1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * rtmutex API
  4 */
  5#include <linux/spinlock.h>
  6#include <linux/export.h>
  7
  8#define RT_MUTEX_BUILD_MUTEX
  9#define WW_RT
 10#include "rtmutex.c"
 11
 12int ww_mutex_trylock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
 13{
 14	struct rt_mutex *rtm = &lock->base;
 15
 16	if (!ww_ctx)
 17		return rt_mutex_trylock(rtm);
 18
 19	/*
 20	 * Reset the wounded flag after a kill. No other process can
 21	 * race and wound us here, since they can't have a valid owner
 22	 * pointer if we don't have any locks held.
 23	 */
 24	if (ww_ctx->acquired == 0)
 25		ww_ctx->wounded = 0;
 26
 27	if (__rt_mutex_trylock(&rtm->rtmutex)) {
 28		ww_mutex_set_context_fastpath(lock, ww_ctx);
 29		mutex_acquire_nest(&rtm->dep_map, 0, 1, &ww_ctx->dep_map, _RET_IP_);
 30		return 1;
 31	}
 32
 33	return 0;
 34}
 35EXPORT_SYMBOL(ww_mutex_trylock);
 36
 37static int __sched
 38__ww_rt_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx,
 39		   unsigned int state, unsigned long ip)
 40{
 41	struct lockdep_map __maybe_unused *nest_lock = NULL;
 42	struct rt_mutex *rtm = &lock->base;
 43	int ret;
 44
 45	might_sleep();
 46
 47	if (ww_ctx) {
 48		if (unlikely(ww_ctx == READ_ONCE(lock->ctx)))
 49			return -EALREADY;
 50
 51		/*
 52		 * Reset the wounded flag after a kill. No other process can
 53		 * race and wound us here, since they can't have a valid owner
 54		 * pointer if we don't have any locks held.
 55		 */
 56		if (ww_ctx->acquired == 0)
 57			ww_ctx->wounded = 0;
 58
 59#ifdef CONFIG_DEBUG_LOCK_ALLOC
 60		nest_lock = &ww_ctx->dep_map;
 61#endif
 62	}
 63	mutex_acquire_nest(&rtm->dep_map, 0, 0, nest_lock, ip);
 64
 65	if (likely(rt_mutex_try_acquire(&rtm->rtmutex))) {
 66		if (ww_ctx)
 67			ww_mutex_set_context_fastpath(lock, ww_ctx);
 68		return 0;
 69	}
 70
 71	ret = rt_mutex_slowlock(&rtm->rtmutex, ww_ctx, state);
 72
 73	if (ret)
 74		mutex_release(&rtm->dep_map, ip);
 75	return ret;
 76}
 77
 78int __sched
 79ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 80{
 81	return __ww_rt_mutex_lock(lock, ctx, TASK_UNINTERRUPTIBLE, _RET_IP_);
 82}
 83EXPORT_SYMBOL(ww_mutex_lock);
 84
 85int __sched
 86ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 87{
 88	return __ww_rt_mutex_lock(lock, ctx, TASK_INTERRUPTIBLE, _RET_IP_);
 89}
 90EXPORT_SYMBOL(ww_mutex_lock_interruptible);
 91
 92void __sched ww_mutex_unlock(struct ww_mutex *lock)
 93{
 94	struct rt_mutex *rtm = &lock->base;
 95
 96	__ww_mutex_unlock(lock);
 97
 98	mutex_release(&rtm->dep_map, _RET_IP_);
 99	__rt_mutex_unlock(&rtm->rtmutex);
100}
101EXPORT_SYMBOL(ww_mutex_unlock);