From mboxrd@z Thu Jan 1 00:00:00 1970 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 B3725C76195 for ; Fri, 17 Mar 2023 11:43:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230007AbjCQLnC (ORCPT ); Fri, 17 Mar 2023 07:43:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230396AbjCQLmt (ORCPT ); Fri, 17 Mar 2023 07:42:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 95436A7295; Fri, 17 Mar 2023 04:42:29 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B4C621480; Fri, 17 Mar 2023 04:35:33 -0700 (PDT) Received: from [10.57.17.87] (unknown [10.57.17.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2D06D3F885; Fri, 17 Mar 2023 04:34:47 -0700 (PDT) Message-ID: <74d8b579-6ea8-d6f3-170f-ea13534b4565@arm.com> Date: Fri, 17 Mar 2023 11:34:49 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v2 4/4] serial: qcom_geni: Use devm_krealloc_array Content-Language: en-US To: Jonathan Cameron , Krzysztof Kozlowski Cc: linux-kernel@vger.kernel.org, linux@roeck-us.net, michal.simek@amd.com, Jonathan Corbet , Jean Delvare , Anand Ashok Dumbre , Lars-Peter Clausen , Michal Simek , Andy Gross , Bjorn Andersson , Konrad Dybcio , Greg Kroah-Hartman , Jiri Slaby , linux-doc@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org References: <20230309150334.216760-1-james.clark@arm.com> <20230309150334.216760-5-james.clark@arm.com> <20230311191800.74ec2b84@jic23-huawei> From: James Clark In-Reply-To: <20230311191800.74ec2b84@jic23-huawei> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On 11/03/2023 19:18, Jonathan Cameron wrote: > On Thu, 9 Mar 2023 15:03:33 +0000 > James Clark wrote: > >> Now that it exists, use it instead of doing the multiplication manually. >> >> Signed-off-by: James Clark > > Hmm. I've stared at the users of this for a bit, and it's not actually obvious > that it's being used as an array of u32. The only typed user of this is as > the 2nd parameter of > tty_insert_flip_string() which is an unsigned char * > > I wonder if that sizeof(u32) isn't a 'correct' description of where the 4 is coming > from even if it has the right value? Perhaps the fifo depth is just a multiple of 4? > > Jonathan > The commit that added it (b8caf69a6946) seems to hint that something reads from it in words. And I see this: /* We always configure 4 bytes per FIFO word */ #define BYTES_PER_FIFO_WORD 4U Perhaps sizeof(u32) isn't as accurate of a description as using BYTES_PER_FIFO_WORD but I'd be reluctant to make a change because I don't really understand the implications. There is also this in handle_rx_console(): unsigned char buf[sizeof(u32)]; James > > >> --- >> drivers/tty/serial/qcom_geni_serial.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c >> index d69592e5e2ec..23fc33d182ac 100644 >> --- a/drivers/tty/serial/qcom_geni_serial.c >> +++ b/drivers/tty/serial/qcom_geni_serial.c >> @@ -1056,9 +1056,9 @@ static int setup_fifos(struct qcom_geni_serial_port *port) >> (port->tx_fifo_depth * port->tx_fifo_width) / BITS_PER_BYTE; >> >> if (port->rx_buf && (old_rx_fifo_depth != port->rx_fifo_depth) && port->rx_fifo_depth) { >> - port->rx_buf = devm_krealloc(uport->dev, port->rx_buf, >> - port->rx_fifo_depth * sizeof(u32), >> - GFP_KERNEL); >> + port->rx_buf = devm_krealloc_array(uport->dev, port->rx_buf, >> + port->rx_fifo_depth, sizeof(u32), >> + GFP_KERNEL); >> if (!port->rx_buf) >> return -ENOMEM; >> } >