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locking/ww_mutex: Implement rt_mutex accessors
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Provide the type defines and the helper inlines for rtmutex based ww_mutexes.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.790760545@linutronix.de
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Peter Zijlstra authored and Ingo Molnar committed Aug 17, 2021
1 parent 653a5b0 commit dc4564f
Showing 1 changed file with 80 additions and 0 deletions.
80 changes: 80 additions & 0 deletions kernel/locking/ww_mutex.h
Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */

#ifndef WW_RT

#define MUTEX mutex
#define MUTEX_WAITER mutex_waiter

@@ -83,6 +85,82 @@ static inline void lockdep_assert_wait_lock_held(struct mutex *lock)
lockdep_assert_held(&lock->wait_lock);
}

#else /* WW_RT */

#define MUTEX rt_mutex
#define MUTEX_WAITER rt_mutex_waiter

static inline struct rt_mutex_waiter *
__ww_waiter_first(struct rt_mutex *lock)
{
struct rb_node *n = rb_first(&lock->rtmutex.waiters.rb_root);
if (!n)
return NULL;
return rb_entry(n, struct rt_mutex_waiter, tree_entry);
}

static inline struct rt_mutex_waiter *
__ww_waiter_next(struct rt_mutex *lock, struct rt_mutex_waiter *w)
{
struct rb_node *n = rb_next(&w->tree_entry);
if (!n)
return NULL;
return rb_entry(n, struct rt_mutex_waiter, tree_entry);
}

static inline struct rt_mutex_waiter *
__ww_waiter_prev(struct rt_mutex *lock, struct rt_mutex_waiter *w)
{
struct rb_node *n = rb_prev(&w->tree_entry);
if (!n)
return NULL;
return rb_entry(n, struct rt_mutex_waiter, tree_entry);
}

static inline struct rt_mutex_waiter *
__ww_waiter_last(struct rt_mutex *lock)
{
struct rb_node *n = rb_last(&lock->rtmutex.waiters.rb_root);
if (!n)
return NULL;
return rb_entry(n, struct rt_mutex_waiter, tree_entry);
}

static inline void
__ww_waiter_add(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, struct rt_mutex_waiter *pos)
{
/* RT unconditionally adds the waiter first and then removes it on error */
}

static inline struct task_struct *
__ww_mutex_owner(struct rt_mutex *lock)
{
return rt_mutex_owner(&lock->rtmutex);
}

static inline bool
__ww_mutex_has_waiters(struct rt_mutex *lock)
{
return rt_mutex_has_waiters(&lock->rtmutex);
}

static inline void lock_wait_lock(struct rt_mutex *lock)
{
raw_spin_lock(&lock->rtmutex.wait_lock);
}

static inline void unlock_wait_lock(struct rt_mutex *lock)
{
raw_spin_unlock(&lock->rtmutex.wait_lock);
}

static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock)
{
lockdep_assert_held(&lock->rtmutex.wait_lock);
}

#endif /* WW_RT */

/*
* Wait-Die:
* The newer transactions are killed when:
@@ -169,7 +247,9 @@ __ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter,

if (waiter->ww_ctx->acquired > 0 &&
__ww_ctx_stamp_after(waiter->ww_ctx, ww_ctx)) {
#ifndef WW_RT
debug_mutex_wake_waiter(lock, waiter);
#endif
wake_up_process(waiter->task);
}

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