net/virtio: avoid unneeded link interrupt configuration

[ upstream commit 5be2325 ]

There is no reason to re-register a interrupt handler for LSC if this
feature was not requested in the first place.
A simple use case is when asking for Rx interrupts without LSC interrupt.

Fixes: 26b683b ("net/virtio: setup Rx queue interrupts")

Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

drivers/net/virtio/virtio_ethdev.c

@@ -1643,13 +1643,15 @@ virtio_configure_intr(struct rte_eth_dev *dev)
 		}
 	}
 
-	/* Re-register callback to update max_intr */
-	rte_intr_callback_unregister(dev->intr_handle,
-				     virtio_interrupt_handler,
-				     dev);
-	rte_intr_callback_register(dev->intr_handle,
-				   virtio_interrupt_handler,
-				   dev);
+	if (dev->data->dev_flags & RTE_ETH_DEV_INTR_LSC) {
+		/* Re-register callback to update max_intr */
+		rte_intr_callback_unregister(dev->intr_handle,
+					     virtio_interrupt_handler,
+					     dev);
+		rte_intr_callback_register(dev->intr_handle,
+					   virtio_interrupt_handler,
+					   dev);
+	}
 
 	/* DO NOT try to remove this! This function will enable msix, or QEMU
 	 * will encounter SIGSEGV when DRIVER_OK is sent.