From mboxrd@z Thu Jan 1 00:00:00 1970 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 CFBB7C6FA82 for ; Tue, 13 Sep 2022 14:45:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230470AbiIMOpM (ORCPT ); Tue, 13 Sep 2022 10:45:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234143AbiIMOmh (ORCPT ); Tue, 13 Sep 2022 10:42:37 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3CE42FFD7; Tue, 13 Sep 2022 07:22:39 -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 DB3C5B80FBC; Tue, 13 Sep 2022 14:22:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FA0DC433D6; Tue, 13 Sep 2022 14:22:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1663078940; bh=tVAbAvCjhuEg7A6fhu9ETVqCIukL5QdM6oRk66+FGAE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BTtIVdpuvWCfWKlsr0dHfyL+CLL+x3T+OHhOxl1gW2Cc8/kkjZ7JJNVx4Eauf6ESA MS9jj4F8Ay2RBM4veKEQPli3RrhgTd+T1gV7sYLm9xih0XrP0DUAG5Uf9CMKgsdio3 KV5RZw0KQGQ2WzxtWv402PixOF0Xtb7JHS/vShEw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?= , SeongJae Park , Juergen Gross Subject: [PATCH 5.10 02/79] xen-blkfront: Cache feature_persistent value before advertisement Date: Tue, 13 Sep 2022 16:04:07 +0200 Message-Id: <20220913140350.404321086@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220913140350.291927556@linuxfoundation.org> References: <20220913140350.291927556@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: SeongJae Park commit fe8f65b018effbf473f53af3538d0c1878b8b329 upstream. Xen blkfront advertises its support of the persistent grants feature when it first setting up and when resuming in 'talk_to_blkback()'. Then, blkback reads the advertised value when it connects with blkfront and decides if it will use the persistent grants feature or not, and advertises its decision to blkfront. Blkfront reads the blkback's decision and it also makes the decision for the use of the feature. Commit 402c43ea6b34 ("xen-blkfront: Apply 'feature_persistent' parameter when connect"), however, made the blkfront's read of the parameter for disabling the advertisement, namely 'feature_persistent', to be done when it negotiate, not when advertise. Therefore blkfront advertises without reading the parameter. As the field for caching the parameter value is zero-initialized, it always advertises as the feature is disabled, so that the persistent grants feature becomes always disabled. This commit fixes the issue by making the blkfront does parmeter caching just before the advertisement. Fixes: 402c43ea6b34 ("xen-blkfront: Apply 'feature_persistent' parameter when connect") Cc: # 5.10.x Reported-by: Marek Marczykowski-Górecki Signed-off-by: SeongJae Park Tested-by: Marek Marczykowski-Górecki Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20220831165824.94815-4-sj@kernel.org Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/block/xen-blkfront.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1852,6 +1852,12 @@ static void free_info(struct blkfront_in kfree(info); } +/* Enable the persistent grants feature. */ +static bool feature_persistent = true; +module_param(feature_persistent, bool, 0644); +MODULE_PARM_DESC(feature_persistent, + "Enables the persistent grants feature"); + /* Common code used when first setting up, and when resuming. */ static int talk_to_blkback(struct xenbus_device *dev, struct blkfront_info *info) @@ -1943,6 +1949,7 @@ again: message = "writing protocol"; goto abort_transaction; } + info->feature_persistent_parm = feature_persistent; err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", info->feature_persistent_parm); if (err) @@ -2019,12 +2026,6 @@ static int negotiate_mq(struct blkfront_ return 0; } -/* Enable the persistent grants feature. */ -static bool feature_persistent = true; -module_param(feature_persistent, bool, 0644); -MODULE_PARM_DESC(feature_persistent, - "Enables the persistent grants feature"); - /** * Entry point to this code when a new device is created. Allocate the basic * structures and the ring buffer for communication with the backend, and @@ -2394,7 +2395,6 @@ static void blkfront_gather_backend_feat if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) blkfront_setup_discard(info); - info->feature_persistent_parm = feature_persistent; if (info->feature_persistent_parm) info->feature_persistent = !!xenbus_read_unsigned(info->xbdev->otherend,