HI,
On 10/11/2024 5:50 AM, Andrii Nakryiko wrote:
> 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)
Thanks for the suggestion. Will do in v2.
>> + __u32 size;
>> + __u32 rsvd;
> please call it __reserved
Got it.
>
>
>> +} __attribute__((aligned(8)));
>> +
>> struct bpf_list_head {
>> __u64 __opaque[2];
>> } __attribute__((aligned(8)));
>> --
>> 2.44.0
>>
