[SCSI] qla2xxx: Disable port-type RSCN handling via driver state-machine.

Given the semantic changes in both the device-model and
fc-transport APIs, the driver's handling of port-type RSCNs
via a series of ADISCs and PLOGIs can cause series of
badness ranging from unexpectedly device loss to devices not
being discovered.

In the interim, disable (via a module-parameter) this
feature and allow RSCN management to continue to occur
within the driver's DPC thread.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/qla2xxx/qla_gbl.h

@@ -62,6 +62,7 @@ extern int qlport_down_retry;
 extern int ql2xplogiabsentdevice;
 extern int ql2xloginretrycount;
 extern int ql2xfdmienable;
+extern int ql2xprocessrscn;
 
 extern void qla2x00_sp_compl(scsi_qla_host_t *, srb_t *);
 

drivers/scsi/qla2xxx/qla_init.c

@@ -2653,7 +2653,8 @@ qla2x00_device_resync(scsi_qla_host_t *ha)
 
 		switch (format) {
 		case 0:
-			if (!IS_QLA2100(ha) && !IS_QLA2200(ha) &&
+			if (ql2xprocessrscn &&
+			    !IS_QLA2100(ha) && !IS_QLA2200(ha) &&
 			    !IS_QLA6312(ha) && !IS_QLA6322(ha) &&
 			    !IS_QLA24XX(ha) && !IS_QLA25XX(ha) &&
 			    ha->flags.init_done) {

drivers/scsi/qla2xxx/qla_isr.c

@@ -519,7 +519,8 @@ qla2x00_async_event(scsi_qla_host_t *ha, uint16_t *mb)
 		 * us, create a new entry in our rscn fcports list and handle
 		 * the event like an RSCN.
 		 */
-		if (!IS_QLA2100(ha) && !IS_QLA2200(ha) && !IS_QLA6312(ha) &&
+		if (ql2xprocessrscn &&
+		    !IS_QLA2100(ha) && !IS_QLA2200(ha) && !IS_QLA6312(ha) &&
 		    !IS_QLA6322(ha) && !IS_QLA24XX(ha) && !IS_QLA25XX(ha) &&
 		    ha->flags.init_done && mb[1] != 0xffff &&
 		    ((ha->operating_mode == P2P && mb[1] != 0) ||

drivers/scsi/qla2xxx/qla_os.c

@@ -71,6 +71,12 @@ MODULE_PARM_DESC(ql2xfdmienable,
 		"Enables FDMI registratons "
 		"Default is 0 - no FDMI. 1 - perfom FDMI.");
 
+int ql2xprocessrscn;
+module_param(ql2xprocessrscn, int, S_IRUGO|S_IRUSR);
+MODULE_PARM_DESC(ql2xprocessrscn,
+		"Option to enable port RSCN handling via a series of less"
+		"fabric intrusive ADISCs and PLOGIs.");
+
 /*
  * SCSI host template entry points
  */