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 CA222C433FE for ; Wed, 8 Dec 2021 12:54:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233796AbhLHM5q (ORCPT ); Wed, 8 Dec 2021 07:57:46 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:49494 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233837AbhLHM5q (ORCPT ); Wed, 8 Dec 2021 07:57:46 -0500 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 EB6D3B81F79 for ; Wed, 8 Dec 2021 12:54:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B493C00446; Wed, 8 Dec 2021 12:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638968052; bh=+sYDWmv1FzbFCUGkaaCGP6VKEYcon894ah6iIzBwK2M=; h=Subject:To:From:Date:From; b=fmg/omWQsWSLBS0JDIZWzDydAe0SGm2s34CB+bdHOgl5TX8wS7Kfb+DwG2rUmrG0f Dr/sqDBDUEg4hmmDbHLRXX98dJtxKGCLSk4zwVWKrA33i5NhAoAO/QYjFLO61DntNA wWpxjo3TK9dwgi78NmZ01jux+W6otWM8R6l3gBB4= Subject: patch "iio: dln2-adc: Fix lockdep complaint" added to char-misc-linus To: noralf@tronnes.org, Jonathan.Cameron@huawei.com, Stable@vger.kernel.org, jackoalan@gmail.com From: Date: Wed, 08 Dec 2021 13:53:54 +0100 Message-ID: <16389680348282@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled iio: dln2-adc: Fix lockdep complaint to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 59f92868176f191eefde70d284bdfc1ed76a84bc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= Date: Mon, 18 Oct 2021 13:37:31 +0200 Subject: iio: dln2-adc: Fix lockdep complaint MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When reading the voltage: $ cat /sys/bus/iio/devices/iio\:device0/in_voltage0_raw Lockdep complains: [ 153.910616] ====================================================== [ 153.916918] WARNING: possible circular locking dependency detected [ 153.923221] 5.14.0+ #5 Not tainted [ 153.926692] ------------------------------------------------------ [ 153.932992] cat/717 is trying to acquire lock: [ 153.937525] c2585358 (&indio_dev->mlock){+.+.}-{3:3}, at: iio_device_claim_direct_mode+0x28/0x44 [ 153.946541] but task is already holding lock: [ 153.952487] c2585860 (&dln2->mutex){+.+.}-{3:3}, at: dln2_adc_read_raw+0x94/0x2bc [dln2_adc] [ 153.961152] which lock already depends on the new lock. Fix this by not calling into the iio core underneath the dln2->mutex lock. Fixes: 7c0299e879dd ("iio: adc: Add support for DLN2 ADC") Cc: Jack Andersen Signed-off-by: Noralf Trønnes Link: https://lore.kernel.org/r/20211018113731.25723-1-noralf@tronnes.org Cc: Signed-off-by: Jonathan Cameron --- drivers/iio/adc/dln2-adc.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/iio/adc/dln2-adc.c b/drivers/iio/adc/dln2-adc.c index 16407664182c..6c67192946aa 100644 --- a/drivers/iio/adc/dln2-adc.c +++ b/drivers/iio/adc/dln2-adc.c @@ -248,7 +248,6 @@ static int dln2_adc_set_chan_period(struct dln2_adc *dln2, static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel) { int ret, i; - struct iio_dev *indio_dev = platform_get_drvdata(dln2->pdev); u16 conflict; __le16 value; int olen = sizeof(value); @@ -257,13 +256,9 @@ static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel) .chan = channel, }; - ret = iio_device_claim_direct_mode(indio_dev); - if (ret < 0) - return ret; - ret = dln2_adc_set_chan_enabled(dln2, channel, true); if (ret < 0) - goto release_direct; + return ret; ret = dln2_adc_set_port_enabled(dln2, true, &conflict); if (ret < 0) { @@ -300,8 +295,6 @@ static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel) dln2_adc_set_port_enabled(dln2, false, NULL); disable_chan: dln2_adc_set_chan_enabled(dln2, channel, false); -release_direct: - iio_device_release_direct_mode(indio_dev); return ret; } @@ -337,10 +330,16 @@ static int dln2_adc_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret < 0) + return ret; + mutex_lock(&dln2->mutex); ret = dln2_adc_read(dln2, chan->channel); mutex_unlock(&dln2->mutex); + iio_device_release_direct_mode(indio_dev); + if (ret < 0) return ret; -- 2.34.1