Ted's recent random.c update broke the periodic rekeying:
schedule_work() doesn't provide synchronization. Additionally the first
syn values after boot are generated with secret 0 - not good.

Attached is a big cleanup. Linus asked me to send to to you for merging:

The tcp sequence number generator needs a random seed that is reset every
few minutes. Since the sequence numbers should be constantly increasing,
for each rekey 2^24 is added to the sequence number.
The actual use of the sequence number generator is lockless,
synchronization is achieved by having two copies of the control structure.

The attached patch:
- fixes a race in rekey_seq_generator(): schedule_work doesn't
   provide synchronization.
- Uses schedule_delayed_work() for the rekey: simplifies synchronization
   and speeds up the hot path.
- Adds a late_initcall for the first initialization after boot.
   init_call would be too early, I've checked that the late_initcall runs
   before net/ipv4/ipconfig.c, i.e. the BOOTP/DHCP autoconfiguration.
Signed-Off-By: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: David S. Miller <davem@davemloft.net>