From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754156AbZGDQ7s (ORCPT ); Sat, 4 Jul 2009 12:59:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751944AbZGDQ7k (ORCPT ); Sat, 4 Jul 2009 12:59:40 -0400 Received: from an-out-0708.google.com ([209.85.132.240]:50867 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751044AbZGDQ7j (ORCPT ); Sat, 4 Jul 2009 12:59:39 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type :content-transfer-encoding; b=k3B7/SGX4uOTqTrHZfkEvv8xIKPfe8WNVbutJ7vZYx41lxyODO15D6DZAR2FXYnSIJ kdFGaLS+rshFOjOIablsFU8+F+LVUBKPlO6SzTHMcYou/O4BJwC4n43R77DX8aL09ano Hf4wBU4ubXeeFS8uEIKGSq+y58YzXcztdKJC8= MIME-Version: 1.0 Date: Sat, 4 Jul 2009 09:59:41 -0700 Message-ID: <46b8a8850907040959q502968bcx8bc4e20c907f9c57@mail.gmail.com> Subject: discard/UNMAP support: prepare_discard_fn does not pass enough info even in 2.6.31rc1 From: Richard Sharpe To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I am trying to get BLKDICARD/unmap support working in SCST, and while I have some code that works if I directly submit requests to scst_local, things _seem_ broken above me. There has been some support for BLKDISCARD requests for a number of kernel releases already (starting about 2.6.28), but for UNMAP, and probably any real support for DISCARD, we need to know the starting sector and the range of sectors being discarded. However, at the point at prepare_unmap_fn is called, that info has not been placed in the request. Probably the simplest change would be to pass the bio to prepare_discard_fn as well. Matthew Wilcox published a patch that looks like it does close to the right things here: http://lkml.org/lkml/2008/11/23/81 This passes the bio to prepare_discard_fn and has implemented a discard function in sd.c so I do not have to do that work in my LLD, but it seems to target an earlier version of the spec. I am working with 08-149r9-3.pdf off of the T10 site. Who should I contact about getting these changes merged or proposing a different set of changes? -- Regards, Richard Sharpe