On 01.11.2023 23:41, Martin KaFai Lau wrote:
On 11/1/23 3:50 PM, Vadim Fedorenko wrote:
+static void *__bpf_dynptr_data_ptr(const struct bpf_dynptr_kern *ptr)
+{
+ enum bpf_dynptr_type type;
+
+ if (!ptr->data)
+ return NULL;
+
+ type = bpf_dynptr_get_type(ptr);
+
+ switch (type) {
+ case BPF_DYNPTR_TYPE_LOCAL:
+ case BPF_DYNPTR_TYPE_RINGBUF:
+ return ptr->data + ptr->offset;
+ case BPF_DYNPTR_TYPE_SKB:
+ return skb_pointer_if_linear(ptr->data, ptr->offset,
__bpf_dynptr_size(ptr));
+ case BPF_DYNPTR_TYPE_XDP:
+ {
+ void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset,
__bpf_dynptr_size(ptr));
I suspect what it is doing here (for skb and xdp in particular) is very
similar to bpf_dynptr_slice. Please check if bpf_dynptr_slice(ptr, 0, NULL,
sz) will work.
Well, yes, it's simplified version of bpf_dynptr_slice. The problem is
that bpf_dynptr_slice bpf_kfunc which cannot be used in another
bpf_kfunc. Should I refactor the code to use it in both places? Like
Sorry, scrolled too fast in my earlier reply :(
I am not aware of this limitation. What error does it have?
The bpf_dynptr_slice_rdwr kfunc() is also calling the bpf_dynptr_slice() kfunc.
Yeah, but they are in the same module. We do not declare prototypes of kfuncs in
linux/bpf.h and that's why we cannot use them outside of helpers.c.
The same problem was with bpf_dynptr_is_rdonly() I believe.
create __bpf_dynptr_slice() which will be internal part of bpf_kfunc?
