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=-7.6 required=3.0 tests=DATE_IN_FUTURE_06_12, DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_SBL,URIBL_SBL_A, USER_AGENT_SANE_1 autolearn=unavailable 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 D7D7CC388F3 for ; Mon, 30 Sep 2019 16:41:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4352215EA for ; Mon, 30 Sep 2019 16:41:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="yJ56Zet3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732285AbfI3Qld (ORCPT ); Mon, 30 Sep 2019 12:41:33 -0400 Received: from gateway22.websitewelcome.com ([192.185.47.168]:36604 "EHLO gateway22.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732151AbfI3Qlc (ORCPT ); Mon, 30 Sep 2019 12:41:32 -0400 X-Greylist: delayed 1321 seconds by postgrey-1.27 at vger.kernel.org; Mon, 30 Sep 2019 12:41:32 EDT Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway22.websitewelcome.com (Postfix) with ESMTP id 3AE2C213AC5 for ; Mon, 30 Sep 2019 11:19:31 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id EyOZiGWNiBnGaEyOZiRKrT; Mon, 30 Sep 2019 11:19:31 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=MfJZMISa5OTKdNXPHLsCROtCu6VTNYBXkGGuJIbv5t4=; b=yJ56Zet3XSJosWaXnnkVFp8of5 Emg89LTRpZY9FX1zwhbSRz7Y4hf7Y3KFMNi/Yi72U975/rN+VyKhsRnh5+55fvTGVJZH9Owg7yPSm Sxn/yvHV653uc3q2RkprHX2xfLl+2wNY0PKe2K80bzPKtBTHQQQylvHaKEvTWo+d1hGijucxR09xF MV6E5OVB6r031JXe8cnnUL8IshjqiRgEOUn81T1RvVeRxx7ERdzfGZw927rFSQN2F1jPRuaQTk4ge US9KRZSQNAoV9160efk5Zkh3uWpUwvMK9kJ9LJyHRczv8hG6YXrlJNfvxatvmGHCCo5853kUrbXFK 9vEpo7rA==; Received: from [38.98.37.138] (port=62616 helo=[192.168.43.131]) by gator4166.hostgator.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.92) (envelope-from ) id 1iEyOX-0027A7-Df; Mon, 30 Sep 2019 11:19:30 -0500 Subject: Re: [PATCH v2] bpf: use flexible array members, not zero-length To: Stephen Kitt , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song Cc: linux-doc@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Linux Kernel Mailing List References: <20190930073858.7639-1-steve@sk2.org> From: "Gustavo A. R. Silva" Openpgp: preference=signencrypt Autocrypt: addr=gustavo@embeddedor.com; keydata= mQINBFssHAwBEADIy3ZoPq3z5UpsUknd2v+IQud4TMJnJLTeXgTf4biSDSrXn73JQgsISBwG 2Pm4wnOyEgYUyJd5tRWcIbsURAgei918mck3tugT7AQiTUN3/5aAzqe/4ApDUC+uWNkpNnSV tjOx1hBpla0ifywy4bvFobwSh5/I3qohxDx+c1obd8Bp/B/iaOtnq0inli/8rlvKO9hp6Z4e DXL3PlD0QsLSc27AkwzLEc/D3ZaqBq7ItvT9Pyg0z3Q+2dtLF00f9+663HVC2EUgP25J3xDd 496SIeYDTkEgbJ7WYR0HYm9uirSET3lDqOVh1xPqoy+U9zTtuA9NQHVGk+hPcoazSqEtLGBk