From patchwork Thu Jan 24 16:40:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steffen Maier X-Patchwork-Id: 10779519 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 52F40746 for ; Thu, 24 Jan 2019 16:41:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4265D31CC1 for ; Thu, 24 Jan 2019 16:41:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4098E31CCB; Thu, 24 Jan 2019 16:41:08 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BB27E31CC1 for ; Thu, 24 Jan 2019 16:41:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727740AbfAXQlH (ORCPT ); Thu, 24 Jan 2019 11:41:07 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:43462 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727573AbfAXQlG (ORCPT ); Thu, 24 Jan 2019 11:41:06 -0500 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x0OGaNrM055398 for ; Thu, 24 Jan 2019 11:41:06 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2q7fprdcfc-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 24 Jan 2019 11:41:05 -0500 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 24 Jan 2019 16:41:00 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0OGewI8721256 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 24 Jan 2019 16:40:58 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5A27042041; Thu, 24 Jan 2019 16:40:58 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0609942049; Thu, 24 Jan 2019 16:40:58 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Thu, 24 Jan 2019 16:40:57 +0000 (GMT) From: Steffen Maier To: "James E . J . Bottomley" , "Martin K . Petersen" Cc: Christoph Hellwig , linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org, Benjamin Block , Martin Schwidefsky , Heiko Carstens , Steffen Maier , Fedor Loshakov , Jens Remus Subject: [PATCH] zfcp: fix sysfs block queue limit output for max_segment_size Date: Thu, 24 Jan 2019 17:40:34 +0100 X-Mailer: git-send-email 2.16.4 X-TM-AS-GCONF: 00 x-cbid: 19012416-0016-0000-0000-00000249EC6F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19012416-0017-0000-0000-000032A432CC Message-Id: <20190124164034.49749-1-maier@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-24_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901240116 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Since v2.6.35 commit 683229845f17 ("[SCSI] zfcp: Report scatter-gather limits to SCSI and block layer"), zfcp set dma_parms.max_segment_size == PAGE_SIZE (but without using the setter dma_set_max_seg_size()) and scsi_host_template.dma_boundary == PAGE_SIZE - 1. v5.0-rc1 commit 50c2e9107f17 ("scsi: introduce a max_segment_size host_template parameters") introduced a new field scsi_host_template.max_segment_size. If an LLDD such as zfcp does not set it, scsi_host_alloc() uses BLK_MAX_SEGMENT_SIZE = 65536 for Scsi_Host.max_segment_size. __scsi_init_queue() announced the minimum of Scsi_Host.max_segment_size and dma_parms.max_segment_size to the block layer. For zfcp: min(65536, 4096) == 4096 which was still good. v5.0 commit a8cf59a6692c ("scsi: communicate max segment size to the DMA mapping code") announces Scsi_Host.max_segment_size to the block layer and overwrites dma_parms.max_segment_size with Scsi_Host.max_segment_size. For zfcp dma_parms.max_segment_size == Scsi_Host.max_segment_size == 65536 which is also reflected in block queue limits. $ cd /sys/bus/ccw/drivers/zfcp $ cd 0.0.3c40/host5/rport-5:0-4/target5:0:4/5:0:4:10/block/sdi/queue $ cat max_segment_size 65536 Zfcp I/O still works because dma_boundary implicitly still keeps the effective max segment size <= PAGE_SIZE. However, dma_boundary does not seem visible to user space, but max_segment_size is visible and shows a misleading wrong value. Fix it and inherit the stable tag of a8cf59a6692c. Devices on our bus ccw support DMA but no DMA mapping. Of multiple device types on the ccw bus, only zfcp needs dma_parms for SCSI limits. So, leave dma_parms setup in zfcp and do not move it to the bus. Signed-off-by: Steffen Maier Fixes: 50c2e9107f ("scsi: introduce a max_segment_size host_template parameters") --- Martin, James, this would be for 5.0/scsi-fixes. drivers/s390/scsi/zfcp_aux.c | 1 - drivers/s390/scsi/zfcp_scsi.c | 2 ++ 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c index 9cf30d124b9e..e390f8c6d5f3 100644 --- a/drivers/s390/scsi/zfcp_aux.c +++ b/drivers/s390/scsi/zfcp_aux.c @@ -403,7 +403,6 @@ struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device) goto failed; /* report size limit per scatter-gather segment */ - adapter->dma_parms.max_segment_size = ZFCP_QDIO_SBALE_LEN; adapter->ccw_device->dev.dma_parms = &adapter->dma_parms; adapter->stat_read_buf_num = FSF_STATUS_READS_RECOM; diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c index 00acc7144bbc..f4f6a07c5222 100644 --- a/drivers/s390/scsi/zfcp_scsi.c +++ b/drivers/s390/scsi/zfcp_scsi.c @@ -428,6 +428,8 @@ static struct scsi_host_template zfcp_scsi_host_template = { .max_sectors = (((QDIO_MAX_ELEMENTS_PER_BUFFER - 1) * ZFCP_QDIO_MAX_SBALS_PER_REQ) - 2) * 8, /* GCD, adjusted later */ + /* report size limit per scatter-gather segment */ + .max_segment_size = ZFCP_QDIO_SBALE_LEN, .dma_boundary = ZFCP_QDIO_SBALE_LEN - 1, .shost_attrs = zfcp_sysfs_shost_attrs, .sdev_attrs = zfcp_sysfs_sdev_attrs,