From owner-svn-src-all@freebsd.org Tue Aug 11 12:31:30 2020 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id C7B6E3AD380; Tue, 11 Aug 2020 12:31:30 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4BQsdY3xn1z4T1b; Tue, 11 Aug 2020 12:31:29 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: by mail-wm1-x344.google.com with SMTP id d190so2411229wmd.4; Tue, 11 Aug 2020 05:31:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=urVBsRCTzk8JhLFX4HhuYkDKJesw/VE+vV1ydiLhVu0=; b=jmKWJ1H/fU9L/+ALlx1L1Jsgc0TVRlQERACvaIwzTOBSdL9f3r1h/4Bav25R5vJL8R LhREE5akojwRs3RyF4m1E91WtckhV09TXKGTHJrilLer9bsvm6vHQT2oXiEFwu5iBGJF cskbpSCocblGYg8dt+3iIhf/c8FgoJId0fpfgUahU2dxSSLgoEY7D6XBYsQgKkBj3/uC skqsrZJgRPDnQfOtLv2sRSFnrFN77TGHYw5T94FZisWq+z220h06mwBNS4JizVJbVGYz a1djiZBN0n3iU1j3Ikh/wF26vB1H3tZby6CpXZVH4fdYKh4KHhHAD2vA9yaiKfPcGIft X9lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=urVBsRCTzk8JhLFX4HhuYkDKJesw/VE+vV1ydiLhVu0=; b=SRn6vGVmvywzV24sm9NiNNew8Xc07S4XLuABJmbG+CUOMuv9HfYrbrBxv6ND/gOSAv wmAJGIUy03xQIiip6YojzV1Pn7FozXtZ2DDTJXTRBL9Vkj87ETnKkk6CJk3U7i52VGD5 LiANMtwux5dJkg5otZPL3zB0DXG20Qkb8BcHz6k4ZuuVhbbO0VYIgY6VVNQb44q60Ls7 MZQyPbYLAtam2fUJ3Y7RME4zPqohY3v4uHyCjEX4lojY412oszN9xmf0qmnPPCWk2fs6 v05rrNCK/q9H5cppc5WEyYBjbvBJ8NqPcGcbqeYmg/67a8uUQvfARueogw4hE2mbh08Y MLdg== X-Gm-Message-State: AOAM532kDMOsW8B/d92I2qiSp+dc1u6JrryWs3XiNbkBHpiJfl51svmQ mUhOS5NBgAGY57sw3mxDy0Yj2nVR0Z7tcz8Yc5E= X-Google-Smtp-Source: ABdhPJxb5e7+aqOgA28VnIHEL0sqDHHHr9JKCTeFKCVAVIHVFcabwHFfnmbZ99weOGkbjBlvKETAyU/NQZ9hkCZeRuQ= X-Received: by 2002:a1c:41c5:: with SMTP id o188mr3914057wma.187.1597149088042; Tue, 11 Aug 2020 05:31:28 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a5d:614c:0:0:0:0:0 with HTTP; Tue, 11 Aug 2020 05:31:26 -0700 (PDT) In-Reply-To: <20200804202541.0b6b3eb6ce26522ee12a796c@bidouilliste.com> References: <202008041525.074FPNLh043749@repo.freebsd.org> <1c90911b-d5f6-f8b1-8f4d-97a88fa028bd@rice.edu> <20200804202541.0b6b3eb6ce26522ee12a796c@bidouilliste.com> From: Mateusz Guzik Date: Tue, 11 Aug 2020 14:31:26 +0200 Message-ID: Subject: Re: svn commit: r363842 - head/sys/compat/linuxkpi/common/include/linux To: Emmanuel Vadot Cc: Alan Cox , Emmanuel Vadot , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4BQsdY3xn1z4T1b X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=jmKWJ1H/; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of mjguzik@gmail.com designates 2a00:1450:4864:20::344 as permitted sender) smtp.mailfrom=mjguzik@gmail.com X-Spamd-Result: default: False [-3.56 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.01)[-1.010]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36:c]; FREEMAIL_FROM(0.00)[gmail.com]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM_LONG(-1.01)[-1.011]; RCPT_COUNT_FIVE(0.00)[6]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::344:from]; NEURAL_HAM_SHORT(-0.54)[-0.539]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Aug 2020 12:31:30 -0000 Hi. This remains unfixed. On 8/4/20, Emmanuel Vadot wrote: > On Tue, 4 Aug 2020 13:11:02 -0500 > Alan Cox wrote: > >> >> On 8/4/20 10:25 AM, Emmanuel Vadot wrote: >> > Author: manu >> > Date: Tue Aug 4 15:25:22 2020 >> > New Revision: 363842 >> > URL: https://svnweb.freebsd.org/changeset/base/363842 >> > >> > Log: >> > linuxkpi: Add clear_bit_unlock >> > >> > This calls clear_bit and adds a memory barrier. >> > >> > Sponsored by: The FreeBSD Foundation >> > >> > Reviewed by: hselasky >> > MFC after: 1 week >> > Differential Revision: https://reviews.freebsd.org/D25943 >> > >> > Modified: >> > head/sys/compat/linuxkpi/common/include/linux/bitops.h >> > >> > Modified: head/sys/compat/linuxkpi/common/include/linux/bitops.h >> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D >> > --- head/sys/compat/linuxkpi/common/include/linux/bitops.h Tue Aug 4 >> > 15:00:02 2020 (r363841) >> > +++ head/sys/compat/linuxkpi/common/include/linux/bitops.h Tue Aug 4 >> > 15:25:22 2020 (r363842) >> > @@ -275,6 +275,13 @@ find_next_zero_bit(const unsigned long *addr, >> > unsigned >> > #define test_bit(i, a) \ >> > !!(READ_ONCE(((volatile const unsigned long *)(a))[BIT_WORD(i)])= & >> > BIT_MASK(i)) >> > >> > +static inline void >> > +clear_bit_unlock(long bit, volatile unsigned long *var) >> > +{ >> > + clear_bit(bit, var); >> > + wmb(); >> >> >> For an unlock operation, the memory barrier should come before the >> clear_bit() call, not after.=C2=A0 See, for example, the alpha implement= ation >> in Linux.=C2=A0 Also, the correct "spelling" for this memory barrier in >> FreeBSD would be atomic_thread_fence_rel(). See, for example, the >> comment at the top of sys/amd64/include/atomic.h. > > Ah yes, thanks. I probably got lost looking for the linux implem but > that does make sense, I'll fix that probably tomorow. > > Thanks. > >> >> > +} >> > + >> > static inline int >> > test_and_clear_bit(long bit, volatile unsigned long *var) >> > { > > > -- > Emmanuel Vadot > --=20 Mateusz Guzik