[patch V3 47/64] locking/ww_mutex: Implement rt_mutex accessors

Thomas Gleixner
2021-08-05T15:44:57Z

From: Peter Zijlstra <peterz@infradead.org>

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>

---
kernel/locking/ww_mutex.h | 80 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 80 insertions(+)
---
--- a/kernel/locking/ww_mutex.h
+++ b/kernel/locking/ww_mutex.h
@@ -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_l
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 @@ static bool

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);
}