[v5,1/5] include: linux: Add stddef.h
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Message ID 20251007-v4l2-params-v5-1-8db451a81398@ideasonboard.com
State Superseded
Headers show
Series
  • ipa: libipa: Introduce V4L2Params
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Commit Message

Jacopo Mondi Oct. 7, 2025, 6:17 p.m. UTC
Import stddef.h from the Linux kernel sources v6.17 at revision
3407caa69a06 ("uapi: stddef.h: Introduce __kernel_nonstring")

The stddef.h header is imported to provide the __counted_by() symbol
which is not available in the header version shipped with, in example,
Debian 12.  __counted_by() will be used by the v4l2-isp.h header which
will be imported next.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
 include/linux/stddef.h         | 75 ++++++++++++++++++++++++++++++++++++++++++
 utils/update-kernel-headers.sh |  1 +
 2 files changed, 76 insertions(+)

Comments

Laurent Pinchart Oct. 8, 2025, 8:14 a.m. UTC | #1
Hi Jacopo,

Thank you for the patch.

On Tue, Oct 07, 2025 at 08:17:43PM +0200, Jacopo Mondi wrote:
> Import stddef.h from the Linux kernel sources v6.17 at revision
> 3407caa69a06 ("uapi: stddef.h: Introduce __kernel_nonstring")
> 
> The stddef.h header is imported to provide the __counted_by() symbol
> which is not available in the header version shipped with, in example,
> Debian 12.  __counted_by() will be used by the v4l2-isp.h header which
> will be imported next.

I'm happy this worked, it should be easier to maintain.

> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

> ---
>  include/linux/stddef.h         | 75 ++++++++++++++++++++++++++++++++++++++++++
>  utils/update-kernel-headers.sh |  1 +
>  2 files changed, 76 insertions(+)
> 
> diff --git a/include/linux/stddef.h b/include/linux/stddef.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..e1fcfcf3b33261939797d79f4e29a28fa1da6e10
> --- /dev/null
> +++ b/include/linux/stddef.h
> @@ -0,0 +1,75 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _LINUX_STDDEF_H
> +#define _LINUX_STDDEF_H
> +
> +
> +
> +#ifndef __always_inline
> +#define __always_inline __inline__
> +#endif
> +
> +/* Not all C++ standards support type declarations inside an anonymous union */
> +#ifndef __cplusplus
> +#define __struct_group_tag(TAG)		TAG
> +#else
> +#define __struct_group_tag(TAG)
> +#endif
> +
> +/**
> + * __struct_group() - Create a mirrored named and anonyomous struct
> + *
> + * @TAG: The tag name for the named sub-struct (usually empty)
> + * @NAME: The identifier name of the mirrored sub-struct
> + * @ATTRS: Any struct attributes (usually empty)
> + * @MEMBERS: The member declarations for the mirrored structs
> + *
> + * Used to create an anonymous union of two structs with identical layout
> + * and size: one anonymous and one named. The former's members can be used
> + * normally without sub-struct naming, and the latter can be used to
> + * reason about the start, end, and size of the group of struct members.
> + * The named struct can also be explicitly tagged for layer reuse (C only),
> + * as well as both having struct attributes appended.
> + */
> +#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
> +	union { \
> +		struct { MEMBERS } ATTRS; \
> +		struct __struct_group_tag(TAG) { MEMBERS } ATTRS NAME; \
> +	} ATTRS
> +
> +#ifdef __cplusplus
> +/* sizeof(struct{}) is 1 in C++, not 0, can't use C version of the macro. */
> +#define __DECLARE_FLEX_ARRAY(T, member)	\
> +	T member[0]
> +#else
> +/**
> + * __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union
> + *
> + * @TYPE: The type of each flexible array element
> + * @NAME: The name of the flexible array member
> + *
> + * In order to have a flexible array member in a union or alone in a
> + * struct, it needs to be wrapped in an anonymous struct with at least 1
> + * named member, but that member can be empty.
> + */
> +#define __DECLARE_FLEX_ARRAY(TYPE, NAME)	\
> +	struct { \
> +		struct { } __empty_ ## NAME; \
> +		TYPE NAME[]; \
> +	}
> +#endif
> +
> +#ifndef __counted_by
> +#define __counted_by(m)
> +#endif
> +
> +#ifndef __counted_by_le
> +#define __counted_by_le(m)
> +#endif
> +
> +#ifndef __counted_by_be
> +#define __counted_by_be(m)
> +#endif
> +
> +#define __kernel_nonstring
> +
> +#endif /* _LINUX_STDDEF_H */
> diff --git a/utils/update-kernel-headers.sh b/utils/update-kernel-headers.sh
> index 9a64dfb5698c67945ab4eee085360c1728589401..666624f9972ea61067e5b5695237ab7a17c61664 100755
> --- a/utils/update-kernel-headers.sh
> +++ b/utils/update-kernel-headers.sh
> @@ -52,6 +52,7 @@ headers="
>  	linux/media-bus-format.h
>  	linux/media.h
>  	linux/rkisp1-config.h
> +	linux/stddef.h
>  	linux/udmabuf.h
>  	linux/v4l2-common.h
>  	linux/v4l2-controls.h
Kieran Bingham Oct. 8, 2025, 10:14 a.m. UTC | #2
Quoting Jacopo Mondi (2025-10-07 19:17:43)
> Import stddef.h from the Linux kernel sources v6.17 at revision
> 3407caa69a06 ("uapi: stddef.h: Introduce __kernel_nonstring")
> 
> The stddef.h header is imported to provide the __counted_by() symbol
> which is not available in the header version shipped with, in example,
> Debian 12.  __counted_by() will be used by the v4l2-isp.h header which
> will be imported next.
> 
> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Not reviewing kernel code:

Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

> ---
>  include/linux/stddef.h         | 75 ++++++++++++++++++++++++++++++++++++++++++
>  utils/update-kernel-headers.sh |  1 +
>  2 files changed, 76 insertions(+)
> 
> diff --git a/include/linux/stddef.h b/include/linux/stddef.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..e1fcfcf3b33261939797d79f4e29a28fa1da6e10
> --- /dev/null
> +++ b/include/linux/stddef.h
> @@ -0,0 +1,75 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _LINUX_STDDEF_H
> +#define _LINUX_STDDEF_H
> +
> +
> +
> +#ifndef __always_inline
> +#define __always_inline __inline__
> +#endif
> +
> +/* Not all C++ standards support type declarations inside an anonymous union */
> +#ifndef __cplusplus
> +#define __struct_group_tag(TAG)                TAG
> +#else
> +#define __struct_group_tag(TAG)
> +#endif
> +
> +/**
> + * __struct_group() - Create a mirrored named and anonyomous struct
> + *
> + * @TAG: The tag name for the named sub-struct (usually empty)
> + * @NAME: The identifier name of the mirrored sub-struct
> + * @ATTRS: Any struct attributes (usually empty)
> + * @MEMBERS: The member declarations for the mirrored structs
> + *
> + * Used to create an anonymous union of two structs with identical layout
> + * and size: one anonymous and one named. The former's members can be used
> + * normally without sub-struct naming, and the latter can be used to
> + * reason about the start, end, and size of the group of struct members.
> + * The named struct can also be explicitly tagged for layer reuse (C only),
> + * as well as both having struct attributes appended.
> + */
> +#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
> +       union { \
> +               struct { MEMBERS } ATTRS; \
> +               struct __struct_group_tag(TAG) { MEMBERS } ATTRS NAME; \
> +       } ATTRS
> +
> +#ifdef __cplusplus
> +/* sizeof(struct{}) is 1 in C++, not 0, can't use C version of the macro. */
> +#define __DECLARE_FLEX_ARRAY(T, member)        \
> +       T member[0]
> +#else
> +/**
> + * __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union
> + *
> + * @TYPE: The type of each flexible array element
> + * @NAME: The name of the flexible array member
> + *
> + * In order to have a flexible array member in a union or alone in a
> + * struct, it needs to be wrapped in an anonymous struct with at least 1
> + * named member, but that member can be empty.
> + */
> +#define __DECLARE_FLEX_ARRAY(TYPE, NAME)       \
> +       struct { \
> +               struct { } __empty_ ## NAME; \
> +               TYPE NAME[]; \
> +       }
> +#endif
> +
> +#ifndef __counted_by
> +#define __counted_by(m)
> +#endif
> +
> +#ifndef __counted_by_le
> +#define __counted_by_le(m)
> +#endif
> +
> +#ifndef __counted_by_be
> +#define __counted_by_be(m)
> +#endif
> +
> +#define __kernel_nonstring
> +
> +#endif /* _LINUX_STDDEF_H */
> diff --git a/utils/update-kernel-headers.sh b/utils/update-kernel-headers.sh
> index 9a64dfb5698c67945ab4eee085360c1728589401..666624f9972ea61067e5b5695237ab7a17c61664 100755
> --- a/utils/update-kernel-headers.sh
> +++ b/utils/update-kernel-headers.sh
> @@ -52,6 +52,7 @@ headers="
>         linux/media-bus-format.h
>         linux/media.h
>         linux/rkisp1-config.h
> +       linux/stddef.h
>         linux/udmabuf.h
>         linux/v4l2-common.h
>         linux/v4l2-controls.h
> 
> -- 
> 2.51.0
>

