On Tue, Oct 19, 2021 at 3:03 AM Gabriel Krisman Bertazi
<krisman@xxxxxxxxxxxxx> wrote:
>
> fanotify_error_event would duplicate this sequence of declarations that
> already exist elsewhere with a slight different size. Create a helper
> macro to avoid code duplication.
>
> Suggested-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
with minor nit
> ---
> Among the suggestions, I think this is simpler because it avoids
> deep nesting the variable-sized attribute, which would have been hidden
> inside fee->ffe->object_fh.buf.
>
> It also avoids touching the allocators, which are nicely hidden inside
> helper KMEM_CACHE() macros that hides several parameters.
I like this option best as well.
> ---
> fs/notify/fanotify/fanotify.h | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
> index 2b032b79d5b0..a5e81d759f65 100644
> --- a/fs/notify/fanotify/fanotify.h
> +++ b/fs/notify/fanotify/fanotify.h
> @@ -171,12 +171,19 @@ static inline void fanotify_init_event(struct fanotify_event *event,
> event->pid = NULL;
> }
>
> +#define FANOTIFY_INLINE_FH(size) \
> +struct { \
> + struct fanotify_fh object_fh; \
> + /* Space for object_fh.buf[] - access with fanotify_fh_buf() */ \
> + unsigned char _inline_fh_buf[(size)]; \
> +}
> +
> struct fanotify_fid_event {
> struct fanotify_event fae;
> __kernel_fsid_t fsid;
> - struct fanotify_fh object_fh;
> - /* Reserve space in object_fh.buf[] - access with fanotify_fh_buf() */
> - unsigned char _inline_fh_buf[FANOTIFY_INLINE_FH_LEN];
> +
> + /* This must be the last element of the structure. */
> + FANOTIFY_INLINE_FH(FANOTIFY_INLINE_FH_LEN);
> };
It's not true that is must be the last element.
this is only true for struct fanotify_fh with zero size buf[].
Thanks,
Amir.
