Re: [PATCH][next] fsnotify: Avoid -Wflex-array-member-not-at-end warning

[Amir Goldstein]

On Wed, Mar 6, 2024 at 1:52 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> On Tue, Mar 05, 2024 at 04:18:46PM -0600, Gustavo A. R. Silva wrote:
> > -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
> > ready to enable it globally.
> >
> > There is currently a local structure `f` that is using a flexible
> > `struct file_handle` as header for an on-stack place-holder for the
> > flexible-array member `unsigned char f_handle[];`.
> >
> > struct {
> >       struct file_handle handle;
> >       u8 pad[MAX_HANDLE_SZ];
> > } f;
>
> This code pattern is "put a flex array struct on the stack", but we have
> a macro for this now:
>
> DEFINE_FLEX(struct file_handle, handle, f_handle, MAX_HANDLE_SZ);
>
> And you can even include the initializer:
>
> _DEFINE_FLEX(struct file_handle, handle, f_handle, MAX_HANDLE_SZ,
>              = { .handle_bytes = MAX_HANDLE_SZ });
>

Indeed that looks much nicer.

Thanks,
Amir.