Patch
diff mbox series

diff --git a/include/linux/stddef.h b/include/linux/stddef.h
new file mode 100644
index 0000000000000000000000000000000000000000..e1fcfcf3b33261939797d79f4e29a28fa1da6e10
--- /dev/null
+++ b/include/linux/stddef.h
@@ -0,0 +1,75 @@ 
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _LINUX_STDDEF_H
+#define _LINUX_STDDEF_H
+
+
+
+#ifndef __always_inline
+#define __always_inline __inline__
+#endif
+
+/* Not all C++ standards support type declarations inside an anonymous union */
+#ifndef __cplusplus
+#define __struct_group_tag(TAG)		TAG
+#else
+#define __struct_group_tag(TAG)
+#endif
+
+/**
+ * __struct_group() - Create a mirrored named and anonyomous struct
+ *
+ * @TAG: The tag name for the named sub-struct (usually empty)
+ * @NAME: The identifier name of the mirrored sub-struct
+ * @ATTRS: Any struct attributes (usually empty)
+ * @MEMBERS: The member declarations for the mirrored structs
+ *
+ * Used to create an anonymous union of two structs with identical layout
+ * and size: one anonymous and one named. The former's members can be used
+ * normally without sub-struct naming, and the latter can be used to
+ * reason about the start, end, and size of the group of struct members.
+ * The named struct can also be explicitly tagged for layer reuse (C only),
+ * as well as both having struct attributes appended.
+ */
+#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
+	union { \
+		struct { MEMBERS } ATTRS; \
+		struct __struct_group_tag(TAG) { MEMBERS } ATTRS NAME; \
+	} ATTRS
+
+#ifdef __cplusplus
+/* sizeof(struct{}) is 1 in C++, not 0, can't use C version of the macro. */
+#define __DECLARE_FLEX_ARRAY(T, member)	\
+	T member[0]
+#else
+/**
+ * __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union
+ *
+ * @TYPE: The type of each flexible array element
+ * @NAME: The name of the flexible array member
+ *
+ * In order to have a flexible array member in a union or alone in a
+ * struct, it needs to be wrapped in an anonymous struct with at least 1
+ * named member, but that member can be empty.
+ */
+#define __DECLARE_FLEX_ARRAY(TYPE, NAME)	\
+	struct { \
+		struct { } __empty_ ## NAME; \
+		TYPE NAME[]; \
+	}
+#endif
+
+#ifndef __counted_by
+#define __counted_by(m)
+#endif
+
+#ifndef __counted_by_le
+#define __counted_by_le(m)
+#endif
+
+#ifndef __counted_by_be
+#define __counted_by_be(m)
+#endif
+
+#define __kernel_nonstring
+
+#endif /* _LINUX_STDDEF_H */
diff --git a/utils/update-kernel-headers.sh b/utils/update-kernel-headers.sh
index 9a64dfb5698c67945ab4eee085360c1728589401..666624f9972ea61067e5b5695237ab7a17c61664 100755
--- a/utils/update-kernel-headers.sh
+++ b/utils/update-kernel-headers.sh
@@ -52,6 +52,7 @@  headers="
 	linux/media-bus-format.h
 	linux/media.h
 	linux/rkisp1-config.h
+	linux/stddef.h
 	linux/udmabuf.h
 	linux/v4l2-common.h
 	linux/v4l2-controls.h