net/netfilter/nf_conntrack_core: Fix net_conntrack_lock()

As we want to remove spin_unlock_wait() and replace it with explicit
spin_lock()/spin_unlock() calls, we can use this to simplify the
locking.

In addition:
- Reading nf_conntrack_locks_all needs ACQUIRE memory ordering.
- The new code avoids the backwards loop.

Only slightly tested, I did not manage to trigger calls to
nf_conntrack_all_lock().

V2: With improved comments, to clearly show how the barriers
    pair.

Fixes: b16c29191dc8 ("netfilter: nf_conntrack: use safer way to lock all buckets")
Signed-off-by: Manfred Spraul <[email protected]>
Cc: <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Pablo Neira Ayuso <[email protected]>
Cc: [email protected]
Signed-off-by: Paul E. McKenney <[email protected]>

0 files changed, 0 insertions, 0 deletions