Rework socket buffers locking for shared netlock.

Shared netlock is not sufficient to call so{r,w}wakeup(). The following
sowakeup() modifies `sb_flags' and knote(9) stuff. Unfortunately, we
can't call so{r,w}wakeup() with `inp_mtx' mutex(9) because sowakeup()
also calls pgsigio() which grabs kernel lock.

However, `so*_filtops' callbacks only perform read-only access to the
socket stuff, so it is enough to hold shared netlock only, but the klist
stuff needs to be protected.

This diff introduces `sb_mtx' mutex(9) to protect sockbuf. This time
`sb_mtx' used to protect only `sb_flags' and `sb_klist'.

Now we have soassertlocked_readonly() and soassertlocked(). The first
one is happy if only shared netlock is held, meanwhile the second wants
`so_lock' or pru_lock() be held together with shared netlock.

To keep soassertlocked*() assertions soft, we need to know mutex(9)
state, so new mtx_owned() macro was introduces. Also, the new optional
(*pru_locked)() handler brings the state of pru_lock().

Tests and ok from bluhm.

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/netinet/ip_var.h b/sys/netinet/ip_var.h
index 789796633e3..663671d1a26 100644
--- a/sys/netinet/ip_var.h
+++ b/sys/netinet/ip_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_var.h,v 1.110 2023/11/26 22:08:10 bluhm Exp $	*/
+/*	$OpenBSD: ip_var.h,v 1.111 2024/02/03 22:50:09 mvs Exp $	*/
 /*	$NetBSD: ip_var.h,v 1.16 1996/02/13 23:43:20 christos Exp $	*/
 
 /*
@@ -260,6 +260,7 @@ int	 rip_attach(struct socket *, int, int);
 int	 rip_detach(struct socket *);
 void	 rip_lock(struct socket *);
 void	 rip_unlock(struct socket *);
+int	 rip_locked(struct socket *);
 int	 rip_bind(struct socket *, struct mbuf *, struct proc *);
 int	 rip_connect(struct socket *, struct mbuf *);
 int	 rip_disconnect(struct socket *);