On Mon, May 05, 2025 at 05:41:47PM +0200, Miklos Szeredi wrote:
> -static inline struct backing_file *backing_file(struct file *f)
> +#define backing_file(f) container_of(f, struct backing_file, file)
> +
> +struct path *backing_file_user_path(struct file *f)
> {
> - return container_of(f, struct backing_file, file);
> + return &backing_file(f)->user_path;
> }
>
> -struct path *backing_file_user_path(struct file *f)
> +const struct path *backing_file_user_path_c(const struct file *f)
> {
> return &backing_file(f)->user_path;
> }
> -EXPORT_SYMBOL_GPL(backing_file_user_path);
> +EXPORT_SYMBOL_GPL(backing_file_user_path_c);
May I suggest:
#define backing_file_user_path(f) (_Generic((f), \
const struct file *: (const struct path *)&backing_file(f)->user_path, \
struct file *: (struct path *)&backing_file(f)->user_path)))
It's the same technique we use for page_folio() so it's quite well
tested.
