From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755631AbcHYHyX (ORCPT ); Thu, 25 Aug 2016 03:54:23 -0400 Received: from mail-ua0-f181.google.com ([209.85.217.181]:33304 "EHLO mail-ua0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752721AbcHYHyW (ORCPT ); Thu, 25 Aug 2016 03:54:22 -0400 MIME-Version: 1.0 In-Reply-To: <20160825073810.GA18622@lst.de> References: <20160825073810.GA18622@lst.de> From: Andy Lutomirski Date: Thu, 25 Aug 2016 00:54:00 -0700 Message-ID: Subject: Re: [PATCH] nvme: Fix nvme_get/set_features() with a NULL result pointer To: Christoph Hellwig Cc: Andy Lutomirski , Keith Busch , Jens Axboe , linux-nvme@lists.infradead.org, "linux-kernel@vger.kernel.org" , stable Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 25, 2016 at 12:38 AM, Christoph Hellwig wrote: > Ooops, yes. > > Are you looking into new nvme_set_features users? Another thing > we need to tackle is either replacing dma_addr argument with a > a real kernel pointer (or just kill it until users show up) I am, and I have a patch to do the former (and to add a length argument). But that's not -stable material. While I have your attention: the new use is to enable APST (power saving). In theory, it seems like I should integrate with dev_pm_qos so that the standard interface for setting a latency limit will work, but, on brief inspection, there are literally no drivers in the entire tree that do this. Am I missing something? My current draft patch just adds a sysfs attribute. (It saves a *lot* of power on my laptop, so supporting APST is worth doing.) --Andy