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