1 files changed, 101 insertions, 0 deletions
diff --git a/kernel/locking/ww_rt_mutex.c b/kernel/locking/ww_rt_mutex.c
new file mode 100644
index 000000000000..d1473c624105
--- /dev/null
+++ b/kernel/locking/ww_rt_mutex.c
@@ -0,0 +1,101 @@
+// 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_cmpxchg_acquire(&rtm->rtmutex, NULL, current))) {
+		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);