From patchwork Wed Aug 31 16:58:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12961136 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 2EF6CC54EE9 for ; Wed, 31 Aug 2022 17:00:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232417AbiHaQ75 (ORCPT ); Wed, 31 Aug 2022 12:59:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232304AbiHaQ7k (ORCPT ); Wed, 31 Aug 2022 12:59:40 -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 16D7EDC09B; Wed, 31 Aug 2022 09:58:37 -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 34F91B82208; Wed, 31 Aug 2022 16:58:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16ED3C433D6; Wed, 31 Aug 2022 16:58:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661965114; bh=dAXL0+XNvWx5LNwHQHyifRYahh/pbyejlx7Mrbu9GZc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Unrckl/0xd5p4L0eslkX+ocOVnSTxmyJWLFH/U+QruZmKX8gJdrduY6/CKskFoEWd ISKZ9pHw2Q/FycQa5vEi4tVNKULPLkBLgmNwT1C2W/w8DAo8qh4Cy3auUpwCxehnB0 8LstTa/XU6ZZ0YxZbVsssX+To30Ks8YUt+o9BArCX6fGGv2Vvq65I2nUKzK116hIA+ MI27LA9tMdpy0d7c5dmH++0KKz2eefkDA0N57lPA4Vl5L5nGk1wsuhlV1WbZKvd3X3 fUptPXshdHkX8Fuoq+D9EglqVBVXgoAzpgDhaRHDEr+f2EjjxQZpAPWWYg3zQSbnjv 0/GI1hfVVorcQ== 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 2/3] xen-blkfront: Advertise feature-persistent as user requested Date: Wed, 31 Aug 2022 16:58:23 +0000 Message-Id: <20220831165824.94815-3-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 74a852479c68 ("xen-blkfront: add a parameter for disabling of persistent grants") made a field of blkfront, 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 blkfront saves the parameter value in a separate place and advertises the support based on only the saved value. Fixes: 74a852479c68 ("xen-blkfront: add a parameter for disabling of persistent grants") Cc: # 5.10.x Suggested-by: Juergen Gross Signed-off-by: SeongJae Park --- drivers/block/xen-blkfront.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 8e56e69fb4c4..dfae08115450 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -213,6 +213,9 @@ struct blkfront_info unsigned int feature_fua:1; unsigned int feature_discard:1; unsigned int feature_secdiscard:1; + /* Connect-time cached feature_persistent parameter */ + unsigned int feature_persistent_parm:1; + /* Persistent grants feature negotiation result */ unsigned int feature_persistent:1; unsigned int bounce:1; unsigned int discard_granularity; @@ -1848,7 +1851,7 @@ static int talk_to_blkback(struct xenbus_device *dev, goto abort_transaction; } err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", - info->feature_persistent); + info->feature_persistent_parm); if (err) dev_warn(&dev->dev, "writing persistent grants feature to xenbus"); @@ -2281,7 +2284,8 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) blkfront_setup_discard(info); - if (feature_persistent) + info->feature_persistent_parm = feature_persistent; + if (info->feature_persistent_parm) info->feature_persistent = !!xenbus_read_unsigned(info->xbdev->otherend, "feature-persistent", 0);