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 X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08373C433E2 for ; Wed, 22 Jul 2020 18:10:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEA6E20B1F for ; Wed, 22 Jul 2020 18:10:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595441401; bh=NmBDYRLXE7yLQ1W+FnfOFlvtKPX0dfdhfwoZ8FHxDT8=; h=Date:From:To:Cc:Subject:List-ID:From; b=i6sGbhQQRUuYy17Ltl1HAXJTBYfD4bmoEAO26ORUeLxDSljW1vYLUKjtjp5Sr/K3r 59LHV3FwXDNoaR/jEBh8Hfel38nbrvt7mEI6SLmN6VGPcqXpquQWXafcM3pngwanzR s54yDswiKPw4L4kUJhxnrzfr9nqXtV6KKX5NYOJo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731569AbgGVSKA (ORCPT ); Wed, 22 Jul 2020 14:10:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:59166 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726535AbgGVSKA (ORCPT ); Wed, 22 Jul 2020 14:10:00 -0400 Received: from embeddedor (unknown [201.162.161.212]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5556820787; Wed, 22 Jul 2020 18:09:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595441399; bh=NmBDYRLXE7yLQ1W+FnfOFlvtKPX0dfdhfwoZ8FHxDT8=; h=Date:From:To:Cc:Subject:From; b=iYVbcMsE8a7W1Haau6s6tTXgFjXgPMpVvTDvGoDTQ/dz8fhA6nyAWpXmz7iDBWBqw GxmT9dleWu7/T82+SNsyX4P3Ijv+Tn3KL0VDu3vX9o6zKApBdYkdhO7OTaxzhPE71r qZoWTJ1H9pXPj9bYXH6AaJke5ycpJ77sRlRUixmw= Date: Wed, 22 Jul 2020 13:15:34 -0500 From: "Gustavo A. R. Silva" To: Arnd Bergmann , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] mei: hdcp: Replace one-element array with flexible-array member Message-ID: <20200722181534.GA31357@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Also, make use of the array_size() helper instead of the open-coded version in memcpy(). These sorts of multiplication factors need to be wrapped in array_size(). And while there, use the preferred form for passing a size of a struct. The alternative form where struct name is spelled out hurts readability and introduces an opportunity for a bug when the pointer variable type is changed but the corresponding sizeof that is passed as argument is not. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/79 Signed-off-by: Gustavo A. R. Silva --- drivers/misc/mei/hdcp/mei_hdcp.c | 2 +- drivers/misc/mei/hdcp/mei_hdcp.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c index e6c3dc595617..d1d3e025ca0e 100644 --- a/drivers/misc/mei/hdcp/mei_hdcp.c +++ b/drivers/misc/mei/hdcp/mei_hdcp.c @@ -572,7 +572,7 @@ static int mei_hdcp_verify_mprime(struct device *dev, HDCP_2_2_MPRIME_LEN); drm_hdcp_cpu_to_be24(verify_mprime_in.seq_num_m, data->seq_num_m); memcpy(verify_mprime_in.streams, data->streams, - (data->k * sizeof(struct hdcp2_streamid_type))); + array_size(data->k, sizeof(*data->streams))); verify_mprime_in.k = cpu_to_be16(data->k); diff --git a/drivers/misc/mei/hdcp/mei_hdcp.h b/drivers/misc/mei/hdcp/mei_hdcp.h index 18ffc773fa18..834757f5e072 100644 --- a/drivers/misc/mei/hdcp/mei_hdcp.h +++ b/drivers/misc/mei/hdcp/mei_hdcp.h @@ -358,7 +358,7 @@ struct wired_cmd_repeater_auth_stream_req_in { u8 seq_num_m[HDCP_2_2_SEQ_NUM_LEN]; u8 m_prime[HDCP_2_2_MPRIME_LEN]; __be16 k; - struct hdcp2_streamid_type streams[1]; + struct hdcp2_streamid_type streams[]; } __packed; struct wired_cmd_repeater_auth_stream_req_out { -- 2.27.0