YE2mm2wzX5q2uoyptseSNceJ+HE9L+z1KlWW63HhddgtRGhbP8pj42bKaUSrrfDUsicfeJf6 m1iJRu0SXYVlMruGUB1PvZQ3O7TsVfAGCv85pFipdgk8KQnlRFkYhUjLft0u7CL1rDGZWDDr NaNj54q2CX9zuSxBn9XDXvGKyzKEZ4NY1Jfw+TAMPCp4buawuOsjONi2X0DfivFY+ZsjAIcx qQMglPtKk/wBs7q2lvJ+pHpgvLhLZyGqzAvKM1sVtRJ5j+ARKA0w4pYs5a5ufqcfT7dN6TBk LXZeD9xlVic93Ju08JSUx2ozlcfxq+BVNyA+dtv7elXUZ2DrYwARAQABtCxHdXN0YXZvIEEu IFIuIFNpbHZhIDxndXN0YXZvQGVtYmVkZGVkb3IuY29tPokCPQQTAQgAJwUCWywcDAIbIwUJ CWYBgAULCQgHAgYVCAkKCwIEFgIDAQIeAQIXgAAKCRBHBbTLRwbbMZ6tEACk0hmmZ2FWL1Xi l/bPqDGFhzzexrdkXSfTTZjBV3a+4hIOe+jl6Rci/CvRicNW4H9yJHKBrqwwWm9fvKqOBAg9 obq753jydVmLwlXO7xjcfyfcMWyx9QdYLERTeQfDAfRqxir3xMeOiZwgQ6dzX3JjOXs6jHBP cgry90aWbaMpQRRhaAKeAS14EEe9TSIly5JepaHoVdASuxklvOC0VB0OwNblVSR2S5i5hSsh ewbOJtwSlonsYEj4EW1noQNSxnN/vKuvUNegMe+LTtnbbocFQ7dGMsT3kbYNIyIsp42B5eCu JXnyKLih7rSGBtPgJ540CjoPBkw2mCfhj2p5fElRJn1tcX2McsjzLFY5jK9RYFDavez5w3lx JFgFkla6sQHcrxH62gTkb9sUtNfXKucAfjjCMJ0iuQIHRbMYCa9v2YEymc0k0RvYr43GkA3N PJYd/vf9vU7VtZXaY4a/dz1d9dwIpyQARFQpSyvt++R74S78eY/+lX8wEznQdmRQ27kq7BJS R20KI/8knhUNUJR3epJu2YFT/JwHbRYC4BoIqWl+uNvDf+lUlI/D1wP+lCBSGr2LTkQRoU8U 64iK28BmjJh2K3WHmInC1hbUucWT7Swz/+6+FCuHzap/cjuzRN04Z3Fdj084oeUNpP6+b9yW e5YnLxF8ctRAp7K4yVlvA7kCDQRbLBwMARAAsHCE31Ffrm6uig1BQplxMV8WnRBiZqbbsVJB H1AAh8tq2ULl7udfQo1bsPLGGQboJSVN9rckQQNahvHAIK8ZGfU4Qj8+CER+fYPp/MDZj+t0 DbnWSOrG7z9HIZo6PR9z4JZza3Hn/35jFggaqBtuydHwwBANZ7A6DVY+W0COEU4of7CAahQo 5NwYiwS0lGisLTqks5R0Vh+QpvDVfuaF6I8LUgQR/cSgLkR//V1uCEQYzhsoiJ3zc1HSRyOP otJTApqGBq80X0aCVj1LOiOF4rrdvQnj6iIlXQssdb+WhSYHeuJj1wD0ZlC7ds5zovXh+FfF l5qH5RFY/qVn3mNIVxeO987WSF0jh+T5ZlvUNdhedGndRmwFTxq2Li6GNMaolgnpO/CPcFpD jKxY/HBUSmaE9rNdAa1fCd4RsKLlhXda+IWpJZMHlmIKY8dlUybP+2qDzP2lY7kdFgPZRU+e zS/pzC/YTzAvCWM3tDgwoSl17vnZCr8wn2/1rKkcLvTDgiJLPCevqpTb6KFtZosQ02EGMuHQ I6Zk91jbx96nrdsSdBLGH3hbvLvjZm3C+fNlVb9uvWbdznObqcJxSH3SGOZ7kCHuVmXUcqoz ol6ioMHMb+InrHPP16aVDTBTPEGwgxXI38f7SUEn+NpbizWdLNz2hc907DvoPm6HEGCanpcA EQEAAYkCJQQYAQgADwUCWywcDAIbDAUJCWYBgAAKCRBHBbTLRwbbMdsZEACUjmsJx2CAY+QS UMebQRFjKavwXB/xE7fTt2ahuhHT8qQ/lWuRQedg4baInw9nhoPE+VenOzhGeGlsJ0Ys52sd XvUjUocKgUQq6ekOHbcw919nO5L9J2ejMf/VC/quN3r3xijgRtmuuwZjmmi8ct24TpGeoBK4 WrZGh/1hAYw4ieARvKvgjXRstcEqM5thUNkOOIheud/VpY+48QcccPKbngy//zNJWKbRbeVn imua0OpqRXhCrEVm/xomeOvl1WK1BVO7z8DjSdEBGzbV76sPDJb/fw+y+VWrkEiddD/9CSfg fBNOb1p1jVnT2mFgGneIWbU0zdDGhleI9UoQTr0e0b/7TU+Jo6TqwosP9nbk5hXw6uR5k5PF 8ieyHVq3qatJ9K1jPkBr8YWtI5uNwJJjTKIA1jHlj8McROroxMdI6qZ/wZ1ImuylpJuJwCDC ORYf5kW61fcrHEDlIvGc371OOvw6ejF8ksX5+L2zwh43l/pKkSVGFpxtMV6d6J3eqwTafL86 YJWH93PN+ZUh6i6Rd2U/i8jH5WvzR57UeWxE4P8bQc0hNGrUsHQH6bpHV2lbuhDdqo+cM9eh GZEO3+gCDFmKrjspZjkJbB5Gadzvts5fcWGOXEvuT8uQSvl+vEL0g6vczsyPBtqoBLa9SNrS VtSixD1uOgytAP7RWS474w== Message-ID: Date: Mon, 30 Sep 2019 18:18:41 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190930073858.7639-1-steve@sk2.