eventfd: add a uapi header for eventfd userspace APIs
Commit Message
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
Comments
On Mon, Jun 12, 2023 at 02:59:20AM +0800, wenyang.linux@foxmail.com wrote:
> 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
> ---
I think the change overall makes sense but see below.
> 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>
Why would you want to include that?
> +
> +/*
> + * 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.
> + */
I would leave that comment together with EFD_SHARED_FCNTL_FLAGS and
EFD_FLAGS_SET in the kernel only header.
> +#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)
I think that doesn't belong into the uapi header and should be left in
the kernel header.
> +
> +#endif /* _UAPI_LINUX_EVENTFD_H */
> --
> 2.34.1
>
@@ -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;
new file mode 100644
@@ -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 */