Re: [Xen-devel] [PATCH net-next v3] xen-netback: implement dynamic multicast control

[David Miller]

From: Paul Durrant 
Date: Tue, 2 Feb 2016 11:55:05 +

> 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 
> Cc: Ian Campbell 
> Cc: Wei Liu 

Applied, thanks.

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

Re: [Xen-devel] [PATCH net-next v3] xen-netback: implement dynamic multicast control

[Wei Liu]

On Tue, Feb 02, 2016 at 11:55:05AM +, Paul Durrant wrote:
> 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 
> Cc: Ian Campbell 
> Cc: Wei Liu 

Acked-by: Wei Liu 

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

[Xen-devel] [PATCH net-next v3] xen-netback: implement dynamic multicast control

[Paul Durrant]

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 
Cc: Ian Campbell 
Cc: Wei Liu 
---

v3:
 - Log (rate limited) error when watch is already registered

v2:
 - Log error on failure to allocate memory for multicast watch
---
 drivers/net/xen-netback/common.h |  1 +
 drivers/net/xen-netback/xenbus.c | 89 
 2 files changed, 82 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..39a303d 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(>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", ) < 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(>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