Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752180AbdHaPpZ (ORCPT ); Thu, 31 Aug 2017 11:45:25 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36684 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752143AbdHaPpW (ORCPT ); Thu, 31 Aug 2017 11:45:22 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hannes Reinecke , Johannes Thumshirn , Christoph Hellwig , "Martin K. Petersen" , Todd Poynor Subject: [PATCH 4.4 14/16] scsi: sg: reset res_in_use after unlinking reserved array Date: Thu, 31 Aug 2017 17:44:07 +0200 Message-Id: <20170831154215.674612782@linuxfoundation.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170831154215.114706015@linuxfoundation.org> References: <20170831154215.114706015@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1163 Lines: 38 4.4-stable 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 --- drivers/scsi/sg.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -2052,6 +2052,8 @@ 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 *