1 files changed, 71 insertions, 3 deletions

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index c8beb5504bcc..a2826dbff2f4 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -25,6 +25,7 @@
 
 enum ntsync_type {
 	NTSYNC_TYPE_SEM,
+	NTSYNC_TYPE_MUTEX,
 };
 
 /*
@@ -55,6 +56,10 @@ struct ntsync_obj {
 			__u32 count;
 			__u32 max;
 		} sem;
+		struct {
+			__u32 count;
+			pid_t owner;
+		} mutex;
 	} u;
 
 	/*
@@ -92,6 +97,7 @@ struct ntsync_q_entry {
 
 struct ntsync_q {
 	struct task_struct *task;
+	__u32 owner;
 
 	/*
 	 * Protected via atomic_try_cmpxchg(). Only the thread that wins the
@@ -214,13 +220,17 @@ static void ntsync_unlock_obj(struct ntsync_device *dev, struct ntsync_obj *obj,
 		       ((lockdep_is_held(&(obj)->dev->wait_all_lock) != LOCK_STATE_NOT_HELD) && \
 			(obj)->dev_locked))
 
-static bool is_signaled(struct ntsync_obj *obj)
+static bool is_signaled(struct ntsync_obj *obj, __u32 owner)
 {
 	ntsync_assert_held(obj);
 
 	switch (obj->type) {
 	case NTSYNC_TYPE_SEM:
 		return !!obj->u.sem.count;
+	case NTSYNC_TYPE_MUTEX:
+		if (obj->u.mutex.owner && obj->u.mutex.owner != owner)
+			return false;
+		return obj->u.mutex.count < UINT_MAX;
 	}
 
 	WARN(1, "bad object type %#x\n", obj->type);
@@ -250,7 +260,7 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
 	}
 
 	for (i = 0; i < count; i++) {
-		if (!is_signaled(q->entries[i].obj)) {
+		if (!is_signaled(q->entries[i].obj, q->owner)) {
 			can_wake = false;
 			break;
 		}
@@ -264,6 +274,10 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
 			case NTSYNC_TYPE_SEM:
 				obj->u.sem.count--;
 				break;
+			case NTSYNC_TYPE_MUTEX:
+				obj->u.mutex.count++;
+				obj->u.mutex.owner = q->owner;
+				break;
 			}
 		}
 		wake_up_process(q->task);
@@ -307,6 +321,30 @@ static void try_wake_any_sem(struct ntsync_obj *sem)
 	}
 }
 
+static void try_wake_any_mutex(struct ntsync_obj *mutex)
+{
+	struct ntsync_q_entry *entry;
+
+	ntsync_assert_held(mutex);
+	lockdep_assert(mutex->type == NTSYNC_TYPE_MUTEX);
+
+	list_for_each_entry(entry, &mutex->any_waiters, node) {
+		struct ntsync_q *q = entry->q;
+		int signaled = -1;
+
+		if (mutex->u.mutex.count == UINT_MAX)
+			break;
+		if (mutex->u.mutex.owner && mutex->u.mutex.owner != q->owner)
+			continue;
+
+		if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) {
+			mutex->u.mutex.count++;
+			mutex->u.mutex.owner = q->owner;
+			wake_up_process(q->task);
+		}
+	}
+}
+
 /*
  * Actually change the semaphore state, returning -EOVERFLOW if it is made
  * invalid.
@@ -451,6 +489,30 @@ static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp)
 	return fd;
 }
 
+static int ntsync_create_mutex(struct ntsync_device *dev, void __user *argp)
+{
+	struct ntsync_mutex_args args;
+	struct ntsync_obj *mutex;
+	int fd;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+
+	if (!args.owner != !args.count)
+		return -EINVAL;
+
+	mutex = ntsync_alloc_obj(dev, NTSYNC_TYPE_MUTEX);
+	if (!mutex)
+		return -ENOMEM;
+	mutex->u.mutex.count = args.count;
+	mutex->u.mutex.owner = args.owner;
+	fd = ntsync_obj_get_fd(mutex);
+	if (fd < 0)
+		kfree(mutex);
+
+	return fd;
+}
+
 static struct ntsync_obj *get_obj(struct ntsync_device *dev, int fd)
 {
 	struct file *file = fget(fd);
@@ -520,7 +582,7 @@ static int setup_wait(struct ntsync_device *dev,
 	struct ntsync_q *q;
 	__u32 i, j;
 
-	if (args->pad[0] || args->pad[1] || args->pad[2] || (args->flags & ~NTSYNC_WAIT_REALTIME))
+	if (args->pad[0] || args->pad[1] || (args->flags & ~NTSYNC_WAIT_REALTIME))
 		return -EINVAL;
 
 	if (args->count > NTSYNC_MAX_WAIT_COUNT)
@@ -534,6 +596,7 @@ static int setup_wait(struct ntsync_device *dev,
 	if (!q)
 		return -ENOMEM;
 	q->task = current;
+	q->owner = args->owner;
 	atomic_set(&q->signaled, -1);
 	q->all = all;
 	q->count = count;
@@ -576,6 +639,9 @@ static void try_wake_any_obj(struct ntsync_obj *obj)
 	case NTSYNC_TYPE_SEM:
 		try_wake_any_sem(obj);
 		break;
+	case NTSYNC_TYPE_MUTEX:
+		try_wake_any_mutex(obj);
+		break;
 	}
 }
 
@@ -765,6 +831,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
 	void __user *argp = (void __user *)parm;
 
 	switch (cmd) {
+	case NTSYNC_IOC_CREATE_MUTEX:
+		return ntsync_create_mutex(dev, argp);
 	case NTSYNC_IOC_CREATE_SEM:
 		return ntsync_create_sem(dev, argp);
 	case NTSYNC_IOC_WAIT_ALL: