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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 51EF0C4360C for ; Wed, 2 Oct 2019 19:08:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3765D21D82 for ; Wed, 2 Oct 2019 19:08:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729545AbfJBTIm (ORCPT ); Wed, 2 Oct 2019 15:08:42 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36190 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729408AbfJBTIZ (ORCPT ); Wed, 2 Oct 2019 15:08:25 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iFjyo-00035m-5T; Wed, 02 Oct 2019 20:08:06 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iFjyn-0003ba-IN; Wed, 02 Oct 2019 20:08:05 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Omar Sandoval" , "Paul E. McKenney" , "Peter Zijlstra" , linux-block@vger.kernel.org, "Andrea Parri" , "Jens Axboe" , "Ming Lei" Date: Wed, 02 Oct 2019 20:06:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 22/87] sbitmap: fix improper use of smp_mb__before_atomic() In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Andrea Parri commit a0934fd2b1208458e55fc4b48f55889809fce666 upstream. This barrier only applies to the read-modify-write operations; in particular, it does not apply to the atomic_set() primitive. Replace the barrier with an smp_mb(). Fixes: 6c0ca7ae292ad ("sbitmap: fix wakeup hang after sbq resize") Reported-by: "Paul E. McKenney" Reported-by: Peter Zijlstra Signed-off-by: Andrea Parri Reviewed-by: Ming Lei Cc: Jens Axboe Cc: Omar Sandoval Cc: Ming Lei Cc: linux-block@vger.kernel.org Cc: "Paul E. McKenney" Cc: Peter Zijlstra Signed-off-by: Jens Axboe [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings --- block/blk-mq-tag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -499,7 +499,7 @@ static void bt_update_count(struct blk_m * Pairs with the memory barrier in bt_clear_tag() to ensure * that the batch size is updated before the wait counts. */ - smp_mb__before_atomic(); + smp_mb(); for (i = 0; i < BT_WAIT_QUEUES; i++) atomic_set(&bt->bs[i].wait_cnt, 1); }