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 6C45F1E5B9A; Mon, 13 Oct 2025 10:35:41 +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=1760351741; cv=none; b=H6JIqlKarEWW1N1pPEY05dPr67QZEY1fKDwUIVeKWmRPc28t7rJPF5WMzklfIEhKIHgom12DOVbhNUZo7I2c5MJMA9lITp5CmhzVIQL/haDfFu58L5T+Fx5LAFgLbyTOQehRFT9lq7SRwJEgHQNouVxw6eNqBaD45emh1Q2S9qI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760351741; c=relaxed/simple; bh=mSlTLpr9dlmJ/MLh0hm/KQWg73tObXOepMvzYnhvn+U=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=Ixsk9zwieC9UPL9/uNxPcP5651oQUMSt6WX1EMjPVLX5JLZYAWp+BWGbOpjHRPUAH9KFoUMqbdSnEitvu9FS8p7iuvtIFCfzrmFRRcojG5UBegxjYsL7+UHuXKqK0u3OzPVjnAK9TqnIjAj+hBmd991LhIBserEoDn/Pvo3aKaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tujRhX6e; 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="tujRhX6e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9F1CC4CEE7; Mon, 13 Oct 2025 10:35:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760351741; bh=mSlTLpr9dlmJ/MLh0hm/KQWg73tObXOepMvzYnhvn+U=; h=Date:From:Subject:To:Cc:References:In-Reply-To:From; b=tujRhX6elWFk1HnyxG44dEeFYaKaNBLQH/8WjzO4isMctYz3Cql1ZVus9RmrS8XoU KzZkEqMO80y49PmWdand+ZFxATx2FIlkX9wXmaLj2jAY0RyIVfxBlz+mFIIgareN6s xSfsBJfz3EERw6w/vvefH7kOgY58ZXydNwQx1QgzBAN/zXb0fofU0IcX6YQ4kXzykO Nr7oFHtfNjFisGCCrKeH2FdXn6D6eMuQSdy/svQ+zAmSbnksN2b5ZuFVzfPNNjU4Ym p8+sZa8duSpBVIVf5vNkGeJxMp2rkzhV+1dpn3hlo6AiMzAhL5UoB7NjWEG1rl9D85 bs64liGYEIA2Q== Message-ID: <958a157f-e01d-499c-9f3e-d19e33b1de74@kernel.org> Date: Mon, 13 Oct 2025 12:35:38 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Hans Verkuil Subject: Re: [PATCH] media: saa6588: Fix unsafe debug printk macro To: Shrikant Raskar , hverkuil@kernel.org, mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250923175927.4380-1-raskar.shree97@gmail.com> Content-Language: en-US, nl In-Reply-To: <20250923175927.4380-1-raskar.shree97@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 23/09/2025 19:59, Shrikant Raskar wrote: > The existing dprintk macro used an unwrapped `if` statement, which can lead > to logic errors when used in if/else constructs. This patch wraps the macro > in a do { } while (0) block to ensure safe usage. > > This change resolves the following checkpatch error: > ERROR: Macros starting with if should be enclosed by a do - while loop to > avoid possible if/else logic defects > > Signed-off-by: Shrikant Raskar > --- > drivers/media/i2c/saa6588.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/i2c/saa6588.c b/drivers/media/i2c/saa6588.c > index fb09e4560d8a..71d34d229564 100644 > --- a/drivers/media/i2c/saa6588.c > +++ b/drivers/media/i2c/saa6588.c > @@ -50,7 +50,7 @@ MODULE_LICENSE("GPL"); > > #define UNSET (-1U) > #define PREFIX "saa6588: " > -#define dprintk if (debug) printk > +#define dprintk(fmt, args...) do { if (debug) printk(fmt, ##args); } while (0) > > struct saa6588 { > struct v4l2_subdev sd; I think we can do better than this. Looking at how dprintk is used in this driver, I see that in almost all cases it is preceded by a 'if (debug > X)' condition. Except for one occurrence in saa6588_configure(). So I would propose to just drop dprintk, and instead change dprintk to pr_info and pr_cont. And add a 'if (debug)' in saa6588_configure(). Actually, v4l2_info(&s->sd, ...) would be even better, then the PREFIX can be dropped as well. Regards, Hans