[SCSI] qla2xxx: Allow the user the option of disabling iIDMA.

iIDMA support requires the driver issue several additional
fabric-managegment (FM) commands per port discovered during SNS
scanning -- GFPN (Get Fabric Port Name) and GPSC (Get Port Speed
Capabilities). It has been found during testing that some
switches do not respond as *well* as expected to these commands
(silence -- no ACC nor BS_RJT). So, to handle such conditions,
allow the user the ability to indirectly disable the FM commands
by disabling iIDMA with the ql2xiidmaenable module-parameter.

Signed-off-by: Andrew Vasquez <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/qla2xxx/qla_gbl.h

···
 extern int ql2xallocfwdump;
 extern int ql2xextended_error_logging;
 extern int ql2xqfullrampup;
+extern int ql2xiidmaenable;
 
 extern int qla2x00_loop_reset(scsi_qla_host_t *);
 extern void qla2x00_abort_all_cmds(scsi_qla_host_t *, int);

drivers/scsi/qla2xxx/qla_init.c

···
 		} else if (qla2x00_gnn_id(ha, swl) != QLA_SUCCESS) {
 			kfree(swl);
 			swl = NULL;
-		} else if (qla2x00_gfpn_id(ha, swl) == QLA_SUCCESS) {
+		} else if (ql2xiidmaenable &&
+		    qla2x00_gfpn_id(ha, swl) == QLA_SUCCESS) {
 			qla2x00_gpsc(ha, swl);
 		}
 	}

drivers/scsi/qla2xxx/qla_os.c

···
 		"depth for a device after a queue-full condition has been "
 		"detected.  Default is 120 seconds.");
 
+int ql2xiidmaenable=1;
+module_param(ql2xiidmaenable, int, S_IRUGO|S_IRUSR);
+MODULE_PARM_DESC(ql2xiidmaenable,
+		"Enables iIDMA settings "
+		"Default is 1 - perform iIDMA. 0 - no iIDMA.");
+
+
 /*
  * SCSI host template entry points
  */