macvtap: Fix the minor device number allocation

On systems that create and delete lots of dynamic devices the
31bit linux ifindex fails to fit in the 16bit macvtap minor,
resulting in unusable macvtap devices.  I have systems running
automated tests that that hit this condition in just a few days.

Use a linux idr allocator to track which mavtap minor numbers
are available and and to track the association between macvtap
minor numbers and macvtap network devices.

Remove the unnecessary unneccessary check to see if the network
device we have found is indeed a macvtap device.  With macvtap
specific data structures it is impossible to find any other
kind of networking device.

Increase the macvtap minor range from 65536 to the full 20 bits
that is supported by linux device numbers.  It doesn't solve the
original problem but there is no penalty for a larger minor
device range.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman 2011-10-20 04:29:24 +00:00 committed by David S. Miller
parent 9bf1907f42
commit e09eff7fc1
2 changed files with 72 additions and 16 deletions

View file

@ -64,6 +64,7 @@ struct macvlan_dev {
int (*forward)(struct net_device *dev, struct sk_buff *skb);
struct macvtap_queue *taps[MAX_MACVTAP_QUEUES];
int numvtaps;
int minor;
};
static inline void macvlan_count_rx(const struct macvlan_dev *vlan,