• NeilBrown's avatar
    rhashtable: clean up dereference of ->future_tbl. · c0690016
    NeilBrown authored
    Using rht_dereference_bucket() to dereference
    ->future_tbl looks like a type error, and could be confusing.
    Using rht_dereference_rcu() to test a pointer for NULL
    adds an unnecessary barrier - rcu_access_pointer() is preferred
    for NULL tests when no lock is held.
    
    This uses 3 different ways to access ->future_tbl.
    - if we know the mutex is held, use rht_dereference()
    - if we don't hold the mutex, and are only testing for NULL,
      use rcu_access_pointer()
    - otherwise (using RCU protection for true dereference),
      use rht_dereference_rcu().
    
    Note that this includes a simplification of the call to
    rhashtable_last_table() - we don't do an extra dereference
    before the call any more.
    Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: default avatarNeilBrown <neilb@suse.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    c0690016
rhashtable.h 34 KB