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Date: Tue, 2 Feb 2016 11:31:08 +0000
From: Paul Durrant <paul.durrant@...rix.com>
To: <netdev@...r.kernel.org>, <xen-devel@...ts.xenproject.org>
CC: Paul Durrant <paul.durrant@...rix.com>,
Ian Campbell <ian.campbell@...rix.com>,
Wei Liu <wei.liu2@...rix.com>
Subject: [PATCH net-next v2] 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: Paul Durrant <paul.durrant@...rix.com>
Cc: Ian Campbell <ian.campbell@...rix.com>
Cc: Wei Liu <wei.liu2@...rix.com>
---
v2:
- Log error on failure to allocate memory for multicast watch
---
drivers/net/xen-netback/common.h | 1 +
drivers/net/xen-netback/xenbus.c | 87 ++++++++++++++++++++++++++++++++++++----
2 files changed, 80 insertions(+), 8 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 0333ab0..1128252 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -251,6 +251,7 @@ struct xenvif {
unsigned int stalled_queues;
struct xenbus_watch credit_watch;
+ struct xenbus_watch mcast_ctrl_watch;
spinlock_t lock;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 56ebd82..f8345ca 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -327,7 +327,7 @@ static int netback_probe(struct xenbus_device *dev,
goto abort_transaction;
}
- /* We support multicast-control. */
+ /* We support dynamic multicast-control. */
err = xenbus_printf(xbt, dev->nodename,
"feature-multicast-control", "%d", 1);
if (err) {
@@ -335,6 +335,14 @@ static int netback_probe(struct xenbus_device *dev,
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);
} 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;
char *node;
@@ -708,7 +717,7 @@ static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
return err;
}
-static void xen_unregister_watchers(struct xenvif *vif)
+static void xen_unregister_credit_watch(struct xenvif *vif)
{
if (vif->credit_watch.node) {
unregister_xenbus_watch(&vif->credit_watch);
@@ -717,6 +726,73 @@ 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)
+ 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)
{
if (be->have_hotplug_status_watch) {
@@ -1030,11 +1106,6 @@ static int read_xenbus_vif_flags(struct backend_info *be)
val = 0;
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;
}
--
2.1.4
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