From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 9161725601 for ; Wed, 7 Feb 2024 10:08:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707300492; cv=none; b=DH9E/yJIqKHfby3ikRbLwK0EsRRL70MqoPQVXc0u2ZxmH5y1uOVd4BQfdPJpHUj+8ktCXLN4b+rDF1ehuMWHM81KTUmwGUgV8daQFRb1BC/gWxXkm+Hi5nfXfnLdyrG+XwiZJFxwgf6srLl2tk5Z2O6B2pn1oplNBWpFe+eNb60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707300492; c=relaxed/simple; bh=LIBAgFjIK5pNH9NWahlxj4MakrFjWDFL6XvopjqVxHM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=i+5R2TPa9fYAyZfxSJy84eiDuraxzalnhcyhjJhArszW9hfE8mRluhny7gbf+zkuAM6uRuIlo3yFSqpBcrvgqc5XzVineO6amEtd1vkLqyMuh+tmfxE7XTfqKZo5lIZqEGTb7aEi3Pn1ns9dDQZCuSeJRFOczCp3n7PFF3fdTOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=Z1Pk5GCZ; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="Z1Pk5GCZ" Received: from pendragon.ideasonboard.com (117.145-247-81.adsl-dyn.isp.belgacom.be [81.247.145.117]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 11A27975; Wed, 7 Feb 2024 11:06:45 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1707300405; bh=LIBAgFjIK5pNH9NWahlxj4MakrFjWDFL6XvopjqVxHM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z1Pk5GCZx2ppkZsxWff6tOhMv/JdAHz+lHCQ4PXXFR9Y56RfP2Z8lPMYyUOR6hbRo Vw+SVegu5J2P+2gY9o1p4xBKPt/1K7vl/p50wAxosdArl/XC6l68E2xB8zrw2sGO3b ogTzBaVntSTRif/ZetnBmDb6PpXQyLkOdf7aijfk= Date: Wed, 7 Feb 2024 12:08:10 +0200 From: Laurent Pinchart To: Sakari Ailus Cc: linux-media@vger.kernel.org, Hans Verkuil Subject: Re: [PATCH v2 10/29] media: mc: Delete character device early Message-ID: <20240207100810.GG23702@pendragon.ideasonboard.com> References: <20231220103713.113386-1-sakari.ailus@linux.intel.com> <20231220103713.113386-11-sakari.ailus@linux.intel.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231220103713.113386-11-sakari.ailus@linux.intel.com> Hi Sakari, Thank you for the patch. On Wed, Dec 20, 2023 at 12:36:54PM +0200, Sakari Ailus wrote: > The parent of the character device related to the media devnode is the > media devnode. Thus the character device needs to be released before the > media devnode's release function. Move it to unregistering of the media > devnode, which mirrors adding the character device in conjunction with > registering the media devnode. > > Signed-off-by: Sakari Ailus > Acked-by: Hans Verkuil > --- > drivers/media/mc/mc-devnode.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c > index 7e22938dfd81..8bc7450ac144 100644 > --- a/drivers/media/mc/mc-devnode.c > +++ b/drivers/media/mc/mc-devnode.c > @@ -51,9 +51,6 @@ static void media_devnode_release(struct device *cd) > > mutex_lock(&media_devnode_lock); > > - /* Delete the cdev on this minor as well */ > - cdev_del(&devnode->cdev); > - > /* Mark device node number as free */ > clear_bit(devnode->minor, media_devnode_nums); Should this be moved to media_devnode_unregister() too ? It can be done in a separate patch. > > @@ -270,6 +267,7 @@ void media_devnode_unregister(struct media_devnode *devnode) > clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); > mutex_unlock(&media_devnode_lock); > > + cdev_del(&devnode->cdev); I initially wondered if this could raise with the cdev access in media_open(), as the media_devnode_lock is released just before calling cdev_dev(), but my understanding is that the dev/open race is properly handled in the cdev layer. Reviewed-by: Laurent Pinchart I wonder if a similar change in v4l2-dev.c would be beneficial. > device_unregister(&devnode->dev); > } > -- Regards, Laurent Pinchart