Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751549AbaAMN63 (ORCPT ); Mon, 13 Jan 2014 08:58:29 -0500 Received: from nat28.tlf.novell.com ([130.57.49.28]:52704 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966AbaAMN61 convert rfc822-to-8bit (ORCPT ); Mon, 13 Jan 2014 08:58:27 -0500 Message-Id: <52D3FF0E02000078001131A5@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.2 Date: Mon, 13 Jan 2014 13:58:22 +0000 From: "Jan Beulich" To: "David Vrabel" Cc: "Olaf Hering" , "Ian Campbell" , , , Subject: Re: [Xen-devel] [PATCH v2] xen-blkfront: remove type check from blkfront_setup_discard References: <1389608052-7139-1-git-send-email-olaf@aepfle.de> <52D3DAEE0200007800112FD4@nat28.tlf.novell.com> <20140113120131.GA15623@aepfle.de> <52D3EB5F02000078001130B5@nat28.tlf.novell.com> <1389618054.13654.57.camel@kazak.uk.xensource.com> <52D3F535020000780011311B@nat28.tlf.novell.com> <52D3EE14.3080609@citrix.com> In-Reply-To: <52D3EE14.3080609@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 13.01.14 at 14:45, David Vrabel wrote: > On 13/01/14 13:16, Jan Beulich wrote: >>>>> On 13.01.14 at 14:00, Ian Campbell wrote: >>> On Mon, 2014-01-13 at 12:34 +0000, Jan Beulich wrote: >>>>>>> On 13.01.14 at 13:01, Olaf Hering wrote: >>>>> On Mon, Jan 13, Jan Beulich wrote: >>>>> >>>>>> You can't do this in one go - the first two and the last one may be >>>>>> set independently (and are independent in their meaning), and >>>>>> hence need to be queried independently (xenbus_gather() fails >>>>>> on the first absent value). >>>>> >>>>> Yes, thats the purpose. Since the properties are required its an all or >>>>> nothing thing. If they are truly optional then blkif.h should be updated >>>>> to say that. >>>> >>>> They _are_ optional. >>> >>> But is it true that either they are all present or they are all absent? >> >> No, it's not. discard-secure is independent of the other two (but >> those other two are tied together). > > Can we have a patch to blkif.h that clarifies this? > > e.g., > > feature-discard > > ... > > discard-granularity and discard-offset must also be present if > feature-discard is enabled It would be "may" here too afaict. But I'll defer to Konrad, who has done more work in this area... Jan > discard-secure may also be present if feature-discard is enabled. > > David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/