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Commit 22fae97d authored by Paul Durrant's avatar Paul Durrant Committed by David S. Miller
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xen-netback: implement dynamic multicast control 



My recent patch to the Xen Project documents a protocol for 'dynamic
multicast control' in netif.h. This extends the previous multicast control
protocol to not require a shared ring reconnection to turn the feature off.
Instead the backend watches the "request-multicast-control" key in xenstore
and turns the feature off if the key value is written to zero.

This patch adds support for dynamic multicast control in xen-netback.

Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ce30905a

drivers/net/xen-netback/common.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -251,6 +251,7 @@ struct xenvif { 
	unsigned int stalled_queues;

	unsigned int stalled_queues;





	struct xenbus_watch credit_watch;

	struct xenbus_watch credit_watch;

	struct xenbus_watch mcast_ctrl_watch;





	spinlock_t lock;

	spinlock_t lock;

drivers/net/xen-netback/xenbus.c

+81 −8
Original line number Original line Diff line number Diff line
@@ -327,7 +327,7 @@ static int netback_probe(struct xenbus_device *dev, 
			goto abort_transaction;

			goto abort_transaction;

		}

		}





		/* We support multicast-control. */

		/* We support dynamic multicast-control. */

		err = xenbus_printf(xbt, dev->nodename,

		err = xenbus_printf(xbt, dev->nodename,

				    "feature-multicast-control", "%d", 1);

				    "feature-multicast-control", "%d", 1);

		if (err) {

		if (err) {
@@ -335,6 +335,14 @@ static int netback_probe(struct xenbus_device *dev, 
			goto abort_transaction;

			goto abort_transaction;

		}

		}





		err = xenbus_printf(xbt, dev->nodename,

				    "feature-dynamic-multicast-control",

				    "%d", 1);

		if (err) {

			message = "writing feature-dynamic-multicast-control";

			goto abort_transaction;

		}



		err = xenbus_transaction_end(xbt, 0);

		err = xenbus_transaction_end(xbt, 0);

	} while (err == -EAGAIN);

	} while (err == -EAGAIN);
@@ -683,7 +691,8 @@ static void xen_net_rate_changed(struct xenbus_watch *watch, 
	}

	}

}

}





static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)

static int xen_register_credit_watch(struct xenbus_device *dev,

				     struct xenvif *vif)

{

{

	int err = 0;

	int err = 0;

	char *node;

	char *node;
@@ -708,7 +717,7 @@ static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif) 
	return err;

	return err;

}

}





static void xen_unregister_watchers(struct xenvif *vif)

static void xen_unregister_credit_watch(struct xenvif *vif)

{

{

	if (vif->credit_watch.node) {

	if (vif->credit_watch.node) {

		unregister_xenbus_watch(&vif->credit_watch);

		unregister_xenbus_watch(&vif->credit_watch);
@@ -717,6 +726,75 @@ static void xen_unregister_watchers(struct xenvif *vif) 
	}

	}

}

}





static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,

				   const char **vec, unsigned int len)

{

	struct xenvif *vif = container_of(watch, struct xenvif,

					  mcast_ctrl_watch);

	struct xenbus_device *dev = xenvif_to_xenbus_device(vif);

	int val;



	if (xenbus_scanf(XBT_NIL, dev->otherend,

			 "request-multicast-control", "%d", &val) < 0)

		val = 0;

	vif->multicast_control = !!val;

}



static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,

					 struct xenvif *vif)

{

	int err = 0;

	char *node;

	unsigned maxlen = strlen(dev->otherend) +

		sizeof("/request-multicast-control");



	if (vif->mcast_ctrl_watch.node) {

		pr_err_ratelimited("Watch is already registered\n");

		return -EADDRINUSE;

	}



	node = kmalloc(maxlen, GFP_KERNEL);

	if (!node) {

		pr_err("Failed to allocate memory for watch\n");

		return -ENOMEM;

	}

	snprintf(node, maxlen, "%s/request-multicast-control",

		 dev->otherend);

	vif->mcast_ctrl_watch.node = node;

	vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;

	err = register_xenbus_watch(&vif->mcast_ctrl_watch);

	if (err) {

		pr_err("Failed to set watcher %s\n",

		       vif->mcast_ctrl_watch.node);

		kfree(node);

		vif->mcast_ctrl_watch.node = NULL;

		vif->mcast_ctrl_watch.callback = NULL;

	}

	return err;

}



static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)

{

	if (vif->mcast_ctrl_watch.node) {

		unregister_xenbus_watch(&vif->mcast_ctrl_watch);

		kfree(vif->mcast_ctrl_watch.node);

		vif->mcast_ctrl_watch.node = NULL;

	}

}



static void xen_register_watchers(struct xenbus_device *dev,

				  struct xenvif *vif)

{

	xen_register_credit_watch(dev, vif);

	xen_register_mcast_ctrl_watch(dev, vif);

}



static void xen_unregister_watchers(struct xenvif *vif)

{

	xen_unregister_mcast_ctrl_watch(vif);

	xen_unregister_credit_watch(vif);

}



static void unregister_hotplug_status_watch(struct backend_info *be)

static void unregister_hotplug_status_watch(struct backend_info *be)

{

{

	if (be->have_hotplug_status_watch) {

	if (be->have_hotplug_status_watch) {
@@ -1030,11 +1108,6 @@ static int read_xenbus_vif_flags(struct backend_info *be) 
		val = 0;

		val = 0;

	vif->ipv6_csum = !!val;

	vif->ipv6_csum = !!val;





	if (xenbus_scanf(XBT_NIL, dev->otherend, "request-multicast-control",

			 "%d", &val) < 0)

		val = 0;

	vif->multicast_control = !!val;



	return 0;

	return 0;

}

}