mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-12-28 16:56:26 +00:00
af9f006393
With DEBUG_RT_MUTEXES enabled the fast-path rt_mutex_cmpxchg_acquire() always fails and all lock operations take the slow path. Provide a new helper inline rt_mutex_try_acquire() which maps to rt_mutex_cmpxchg_acquire() in the non-debug case. For the debug case it invokes rt_mutex_slowtrylock() which can acquire a non-contended rtmutex under full debug coverage. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230908162254.999499-3-bigeasy@linutronix.de
102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* rtmutex API
|
|
*/
|
|
#include <linux/spinlock.h>
|
|
#include <linux/export.h>
|
|
|
|
#define RT_MUTEX_BUILD_MUTEX
|
|
#define WW_RT
|
|
#include "rtmutex.c"
|
|
|
|
int ww_mutex_trylock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
|
|
{
|
|
struct rt_mutex *rtm = &lock->base;
|
|
|
|
if (!ww_ctx)
|
|
return rt_mutex_trylock(rtm);
|
|
|
|
/*
|
|
* Reset the wounded flag after a kill. No other process can
|
|
* race and wound us here, since they can't have a valid owner
|
|
* pointer if we don't have any locks held.
|
|
*/
|
|
if (ww_ctx->acquired == 0)
|
|
ww_ctx->wounded = 0;
|
|
|
|
if (__rt_mutex_trylock(&rtm->rtmutex)) {
|
|
ww_mutex_set_context_fastpath(lock, ww_ctx);
|
|
mutex_acquire_nest(&rtm->dep_map, 0, 1, &ww_ctx->dep_map, _RET_IP_);
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(ww_mutex_trylock);
|
|
|
|
static int __sched
|
|
__ww_rt_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx,
|
|
unsigned int state, unsigned long ip)
|
|
{
|
|
struct lockdep_map __maybe_unused *nest_lock = NULL;
|
|
struct rt_mutex *rtm = &lock->base;
|
|
int ret;
|
|
|
|
might_sleep();
|
|
|
|
if (ww_ctx) {
|
|
if (unlikely(ww_ctx == READ_ONCE(lock->ctx)))
|
|
return -EALREADY;
|
|
|
|
/*
|
|
* Reset the wounded flag after a kill. No other process can
|
|
* race and wound us here, since they can't have a valid owner
|
|
* pointer if we don't have any locks held.
|
|
*/
|
|
if (ww_ctx->acquired == 0)
|
|
ww_ctx->wounded = 0;
|
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
nest_lock = &ww_ctx->dep_map;
|
|
#endif
|
|
}
|
|
mutex_acquire_nest(&rtm->dep_map, 0, 0, nest_lock, ip);
|
|
|
|
if (likely(rt_mutex_try_acquire(&rtm->rtmutex))) {
|
|
if (ww_ctx)
|
|
ww_mutex_set_context_fastpath(lock, ww_ctx);
|
|
return 0;
|
|
}
|
|
|
|
ret = rt_mutex_slowlock(&rtm->rtmutex, ww_ctx, state);
|
|
|
|
if (ret)
|
|
mutex_release(&rtm->dep_map, ip);
|
|
return ret;
|
|
}
|
|
|
|
int __sched
|
|
ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
|
|
{
|
|
return __ww_rt_mutex_lock(lock, ctx, TASK_UNINTERRUPTIBLE, _RET_IP_);
|
|
}
|
|
EXPORT_SYMBOL(ww_mutex_lock);
|
|
|
|
int __sched
|
|
ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
|
|
{
|
|
return __ww_rt_mutex_lock(lock, ctx, TASK_INTERRUPTIBLE, _RET_IP_);
|
|
}
|
|
EXPORT_SYMBOL(ww_mutex_lock_interruptible);
|
|
|
|
void __sched ww_mutex_unlock(struct ww_mutex *lock)
|
|
{
|
|
struct rt_mutex *rtm = &lock->base;
|
|
|
|
__ww_mutex_unlock(lock);
|
|
|
|
mutex_release(&rtm->dep_map, _RET_IP_);
|
|
__rt_mutex_unlock(&rtm->rtmutex);
|
|
}
|
|
EXPORT_SYMBOL(ww_mutex_unlock);
|