Commit c81d3d24 authored by Jan Beulich's avatar Jan Beulich Committed by Juergen Gross
Browse files

xen-pciback: reconfigure also from backend watch handler 



When multiple PCI devices get assigned to a guest right at boot, libxl
incrementally populates the backend tree. The writes for the first of
the devices trigger the backend watch. In turn xen_pcibk_setup_backend()
will set the XenBus state to Initialised, at which point no further
reconfigures would happen unless a device got hotplugged. Arrange for
reconfigure to also get triggered from the backend watch handler.

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/2337cbd6-94b9-4187-9862-c03ea12e0c61@suse.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 4ba50e7c

drivers/xen/xen-pciback/xenbus.c

+17 −5
Original line number Diff line number Diff line
@@ -359,7 +359,8 @@ static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev, 
	return err;

}



static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)

static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev,

				 enum xenbus_state state)

{

	int err = 0;

	int num_devs;
@@ -373,9 +374,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev) 
	dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");



	mutex_lock(&pdev->dev_lock);

	/* Make sure we only reconfigure once */

	if (xenbus_read_driver_state(pdev->xdev->nodename) !=

	    XenbusStateReconfiguring)

	if (xenbus_read_driver_state(pdev->xdev->nodename) != state)

		goto out;



	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
@@ -500,6 +499,10 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev) 
		}

	}



	if (state != XenbusStateReconfiguring)

		/* Make sure we only reconfigure once. */

		goto out;



	err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);

	if (err) {

		xenbus_dev_fatal(pdev->xdev, err,
@@ -525,7 +528,7 @@ static void xen_pcibk_frontend_changed(struct xenbus_device *xdev, 
		break;



	case XenbusStateReconfiguring:

		xen_pcibk_reconfigure(pdev);

		xen_pcibk_reconfigure(pdev, XenbusStateReconfiguring);

		break;



	case XenbusStateConnected:
@@ -664,6 +667,15 @@ static void xen_pcibk_be_watch(struct xenbus_watch *watch, 
		xen_pcibk_setup_backend(pdev);

		break;



	case XenbusStateInitialised:

		/*

		 * We typically move to Initialised when the first device was

		 * added. Hence subsequent devices getting added may need

		 * reconfiguring.

		 */

		xen_pcibk_reconfigure(pdev, XenbusStateInitialised);

		break;



	default:

		break;

	}