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 8D8583112B4; Thu, 29 Jan 2026 01:09:51 +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=1769648992; cv=none; b=GUr/0pdGA7WvicwPASDJfLwx+m9dvm+fGVJf5+jiGpzVCfJm3hrdK+h3Z9l2oBkSQWUamTTDmafcnwKRVNGYEaAEk8GdhqGu4xweged+os0eH1ixko8bkSgh6/hJCEJG5kHAae7R33+B5zUfhKzWkmH3AfaS1NCtC3eXXc4BiRA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769648992; c=relaxed/simple; bh=1NZ7Q0fzMrKycm9djpADcZBie3m0VuDp/W9FsV9ep7M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Nw4AY5oiIYWgdEBhPZdMSVmBjE3z4nmQIfBjJA5KS2q1bqw7/6kVO92/KoJBeOzotf7r6d9ZadNJj0cDqaCb7YbkfAS0PD6tUHACMV2QueQg5AWxweGQjh2X+1HhHa7Ie+6pXe6jZWf8I8wpPz5KcyoW7kW2qygkRAkAVmHKqV8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=eWhhkOsi; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="eWhhkOsi" Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id D5FBB6A6; Thu, 29 Jan 2026 02:09:12 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1769648953; bh=1NZ7Q0fzMrKycm9djpADcZBie3m0VuDp/W9FsV9ep7M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eWhhkOsieAgsOXXz+SRW7PyuigZ1jlygJpdFiLbCtAO8TlsyUXSqSvF8stT8BuG33 1HmZNnU9auHGv8LCx96zwryvopwg0YeTKGbqxB+zXzwFyoXAzHcnkZk0W/XtVzWeVQ nEYxbJ1iV5zhRtQ2d5h3L/Z0+FGEd8bUdh2PICMQ= Date: Thu, 29 Jan 2026 03:09:48 +0200 From: Laurent Pinchart To: Danilo Krummrich Cc: Greg Kroah-Hartman , Johan Hovold , "Rafael J . Wysocki" , Tzung-Bi Shih , Bartosz Golaszewski , Linus Walleij , Jonathan Corbet , Shuah Khan , Wolfram Sang , Simona Vetter , Dan Williams , Jason Gunthorpe , linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] Revert "revocable: Revocable resource management" Message-ID: <20260129010948.GD3275574@killaraus> References: <20260124170535.11756-1-johan@kernel.org> <2026012554-chatty-policy-42a1@gregkh> <20260125132250.GP215800@killaraus> Precedence: bulk X-Mailing-List: linux-kernel@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: On Sun, Jan 25, 2026 at 03:07:41PM +0100, Danilo Krummrich wrote: > On Sun Jan 25, 2026 at 2:22 PM CET, Laurent Pinchart wrote: > > It's the wrong solution for most cases, if not all. It will spread in drivers > > and then become another big piece of technical debt we'll wish we had never > > merged. > > It is a matter of how the revocable pattern is adopted. I.e. I don't think > drivers should create instances of revocable (device) resources by themselves. > Instead, I think it should be up to the corresponding subsystems to adopt the > pattern in the way necessary and make it accessible to drivers instead. > > > We know what the right solution to the cdev race is > > So, what is it? Assuming that this is what you are referring to, how do you > prevent accesses to (potentially freed) device resources after the bus device > has been unbound from the driver for subsystems that may still call back into > the driver after device unbind? I've answered this question in another e-mail in this thread, see https://lore.kernel.org/all/20260129010822.GA3310904@killaraus/ -- Regards, Laurent Pinchart