[PATCH] eventfd: add a uapi header for eventfd userspace APIs

[wenyang.linux@foxmail.com]

From: Wen Yang <wenyang.linux@foxmail.com>

Create a uapi header include/uapi/linux/eventfd.h, move the associated
flags to the uapi header, and include it from linux/eventfd.h.

Signed-off-by: Wen Yang <wenyang.linux@foxmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dylan Yudaken <dylany@fb.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Eric Biggers <ebiggers@google.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 include/linux/eventfd.h      | 16 +---------------
 include/uapi/linux/eventfd.h | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 15 deletions(-)
 create mode 100644 include/uapi/linux/eventfd.h

diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index 98d31cdaca40..c8be8fa6795d 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -9,26 +9,12 @@
 #ifndef _LINUX_EVENTFD_H
 #define _LINUX_EVENTFD_H
 
-#include <linux/fcntl.h>
 #include <linux/wait.h>
 #include <linux/err.h>
 #include <linux/percpu-defs.h>
 #include <linux/percpu.h>
 #include <linux/sched.h>
-
-/*
- * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
- * new flags, since they might collide with O_* ones. We want
- * to re-use O_* flags that couldn't possibly have a meaning
- * from eventfd, in order to leave a free define-space for
- * shared O_* flags.
- */
-#define EFD_SEMAPHORE (1 << 0)
-#define EFD_CLOEXEC O_CLOEXEC
-#define EFD_NONBLOCK O_NONBLOCK
-
-#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
-#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
+#include <uapi/linux/eventfd.h>
 
 struct eventfd_ctx;
 struct file;
diff --git a/include/uapi/linux/eventfd.h b/include/uapi/linux/eventfd.h
new file mode 100644
index 000000000000..02e9dcdb8d29
--- /dev/null
+++ b/include/uapi/linux/eventfd.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_EVENTFD_H
+#define _UAPI_LINUX_EVENTFD_H
+
+#include <linux/types.h>
+
+/* For O_CLOEXEC and O_NONBLOCK */
+#include <linux/fcntl.h>
+
+/* For _IO helpers */
+#include <linux/ioctl.h>
+
+/*
+ * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
+ * new flags, since they might collide with O_* ones. We want
+ * to re-use O_* flags that couldn't possibly have a meaning
+ * from eventfd, in order to leave a free define-space for
+ * shared O_* flags.
+ */
+#define EFD_SEMAPHORE (1 << 0)
+#define EFD_CLOEXEC O_CLOEXEC
+#define EFD_NONBLOCK O_NONBLOCK
+
+#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
+#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
+
+#endif /* _UAPI_LINUX_EVENTFD_H */
-- 
2.34.1