Fix the recent panics/LORs/hangs created by my kqueue commit by:

- Introducing the possibility of using locks different than mutexes
for the knlist locking. In order to do this, we add three arguments to
knlist_init() to specify the functions to use to lock, unlock and
check if the lock is owned. If these arguments are NULL, we assume
mtx_lock, mtx_unlock and mtx_owned, respectively.

- Using the vnode lock for the knlist locking, when doing kqueue operations
on a vnode. This way, we don't have to lock the vnode while holding a
mutex, in filt_vfsread.

Reviewed by:	jmg
Approved by:	re (scottl), scottl (mentor override)
Pointyhat to:	ssouhlal
Will be happy:	everyone

1 files changed, 4 insertions, 2 deletions

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 7ffc1c4..c776c0c 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -211,8 +211,10 @@ socreate(dom, aso, type, proto, cred, td)
 #ifdef MAC
 	mac_create_socket(cred, so);
 #endif
-	knlist_init(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv));
-	knlist_init(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd));
+	knlist_init(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv),
+	    NULL, NULL, NULL);
+	knlist_init(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd),
+	    NULL, NULL, NULL);
 	so->so_count = 1;
 	error = (*prp->pr_usrreqs->pru_attach)(so, proto, td);
 	if (error) {