From patchwork Fri Jul 22 09:53:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?UGV0ZXIgV2FuZyAo546L5L+h5Y+LKQ==?= X-Patchwork-Id: 593115 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 49CAFC433EF for ; Fri, 22 Jul 2022 09:53:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234522AbiGVJxV (ORCPT ); Fri, 22 Jul 2022 05:53:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231913AbiGVJxU (ORCPT ); Fri, 22 Jul 2022 05:53:20 -0400 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCBA42ED for ; Fri, 22 Jul 2022 02:53:14 -0700 (PDT) X-UUID: 2749a9920fdd4456b54b0af0572a9b64-20220722 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.8, REQID:3a4d175d-4faf-437b-b787-44fee4ef5763, OB:0, LO B:0,IP:0,URL:5,TC:0,Content:-5,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACT ION:release,TS:0 X-CID-META: VersionHash:0f94e32, CLOUDID:66d79029-fd69-41f1-91fc-8b8a329d3a88, C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:1,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: 2749a9920fdd4456b54b0af0572a9b64-20220722 Received: from mtkmbs11n1.mediatek.inc [(172.21.101.185)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 158808918; Fri, 22 Jul 2022 17:53:11 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs10n2.mediatek.inc (172.21.101.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Fri, 22 Jul 2022 17:53:10 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 22 Jul 2022 17:53:10 +0800 From: To: , , , , , CC: , , , , , , , , , , Subject: [PATCH v1] ufs: core: fix lockdep warning of clk_scaling_lock Date: Fri, 22 Jul 2022 17:53:08 +0800 Message-ID: <20220722095308.10112-1-peter.wang@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Peter Wang There have a lockdep warning like below in current flow. kworker/u16:0: Possible unsafe locking scenario: kworker/u16:0: CPU0 CPU1 kworker/u16:0: ---- ---- kworker/u16:0: lock(&hba->clk_scaling_lock); kworker/u16:0: lock(&hba->dev_cmd.lock); kworker/u16:0: lock(&hba->clk_scaling_lock); kworker/u16:0: lock(&hba->dev_cmd.lock); kworker/u16:0: Because ufshcd_wb_toggle -> ufshcd_query_flag -> ufshcd_exec_dev_cmd will get read lock of clk_scaling_lock, so ufshcd_devfreq_scale can release read lock before call ufshcd_wb_toggle. This patch only release write lock of clk_scaling_lock before ufshcd_wb_toggle. --- drivers/ufs/core/ufshcd.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index c7b337480e3e..209089bd8085 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -1249,12 +1249,10 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba) return ret; } -static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, bool writelock) +static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba) { - if (writelock) - up_write(&hba->clk_scaling_lock); - else - up_read(&hba->clk_scaling_lock); + up_write(&hba->clk_scaling_lock); + ufshcd_scsi_unblock_requests(hba); ufshcd_release(hba); } @@ -1271,7 +1269,7 @@ static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, bool writelock) static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up) { int ret = 0; - bool is_writelock = true; + bool wb_toggle = false; ret = ufshcd_clock_scaling_prepare(hba); if (ret) @@ -1300,13 +1298,15 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up) } } - /* Enable Write Booster if we have scaled up else disable it */ - downgrade_write(&hba->clk_scaling_lock); - is_writelock = false; - ufshcd_wb_toggle(hba, scale_up); + wb_toggle = true; out_unprepare: - ufshcd_clock_scaling_unprepare(hba, is_writelock); + ufshcd_clock_scaling_unprepare(hba); + + /* Enable Write Booster if we have scaled up else disable it */ + if (wb_toggle) + ufshcd_wb_toggle(hba, scale_up); + return ret; }