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 5E0F9C433F5 for ; Sun, 27 Feb 2022 17:41:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229845AbiB0RmZ (ORCPT ); Sun, 27 Feb 2022 12:42:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229664AbiB0RmZ (ORCPT ); Sun, 27 Feb 2022 12:42:25 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D0593AA48; Sun, 27 Feb 2022 09:41:48 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BB73C60FD3; Sun, 27 Feb 2022 17:41:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7F08C340EF; Sun, 27 Feb 2022 17:41:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645983707; bh=u7vdYl/msJzciiBUb4kqi0WTExjnG9fioQPXlI5ief0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Xs1LWFkSqwXAGfmnXXhvfL+kVt07aTnfpsB52Vxlux/P31uUqSsWqquz/BZ3egW9E 5AWcpUjRB/JozILkJNE5e8q26bz/NxH5/BttXnZJ5KVqduarQgYYheQ4M3ah7QaQUI 7/iK9RUTN+DtNx72HR8wCi7F5FbIebSFBFfIFdyaf8ugdWH2hdojy40ObPY1ps4fJ8 aVEBo3JQaWgTMndrBBFu8JtBuVT0rS5+jT1uah64W7P88fR5eYtu1hSrvQNZFGoA9/ V5N+jMGQQSQlfmauloQcU0gkD4fh7skp8AZmE+x+oNY1vmkidNRXZa6wM75IFoHzFg dis9WveVLuDOQ== Date: Sun, 27 Feb 2022 17:48:50 +0000 From: Jonathan Cameron To: trix@redhat.com Cc: roan@protonic.nl, lars@metafoo.de, nathan@kernel.org, ndesaulniers@google.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH] iio: scd4x: check return of scd4x_write_and_fetch Message-ID: <20220227174850.73520e39@jic23-huawei> In-Reply-To: <20220227154331.80338-1-trix@redhat.com> References: <20220227154331.80338-1-trix@redhat.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sun, 27 Feb 2022 07:43:31 -0800 trix@redhat.com wrote: > From: Tom Rix > > Clang static analysis reports this problem > scd4x.c:474:10: warning: The left operand of '==' is a > garbage value > if (val == 0xff) { > ~~~ ^ > val is only set from a successful call to scd4x_write_and_fetch() > So check it's return. > > Fixes: 49d22b695cbb ("drivers: iio: chemical: Add support for Sensirion SCD4x CO2 sensor") > Signed-off-by: Tom Rix Good find, but I'd prefer a separate check on ret inline with what the other error checking paths in that function are doing. > --- > drivers/iio/chemical/scd4x.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iio/chemical/scd4x.c b/drivers/iio/chemical/scd4x.c > index 20d4e7584e923..b978330fb761c 100644 > --- a/drivers/iio/chemical/scd4x.c > +++ b/drivers/iio/chemical/scd4x.c > @@ -471,7 +471,7 @@ static ssize_t calibration_forced_value_store(struct device *dev, > ret = scd4x_write_and_fetch(state, CMD_FRC, arg, &val, sizeof(val)); > mutex_unlock(&state->lock); > > - if (val == 0xff) { > + if (!ret && val == 0xff) { > dev_err(dev, "forced calibration has failed"); > return -EINVAL; > } Prefer if (ret) return ret; if (val == 0xff) { dev_err(dev, "... return -EINVAL; } Thanks, Jonathan