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 
ww_mutex_trylock(struct ww_mutex * lock,struct ww_acquire_ctx * ww_ctx)12 int 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 }
35 EXPORT_SYMBOL(ww_mutex_trylock);
36 
37 static int __sched
__ww_rt_mutex_lock(struct ww_mutex * lock,struct ww_acquire_ctx * ww_ctx,unsigned int state,unsigned long ip)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_cmpxchg_acquire(&rtm->rtmutex, NULL, current))) {
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 
78 int __sched
ww_mutex_lock(struct ww_mutex * lock,struct ww_acquire_ctx * ctx)79 ww_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 }
83 EXPORT_SYMBOL(ww_mutex_lock);
84 
85 int __sched
ww_mutex_lock_interruptible(struct ww_mutex * lock,struct ww_acquire_ctx * ctx)86 ww_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 }
90 EXPORT_SYMBOL(ww_mutex_lock_interruptible);
91 
ww_mutex_unlock(struct ww_mutex * lock)92 void __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 }
101 EXPORT_SYMBOL(ww_mutex_unlock);
102