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From: Elizabeth Figura <zfigura@codeweavers.com>
To: Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Shuah Khan <shuah@kernel.org>
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	Arkadiusz Hiler <ahiler@codeweavers.com>,
	Peter Zijlstra <peterz@infradead.org>,
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	Randy Dunlap <rdunlap@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Will Deacon <will@kernel.org>,
	Waiman Long <longman@redhat.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Elizabeth Figura <zfigura@codeweavers.com>
Subject: [PATCH v4 08/27] ntsync: Introduce NTSYNC_IOC_EVENT_RESET.
Date: Mon, 15 Apr 2024 20:08:18 -0500
Message-ID: <20240416010837.333694-9-zfigura@codeweavers.com>
In-Reply-To: <20240416010837.333694-1-zfigura@codeweavers.com>
References: <20240416010837.333694-1-zfigura@codeweavers.com>
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This corresponds to the NT syscall NtResetEvent().

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

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
---
 drivers/misc/ntsync.c       | 22 ++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 69f359241cf6..ae78425c87d1 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -508,6 +508,26 @@ static int ntsync_event_set(struct ntsync_obj *event, void __user *argp)
 	return 0;
 }
 
+static int ntsync_event_reset(struct ntsync_obj *event, void __user *argp)
+{
+	__u32 prev_state;
+
+	if (event->type != NTSYNC_TYPE_EVENT)
+		return -EINVAL;
+
+	spin_lock(&event->lock);
+
+	prev_state = event->u.event.signaled;
+	event->u.event.signaled = false;
+
+	spin_unlock(&event->lock);
+
+	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;
@@ -533,6 +553,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
 		return ntsync_mutex_kill(obj, argp);
 	case NTSYNC_IOC_EVENT_SET:
 		return ntsync_event_set(obj, argp);
+	case NTSYNC_IOC_EVENT_RESET:
+		return ntsync_event_reset(obj, argp);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 65329d15a472..657542107328 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -53,5 +53,6 @@ struct ntsync_wait_args {
 #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)
+#define NTSYNC_IOC_EVENT_RESET		_IOR ('N', 0x89, __u32)
 
 #endif
-- 
2.43.0