Push the KERNEL_LOCK() insidge pgsigio() and selwakeup().

The 3 subsystems: signal, poll/select and kqueue can now be addressed
separatly.

Note that bpf(4) and audio(4) currently delay the wakeups to a separate
context in order to respect the KERNEL_LOCK() requirement.  Sockets (UDP,
TCP) and pipes spin to grab the lock for the sames reasons.

ok anton@, visa@

5 files changed, 25 insertions, 17 deletions

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 1e781ac7018..bc4d54495b4 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sig.c,v 1.245 2020/02/01 15:52:34 anton Exp $	*/
+/*	$OpenBSD: kern_sig.c,v 1.246 2020/02/14 14:32:44 mpi Exp $	*/
 /*	$NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $	*/
 
 /*
@@ -740,6 +740,7 @@ pgsigio(struct sigio_ref *sir, int sig, int checkctty)
 	if (sir->sir_sigio == NULL)
 		return;
 
+	KERNEL_LOCK();
 	mtx_enter(&sigio_lock);
 	sigio = sir->sir_sigio;
 	if (sigio == NULL)
@@ -756,6 +757,7 @@ pgsigio(struct sigio_ref *sir, int sig, int checkctty)
 	}
 out:
 	mtx_leave(&sigio_lock);
+	KERNEL_UNLOCK();
 }
 
 /*
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 7a5a1a18749..eb021208d0f 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_generic.c,v 1.129 2020/02/01 08:57:27 anton Exp $	*/
+/*	$OpenBSD: sys_generic.c,v 1.130 2020/02/14 14:32:44 mpi Exp $	*/
 /*	$NetBSD: sys_generic.c,v 1.24 1996/03/29 00:25:32 cgd Exp $	*/
 
 /*
@@ -73,6 +73,7 @@ int dopselect(struct proc *, int, fd_set *, fd_set *, fd_set *,
     struct timespec *, const sigset_t *, register_t *);
 int doppoll(struct proc *, struct pollfd *, u_int, struct timespec *,
     const sigset_t *, register_t *);
+void doselwakeup(struct selinfo *);
 
 int
 iovec_copyin(const struct iovec *uiov, struct iovec **iovp, struct iovec *aiov,
@@ -750,6 +751,8 @@ selrecord(struct proc *selector, struct selinfo *sip)
 	struct proc *p;
 	pid_t mytid;
 
+	KERNEL_ASSERT_LOCKED();
+
 	mytid = selector->p_tid;
 	if (sip->si_seltid == mytid)
 		return;
@@ -766,9 +769,19 @@ selrecord(struct proc *selector, struct selinfo *sip)
 void
 selwakeup(struct selinfo *sip)
 {
+	KERNEL_LOCK();
+	KNOTE(&sip->si_note, NOTE_SUBMIT);
+	doselwakeup(sip);
+	KERNEL_UNLOCK();
+}
+
+void
+doselwakeup(struct selinfo *sip)
+{
 	struct proc *p;
 
-	KNOTE(&sip->si_note, NOTE_SUBMIT);
+	KERNEL_ASSERT_LOCKED();
+
 	if (sip->si_seltid == 0)
 		return;
 	if (sip->si_flags & SI_COLL) {
diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c
index d266a201d3d..ddc41bed9b6 100644
--- a/sys/kern/sys_pipe.c
+++ b/sys/kern/sys_pipe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_pipe.c,v 1.115 2020/02/01 15:52:34 anton Exp $	*/
+/*	$OpenBSD: sys_pipe.c,v 1.116 2020/02/14 14:32:44 mpi Exp $	*/
 
 /*
  * Copyright (c) 1996 John S. Dyson
@@ -372,20 +372,17 @@ pipeselwakeup(struct pipe *cpipe)
 {
 	rw_assert_wrlock(cpipe->pipe_lock);
 
-	KERNEL_LOCK();
-
-	/* Kernel lock needed in order to prevent race with kevent. */
 	if (cpipe->pipe_state & PIPE_SEL) {
 		cpipe->pipe_state &= ~PIPE_SEL;
 		selwakeup(&cpipe->pipe_sel);
-	} else
+	} else {
+		KERNEL_LOCK();
 		KNOTE(&cpipe->pipe_sel.si_note, NOTE_SUBMIT);
+		KERNEL_UNLOCK();
+	}
 
-	/* Kernel lock needed since pgsigio() calls ptsignal(). */
 	if (cpipe->pipe_state & PIPE_ASYNC)
 		pgsigio(&cpipe->pipe_sigio, SIGIO, 0);
-
-	KERNEL_UNLOCK();
 }
 
 int
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 7d497af7426..c14924082a1 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket.c,v 1.239 2020/01/15 13:17:35 mpi Exp $	*/
+/*	$OpenBSD: uipc_socket.c,v 1.240 2020/02/14 14:32:44 mpi Exp $	*/
 /*	$NetBSD: uipc_socket.c,v 1.21 1996/02/04 02:17:52 christos Exp $	*/
 
 /*
@@ -1988,10 +1988,8 @@ sogetopt(struct socket *so, int level, int optname, struct mbuf *m)
 void
 sohasoutofband(struct socket *so)
 {
-	KERNEL_LOCK();
 	pgsigio(&so->so_sigio, SIGURG, 0);
 	selwakeup(&so->so_rcv.sb_sel);
-	KERNEL_UNLOCK();
 }
 
 int
diff --git a/sys/kern/uipc_socket2.c b/sys/kern/uipc_socket2.c
index 9c2492f39a5..f1ef9593c4c 100644
--- a/sys/kern/uipc_socket2.c
+++ b/sys/kern/uipc_socket2.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket2.c,v 1.102 2020/01/15 13:17:35 mpi Exp $	*/
+/*	$OpenBSD: uipc_socket2.c,v 1.103 2020/02/14 14:32:44 mpi Exp $	*/
 /*	$NetBSD: uipc_socket2.c,v 1.11 1996/02/04 02:17:55 christos Exp $	*/
 
 /*
@@ -408,11 +408,9 @@ sowakeup(struct socket *so, struct sockbuf *sb)
 		sb->sb_flags &= ~SB_WAIT;
 		wakeup(&sb->sb_cc);
 	}
-	KERNEL_LOCK();
 	if (so->so_state & SS_ASYNC)
 		pgsigio(&so->so_sigio, SIGIO, 0);
 	selwakeup(&sb->sb_sel);
-	KERNEL_UNLOCK();
 }
 
 /*