On Wed, Jul 6, 2022 at 4:26 PM Joanne Koong <joannelkoong@xxxxxxxxx> wrote:
>
> Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
> added the bpf_dynptr_write and bpf_dynptr_read APIs.
>
> However, it will be useful for some dynptr types to pass in flags as
> well (eg when writing to a skb, the user may like to invalidate the
> hash or recompute the checksum).
>
> This patch adds a "u64 flags" arg to the bpf_dynptr_read and
> bpf_dynptr_write APIs.
>
> Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
> Fixes: 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
Ouch. It's an uapi change in the released kernel :(
It has to go via bpf tree instead of bpf-next.
We have to add support for bpf_dynptr to kfunc and the verifier,
so we can use kfunc-s for all future extensions in dynptr area.
> ---
> include/uapi/linux/bpf.h | 11 +++++++----
> kernel/bpf/helpers.c | 12 ++++++++----
> tools/include/uapi/linux/bpf.h | 11 +++++++----
> tools/testing/selftests/bpf/progs/dynptr_fail.c | 10 +++++-----
> tools/testing/selftests/bpf/progs/dynptr_success.c | 4 ++--
> 5 files changed, 29 insertions(+), 19 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 379e68fb866f..3dd13fe738b9 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -5226,22 +5226,25 @@ union bpf_attr {
> * Return
> * Nothing. Always succeeds.
> *
> - * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset)
> + * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags)
