[SCSI] libsas: async ata scanning

libsas ata error handling is already async but this does not help the
scan case.  Move initial link recovery out from under host->scan_mutex,
and delay synchronization with eh until after all port probe/recovery
work has been queued.

Device ordering is maintained with scan order by still calling
sas_rphy_add() in order of domain discovery.

Since we now scan the domain list when invoking libata-eh we need to be
careful to check for fully initialized ata ports.

Acked-by: Jack Wang <jack_wang@usish.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 508a60b..1ee00c8 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3838,6 +3838,19 @@
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_stop);
 
+int ata_sas_async_port_init(struct ata_port *ap)
+{
+	int rc = ap->ops->port_start(ap);
+
+	if (!rc) {
+		ap->print_id = ata_print_id++;
+		__ata_port_probe(ap);
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ata_sas_async_port_init);
+
 /**
  *	ata_sas_port_init - Initialize a SATA device
  *	@ap: SATA port to initialize