we want to defer work traditionally (in openbsd) handled in an

interrupt context to a taskq running in a thread. however, there
is a concern that if we do that then we allow accidental use of
sleeping APIs in this work, which will make it harder to move the
work back to interrupts in the future.

guenther and kettenis came up with the idea of marking a proc with
CANTSLEEP which the sleep paths can check and panic on.

this builds on that so you create taskqs that run with CANTSLEEP
set except when they need to sleep for more tasks to run.

the taskq_create api is changed to take a flags argument so users
can specify CANTSLEEP. MPSAFE is also passed via this flags field
now.  this means archs that defined IPL_MPSAFE to 0 can now create
mpsafe taskqs too.

lots of discussion at s2k15
ok guenther@ miod@ mpi@ tedu@ pelikan@

1 files changed, 3 insertions, 1 deletions

diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index fbf768457d5..9f8eff7e5f8 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_synch.c,v 1.116 2014/07/08 17:19:25 deraadt Exp $	*/
+/*	$OpenBSD: kern_synch.c,v 1.117 2015/02/09 03:15:41 dlg Exp $	*/
 /*	$NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $	*/
 
 /*
@@ -191,6 +191,8 @@ sleep_setup(struct sleep_state *sls, const volatile void *ident, int prio,
 	struct proc *p = curproc;
 
 #ifdef DIAGNOSTIC
+	if (p->p_flag & P_CANTSLEEP)
+		panic("sleep: %s failed insomnia", p->p_comm);
 	if (ident == NULL)
 		panic("tsleep: no ident");
 	if (p->p_stat != SONPROC)