[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 14:52:19 UTC 2014

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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