ieee1394: sbp2: change some module parameters from int to bool

This is upwards compatible, except that integer values other than 0 or 1
are no longer accepted.  But values like "Y", "N", "no", "nnoooh!" work
now.

Also, improve a comment on the serialize_io parameter and make the
ORB_SET_EXCLUSIVE macro ultra-safe.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 3f873cc7..e0c385a 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -118,14 +118,13 @@
 		 "(3 = 800Mb/s, 2 = 400Mb/s, 1 = 200Mb/s, 0 = 100Mb/s)");
 
 /*
- * Set serialize_io to 1 if you'd like only one scsi command sent
- * down to us at a time (debugging). This might be necessary for very
- * badly behaved sbp2 devices.
+ * Set serialize_io to 0 or N to use dynamically appended lists of command ORBs.
+ * This is and always has been buggy in multiple subtle ways. See above TODOs.
  */
 static int sbp2_serialize_io = 1;
-module_param_named(serialize_io, sbp2_serialize_io, int, 0444);
-MODULE_PARM_DESC(serialize_io, "Serialize I/O coming from scsi drivers "
-		 "(default = 1, faster = 0)");
+module_param_named(serialize_io, sbp2_serialize_io, bool, 0444);
+MODULE_PARM_DESC(serialize_io, "Serialize requests coming from SCSI drivers "
+		 "(default = Y, faster but buggy = N)");
 
 /*
  * Bump up max_sectors if you'd like to support very large sized
@@ -154,9 +153,9 @@
  * are possible on OXFW911 and newer Oxsemi bridges.
  */
 static int sbp2_exclusive_login = 1;
-module_param_named(exclusive_login, sbp2_exclusive_login, int, 0644);
+module_param_named(exclusive_login, sbp2_exclusive_login, bool, 0644);
 MODULE_PARM_DESC(exclusive_login, "Exclusive login to sbp2 device "
-		 "(default = 1)");
+		 "(default = Y, use N for concurrent initiators)");
 
 /*
  * If any of the following workarounds is required for your device to work,