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 1F47CC433FE for ; Fri, 29 Apr 2022 11:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358249AbiD2Lxf (ORCPT ); Fri, 29 Apr 2022 07:53:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242846AbiD2Lxd (ORCPT ); Fri, 29 Apr 2022 07:53:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16BB25595; Fri, 29 Apr 2022 04:50:13 -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 F014F62002; Fri, 29 Apr 2022 11:50:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAB19C385A4; Fri, 29 Apr 2022 11:50:10 +0000 (UTC) Message-ID: <6b2ff63b-7fa6-935b-002a-3ecd46273877@xs4all.nl> Date: Fri, 29 Apr 2022 13:50:09 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH V0 1/1] media: v4l2-core: Enable reserved field of v4l2_event Content-Language: en-US To: Naina Vaskenly , Mauro Carvalho Chehab , lijian , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Kumar Anshuman References: From: Hans Verkuil In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/04/2022 13:45, Naina Vaskenly wrote: > 'reserved' member of struct v4l2_event is currently not enabled. > This field can be used to transfer data, if >64 bytes of data > has to be sent. Hence, added this change to copy the reserved field in > __v4l2_event_queue_fh. > > Signed-off-by: Naina Vaskenly > --- > drivers/media/v4l2-core/v4l2-event.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c > index c5ce9f1..3d741cb 100644 > --- a/drivers/media/v4l2-core/v4l2-event.c > +++ b/drivers/media/v4l2-core/v4l2-event.c > @@ -137,8 +137,10 @@ static void __v4l2_event_queue_fh(struct v4l2_fh *fh, > /* Take one and fill it. */ > kev = sev->events + sev_pos(sev, sev->in_use); > kev->event.type = ev->type; > - if (copy_payload) > + if (copy_payload) { > kev->event.u = ev->u; > + memcpy(kev->event.reserved, ev->reserved, sizeof(ev->reserved)); > + } > kev->event.id = ev->id; > kev->ts = ts; > kev->event.sequence = fh->sequence; What's the point of this? It's a reserved field, it must be 0. If you want to use it for something else, then make a proposal to repurpose some of the reserved fields. This looks like you are trying to copy reserved data for some driver-specific hack. That's not going to be accepted. For the record: Nacked-by: Hans Verkuil Regards, Hans