From owner-svn-src-head@freebsd.org Tue Dec 19 10:05:46 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A0B8DE9C57A; Tue, 19 Dec 2017 10:05:46 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 6CD9571123; Tue, 19 Dec 2017 10:05:46 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id vBJA5jf7037300; Tue, 19 Dec 2017 10:05:45 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id vBJA5jbQ037299; Tue, 19 Dec 2017 10:05:45 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201712191005.vBJA5jbQ037299@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Tue, 19 Dec 2017 10:05:45 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r326973 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 326973 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Dec 2017 10:05:46 -0000 Author: kib Date: Tue Dec 19 10:05:45 2017 New Revision: 326973 URL: https://svnweb.freebsd.org/changeset/base/326973 Log: Use atomic_load(9) to read ppsinfo sequence numbers. In this case volatile qualifiers enusre that a compiler does not optimize the accesses out. Reviewed by: alc, jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D13534 Modified: head/sys/kern/kern_tc.c Modified: head/sys/kern/kern_tc.c ============================================================================== --- head/sys/kern/kern_tc.c Tue Dec 19 10:02:09 2017 (r326972) +++ head/sys/kern/kern_tc.c Tue Dec 19 10:05:45 2017 (r326973) @@ -1601,10 +1601,10 @@ pps_fetch(struct pps_fetch_args *fapi, struct pps_stat tv.tv_usec = fapi->timeout.tv_nsec / 1000; timo = tvtohz(&tv); } - aseq = pps->ppsinfo.assert_sequence; - cseq = pps->ppsinfo.clear_sequence; - while (aseq == pps->ppsinfo.assert_sequence && - cseq == pps->ppsinfo.clear_sequence) { + aseq = atomic_load_int(&pps->ppsinfo.assert_sequence); + cseq = atomic_load_int(&pps->ppsinfo.clear_sequence); + while (aseq == atomic_load_int(&pps->ppsinfo.assert_sequence) && + cseq == atomic_load_int(&pps->ppsinfo.clear_sequence)) { if (abi_aware(pps, 1) && pps->driver_mtx != NULL) { if (pps->flags & PPSFLAG_MTX_SPIN) { err = msleep_spin(pps, pps->driver_mtx,