rhashtable: Notify on resize to allow signaling interrupted dumps

Netlink dumps have a traditional weakness of being interruptible and non-atomic. Once the message buffer has been filled, all protective locks must be released and the buffer is handed over to the user to copy the data. The dumping then continues from the previously stored offsets in the data structures. Due to dropping of the locks, mutations can occur.

This first series introduces a new notification mechanism which allows users of rhashtable to bump a sequence number on resizes and report an inconsistent dump to user space.

As discussed in the netdev thread ("[PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking").

Thomas Graf (3):
rhashtable: Provide notifier for deferred resizes
netlink: Mark dumps as inconsistent which have been interrupted by a
resize
netlink: Lock out table resizes while dumping Netlink sockets

 include/linux/rhashtable.h | 10 +++++++++-
 lib/rhashtable.c           | 13 ++++++++++---
 net/netlink/af_netlink.c   | 10 ++++++++++
 net/netlink/af_netlink.h   |  1 +
 net/netlink/diag.c         |  4 ++++
 5 files changed, 34 insertions(+), 4 deletions(-)

1.9.3