From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from msg-4.mailo.com (msg-4.mailo.com [213.182.54.15]) (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 E8C5420E2 for ; Mon, 28 Nov 2022 08:22:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailo.com; s=mailo; t=1669623723; bh=HoI7IPlyKWHD9Kn5X10ZHl3UFFv8o6ZZDjqQm365fyQ=; h=X-EA-Auth:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:In-Reply-To; b=cY6XYfSBgOawZ8YaNqeXmP6jyxqpCZFYLNI28OoXMK4A3C+p/hdakSydDk/j2WtkM LAjmXY72W2MxJlE/Yk8FNSzAikJWRnwPoKgf77JKw62a6eJWCYK/85VLDkbgwg+ddD XEgUh2eWj5nAWTbQc9o0ahVB52aumbNZhohYlvBw= Received: by b-3.in.mailobj.net [192.168.90.13] with ESMTP via ip-206.mailobj.net [213.182.55.206] Mon, 28 Nov 2022 09:22:03 +0100 (CET) X-EA-Auth: Z5uIHs5CpSgjU332Ikz4u8b+XZa03kuBLMdLqLTeFqTcZc5po3StYuaZUVJMKCr04rF8s2HCvhTHZ/3OSytxENj19ruxRHel Date: Mon, 28 Nov 2022 13:51:58 +0530 From: Deepak R Varma To: Dan Carpenter Cc: Greg Kroah-Hartman , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, gustavoars@kernel.org Subject: Re: [PATCH] staging: wlan-ng: Replace zero-length arrays with DECLARE_FLEX_ARRAY() helper Message-ID: References: Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Nov 28, 2022 at 10:50:19AM +0300, Dan Carpenter wrote: > On Mon, Nov 28, 2022 at 01:15:43PM +0530, Deepak R Varma wrote: > > On Sat, Nov 19, 2022 at 08:08:15PM +0530, Deepak R Varma wrote: > > > On Thu, Nov 17, 2022 at 07:03:21PM +0100, Greg Kroah-Hartman wrote: > > > > On Thu, Nov 17, 2022 at 06:50:55PM +0530, Deepak R Varma wrote: > > > > > On Thu, Nov 17, 2022 at 01:54:49PM +0100, Greg Kroah-Hartman wrote: > > > > > > On Thu, Nov 17, 2022 at 03:48:45PM +0530, Deepak R Varma wrote: > > > > > > > > > > > > > > struct hfa384x_pdr_refdac_measurements { > > > > > > > - u16 value[0]; > > > > > > > + DECLARE_FLEX_ARRAY(u16, value); > > > > > > > } __packed; > > > > > > > > > > > > Why? This structure is never used anywhere, right? So why is this > > > > > > needed to be changed and not just removed entirely? Same for the other > > > > > > structures in this patch. > > > > > > > > > > Hello Greg, > > > > > I am unable to confirm that these structures are truly not needed in the absence > > > > > if a real device based testing. I could only validate that using the compile > > > > > build and driver loading. > > > > > > > > Think this through, if no one is actually using this structure, and it > > > > is of 0 size, then do you think it is being used? > > > > > > Hello Greg, > > > I did not find any memory allocation for these zero length array structures. > > > Also, the union or its enclosing structure do not appear to access the members. > > > Hence I am leaning towards concluding that these zero length array structures do > > > not appear to be necessary. > > > > > > There are a few other structures that are part of the same union, however, they > > > too do not appear to be used for accessing the memory assigned to the union [or > > > its enclosing structure]. I think most of the members of these unions can be > > > replaced by one max size structure of this union [e.g. struct > > > hfa384x_pdr_mkk_measurements]. > > > > > > Could you please comment if I am reading the code right? > > > > > > For your quick reference, the zero length structure declaration are online 963 > > > whereas the union is on line number 1080 of the file drivers/staging/wlan-ng/hfa384x.h > > > > Hello Greg, > > can you please suggest how should I approach this clean-up/correction? > > > > Like this: Thank you Dan. This takes me back to the very first version of this patch. I will send in the clean up. ./drv > > diff --git a/drivers/staging/wlan-ng/hfa384x.h b/drivers/staging/wlan-ng/hfa384x.h > index 0611e37df6ac..6a3df58c9e9c 100644 > --- a/drivers/staging/wlan-ng/hfa384x.h > +++ b/drivers/staging/wlan-ng/hfa384x.h > @@ -959,10 +959,6 @@ struct hfa384x_pdr_nicid { > u16 minor; > } __packed; > > -struct hfa384x_pdr_refdac_measurements { > - u16 value[0]; > -} __packed; > - > struct hfa384x_pdr_vgdac_measurements { > u16 value[0]; > } __packed; > @@ -1077,7 +1073,6 @@ struct hfa384x_pdrec { > struct hfa384x_pdr_mfisuprange mfisuprange; > struct hfa384x_pdr_cfisuprange cfisuprange; > struct hfa384x_pdr_nicid nicid; > - struct hfa384x_pdr_refdac_measurements refdac_measurements; > struct hfa384x_pdr_vgdac_measurements vgdac_measurements; > struct hfa384x_pdr_level_comp_measurements level_compc_measurements; > struct hfa384x_pdr_mac_address mac_address; >