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xen-netback: implement dynamic multicast control

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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>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paul Durrant 2016-02-02 11:55:05 +00:00 committed by David S. Miller
parent ce30905aa1
commit 22fae97d86
2 changed files with 82 additions and 8 deletions
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1
drivers/net/xen-netback/common.h
View file

@ -251,6 +251,7 @@ struct xenvif {
unsigned int stalled_queues;
struct xenbus_watch credit_watch;
struct xenbus_watch mcast_ctrl_watch;
spinlock_t lock;

89
drivers/net/xen-netback/xenbus.c
View file

@ -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 +726,75 @@ 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)
{
if (be->have_hotplug_status_watch) {
@ -1030,11 +1108,6 @@ 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;
}