From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752434AbdC0LfD (ORCPT ); Mon, 27 Mar 2017 07:35:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56910 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751787AbdC0LfB (ORCPT ); Mon, 27 Mar 2017 07:35:01 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com DBBF8C00AFDF Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=pbonzini@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com DBBF8C00AFDF Subject: Re: [virtio-dev] [PATCH] virtio-blk: add DISCARD support to virtio-blk driver To: Changpeng Liu , virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, hch@lst.de References: <1490690365-21109-1-git-send-email-changpeng.liu@intel.com> Cc: qemu-devel@nongnu.org From: Paolo Bonzini Message-ID: <00d28fcc-446b-eff6-a5a3-6675216802b9@redhat.com> Date: Mon, 27 Mar 2017 13:34:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <1490690365-21109-1-git-send-email-changpeng.liu@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 27 Mar 2017 11:34:21 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/03/2017 10:39, Changpeng Liu wrote: > + if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) { > + q->limits.discard_zeroes_data = 0; Maybe you could use another feature bit to populate discard_zeroes_data. Paolo > + q->limits.discard_alignment = blk_size; > + q->limits.discard_granularity = blk_size; > + blk_queue_max_discard_sectors(q, UINT_MAX); > + blk_queue_max_discard_segments(q, 1); > + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); > + } > +