Hi,
On 9/11/2022 8:23 PM, Shmulik Ladkani wrote:
> This allows kernel code dealing with dynptrs obtain dynptr's available
> size and current (w. proper offset) data pointer.
>
> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@xxxxxxxxx>
SNIP
> +
> +static inline void *bpf_dynptr_get_data(struct bpf_dynptr_kern *ptr)
> +{
> + return ptr->data ? ptr->data + ptr->offset : NULL;
> +}
Have one dummy question here. Is ptr->data == NULL is possible ? According to
the function prototype of bpf_dynptr_from_mem(), data can not be NULL. And IMO
in order to simplify the usage of bpf_dynptr_kernel, we need to ensure ptr->data
should be not NULL, else will need to add a NULL checking for every access of
bpf_dynptr_kernel in kernel.
>
> #ifdef CONFIG_BPF_LSM
> void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype);
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index fc08035f14ed..824864ac82d1 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -1408,7 +1408,7 @@ static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_typ
> ptr->size |= type << DYNPTR_TYPE_SHIFT;
> }
>
> -static u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
> +u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
> {
> return ptr->size & DYNPTR_SIZE_MASK;
> }
