Add a reference count to struct inpcb, which may be explicitly

incremented using in_pcbref(), and decremented using in_pcbfree()
or inpcbrele().  Protocols using only current in_pcballoc() and
in_pcbfree() calls will see the same semantics, but it is now
possible for TCP to call in_pcbref() and in_pcbrele() to prevent
an inpcb from being freed when both tcbinfo and per-inpcb locks
are released.  This makes it possible to safely transition from
holding only the inpcb lock to both tcbinfo and inpcb lock
without re-looking up a connection in the input path, timer
path, etc.

Notice that in_pcbrele() does not unlock the connection after
decrementing the refcount, if the connection remains, so that
the caller can continue to use it; in_pcbrele() returns a flag
indicating whether or not the inpcb pointer is still valid, and
in_pcbfee() is now a simple wrapper around in_pcbrele().

MFC after:	1 month
Discussed with:	bz, kmacy
Reviewed by:	bz, gnn, kmacy
Tested by:	kmacy

0 files changed, 0 insertions, 0 deletions