From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-22.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 441DDC433EF for ; Thu, 9 Sep 2021 13:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 291E761051 for ; Thu, 9 Sep 2021 13:02:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351710AbhIINDv (ORCPT ); Thu, 9 Sep 2021 09:03:51 -0400 Received: from www62.your-server.de ([213.133.104.62]:50340 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357081AbhIIM7h (ORCPT ); Thu, 9 Sep 2021 08:59:37 -0400 Received: from sslproxy06.your-server.de ([78.46.172.3]) by www62.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1mOJdC-000Bd2-VY; Thu, 09 Sep 2021 14:58:19 +0200 Received: from [85.5.47.65] (helo=linux.home) by sslproxy06.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mOJdC-000NqE-Pe; Thu, 09 Sep 2021 14:58:18 +0200 Subject: Re: [PATCH v3 bpf-next] libbpf: add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations To: Andrii Nakryiko , bpf@vger.kernel.org, ast@kernel.org, quentin@isovalent.com Cc: kernel-team@fb.com References: <20210908213226.1871016-1-andrii@kernel.org> From: Daniel Borkmann Message-ID: Date: Thu, 9 Sep 2021 14:58:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20210908213226.1871016-1-andrii@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.103.2/26289/Thu Sep 9 10:20:35 2021) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 9/8/21 11:32 PM, Andrii Nakryiko wrote: > From: Quentin Monnet > > Introduce a macro LIBBPF_DEPRECATED_SINCE(major, minor, message) to prepare > the deprecation of two API functions. This macro marks functions as deprecated > when libbpf's version reaches the values passed as an argument. > > As part of this change libbpf_version.h header is added with recorded major > (LIBBPF_MAJOR_VERSION) and minor (LIBBPF_MINOR_VERSION) libbpf version macros. > They are now part of libbpf public API and can be relied upon by user code. > libbpf_version.h is installed system-wide along other libbpf public headers. > > Due to this new build-time auto-generated header, in-kernel applications > relying on libbpf (resolve_btfids, bpftool, bpf_preload) are updated to > include libbpf's output directory as part of a list of include search paths. > Better fix would be to use libbpf's make_install target to install public API > headers, but that clean up is left out as a future improvement. The build > changes were tested by building kernel (with KBUILD_OUTPUT and O= specified > explicitly), bpftool, libbpf, selftests/bpf, and resolve_btfids builds. No > problems were detected. > > Note that because of the constraints of the C preprocessor we have to write > a few lines of macro magic for each version used to prepare deprecation (0.6 > for now). > > Also, use LIBBPF_DEPRECATED_SINCE() to schedule deprecation of > btf__get_from_id() and btf__load(), which are replaced by > btf__load_from_kernel_by_id() and btf__load_into_kernel(), respectively, > starting from future libbpf v0.6. This is part of libbpf 1.0 effort ([0]). > > [0] Closes: https://github.com/libbpf/libbpf/issues/278 > > Co-developed-by: Quentin Monnet > Signed-off-by: Quentin Monnet > Signed-off-by: Andrii Nakryiko > --- > v2->v3: > - adding `sleep 10` revealed two more missing dependencies in resolve_btfids > and selftest/bpf's bench, which were fixed (BPF CI); > v1->v2: > - fix bpf_preload build by adding dependency for iterators/iterators.o on > libbpf.a generation (caught by BPF CI); > > kernel/bpf/preload/Makefile | 7 +++++-- > tools/bpf/bpftool/Makefile | 4 ++++ > tools/bpf/resolve_btfids/Makefile | 6 ++++-- > tools/lib/bpf/Makefile | 24 +++++++++++++++++------- > tools/lib/bpf/btf.h | 2 ++ > tools/lib/bpf/libbpf_common.h | 19 +++++++++++++++++++ > tools/testing/selftests/bpf/Makefile | 4 ++-- > 7 files changed, 53 insertions(+), 13 deletions(-) > > diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile > index 1951332dd15f..ac29d4e9a384 100644 > --- a/kernel/bpf/preload/Makefile > +++ b/kernel/bpf/preload/Makefile > @@ -10,12 +10,15 @@ LIBBPF_OUT = $(abspath $(obj)) > $(LIBBPF_A): > $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a > > -userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \ > +userccflags += -I$(LIBBPF_OUT) -I $(srctree)/tools/include/ \ > + -I $(srctree)/tools/include/uapi \ > -I $(srctree)/tools/lib/ -Wno-unused-result > > userprogs := bpf_preload_umd > > -clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ > +clean-files := $(userprogs) libbpf_version.h bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ > + > +$(obj)/iterators/iterators.o: $(LIBBPF_A) > > bpf_preload_umd-objs := iterators/iterators.o > bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz One small issue I ran into by accident while testing: [root@linux bpf-next]# make -j8 kernel/bpf/ SYNC include/config/auto.conf.cmd DESCEND objtool CALL scripts/atomic/check-atomics.sh CALL scripts/checksyscalls.sh CC kernel/bpf/syscall.o AR kernel/bpf/preload/built-in.a CC [M] kernel/bpf/preload/bpf_preload_kern.o CC [U] kernel/bpf/preload/iterators/iterators.o In file included from ./tools/lib/bpf/libbpf.h:20, from kernel/bpf/preload/iterators/iterators.c:10: ./tools/lib/bpf/libbpf_common.h:13:10: fatal error: libbpf_version.h: No such file or directory 13 | #include "libbpf_version.h" | ^~~~~~~~~~~~~~~~~~ compilation terminated. make[3]: *** [scripts/Makefile.userprogs:43: kernel/bpf/preload/iterators/iterators.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [scripts/Makefile.build:540: kernel/bpf/preload] Error 2 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [scripts/Makefile.build:540: kernel/bpf] Error 2 make: *** [Makefile:1872: kernel] Error 2 For me it was the case where tools/lib/bpf/ was already built _before_ this patch was applied, then I applied it, and just ran make -j8 kernel/bpf/ where the above can then be reproduced. I'd assume that as-is, this would affect many folks on update. Thanks, Daniel