[ovs-dev] [PATCH] netdev: Remove netdev from global shash when the user is changing interface configuration.

Ben Pfaff blp at nicira.com
Fri May 16 15:49:17 UTC 2014


Perfect. Thanks!
On May 16, 2014 8:16 AM, "Ryan Wilson 76511" <wryan at vmware.com> wrote:

> In netdev_remove, the netdev is unreffed after being removed from the
> global shash. If the ref count is 0, the netdev is destroyed.
>
> I'll re-submit with a more accurate comment for netdev_remove (it unrefs
> rather than destroys the netdev) and also adding a comment with
> netdev_remove in iface_destroy__ (which Alex recommended).
>
> ----- Original Message -----
> From: "Ben Pfaff" <blp at nicira.com>
> To: "Ryan Wilson" <wryan at nicira.com>
> Cc: dev at openvswitch.org
> Sent: Friday, May 16, 2014 7:52:19 AM
> Subject: Re: [ovs-dev] [PATCH] netdev: Remove netdev from global shash
> when the user is changing interface configuration.
>
> On Thu, May 15, 2014 at 03:01:19AM -0700, Ryan Wilson wrote:
> > When the user changes port type (i.e. changing p0 from type 'internal' to
> > 'gre'), the netdev must first be deleted, then re-created with the new
> type.
> > Deleting the netdev requires there exist no more references to the
> netdev.
> > However, the xlate cache holds references to netdevs and the cache is
> only
> > invalidated by revalidator threads. Thus, if cache is not invalidated
> prior to
> > the netdev being re-created, the netdev will not be able to be
> re-created and
> > the configuration change will fail.
> >
> > This patch always removes the netdev from the global netdev shash when
> the
> > user changes port type. This ensures that the new netdev can always be
> created
> > while handler and revalidator threads can retain references to the old
> netdev
> > until they are finished.
>
> I think that the comment on netdev_remove() is not entirely correct: I
> don't see anything in the function that "destroys 'netdev' if possible."
>
> Acked-by: Ben Pfaff <blp at nicira.com>
>
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