Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / include / linux / eventpoll.h

diff --git a/kernel/include/linux/eventpoll.h b/kernel/include/linux/eventpoll.h
new file mode 100644 (file)
index 0000000..6daf6d4
--- /dev/null
+++ b/kernel/include/linux/eventpoll.h
@@ -0,0 +1,71 @@
+/*
+ *  include/linux/eventpoll.h ( Efficient event polling implementation )
+ *  Copyright (C) 2001,...,2006         Davide Libenzi
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+#ifndef _LINUX_EVENTPOLL_H
+#define _LINUX_EVENTPOLL_H
+
+#include <uapi/linux/eventpoll.h>
+
+
+/* Forward declarations to avoid compiler errors */
+struct file;
+
+
+#ifdef CONFIG_EPOLL
+
+/* Used to initialize the epoll bits inside the "struct file" */
+static inline void eventpoll_init_file(struct file *file)
+{
+       INIT_LIST_HEAD(&file->f_ep_links);
+       INIT_LIST_HEAD(&file->f_tfile_llink);
+}
+
+
+/* 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(list_empty(&file->f_ep_links)))
+               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);
+}
+
+#else
+
+static inline void eventpoll_init_file(struct file *file) {}
+static inline void eventpoll_release(struct file *file) {}
+
+#endif
+
+#endif /* #ifndef _LINUX_EVENTPOLL_H */