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>

drivers/ieee1394/sbp2.c

@@ -118,14 +118,13 @@ MODULE_PARM_DESC(max_speed, "Force max speed "
 		 "(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 @@ MODULE_PARM_DESC(max_sectors, "Change max sectors per I/O supported "
  * 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,

drivers/ieee1394/sbp2.h

@@ -67,7 +67,7 @@ struct sbp2_command_orb {
 #define ORB_SET_LUN(v)			((v) & 0xffff)
 #define ORB_SET_FUNCTION(v)		(((v) & 0xf) << 16)
 #define ORB_SET_RECONNECT(v)		(((v) & 0xf) << 20)
-#define ORB_SET_EXCLUSIVE(v)		(((v) & 0x1) << 28)
+#define ORB_SET_EXCLUSIVE(v)		((v) ? 1 << 28 : 0)
 #define ORB_SET_LOGIN_RESP_LENGTH(v)	((v) & 0xffff)
 #define ORB_SET_PASSWD_LENGTH(v)	(((v) & 0xffff) << 16)