From patchwork Sun Apr 10 17:36:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Gilbert X-Patchwork-Id: 12808219 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69D58C433EF for ; Sun, 10 Apr 2022 17:37:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239997AbiDJRjQ (ORCPT ); Sun, 10 Apr 2022 13:39:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237246AbiDJRjP (ORCPT ); Sun, 10 Apr 2022 13:39:15 -0400 Received: from smtp.infotech.no (smtp.infotech.no [82.134.31.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 16EC628E13 for ; Sun, 10 Apr 2022 10:37:01 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id 933BC2041CB; Sun, 10 Apr 2022 19:36:58 +0200 (CEST) X-Virus-Scanned: by amavisd-new-2.6.6 (20110518) (Debian) at infotech.no Received: from smtp.infotech.no ([127.0.0.1]) by localhost (smtp.infotech.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 12FZvKJlLKcM; Sun, 10 Apr 2022 19:36:56 +0200 (CEST) Received: from xtwo70.bingwo.ca (host-45-78-195-155.dyn.295.ca [45.78.195.155]) by smtp.infotech.no (Postfix) with ESMTPA id A1081204179; Sun, 10 Apr 2022 19:36:55 +0200 (CEST) From: Douglas Gilbert To: linux-scsi@vger.kernel.org Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, hare@suse.de, bvanassche@acm.org, hch@lst.de Subject: [PATCH v2 0/6] scsi: fix scsi_cmd::cmd_len Date: Sun, 10 Apr 2022 13:36:46 -0400 Message-Id: <20220410173652.313016-1-dgilbert@interlog.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org As described in the first patch of this set, commit ce70fd9a551af reduced the maximum size of any SCSI commands (CDB length) to 32 bytes. It was previously larger in struct scsi_request which has now (lk 5.18.0-rc1) been removed. Use a slightly different scheme than before to support CDB lengths greater than 16 bytes. Three access function are added, one for read access, one for writable access that doesn't increase the cdb length, and the third for create/write access to the CDB held inside a scsi_cmnd object. This reduces the size of struct scsi_cmnd by 16 bytes. A scsi_cmnd object is always paired with a struct request object that immediately precedes it. To note this pairing the new comments refer to a scsi_cmnd "sub-object". Prior to this patch the constructor/destructor naming was confusing: - scsi_alloc_request() to create a pair - blk_mq_free_request() to destruct a pair Add a new destructor function: scsi_free_cmnd(struct scsi_cmnd *scmd) to make this a bit clearer. Also scsi_free_cmnd() will free up a pointer to a long cdb buffer on the heap, if one is present. These changes have been applied to SCSI mid-level and the upper level drivers (ULDs, e.g. sd). Only one low level driver (LLD) has been updated: scsi_debug. The rest of the LLDs can continue to use scsi_cmnd::cmnd directly _unless_ they wish to support CDB lengths > 16 bytes; in that case they should use scsi_cmnd_get_cdb(). This patchset is against lk 5.18.0-rc1 and also applies cleanly to MKP's 5.19/scsi-queue branch. Changes since the first revision: - introduce a new SCSI_MAX_RUN_TIME_8BIT_CDB_LEN define for the case where hp->cmd_len is an 8 bit quantity. This addresses a kernel test robot report on patch 1 sent 20220408 - take up Bart's suggestion to reduce SCSI_MAX_COMPILE_TIME_CDB_LEN to 16, hence shaving 16 bytes off the size of struct scsi_cmnd - introduce scsi_cmnd_get_changeable_cdb() access function for the case when the code wants to change some bytes in an existing cdb but not increase its size - add a broad description of how struct scsi_cmnd fits into overall architecture, tweak some other comments - further work on the sr and stex ULDs Douglas Gilbert (6): scsi_cmnd: reinstate support for cmd_len > 32 sd, sd_zbc: use scsi_cmnd cdb access functions sg: reinstate cmd_len > 32 bsg: allow cmd_len > 32 scsi_debug: reinstate cmd_len > 32 st,sr,stex: use scsi_cmnd cdb access functions drivers/scsi/scsi_bsg.c | 22 +- drivers/scsi/scsi_debug.c | 410 +++++++++++++++++++----------------- drivers/scsi/scsi_debugfs.c | 3 +- drivers/scsi/scsi_error.c | 76 ++++--- drivers/scsi/scsi_ioctl.c | 21 +- drivers/scsi/scsi_lib.c | 75 ++++++- drivers/scsi/scsi_logging.c | 11 +- drivers/scsi/sd.c | 176 +++++++++------- drivers/scsi/sd_zbc.c | 12 +- drivers/scsi/sg.c | 23 +- drivers/scsi/sr.c | 40 ++-- drivers/scsi/st.c | 12 +- drivers/scsi/stex.c | 22 +- include/scsi/scsi_cmnd.h | 116 ++++++++-- include/scsi/scsi_eh.h | 6 +- 15 files changed, 623 insertions(+), 402 deletions(-)