From patchwork Fri Jun 23 00:29:12 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: 696139 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 DDBA9EB64DA for ; Fri, 23 Jun 2023 00:29:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229743AbjFWA3R (ORCPT ); Thu, 22 Jun 2023 20:29:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229450AbjFWA3P (ORCPT ); Thu, 22 Jun 2023 20:29:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3768C170E for ; Thu, 22 Jun 2023 17:29:15 -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 A562061935 for ; Fri, 23 Jun 2023 00:29:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E107C433C8; Fri, 23 Jun 2023 00:29:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687480154; bh=9WsA5vj2mNv67bpSROnniP5CyJ4/6MwfhvyJbuQuVuI=; h=From:To:Cc:Subject:Date:From; b=Pg6A9xPkcUq+wrJB88Yt05AQZ8+8+cmMZ3QkJ0Qitjb8Zio+sqtX14/gbd6Shhf9c l91J0bTNrPumVzkqwOVlVMRroQ72AEhDnG0EgyJvvmU7FlqiQ0ZzGHU1KI6kDDb0HZ /oGUryS4ot6WmMlMm0sPJ0gEo1gRx1NzqyTF+nXmx7bQy2JxJ2eDyBoMhcXaFYUQq8 +WNdtHq5F1S4Pinzh1SH45ed+OyCJTWiYvoEX1IBTtV9VsVzTzh86/nyoQyPFtjVto sMkGbJkOoWyv6Ud7Yz6m35L/6A++B830SW1oqZLIGiCOz6Y5hqVmiQZJFLv0Rwo9Vr EZRmDUXmXOqPg== From: Damien Le Moal To: "Martin K . Petersen" , linux-scsi@vger.kernel.org Cc: Niklas Cassel Subject: [PATCH] scsi: Simplify scsi_cdl_check_cmd() Date: Fri, 23 Jun 2023 09:29:12 +0900 Message-Id: <20230623002912.808251-1-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 --- 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..cea10616e630 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 format of 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; } /**