Re: [RFC PATCH bpf-next 11/16] bpf: implement query for target_proto and file dumper prog_id

From: Yonghong Song <yhs@fb.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andriin@fb.com>, <bpf@vger.kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, <netdev@vger.kernel.org>,
	Alexei Starovoitov <ast@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>
Subject: Re: [RFC PATCH bpf-next 11/16] bpf: implement query for target_proto and file dumper prog_id
Date: Thu, 9 Apr 2020 23:11:37 -0700	[thread overview]
Message-ID: <6d706f4c-37b6-a956-372b-5d584e1330d7@fb.com> (raw)
In-Reply-To: <20200410031043.lza5p6rzi6vajy7h@ast-mbp.dhcp.thefacebook.com>

On 4/9/20 8:10 PM, Alexei Starovoitov wrote:
> On Wed, Apr 08, 2020 at 04:25:33PM -0700, Yonghong Song wrote:
>> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
>> index a245f0df53c4..fc2157e319f1 100644
>> --- a/tools/include/uapi/linux/bpf.h
>> +++ b/tools/include/uapi/linux/bpf.h
>> @@ -113,6 +113,7 @@ enum bpf_cmd {
>>   	BPF_MAP_DELETE_BATCH,
>>   	BPF_LINK_CREATE,
>>   	BPF_LINK_UPDATE,
>> +	BPF_DUMP_QUERY,
>>   };
>>   
>>   enum bpf_map_type {
>> @@ -594,6 +595,18 @@ union bpf_attr {
>>   		__u32		old_prog_fd;
>>   	} link_update;
>>   
>> +	struct {
>> +		__u32		query_fd;
>> +		__u32		flags;
>> +		union {
>> +			struct {
>> +				__aligned_u64	target_proto;
>> +				__u32		proto_buf_len;
>> +			};
>> +			__u32			prog_id;
>> +		};
>> +	} dump_query;
> 
> I think it would be cleaner to use BPF_OBJ_GET_INFO_BY_FD instead of
> introducing new command.

Right, using BPF_OBJ_GET_INFO_BY_FD should be good. Previously, I
am using target/dumper name to query and later I changed to fd,
but still used BPF_DUMP_QUERY...