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=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 52849C47094 for ; Thu, 10 Jun 2021 04:33:44 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0CD9E6139A for ; Thu, 10 Jun 2021 04:33:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CD9E6139A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=renesas.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 6AD951714; Thu, 10 Jun 2021 06:32:51 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 6AD951714 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1623299621; bh=MrzESbcWzlkfLVKrF9RihC9KNs3rLWfKHp0OVaHiZz8=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=Q38XqTMd5Ix6vrW1D2ik4eUlC9K14x/DxccMIhGssVSXn+WSLqH9Ty9GEub7Ao40S ddNT2Nusnjz9NWUxhAWCKPnEzBe7KT7pW++uf9cqdMUyDe63Rb1ma2jVhlDFnyNEjH j1cFUUTsnxiZAEEXkoXzxdUnw/KQ6BAyGgUAwtSo= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 05D03F800FC; Thu, 10 Jun 2021 06:32:51 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id C46B9F80218; Thu, 10 Jun 2021 06:32:49 +0200 (CEST) Received: from relmlie5.idc.renesas.com (relmlor1.renesas.com [210.160.252.171]) by alsa1.perex.cz (Postfix) with ESMTP id 51B88F800FC for ; Thu, 10 Jun 2021 06:32:42 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 51B88F800FC Date: 10 Jun 2021 13:32:40 +0900 X-IronPort-AV: E=Sophos;i="5.83,262,1616425200"; d="scan'208";a="83939169" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie5.idc.renesas.com with ESMTP; 10 Jun 2021 13:32:40 +0900 Received: from mercury.renesas.com (unknown [10.166.252.133]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id 554EA400C424; Thu, 10 Jun 2021 13:32:40 +0900 (JST) Message-ID: <871r9atk47.wl-kuninori.morimoto.gx@renesas.com> From: Kuninori Morimoto To: Dan Carpenter Subject: Re: [bug report] ASoC: rsnd: add null CLOCKIN support In-Reply-To: <20210610042400.GU10983@kadam> References: <87tum6booi.wl-kuninori.morimoto.gx@renesas.com> <20210610042400.GU10983@kadam> User-Agent: Wanderlust/2.15.9 Emacs/26.3 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Cc: alsa-devel@alsa-project.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" Hi Dan Thank you for your feedback > > if (IS_ERR(clk)) { > > dev_err(dev, "create null clk error\n"); > > - return NULL; > > + return PTR_ERR(clk); > > Yes, I think this part is correct. If an error happens, then it should > be reported to the user so they can fix it. Good ! > > @@ -430,9 +430,9 @@ static int rsnd_adg_get_clkin(struct rsnd_priv *priv) > > for (i = 0; i < CLKMAX; i++) { > > clk = devm_clk_get(dev, clk_name[i]); > > > > - if (IS_ERR(clk)) > > + if (IS_ERR_OR_NULL(clk)) > > clk = rsnd_adg_null_clk_get(priv); > > - if (IS_ERR(clk)) > > + if (IS_ERR_OR_NULL(clk)) > > goto err; > > But this is not correct. > > If a function like devm_clk_get() returns NULL, then it's not an error, > it's something where the user deliberately chose to disable the feature. > It shouldn't trigger an error message and the rest of the driver should > be written to accomodate it. > > > > > adg->clk[i] = clk; > > So we should assign the NULL pointer here and add NULL checks to make > sure that it doesn't lead to a NULL dereference. Ah, in this driver, if it got error or NULL clk, it try to call rsnd_adg_null_clk_get() and use null_clk instead of NULL. In other words, all adg->clk[i] should not NULL. If one of them was NULL, it is error for this driver. If so, my suggested code was OK, I hope. Thank you for your help !! Best regards --- Kuninori Morimoto