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 D7F3520E2 for ; Mon, 28 Nov 2022 07:53:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCB8BC433C1; Mon, 28 Nov 2022 07:53:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669622013; bh=um03zoPpxKsSPE+M2zpAJXsHvH/peut6tDHzA78ZNoM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Jkdq03L2qV0u5uszScn4GnxkJ4wH4lW1f++a+IEgzYsJg5muigr6IoZU5+L2o4XUU EbPVIDsb1DEBMWPOGkAU/p4KGA0byXjOTXP8C/yFqHTVUblSV4zr1LgMi4lXsQ86eZ CXSB8knab1krmTsd5FbaPDmuVIU2Y1kjY/NjfNTk= Date: Mon, 28 Nov 2022 08:53:28 +0100 From: Greg Kroah-Hartman To: Deepak R Varma Cc: 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 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? Sorry, but I do not have the bandwidth to help out with this. I will gladly review changes submitted only. greg k-h