[SCSI] libsas: Destroy the task collector thread after releasing ports

If we use task collector mode, we can end up destroying the task collector
thread before we release the ports, which is bad if a port release causes
a disk I/O (such as cache flushing).

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/libsas/sas_init.c

@@ -127,12 +127,13 @@ int sas_register_ha(struct sas_ha_struct *sas_ha)
 
 int sas_unregister_ha(struct sas_ha_struct *sas_ha)
 {
+	sas_unregister_ports(sas_ha);
+
 	if (sas_ha->lldd_max_execute_num > 1) {
 		sas_shutdown_queue(sas_ha);
+		sas_ha->lldd_max_execute_num = 1;
 	}
 
-	sas_unregister_ports(sas_ha);
-
 	return 0;
 }