From patchwork Sun Jan 2 23:23:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 529728 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 13544C433F5 for ; Sun, 2 Jan 2022 23:33:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231162AbiABXc6 (ORCPT ); Sun, 2 Jan 2022 18:32:58 -0500 Received: from angie.orcam.me.uk ([78.133.224.34]:38430 "EHLO angie.orcam.me.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230115AbiABXcz (ORCPT ); Sun, 2 Jan 2022 18:32:55 -0500 Received: by angie.orcam.me.uk (Postfix, from userid 500) id 6D8829200B3; Mon, 3 Jan 2022 00:23:57 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 69AB092009B; Sun, 2 Jan 2022 23:23:57 +0000 (GMT) Date: Sun, 2 Jan 2022 23:23:57 +0000 (GMT) From: "Maciej W. Rozycki" To: Khalid Aziz , "James E.J. Bottomley" , "Martin K. Petersen" cc: Christoph Hellwig , Nix , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/3] scsi: Set allocation length to 255 for ATA Information VPD page In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Set the allocation length to 255 for the ATA Information VPD page requested in the WRITE SAME handler, so as not to limit information examined by `scsi_get_vpd_page' in the supported vital product data pages unnecessarily. Originally it was thought that Areca hardware may have issues with a valid allocation length supplied for a VPD inquiry, however older SCSI standard revisions[1] consider 255 the maximum length allowed and what has later become the high order byte is considered reserved and must be zero with the INQUIRY command. Therefore it was unnecessary to reduce the amount of data requested from 512 as far down as to 64, arbitrarily chosen, and 255 would as well do. With commit b3ae8780b429 ("[SCSI] Add EVPD page 0x83 and 0x80 to sysfs") we have since got the SCSI_VPD_PG_LEN macro, so use that instead. References: [1] "Information technology - Small Computer System Interface - 2", WORKING DRAFT, X3T9.2, Project 375D, Revision 10L, 7-SEP-93, Section 8.2.5 "INQUIRY command", pp.104-108 Signed-off-by: Maciej W. Rozycki Fixes: af73623f5f10 ("[SCSI] sd: Reduce buffer size for vpd request") Tested-by: Nick Alcock --- Changes from v2: - Add Nick's Tested-by annotation. No changes from v1. --- drivers/scsi/sd.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) linux-scsi-write-same-vpd-buffer.diff Index: linux-macro/drivers/scsi/sd.c =================================================================== --- linux-macro.orig/drivers/scsi/sd.c +++ linux-macro/drivers/scsi/sd.c @@ -3101,16 +3101,13 @@ static void sd_read_write_same(struct sc } if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, INQUIRY) < 0) { - /* too large values might cause issues with arcmsr */ - int vpd_buf_len = 64; - sdev->no_report_opcodes = 1; /* Disable WRITE SAME if REPORT SUPPORTED OPERATION * CODES is unsupported and the device has an ATA * Information VPD page (SAT). */ - if (!scsi_get_vpd_page(sdev, 0x89, buffer, vpd_buf_len)) + if (!scsi_get_vpd_page(sdev, 0x89, buffer, SCSI_VPD_PG_LEN)) sdev->no_write_same = 1; }