Use the IPX PCB list mutex and IPX PCB mutexes to lock down the SPX

portion of IPX/SPX:

- Protect IPX PCB lists with the IPX PCB list mutex, in particular
  when calling PCB and PCB list manipulation routines in ipx_pcb.c.
- Protect both IPX PCB state and SPX PCB state using the IPX PCB
  mutex.
- Generally annotate locking, as well as adding liberal use of lock
  assertions to document locking requirements.
- Where possible, use unlocked reads when reading integer or smaller
  sized socket options on SPX sockets.
- De-spl throughout.

Notes:

- spx_input() expects both the list mutex and PCB mutex to be held
  on entry, but will release both on return.  Because sonewconn() is
  called from spx_input(), it may actually drop one PCB lock and
  acquire another during generation of a new connection, meaning the
  caller is not in a position to unlock the PCB mutex.

MFC after:	3 weeks

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/netipx/ipx_input.c b/sys/netipx/ipx_input.c
index ee1ca23..53d8d9a 100644
--- a/sys/netipx/ipx_input.c
+++ b/sys/netipx/ipx_input.c
@@ -277,8 +277,9 @@ ours:
 		if ((ipxp->ipxp_flags & IPXP_ALL_PACKETS) == 0)
 			switch (ipx->ipx_pt) {
 			case IPXPROTO_SPX:
+				IPX_LOCK(ipxp);
+				/* Will release both locks. */
 				spx_input(m, ipxp);
-				IPX_LIST_UNLOCK();
 				return;
 			}
 		IPX_LOCK(ipxp);