From patchwork Fri Jun 23 07:30:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 696138 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 F2148EB64D7 for ; Fri, 23 Jun 2023 07:31:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230458AbjFWHbH (ORCPT ); Fri, 23 Jun 2023 03:31:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230091AbjFWHbG (ORCPT ); Fri, 23 Jun 2023 03:31:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 566F32128 for ; Fri, 23 Jun 2023 00:31:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D7DB66198E for ; Fri, 23 Jun 2023 07:30:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D35D0C433C0; Fri, 23 Jun 2023 07:30:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687505459; bh=DRXD/f6g0JWBc8hYMCFtLqO8imOHceLXOWDtWDSAFuU=; h=From:To:Cc:Subject:Date:From; b=H3oJVFGJKhIp0fozg+9u5P3LjSNKKgYOjuf7cxsoc8OsIa8wIQoB/GiCGfFi79oVG FnnEKROz37GyriPPVE0TiskTG0lgnVVQwtXGBiwt+j/CZ8gqoThEt1v8HaSOJ5qlFX S0cwXCaWRt27b771DwJnWIxMQXM8/TAL1lm15AnlSPeGFZe/zkHM2+Rsw+NJUp0cqJ WPJMiYHbRst/nN0PuGSQSOloT0njLTMCSHcZ3ZJroH7X8hcgVGsFkPhVZnWI1e2btg g5UCZiFtQHr8Yu0t0Er8aA6Fe3oPeR9oQx97p/+mvzQbM+eRHrit/XqTQGqKs51OUO SsRRQXLslkL4w== From: Damien Le Moal To: "Martin K . Petersen" , linux-scsi@vger.kernel.org Cc: Niklas Cassel Subject: [PATCH v2] scsi: Simplify scsi_cdl_check_cmd() Date: Fri, 23 Jun 2023 16:30:57 +0900 Message-Id: <20230623073057.816199-1-dlemoal@kernel.org> X-Mailer: git-send-email 2.40.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Reading the 800+ pages of SPC often leads to a brain shutdown and to less than ideal code... This resulted in the checks of the rwcdlp and cdlp fields in scsi_cdl_check_cmd() to have identical if-else branches. Replace this with a comment describing the cases we are interested in and replace the if-else code block with a simple test of the cdlp field that is used as the function return value. Reported-by: kernel test robot Reported-by: Julia Lawall Closes: https://lore.kernel.org/r/202306221657.BJHEADkz-lkp@intel.com/ Signed-off-by: Damien Le Moal Reviewed-by: Christoph Hellwig --- Changes from v1: * Reword the comment to follow SPC wording for "One_command parameter data format" drivers/scsi/scsi.c | 37 ++++++++++++++----------------------- 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index c4bf99a842f3..d0911bc28663 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -586,31 +586,22 @@ static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa, if ((buf[1] & 0x03) != 0x03) return false; - /* See SPC-6, one command format of REPORT SUPPORTED OPERATION CODES */ + /* + * See SPC-6, One_command parameter data format for + * REPORT SUPPORTED OPERATION CODES. We have the following cases + * depending on rwcdlp (buf[0] & 0x01) value: + * - rwcdlp == 0: then cdlp indicates support for the A mode page when + * it is equal to 1 and for the B mode page when it is + * equal to 2. + * - rwcdlp == 1: then cdlp indicates support for the T2A mode page + * when it is equal to 1 and for the T2B mode page when + * it is equal to 2. + * Overall, to detect support for command duration limits, we only need + * to check that cdlp is 1 or 2. + */ cdlp = (buf[1] & 0x18) >> 3; - if (buf[0] & 0x01) { - /* rwcdlp == 1 */ - switch (cdlp) { - case 0x01: - /* T2A page */ - return true; - case 0x02: - /* T2B page */ - return true; - } - } else { - /* rwcdlp == 0 */ - switch (cdlp) { - case 0x01: - /* A page */ - return true; - case 0x02: - /* B page */ - return true; - } - } - return false; + return cdlp == 0x01 || cdlp == 0x02; } /**