1 files changed, 89 insertions, 0 deletions
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
new file mode 100644
index 000000000..3337745d8
--- /dev/null
+++ b/include/linux/eventpoll.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  include/linux/eventpoll.h ( Efficient event polling implementation )
+ *  Copyright (C) 2001,...,2006	 Davide Libenzi
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ */
+#ifndef _LINUX_EVENTPOLL_H
+#define _LINUX_EVENTPOLL_H
+
+#include <uapi/linux/eventpoll.h>
+#include <uapi/linux/kcmp.h>
+
+
+/* Forward declarations to avoid compiler errors */
+struct file;
+
+
+#ifdef CONFIG_EPOLL
+
+#ifdef CONFIG_KCMP
+struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
+#endif
+
+/* Used to release the epoll bits inside the "struct file" */
+void eventpoll_release_file(struct file *file);
+
+/*
+ * This is called from inside fs/file_table.c:__fput() to unlink files
+ * from the eventpoll interface. We need to have this facility to cleanup
+ * correctly files that are closed without being removed from the eventpoll
+ * interface.
+ */
+static inline void eventpoll_release(struct file *file)
+{
+
+	/*
+	 * Fast check to avoid the get/release of the semaphore. Since
+	 * we're doing this outside the semaphore lock, it might return
+	 * false negatives, but we don't care. It'll help in 99.99% of cases
+	 * to avoid the semaphore lock. False positives simply cannot happen
+	 * because the file in on the way to be removed and nobody ( but
+	 * eventpoll ) has still a reference to this file.
+	 */
+	if (likely(!file->f_ep))
+		return;
+
+	/*
+	 * The file is being closed while it is still linked to an epoll
+	 * descriptor. We need to handle this by correctly unlinking it
+	 * from its containers.
+	 */
+	eventpoll_release_file(file);
+}
+
+int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
+		 bool nonblock);
+
+/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */
+static inline int ep_op_has_event(int op)
+{
+	return op != EPOLL_CTL_DEL;
+}
+
+#else
+
+static inline void eventpoll_release(struct file *file) {}
+
+#endif
+
+#if defined(CONFIG_ARM) && defined(CONFIG_OABI_COMPAT)
+/* ARM OABI has an incompatible struct layout and needs a special handler */
+extern struct epoll_event __user *
+epoll_put_uevent(__poll_t revents, __u64 data,
+		 struct epoll_event __user *uevent);
+#else
+static inline struct epoll_event __user *
+epoll_put_uevent(__poll_t revents, __u64 data,
+		 struct epoll_event __user *uevent)
+{
+	if (__put_user(revents, &uevent->events) ||
+	    __put_user(data, &uevent->data))
+		return NULL;
+
+	return uevent+1;
+}
+#endif
+
+#endif /* #ifndef _LINUX_EVENTPOLL_H */