Linux 6.7-rc7
[linux-modified.git] / kernel / locking / ww_rt_mutex.c
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
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
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
78 int __sched
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
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
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);