From mboxrd@z Thu Jan 1 00:00:00 1970 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 B748A28BF4F; Thu, 3 Apr 2025 19:10:54 +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=1743707456; cv=none; b=tYiRsGyVmm68t2hAliv2t1Qkg4bOJoSsE3oXEfNO1OKRWXjkd4hCbJUd7V9/Bw6s3z1hubygIWgpXA3L+5NliODHhUbShCtcb2g7lUW9fmN96vXqdKygg6M5iYzMi5GZe3tlFit28pynup/nCpRDxuy6EduHLlwmnU7F0wBrtj8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707456; c=relaxed/simple; bh=7c+ZtG8m58hO7ouguvRL/6h31VTskTGgggUlpWydVOU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=NE8G9+LEeTU1qZkrPDeY6XCU7rbr/vFuIFdHpwCPa0vQyi4FM4pkvqRRWuo3GkXEETNkuXZnCaQlvgVfT5vgDIqvq3B9mS2HJrRuc/wtKFyKlju9OBCrtDu4NsxHkOGI3aqmkNdUPP3dG8ao7QbKe5xqeHFqnNQSvpN/VtZ5M0A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tWOE1B2y; 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="tWOE1B2y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 479BBC4CEE8; Thu, 3 Apr 2025 19:10:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743707454; bh=7c+ZtG8m58hO7ouguvRL/6h31VTskTGgggUlpWydVOU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tWOE1B2ySD9SWNrc+0RDNnJnvBYpzgY3+sEzvyoy6B07hZwsXvUH3QstvMgbPyHNr YOY/SBzTDcMhM2HVQL+bWVIlXcEVt3MQQHWeIEuXNtvmqWEx9dxgGUO6jaiGBkWSfj YSG81b5Z8R5vsHhQ/kOjuOX1YwDJHkoNcCzthEfK4gjsyx4DN4axeSeNDSwxJ5G+v5 z/rGD59ktUgIMLkqreI525muzB9iIFknxG0jz3zlQPzKQPYUB3kBZLSkWUCxsd7Tcx f4Zx5vAVLaGf6UN1hOZqj1La7KkUURK/jaIqXuywVyGqbLT4JFq598m8pSXTFiyz5J cWRernWzQymtQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Niklas Cassel , Philip Pemberton , Damien Le Moal , Sasha Levin , linux-ide@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 06/14] ata: libata-eh: Do not use ATAPI DMA for a device limited to PIO mode Date: Thu, 3 Apr 2025 15:10:28 -0400 Message-Id: <20250403191036.2678799-6-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250403191036.2678799-1-sashal@kernel.org> References: <20250403191036.2678799-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-ide@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.291 Content-Transfer-Encoding: 8bit From: Niklas Cassel [ Upstream commit 91ec84f8eaddbc93d7c62e363d68aeb7b89879c7 ] atapi_eh_request_sense() currently uses ATAPI DMA if the SATA controller has ATA_FLAG_PIO_DMA (PIO cmds via DMA) set. However, ATA_FLAG_PIO_DMA is a flag that can be set by a low-level driver on a port at initialization time, before any devices are scanned. If a controller detects a connected device that only supports PIO, we set the flag ATA_DFLAG_PIO. Modify atapi_eh_request_sense() to not use ATAPI DMA if the connected device only supports PIO. Reported-by: Philip Pemberton Closes: https://lore.kernel.org/linux-ide/c6722ee8-5e21-4169-af59-cbbae9edc02f@philpem.me.uk/ Tested-by: Philip Pemberton Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20250221015422.20687-2-cassel@kernel.org Signed-off-by: Niklas Cassel Signed-off-by: Sasha Levin --- drivers/ata/libata-eh.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index fa3f08ca5f6ce..4677eaf737141 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -1603,8 +1603,15 @@ unsigned int atapi_eh_request_sense(struct ata_device *dev, tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; tf.command = ATA_CMD_PACKET; - /* is it pointless to prefer PIO for "safety reasons"? */ - if (ap->flags & ATA_FLAG_PIO_DMA) { + /* + * Do not use DMA if the connected device only supports PIO, even if the + * port prefers PIO commands via DMA. + * + * Ideally, we should call atapi_check_dma() to check if it is safe for + * the LLD to use DMA for REQUEST_SENSE, but we don't have a qc. + * Since we can't check the command, perhaps we should only use pio? + */ + if ((ap->flags & ATA_FLAG_PIO_DMA) && !(dev->flags & ATA_DFLAG_PIO)) { tf.protocol = ATAPI_PROT_DMA; tf.feature |= ATAPI_PKT_DMA; } else { -- 2.39.5