On Thu, Feb 13, 2025 at 03:29:12PM +1030, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
>
> So, in order to avoid ending up with flexible-array members in the
> middle of other structs, we use the `__struct_group()` helper to
> separate the flexible array from the rest of the members in the
> flexible structure. We then use the newly created tagged `struct
> nd_cmd_pkg_hdr` to replace the type of the objects causing trouble
> (`pkg`) in multiple structs.
>
> So, with these changes, fix the following warnings:
>
> drivers/acpi/nfit/intel.c:692:35: warning: structure containing a flexible
> array member is not at the end of another structure
> [-Wflex-array-member-not-at-end]
One sample warning is good.
How about adding a comment on why the usage of __struct_group() here
means this doesn't break userspace.
snip
> diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h
> index 73516e263627..34c11644d5d7 100644
> --- a/include/uapi/linux/ndctl.h
> +++ b/include/uapi/linux/ndctl.h
FWIW: In a patch like this where reviewers likely want to see
the header file change first, put it first in the diff.
(git diff.orderfile)
> @@ -227,12 +227,15 @@ enum ars_masks {
> */
>
> struct nd_cmd_pkg {
> - __u64 nd_family; /* family of commands */
> - __u64 nd_command;
> - __u32 nd_size_in; /* INPUT: size of input args */
> - __u32 nd_size_out; /* INPUT: size of payload */
> - __u32 nd_reserved2[9]; /* reserved must be zero */
> - __u32 nd_fw_size; /* OUTPUT: size fw wants to return */
> + /* New members MUST be added within the __struct_group() macro below. */
> + __struct_group(nd_cmd_pkg_hdr, __hdr, /* no attrs */,
> + __u64 nd_family; /* family of commands */
> + __u64 nd_command;
> + __u32 nd_size_in; /* INPUT: size of input args */
> + __u32 nd_size_out; /* INPUT: size of payload */
> + __u32 nd_reserved2[9]; /* reserved must be zero */
> + __u32 nd_fw_size; /* OUTPUT: size fw wants to
> return */
> + );
> unsigned char nd_payload[]; /* Contents of call */
> };
>
> --
> 2.43.0
>
>
