| Message ID | 1454337653-8517-1-git-send-email-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.
> -----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.
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; }
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(-)