int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, size_t *uctx_len,
		      void *val, size_t val_len,
		      u64 id, u64 flags)
int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len,
		      void *val, size_t val_len,
		      u64 id, u64 flags)