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Date: Tue, 2 Feb 2016 11:08:37 +0000
From: Wei Liu <wei.liu2@...rix.com>
To: Paul Durrant <paul.durrant@...rix.com>
CC: <netdev@...r.kernel.org>, <xen-devel@...ts.xenproject.org>,
Ian Campbell <ian.campbell@...rix.com>,
Wei Liu <wei.liu2@...rix.com>
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 ...
> + 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.
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