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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 670B0C433DF for ; Tue, 9 Jun 2020 18:09:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44A0520737 for ; Tue, 9 Jun 2020 18:09:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388446AbgFISJD (ORCPT ); Tue, 9 Jun 2020 14:09:03 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41480 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388182AbgFISF7 (ORCPT ); Tue, 9 Jun 2020 14:05:59 -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 1jiidG-0001pF-8u; Tue, 09 Jun 2020 19:05:54 +0100 Received: from ben by deadeye with local (Exim 4.94) (envelope-from ) id 1jiidF-006Vvp-9A; Tue, 09 Jun 2020 19:05:53 +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 , "Hannes Reinecke" , "Greg Kroah-Hartman" , "Hannes Reinecke" , "Todd Poynor" , "Christoph Hellwig" , "Martin K. Petersen" , "Johannes Thumshirn" Date: Tue, 09 Jun 2020 19:04:18 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 27/61] scsi: sg: reset 'res_in_use' after unlinking reserved array 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 3.16.85-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Hannes Reinecke commit e791ce27c3f6a1d3c746fd6a8f8e36c9540ec6f9 upstream. Once the reserved page array is unused we can reset the 'res_in_use' state; here we can do a lazy update without holding the mutex as we only need to check against concurrent access, not concurrent release. [mkp: checkpatch] Fixes: 1bc0eb044615 ("scsi: sg: protect accesses to 'reserved' page array") Signed-off-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen Cc: Todd Poynor Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/scsi/sg.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -2062,6 +2062,8 @@ sg_unlink_reserve(Sg_fd * sfp, Sg_reques req_schp->sglist_len = 0; sfp->save_scat_len = 0; srp->res_used = 0; + /* Called without mutex lock to avoid deadlock */ + sfp->res_in_use = 0; } static Sg_request *