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 38.98.37.138 X-Source-L: No X-Exim-ID: 1iEyOX-0027A7-Df X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.43.131]) [38.98.37.138]:62616 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 10 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/30/19 02:38, Stephen Kitt wrote: > This switches zero-length arrays in variable-length structs to C99 > flexible array members. GCC will then ensure that the arrays are > always the last element in the struct. > > Coccinelle: > @@ > identifier S, fld; > type T; > @@ > > struct S { > ... > T fld[ > - 0 > ]; > ... > }; > > Signed-off-by: Stephen Kitt > --- What changed in v2? You should include a changelog here. I encourage you to read the following document: https://kernelnewbies.org/Outreachyfirstpatch In particular this section "Versioning one patch revision" Also, always CC the lkml: linux-kernel@vger.kernel.org Thanks -- Gustavo > Documentation/bpf/btf.rst | 2 +- > tools/lib/bpf/libbpf.c | 2 +- > tools/lib/bpf/libbpf_internal.h | 2 +- > 3 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst > index 4d565d202ce3..24ce50fc1fc1 100644 > --- a/Documentation/bpf/btf.rst > +++ b/Documentation/bpf/btf.rst > @@ -670,7 +670,7 @@ func_info for each specific ELF section.:: > __u32 sec_name_off; /* offset to section name */ > __u32 num_info; > /* Followed by num_info * record_size number of bytes */ > - __u8 data[0]; > + __u8 data[]; > }; > > Here, num_info must be greater than 0. > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index e0276520171b..c02ea0e1a588 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -5577,7 +5577,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, > struct perf_sample_raw { > struct perf_event_header header; > uint32_t size; > - char data[0]; > + char data[]; > }; > > struct perf_sample_lost { > diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h > index 2e83a34f8c79..930ada2276bf 100644 > --- a/tools/lib/bpf/libbpf_internal.h > +++ b/tools/lib/bpf/libbpf_internal.h > @@ -86,7 +86,7 @@ struct btf_ext_info_sec { > __u32 sec_name_off; > __u32 num_info; > /* Followed by num_info * record_size number of bytes */ > - __u8 data[0]; > + __u8 data[]; > }; > > /* The minimum bpf_func_info checked by the loader */ >