From: Jiri Olsa <jolsa@redhat.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
Martin KaFai Lau <kafai@fb.com>, David Miller <davem@redhat.com>,
Wenbo Zhang <ethercflow@gmail.com>,
KP Singh <kpsingh@chromium.org>, Andrii Nakryiko <andriin@fb.com>,
Brendan Gregg <bgregg@netflix.com>,
Florent Revest <revest@chromium.org>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCHv3 0/9] bpf: Add d_path helper
Date: Fri, 19 Jun 2020 14:35:27 +0200 [thread overview]
Message-ID: <20200619123527.GA2465907@krava> (raw)
In-Reply-To: <5eebd52fc68ee_6d292ad5e7a285b816@john-XPS-13-9370.notmuch>
On Thu, Jun 18, 2020 at 01:57:19PM -0700, John Fastabend wrote:
> Jiri Olsa wrote:
> > hi,
> > adding d_path helper to return full path for 'path' object.
> >
> > I originally added and used 'file_path' helper, which did the same,
> > but used 'struct file' object. Then realized that file_path is just
> > a wrapper for d_path, so we'd cover more calling sites if we add
> > d_path helper and allowed resolving BTF object within another object,
> > so we could call d_path also with file pointer, like:
> >
> > bpf_d_path(&file->f_path, buf, size);
> >
> > This feature is mainly to be able to add dpath (filepath originally)
> > function to bpftrace:
> >
> > # bpftrace -e 'kfunc:vfs_open { printf("%s\n", dpath(args->path)); }'
> >
> > v3 changes:
> > - changed tests to use seleton and vmlinux.h [Andrii]
> > - refactored to define ID lists in C object [Andrii]
> > - changed btf_struct_access for nested ID check,
> > instead of adding new function for that [Andrii]
> > - fail build with CONFIG_DEBUG_INFO_BTF if libelf is not detected [Andrii]
> >
> > Also available at:
> > https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
> > bpf/d_path
> >
> > thanks,
> > jirka
>
> Hi Jira, Apologize for waiting until v3 to look at this series, but a
> couple general requests as I review this.
>
> In the cover letter can we get some more details. The above is really
> terse/cryptic in my opinion. The bpftrace example gives good motiviation,
> but nothing above mentions a new .BTF_ids section and the flow to create
> and use this section.
ok, will add more details in next version
>
> Also if we add a BTF_ids section adding documentation in btf.rst should
> happen as well. I would like to see something in the ELF File Format
> Interface section and BTF Generation sections.
did not know there was bpf.rst ;-) will update
>
> I'm not going to nitpick if its in this series or a stand-alone patch
> but do want to see it. So far the Documentation on BTF is fairly
> good and I want to avoid these kind of gaps.
sure, thanks
jirka
>
> Thanks!
> John
>
prev parent reply other threads:[~2020-06-19 12:36 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-16 10:05 [PATCHv3 0/9] bpf: Add d_path helper Jiri Olsa
2020-06-16 10:05 ` [PATCH 01/11] bpf: Add btfid tool to resolve BTF IDs in ELF object Jiri Olsa
2020-06-19 0:38 ` Andrii Nakryiko
2020-06-19 13:03 ` Jiri Olsa
2020-06-19 18:12 ` Andrii Nakryiko
2020-06-22 8:59 ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 02/11] bpf: Compile btfid tool at kernel compilation start Jiri Olsa
2020-06-18 20:40 ` John Fastabend
2020-06-18 21:17 ` John Fastabend
2020-06-19 13:23 ` Jiri Olsa
2020-06-19 0:40 ` Andrii Nakryiko
2020-06-19 0:47 ` Arnaldo Carvalho de Melo
2020-06-19 2:08 ` Alexei Starovoitov
2020-06-19 3:51 ` Andrii Nakryiko
2020-06-16 10:05 ` [PATCH 03/11] bpf: Add btf_ids object Jiri Olsa
2020-06-19 0:56 ` Andrii Nakryiko
2020-06-19 1:06 ` Andrii Nakryiko
2020-06-19 13:16 ` Jiri Olsa
2020-06-19 13:13 ` Jiri Olsa
2020-06-19 18:15 ` Andrii Nakryiko
2020-06-19 1:02 ` Andrii Nakryiko
2020-06-19 13:05 ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 04/11] bpf: Resolve BTF IDs in vmlinux image Jiri Olsa
2020-06-16 10:05 ` [PATCH 05/11] bpf: Remove btf_id helpers resolving Jiri Olsa
2020-06-19 1:10 ` Andrii Nakryiko
2020-06-19 13:18 ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 06/11] bpf: Do not pass enum bpf_access_type to btf_struct_access Jiri Olsa
2020-06-19 3:58 ` Andrii Nakryiko
2020-06-19 13:23 ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 07/11] bpf: Allow nested BTF object to be refferenced by BTF object + offset Jiri Olsa
2020-06-16 10:05 ` [PATCH 08/11] bpf: Add BTF whitelist support Jiri Olsa
2020-06-19 4:29 ` Andrii Nakryiko
2020-06-19 13:29 ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 09/11] bpf: Add d_path helper Jiri Olsa
2020-06-19 4:35 ` Andrii Nakryiko
2020-06-19 13:31 ` Jiri Olsa
2020-06-19 18:25 ` Andrii Nakryiko
2020-06-22 9:02 ` Jiri Olsa
2020-06-22 19:18 ` Andrii Nakryiko
2020-06-23 10:02 ` Jiri Olsa
2020-06-23 18:58 ` Andrii Nakryiko
2020-06-23 20:14 ` Jiri Olsa
2020-06-23 20:17 ` Andrii Nakryiko
2020-06-16 10:05 ` [PATCH 10/11] selftests/bpf: Add verifier test for " Jiri Olsa
2020-06-19 4:38 ` Andrii Nakryiko
2020-06-19 13:32 ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 11/11] selftests/bpf: Add " Jiri Olsa
2020-06-19 4:44 ` Andrii Nakryiko
2020-06-19 13:34 ` Jiri Olsa
2020-06-18 20:57 ` [PATCHv3 0/9] bpf: Add " John Fastabend
2020-06-19 12:35 ` Jiri Olsa [this message]
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