[v2,net-next,00/11] af_unix: Remove spin_lock_nested() and convert to lock_cmp_fn.

Message

Kuniyuki Iwashima June 11, 2024, 10:28 p.m. UTC

This series removes spin_lock_nested() in AF_UNIX and instead
defines the locking orders as functions tied to each lock by
lockdep_set_lock_cmp_fn().

When the defined function returns a negative value, lockdep
considers it will not cause deadlock.  (See ->cmp_fn() in
check_deadlock() and check_prev_add().)

When we cannot define the total ordering, we return -1 for
the allowed order and otherwise 0 as undefined. [0]

[0]: https://lore.kernel.org/netdev/thzkgbuwuo3knevpipu4rzsh5qgmwhklihypdgziiruabvh46f@uwdkpcfxgloo/


Kuniyuki Iwashima (11):
  af_unix: Define locking order for unix_table_double_lock().
  af_unix: Define locking order for U_LOCK_SECOND in
    unix_state_double_lock().
  af_unix: Don't retry after unix_state_lock_nested() in
    unix_stream_connect().
  af_unix: Define locking order for U_LOCK_SECOND in
    unix_stream_connect().
  af_unix: Don't acquire unix_state_lock() for sock_i_ino().
  af_unix: Remove U_LOCK_DIAG.
  af_unix: Remove U_LOCK_GC_LISTENER.
  af_unix: Define locking order for U_RECVQ_LOCK_EMBRYO in
    unix_collect_skb().
  af_unix: Set sk_peer_pid/sk_peer_cred locklessly for new socket.
  af_unix: Remove put_pid()/put_cred() in copy_peercred().
  af_unix: Don't use spin_lock_nested() in copy_peercred().

 include/net/af_unix.h |  14 -----
 net/unix/af_unix.c    | 136 +++++++++++++++++++++++++++---------------
 net/unix/diag.c       |  47 ++++-----------
 net/unix/garbage.c    |   8 +--
 4 files changed, 101 insertions(+), 104 deletions(-)