[SCSI] aacraid: expose physical devices

Received from Mark Salyzyn:

I am placing this functionality into an insmod parameter. Normally the physical
components are exported to sg, and are blocked from showing up in sd.

Note that the pass-through I/O path via the driver through the Firmware to the
physical disks is not an optimized path, the card is designed for Hardware
RAID, elevator sorting and caching. This should not be used as a means for
utilizing the aacraid based controllers as a generic scsi/SATA/SAS controller,
performance should suck by a few percentage points, any RAID meta-data on the
drives will confuse the controller about who owns the drives and there is a
high risk of destroying content in both directions. Unreliable and for
experimentation or strange controlled circumstances only.

Signed-off-by: Mark Haverkamp <markh@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/aacraid/aachba.c

@@ -169,6 +169,10 @@ MODULE_PARM_DESC(numacb, "Request a limit to the number of adapter control block
 int acbsize = -1;
 module_param(acbsize, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(acbsize, "Request a specific adapter control block (FIB) size. Valid values are 512, 2048, 4096 and 8192. Default is to use suggestion from Firmware.");
+
+int expose_physicals = 0;
+module_param(expose_physicals, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(expose_physicals, "Expose physical components of the arrays. 0=off, 1=on");
 /**
  *	aac_get_config_status	-	check the adapter configuration
  *	@common: adapter to query
@@ -1535,7 +1539,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
 				return 0;
 			}
 		} else {  /* check for physical non-dasd devices */
-			if(dev->nondasd_support == 1){
+			if ((dev->nondasd_support == 1) || expose_physicals) {
 				if (dev->in_reset)
 					return -1;
 				return aac_send_srb_fib(scsicmd);