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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable 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 00778C433DF for ; Tue, 14 Jul 2020 23:03:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D76F9206D9 for ; Tue, 14 Jul 2020 23:03:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726942AbgGNXDt (ORCPT ); Tue, 14 Jul 2020 19:03:49 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:25846 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726358AbgGNXDs (ORCPT ); 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Tue, 14 Jul 2020 23:03:15 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D1AE77805C; Tue, 14 Jul 2020 23:03:16 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B6A587805F; Tue, 14 Jul 2020 23:03:15 +0000 (GMT) Received: from [153.66.254.194] (unknown [9.85.141.100]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 14 Jul 2020 23:03:15 +0000 (GMT) Message-ID: <1594767794.14804.21.camel@linux.ibm.com> Subject: Re: [PATCH v2 24/24] scsi: aic7xxx: aic79xx_osm: Remove set but unused variabes 'saved_scsiid' and 'saved_modes' From: James Bottomley Reply-To: jejb@linux.ibm.com To: Lee Jones Cc: Hannes Reinecke , martin.petersen@oracle.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Hannes Reinecke Date: Tue, 14 Jul 2020 16:03:14 -0700 In-Reply-To: <20200714213951.GL1398296@dell> References: <20200713080001.128044-1-lee.jones@linaro.org> <20200713080001.128044-25-lee.jones@linaro.org> <559e47de-fa26-9ae5-a3c5-4adeae606309@suse.de> <1594741430.4545.15.camel@linux.ibm.com> <20200714213951.GL1398296@dell> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-14_09:2020-07-14,2020-07-14 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 mlxscore=0 adultscore=0 spamscore=0 lowpriorityscore=0 priorityscore=1501 mlxlogscore=999 bulkscore=0 suspectscore=0 clxscore=1015 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007140155 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2020-07-14 at 22:39 +0100, Lee Jones wrote: > On Tue, 14 Jul 2020, James Bottomley wrote: > > > On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: > > > On 7/13/20 10:00 AM, Lee Jones wrote: > > > > Haven't been used since 2006. > > > > > > > > Fixes the following W=1 kernel build warning(s): > > > > > > > > drivers/scsi/aic7xxx/aic79xx_osm.c: In function > > > > ‘ahd_linux_queue_abort_cmd’: > > > > drivers/scsi/aic7xxx/aic79xx_osm.c:2155:17: warning: variable > > > > ‘saved_modes’ set but not used [-Wunused-but-set-variable] > > > > drivers/scsi/aic7xxx/aic79xx_osm.c:2148:9: warning: variable > > > > ‘saved_scsiid’ set but not used [-Wunused-but-set-variable] > > > > > > > > Cc: Hannes Reinecke > > > > Signed-off-by: Lee Jones > > > > --- > > > > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > > > > 1 file changed, 4 deletions(-) > > > > > > > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > b/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > index 3782a20d58885..140c4e74ddd7e 100644 > > > > --- a/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > +++ b/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > @@ -2141,14 +2141,12 @@ ahd_linux_queue_abort_cmd(struct > > > > scsi_cmnd > > > > *cmd) > > > > u_int saved_scbptr; > > > > u_int active_scbptr; > > > > u_int last_phase; > > > > - u_int saved_scsiid; > > > > u_int cdb_byte; > > > > int retval; > > > > int was_paused; > > > > int paused; > > > > int wait; > > > > int disconnected; > > > > - ahd_mode_state saved_modes; > > > > unsigned long flags; > > > > > > > > pending_scb = NULL; > > > > @@ -2239,7 +2237,6 @@ ahd_linux_queue_abort_cmd(struct > > > > scsi_cmnd > > > > *cmd) > > > > goto done; > > > > } > > > > > > > > - saved_modes = ahd_save_modes(ahd); > > > > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > > > > last_phase = ahd_inb(ahd, LASTPHASE); > > > > saved_scbptr = ahd_get_scbptr(ahd); > > > > @@ -2257,7 +2254,6 @@ ahd_linux_queue_abort_cmd(struct > > > > scsi_cmnd > > > > *cmd) > > > > * passed in command. That command is currently > > > > active on > > > > the > > > > * bus or is in the disconnected state. > > > > */ > > > > - saved_scsiid = ahd_inb(ahd, SAVED_SCSIID); > > > > if (last_phase != P_BUSFREE > > > > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > > > > > > > > > > > > > Reviewed-by: Hannes Reinecke > > > > Hey, you don't get to do that ... I asked you to figure out why > > we're missing an ahd_restore_modes(). Removing the > > ahd_save_modes() is cosmetic: it gets rid of a warning but doesn't > > fix the problem. I'd rather keep the warning until the problem is > > fixed and the problem is we need a mode save/restore around the > > ahd_set_modes() which is only partially implemented in this > > function. > > I had a look. Traced it back to the dawn of time (time == Git), then > delved even further back by downloading and trawling through ~10-15 > tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was > upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been > unused since at least then. If no one has complained in 2 decades, > I'd say it probably isn't an issue worth perusing. Well, we have what looks like a fix now. The reason it matters is that if the bus is not in AHD_MODE_SCSI when the routine is called, it ends up being in a wrong state when the routine exits, so you abort one command and screw up another. Ultimately I bet escalation to bus reset fixes it, so everything appears to work, but it might have worked a lot better if the original mode were restored. This is error handling code, so most installations run just fine without ever invoking it. James