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 928F7ECAAA1 for ; Sun, 11 Sep 2022 07:25:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229971AbiIKHZJ (ORCPT ); Sun, 11 Sep 2022 03:25:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229923AbiIKHZD (ORCPT ); Sun, 11 Sep 2022 03:25:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1CF2255A4 for ; Sun, 11 Sep 2022 00:25:02 -0700 (PDT) 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 1115B60E9A for ; Sun, 11 Sep 2022 07:25:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21F1FC433D6; Sun, 11 Sep 2022 07:25:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1662881101; bh=OrAu6mHIVqYRRW/CQFimPqBKISrkvqtpRN9Epl3Dyxg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=slDYJmis3ItMPuBIHoHNT3dHscIivy08miuXqCAL0AjgKn5uM6Pr1LdrkTOmXpsEi 1J5/JHa5KHtCSKx8oyEtVUDwl3iUfGAH4pTzL8YswRreXy+A7Fdw1DDgRq+DQ0dLeS zRxd7J0HjaSiY3GEANn6RPX8rEBCTjQlPISulNHY= Date: Sun, 11 Sep 2022 09:25:23 +0200 From: Greg KH To: Nam Cao Cc: forest@alittletooquiet.net, linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev Subject: Re: [PATCH v3 1/2] staging: vt6655: remove unnecessary volatile qualifier Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 11, 2022 at 09:12:44AM +0200, Nam Cao wrote: > On Fri, Sep 9, 2022 at 8:03 PM Greg KH wrote: > > > > On Fri, Sep 09, 2022 at 02:17:55PM +0200, Nam Cao wrote: > > > Remove volatile qualifier for the member rd0 of struct vnt_rx_desc, > > > because there is no reason it must be volatile. > > > > > > Signed-off-by: Nam Cao > > > --- > > > drivers/staging/vt6655/desc.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/staging/vt6655/desc.h b/drivers/staging/vt6655/desc.h > > > index 17a40c53b8ff..3f0f287b1693 100644 > > > --- a/drivers/staging/vt6655/desc.h > > > +++ b/drivers/staging/vt6655/desc.h > > > @@ -182,7 +182,7 @@ struct vnt_rdes1 { > > > > > > /* Rx descriptor*/ > > > struct vnt_rx_desc { > > > - volatile struct vnt_rdes0 rd0; > > > + struct vnt_rdes0 rd0; > > > > You can not just remove this without describing _WHY_ it is ok to do so. > > > > Have you properly determined why it is, or is not, ok to use volatile > > here? > > I did not carefully look at the volatile usage here. After looking at it > again, using volatile is actually valid: the structure resides on coherent > memory. Are you sure? That's a very odd thing for a driver to need. Looks like they are allocating some dma memory and then pointing structures on top of that memory. Why would you need to have "volatile" markings on a structure definition for that? Dig into this some more please, I don't think this is correct. thanks, greg k-h