgpnt, scsi_sg_count(cmd), k) {
	kaddr = kmap_atomic(sg_page(sgpnt), KM_IRQ0);
We cannot do something like that with the clustering enabled (or we
can use scsi_kmap_atomic_sg).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
        .cmd_per_lun =          1,
        .emulated =             1,              /* only sg driver uses this */
        .max_sectors =          PS3ROM_MAX_SECTORS,
-       .use_clustering =       ENABLE_CLUSTERING,
+       .use_clustering =       DISABLE_CLUSTERING,
        .module =               THIS_MODULE,
 };