ntsync: Introduce NTSYNC_IOC_EVENT_SET.

This corresponds to the NT syscall NtSetEvent().

This sets the event to the signaled state, and returns its previous state.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20241213193511.457338-10-zfigura@codeweavers.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/ntsync.c

@@ -534,6 +534,31 @@ static int ntsync_mutex_kill(struct ntsync_obj *mutex, void __user *argp)
 	return ret;
 }
 
+static int ntsync_event_set(struct ntsync_obj *event, void __user *argp)
+{
+	struct ntsync_device *dev = event->dev;
+	__u32 prev_state;
+	bool all;
+
+	if (event->type != NTSYNC_TYPE_EVENT)
+		return -EINVAL;
+
+	all = ntsync_lock_obj(dev, event);
+
+	prev_state = event->u.event.signaled;
+	event->u.event.signaled = true;
+	if (all)
+		try_wake_all_obj(dev, event);
+	try_wake_any_event(event);
+
+	ntsync_unlock_obj(dev, event, all);
+
+	if (put_user(prev_state, (__u32 __user *)argp))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
 	struct ntsync_obj *obj = file->private_data;
@@ -557,6 +582,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
 		return ntsync_mutex_unlock(obj, argp);
 	case NTSYNC_IOC_MUTEX_KILL:
 		return ntsync_mutex_kill(obj, argp);
+	case NTSYNC_IOC_EVENT_SET:
+		return ntsync_event_set(obj, argp);
 	default:
 		return -ENOIOCTLCMD;
 	}

include/uapi/linux/ntsync.h

@@ -48,5 +48,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_SEM_RELEASE		_IOWR('N', 0x81, __u32)
 #define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)
 #define NTSYNC_IOC_MUTEX_KILL		_IOW ('N', 0x86, __u32)
+#define NTSYNC_IOC_EVENT_SET		_IOR ('N', 0x88, __u32)
 
 #endif