From patchwork Fri Apr 18 07:55:17 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 882752 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C7DB11ADC8D; Fri, 18 Apr 2025 07:56:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744962971; cv=none; b=roQi1Nd/W7Mc9yKa43BKkDMJ9iabzhimN5Ht5h7MfYhlVoq7cDU2UzxBvQ3PzoSKM2DmC4QQavGNHkKvk8VAtpBErXgAbb9EzJcP1p75UWJDg8eI/AfWiHxQTbp9SSxUzA+85Fq5TCtxHPldqGanPequaSpqL25KsEyfnf8s2PI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744962971; c=relaxed/simple; bh=CrRCKqz/JA5HsPhH6mB3lb5rhNmWhPIYyZNe/G7Iz0Y=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IdVpBlX8+K6Mpz9CdNKN7n0Ao1/GyTEaz7huwTn1+67SWzj/mHWza0L9jn+yziE/oOEwVu4sq4x5vIMnOkDpV5GjY4fbR6JI+gnEfsjtKX+QBqTI21TAuvSJyDLAxwmKyy4M5XYzMLAQHrrkdPuI0uQiRjxrm7oyhaq8IyZo7ZE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nkK0jWcP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nkK0jWcP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A2E0C4CEEC; Fri, 18 Apr 2025 07:56:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744962971; bh=CrRCKqz/JA5HsPhH6mB3lb5rhNmWhPIYyZNe/G7Iz0Y=; h=From:To:Subject:Date:In-Reply-To:References:From; b=nkK0jWcP6ZMIrW0BQWYExDSAnBlZlKGJLcUeZ2utXdnwUmaCvUELvdKbZ/Y7Wud6H UdMtZ6utU/NEMRycM06ZcXH2ydUCK8cJ3Lpl3aunZxfy1+/YJwN8XfhvFpr7Hvtb0R RCnMCFCKcNipOK9l89RTLRk84tIOfwUFWeYOq2zqf5eXXiuiiTAJluCmfLl5FqYIYi PCYIr21iUVOB7c+Jk3rNKvL6aNrN2SjuMzrLgimb1Yg7bOR9fXRO+FVQdf7haiSGLu ahi50KMHJDRc+N7/NETjHu+4W9U+Fy9hf3dQJLku+Dz0M7FH3IZKnUsi9fu6FnMsM4 bCSpLruY7fOIg== From: Damien Le Moal To: linux-ide@vger.kernel.org, Niklas Cassel , linux-scsi@vger.kernel.org, "Martin K . Petersen" Subject: [PATCH v2 5/5] scsi: Improve CDL control Date: Fri, 18 Apr 2025 16:55:17 +0900 Message-ID: <20250418075517.369098-6-dlemoal@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250418075517.369098-1-dlemoal@kernel.org> References: <20250418075517.369098-1-dlemoal@kernel.org> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 With ATA devices supporting the CDL feature, using CDL requires that the feature be enabled with a SET FEATURES command. This command is issued as the translated command for the MODE SELECT command issued by scsi_cdl_enable() when the user enables CDL through the device cdl_enable sysfs attribute. However, the implementation of scsi_cdl_enable() always issues a MODE SELECT command for ATA devices when the enable argument is true, even if CDL is already enabled on the device. While this does not cause any issue with using CDL descriptors with read/write commands (the CDL feature will be enabled on the drive), issuing the MODE SELECT command even when the device CDL feature is already enabled will cause a reset of the ATA device CDL statistics log page (as defined in ACS, any CDL enable action must reset the device statistics). Avoid this needless actions (and the implied statistics log page reset) by modifying scsi_cdl_enable() to issue the MODE SELECT command to enable CDL if and only if CDL is not reported as already enabled on the device. And while at it, simplify the initialization of the is_ata boolean variable and move the declaration of the scsi mode data and sense header variables to within the scope of ATA device handling. Fixes: 1b22cfb14142 ("scsi: core: Allow enabling and disabling command duration limits") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Igor Pylypiv --- drivers/scsi/scsi.c | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 53daf923ad8e..518a252eb6aa 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -707,26 +707,23 @@ void scsi_cdl_check(struct scsi_device *sdev) */ int scsi_cdl_enable(struct scsi_device *sdev, bool enable) { - struct scsi_mode_data data; - struct scsi_sense_hdr sshdr; - struct scsi_vpd *vpd; - bool is_ata = false; char buf[64]; + bool is_ata; int ret; if (!sdev->cdl_supported) return -EOPNOTSUPP; rcu_read_lock(); - vpd = rcu_dereference(sdev->vpd_pg89); - if (vpd) - is_ata = true; + is_ata = rcu_dereference(sdev->vpd_pg89); rcu_read_unlock(); /* * For ATA devices, CDL needs to be enabled with a SET FEATURES command. */ if (is_ata) { + struct scsi_mode_data data; + struct scsi_sense_hdr sshdr; char *buf_data; int len; @@ -735,16 +732,30 @@ int scsi_cdl_enable(struct scsi_device *sdev, bool enable) if (ret) return -EINVAL; - /* Enable CDL using the ATA feature page */ + /* Enable or disable CDL using the ATA feature page */ len = min_t(size_t, sizeof(buf), data.length - data.header_length - data.block_descriptor_length); buf_data = buf + data.header_length + data.block_descriptor_length; - if (enable) - buf_data[4] = 0x02; - else - buf_data[4] = 0; + + /* + * If we want to enable CDL and CDL is already enabled on the + * device, do nothing. This avoids needlessly resetting the CDL + * statistics on the device as that is implied by the CDL enable + * action. Similar to this, there is no need to do anything if + * we want to disable CDL and CDL is already disabled. + */ + if (enable) { + if ((buf_data[4] & 0x03) == 0x02) + goto out; + buf_data[4] &= ~0x03; + buf_data[4] |= 0x02; + } else { + if ((buf_data[4] & 0x03) == 0x00) + goto out; + buf_data[4] &= ~0x03; + } ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3, &data, &sshdr); @@ -756,6 +767,7 @@ int scsi_cdl_enable(struct scsi_device *sdev, bool enable) } } +out: sdev->cdl_enable = enable; return 0;