cxl/pci: Delay event buffer allocation

The event buffer does not need to be allocated if something has failed in
setting up event irq's.

In prep for adjusting event configuration for DCD events move the buffer
allocation to the end of the event configuration.

Reviewed-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Reviewed-by: Fan Ni <[email protected]>
Reviewed-by: Li Ming <[email protected]>
Link: https://lore.kernel.org/all/[email protected]/ [1]
Suggested-by: Dan Williams <[email protected]>
Signed-off-by: Ira Weiny <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Dave Jiang <[email protected]>

Author: weiny2

drivers/cxl/pci.c

@@ -764,10 +764,6 @@ static int cxl_event_config(struct pci_host_bridge *host_bridge,
 		return 0;
 	}
 
-	rc = cxl_mem_alloc_event_buf(mds);
-	if (rc)
-		return rc;
-
 	rc = cxl_event_get_int_policy(mds, &policy);
 	if (rc)
 		return rc;
@@ -781,6 +777,10 @@ static int cxl_event_config(struct pci_host_bridge *host_bridge,
 		return -EBUSY;
 	}
 
+	rc = cxl_mem_alloc_event_buf(mds);
+	if (rc)
+		return rc;
+
 	rc = cxl_event_irqsetup(mds);
 	if (rc)
 		return rc;