* [PATCH net-next v1] xen-netback: implement dynamic multicast control
@ 2016-02-01 14:40 Paul Durrant
2016-02-02 11:08 ` Wei Liu
0 siblings, 1 reply; 3+ messages in thread
From: Paul Durrant @ 2016-02-01 14:40 UTC (permalink / raw)
To: netdev, xen-devel; +Cc: Paul Durrant, Ian Campbell, Wei Liu
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@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
---
drivers/net/xen-netback/common.h | 1 +
drivers/net/xen-netback/xenbus.c | 85 ++++++++++++++++++++++++++++++++++++----
2 files changed, 78 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..2f12609 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 +726,71 @@ 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)
+ 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 +1104,6 @@ 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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next v1] xen-netback: implement dynamic multicast control
2016-02-01 14:40 [PATCH net-next v1] xen-netback: implement dynamic multicast control Paul Durrant
@ 2016-02-02 11:08 ` Wei Liu
2016-02-02 11:15 ` Paul Durrant
0 siblings, 1 reply; 3+ messages in thread
From: Wei Liu @ 2016-02-02 11:08 UTC (permalink / raw)
To: Paul Durrant; +Cc: netdev, xen-devel, Ian Campbell, Wei Liu
On Mon, Feb 01, 2016 at 02:40:53PM +0000, Paul Durrant wrote:
[...]
> +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)
> + return -ENOMEM;
This is one error path that has no logging, so please either add logging
in each error patch ...
> + 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);
> +}
... or check if these register/unregister function calls' return value
and log if something fails.
Wei.
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [PATCH net-next v1] xen-netback: implement dynamic multicast control
2016-02-02 11:08 ` Wei Liu
@ 2016-02-02 11:15 ` Paul Durrant
0 siblings, 0 replies; 3+ messages in thread
From: Paul Durrant @ 2016-02-02 11:15 UTC (permalink / raw)
To: Wei Liu
Cc: netdev@vger.kernel.org, xen-devel@lists.xenproject.org,
Ian Campbell, Wei Liu
> -----Original Message-----
> From: Wei Liu [mailto:wei.liu2@citrix.com]
> Sent: 02 February 2016 11:09
> To: Paul Durrant
> Cc: netdev@vger.kernel.org; xen-devel@lists.xenproject.org; Ian Campbell;
> Wei Liu
> Subject: Re: [PATCH net-next v1] xen-netback: implement dynamic multicast
> control
>
> On Mon, Feb 01, 2016 at 02:40:53PM +0000, Paul Durrant wrote:
> [...]
> > +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)
> > + return -ENOMEM;
>
> This is one error path that has no logging, so please either add logging
> in each error patch ...
>
Sure.
> > + 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);
> > +}
>
> ... or check if these register/unregister function calls' return value
> and log if something fails.
>
Given that the similar failure path in credit watch registration never logged adding a check here may create noise where there was none before.
Paul
> Wei.
^ permalink raw reply [flat|nested] 3+ messages in thread
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