From patchwork Wed Aug 31 16:58:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12961135 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE764ECAAD1 for ; Wed, 31 Aug 2022 16:59:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232270AbiHaQ75 (ORCPT ); Wed, 31 Aug 2022 12:59:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232167AbiHaQ7j (ORCPT ); Wed, 31 Aug 2022 12:59:39 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC3F9E01C8; Wed, 31 Aug 2022 09:58:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2E5C2B82207; Wed, 31 Aug 2022 16:58:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22B88C433C1; Wed, 31 Aug 2022 16:58:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661965112; bh=2M6XIQVeSqrPrYytDvGmk8JSZnX1cUCppYJ4t0zteug=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r+yj2nUL8cBvYHbhNGByKXHfolByjrFRe687uj1BUUB6mIbeXN2akLAiQRdvStbqP NMb5qiC+ThAz7uY10jHDz33BEKstZU2iTWJpSn0pPMwG29otA0+v7b4oevDXX9xywt daiS3FmM4D7SFz4ZS2QhL+z/hmZONNOucXCZH3i5gYjg1q8QBAYtaXJ65YwQKdQzb0 vUEOeCFozOnzBRrMkAQ5iuwNZdviUg+Q7J75Jt4uuZwxML8bP5XUh9fA3KShUEsq9Y 3L8j6pjOgw50j/r6rdnjpE4dC/uRqcRZVpRbxbOCphVbmdYWOEHGFNP8VkJoa9oNlQ OeAJ+c6yTMvqA== From: SeongJae Park To: jgross@suse.com, roger.pau@citrix.com Cc: SeongJae Park , marmarek@invisiblethingslab.com, mheyne@amazon.de, xen-devel@lists.xenproject.org, axboe@kernel.dk, ptyadav@amazon.de, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2 1/3] xen-blkback: Advertise feature-persistent as user requested Date: Wed, 31 Aug 2022 16:58:22 +0000 Message-Id: <20220831165824.94815-2-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220831165824.94815-1-sj@kernel.org> References: <20220831165824.94815-1-sj@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org The advertisement of the persistent grants feature (writing 'feature-persistent' to xenbus) should mean not the decision for using the feature but only the availability of the feature. However, commit aac8a70db24b ("xen-blkback: add a parameter for disabling of persistent grants") made a field of blkback, which was a place for saving only the negotiation result, to be used for yet another purpose: caching of the 'feature_persistent' parameter value. As a result, the advertisement, which should follow only the parameter value, becomes inconsistent. This commit fixes the misuse of the semantic by making blkback saves the parameter value in a separate place and advertises the support based on only the saved value. Fixes: aac8a70db24b ("xen-blkback: add a parameter for disabling of persistent grants") Cc: # 5.10.x Suggested-by: Juergen Gross Signed-off-by: SeongJae Park Reviewed-by: Pratyush Yadav --- drivers/block/xen-blkback/common.h | 3 +++ drivers/block/xen-blkback/xenbus.c | 6 ++++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index bda5c815e441..a28473470e66 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -226,6 +226,9 @@ struct xen_vbd { sector_t size; unsigned int flush_support:1; unsigned int discard_secure:1; + /* Connect-time cached feature_persistent parameter value */ + unsigned int feature_gnt_persistent_parm:1; + /* Persistent grants feature negotiation result */ unsigned int feature_gnt_persistent:1; unsigned int overflow_max_grants:1; }; diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index ee7ad2fb432d..c0227dfa4688 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -907,7 +907,7 @@ static void connect(struct backend_info *be) xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", - be->blkif->vbd.feature_gnt_persistent); + be->blkif->vbd.feature_gnt_persistent_parm); if (err) { xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", dev->nodename); @@ -1085,7 +1085,9 @@ static int connect_ring(struct backend_info *be) return -ENOSYS; } - blkif->vbd.feature_gnt_persistent = feature_persistent && + blkif->vbd.feature_gnt_persistent_parm = feature_persistent; + blkif->vbd.feature_gnt_persistent = + blkif->vbd.feature_gnt_persistent_parm && xenbus_read_unsigned(dev->otherend, "feature-persistent", 0); blkif->vbd.overflow_max_grants = 0;