On Tue, Oct 8, 2024 at 2:02 AM Hou Tao <houtao@xxxxxxxxxxxxxxx> wrote:
>
> From: Hou Tao <houtao1@xxxxxxxxxx>
>
> For bpf map with dynptr key support, the userspace application will use
> bpf_dynptr_user to represent the bpf_dynptr in the map key and pass it
> to bpf syscall. The bpf syscall will copy from bpf_dynptr_user to
> construct a corresponding bpf_dynptr_kern object when the map key is an
> input argument, and copy to bpf_dynptr_user from a bpf_dynptr_kern
> object when the map key is an output argument.
>
> For now the size of bpf_dynptr_user must be the same as bpf_dynptr, but
> the last u32 field is not used, so make it a reserved field.
>
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> include/uapi/linux/bpf.h | 6 ++++++
> tools/include/uapi/linux/bpf.h | 6 ++++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 07f7df308a01..72fe6a96b54c 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -7329,6 +7329,12 @@ struct bpf_dynptr {
> __u64 __opaque[2];
> } __attribute__((aligned(8)));
>
> +struct bpf_dynptr_user {
bikeshedding: maybe just bpf_udynptr?
> + __u64 data;
> + __u32 size;
> + __u32 rsvd;
> +} __attribute__((aligned(8)));
> +
> struct bpf_list_head {
> __u64 __opaque[2];
> } __attribute__((aligned(8)));
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 14f223282bfa..f12ce268e6be 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -7328,6 +7328,12 @@ struct bpf_dynptr {
> __u64 __opaque[2];
> } __attribute__((aligned(8)));
>
> +struct bpf_dynptr_user {
> + __u64 data;
what if we use __bpf_md_ptr(void *, data), so users can just directly
use this struct (and then the next patch won't be necessary at all)
> + __u32 size;
> + __u32 rsvd;
please call it __reserved
> +} __attribute__((aligned(8)));
> +
> struct bpf_list_head {
> __u64 __opaque[2];
> } __attribute__((aligned(8)));
> --
> 2.44.0
>
