diff options
Diffstat (limited to 'sys/arch/sgi/include/mutex.h')
| -rw-r--r-- | sys/arch/sgi/include/mutex.h | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/sys/arch/sgi/include/mutex.h b/sys/arch/sgi/include/mutex.h index 490d62b4f5c..1727d60f032 100644 --- a/sys/arch/sgi/include/mutex.h +++ b/sys/arch/sgi/include/mutex.h @@ -1,4 +1,4 @@ -/* $OpenBSD: mutex.h,v 1.6 2009/12/28 06:55:27 syuu Exp $ */ +/* $OpenBSD: mutex.h,v 1.7 2014/02/10 20:30:05 kettenis Exp $ */ /* * Copyright (c) 2004 Artur Grabowski <art@openbsd.org> @@ -35,9 +35,24 @@ struct mutex { void *mtx_owner; }; -void mtx_init(struct mutex *, int); +/* + * To prevent lock ordering problems with the kernel lock, we need to + * make sure we block all interrupts that can grab the kernel lock. + * The simplest way to achieve this is to make sure mutexes always + * raise the interrupt priority level to the highest level that has + * interrupts that grab the kernel lock. + */ +#ifdef MULTIPROCESSOR +#define __MUTEX_IPL(ipl) \ + (((ipl) > IPL_NONE && (ipl) < IPL_TTY) ? IPL_TTY : (ipl)) +#else +#define __MUTEX_IPL(ipl) (ipl) +#endif + +#define MUTEX_INITIALIZER(ipl) { 0, __MUTEX_IPL((ipl)), IPL_NONE } -#define MUTEX_INITIALIZER(ipl) { 0, (ipl), IPL_NONE } +void __mtx_init(struct mutex *, int); +#define mtx_init(mtx, ipl) __mtx_init((mtx), __MUTEX_IPL((ipl))) #ifdef DIAGNOSTIC #define MUTEX_ASSERT_LOCKED(mtx) do { \ |