From patchwork Thu Feb 18 15:47:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Charles Keepax X-Patchwork-Id: 8351611 Return-Path: X-Original-To: patchwork-alsa-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6373FC0553 for ; Thu, 18 Feb 2016 15:47:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 75C5C2034A for ; Thu, 18 Feb 2016 15:47:34 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) by mail.kernel.org (Postfix) with ESMTP id 4403A20274 for ; Thu, 18 Feb 2016 15:47:32 +0000 (UTC) Received: by alsa0.perex.cz (Postfix, from userid 1000) id 5B17E261583; Thu, 18 Feb 2016 16:47:30 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,NO_DNS_FOR_FROM, RCVD_IN_DNSWL_NONE,UNPARSEABLE_RELAY autolearn=no version=3.3.1 Received: from alsa0.perex.cz (localhost [127.0.0.1]) by alsa0.perex.cz (Postfix) with ESMTP id 91E772606E2; Thu, 18 Feb 2016 16:47:22 +0100 (CET) X-Original-To: alsa-devel@alsa-project.org Delivered-To: alsa-devel@alsa-project.org Received: by alsa0.perex.cz (Postfix, from userid 1000) id 685B02612D7; Thu, 18 Feb 2016 16:47:21 +0100 (CET) Received: from mx0a-001ae601.pphosted.com (mx0a-001ae601.pphosted.com [67.231.149.25]) by alsa0.perex.cz (Postfix) with ESMTP id EB2492606BA for ; Thu, 18 Feb 2016 16:47:13 +0100 (CET) Received: from pps.filterd (m0077473.ppops.net [127.0.0.1]) by mx0a-001ae601.pphosted.com (8.15.0.59/8.15.0.59) with SMTP id u1IFigYt009196; Thu, 18 Feb 2016 09:47:13 -0600 Authentication-Results: ppops.net; spf=none smtp.mail=ckeepax@opensource.wolfsonmicro.com Received: from mail1.cirrus.com (mail1.cirrus.com [141.131.3.20]) by mx0a-001ae601.pphosted.com with ESMTP id 213ckb5sfp-1; Thu, 18 Feb 2016 09:47:12 -0600 Received: from EX12.ad.cirrus.com (unknown [172.19.9.182]) by mail1.cirrus.com (Postfix) with ESMTP id EF16034036; Thu, 18 Feb 2016 09:48:37 -0600 (CST) Received: from imbe.wolfsonmicro.main (172.20.9.178) by EX12.ad.cirrus.com (172.19.9.182) with Microsoft SMTP Server id 14.3.248.2; Thu, 18 Feb 2016 15:47:11 +0000 Received: from algalon.wolfsonmicro.main ([172.22.20.24]) by imbe.wolfsonmicro.main (8.14.4/8.14.4) with ESMTP id u1IFl8Qj020317; Thu, 18 Feb 2016 15:47:08 GMT From: Charles Keepax To: Date: Thu, 18 Feb 2016 15:47:13 +0000 Message-ID: <1455810433-10305-1-git-send-email-ckeepax@opensource.wolfsonmicro.com> X-Mailer: git-send-email 2.1.4 MIME-Version: 1.0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1601100000 definitions=main-1602180233 Cc: alsa-devel@alsa-project.org, linux-samsung-soc@vger.kernel.org, sbkim73@samsung.com, patches@opensource.wolfsonmicro.com, lgirdwood@gmail.com, s.nawrocki@samsung.com Subject: [alsa-devel] [PATCH] ASoC: samsung: Use IRQ safe spin lock calls X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org X-Virus-Scanned: ClamAV using ClamSMTP Lockdep warns of a potential lock inversion, i2s->lock is held numerous times whilst we are under the substream lock (snd_pcm_stream_lock). If we use the IRQ unsafe spin lock calls, you can also end up locking snd_pcm_stream_lock whilst under i2s->lock (if an IRQ happens whilst we are holding i2s->lock). This could result in deadlock. [ 18.147001] CPU0 CPU1 [ 18.151509] ---- ---- [ 18.156022] lock(&(&pri_dai->spinlock)->rlock); [ 18.160701] local_irq_disable(); [ 18.166622] lock(&(&substream->self_group.lock)->rlock); [ 18.174595] lock(&(&pri_dai->spinlock)->rlock); [ 18.181806] [ 18.184408] lock(&(&substream->self_group.lock)->rlock); [ 18.190045] [ 18.190045] *** DEADLOCK *** This patch changes to using the irq safe spinlock calls, to avoid this issue. Fixes: ce8bcdbb61d9 ("ASoC: samsung: i2s: Protect more registers with a spinlock") Signed-off-by: Charles Keepax Tested-by: Anand Moon Acked-by: Sylwester Nawrocki --- sound/soc/samsung/i2s.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c index 84d9e77..70a2559 100644 --- a/sound/soc/samsung/i2s.c +++ b/sound/soc/samsung/i2s.c @@ -481,10 +481,11 @@ static int i2s_set_sysclk(struct snd_soc_dai *dai, unsigned int cdcon_mask = 1 << i2s_regs->cdclkcon_off; unsigned int rsrc_mask = 1 << i2s_regs->rclksrc_off; u32 mod, mask, val = 0; + unsigned long flags; - spin_lock(i2s->lock); + spin_lock_irqsave(i2s->lock, flags); mod = readl(i2s->addr + I2SMOD); - spin_unlock(i2s->lock); + spin_unlock_irqrestore(i2s->lock, flags); switch (clk_id) { case SAMSUNG_I2S_OPCLK: @@ -575,11 +576,11 @@ static int i2s_set_sysclk(struct snd_soc_dai *dai, return -EINVAL; } - spin_lock(i2s->lock); + spin_lock_irqsave(i2s->lock, flags); mod = readl(i2s->addr + I2SMOD); mod = (mod & ~mask) | val; writel(mod, i2s->addr + I2SMOD); - spin_unlock(i2s->lock); + spin_unlock_irqrestore(i2s->lock, flags); return 0; } @@ -590,6 +591,7 @@ static int i2s_set_fmt(struct snd_soc_dai *dai, struct i2s_dai *i2s = to_info(dai); int lrp_shift, sdf_shift, sdf_mask, lrp_rlow, mod_slave; u32 mod, tmp = 0; + unsigned long flags; lrp_shift = i2s->variant_regs->lrp_off; sdf_shift = i2s->variant_regs->sdf_off; @@ -649,7 +651,7 @@ static int i2s_set_fmt(struct snd_soc_dai *dai, return -EINVAL; } - spin_lock(i2s->lock); + spin_lock_irqsave(i2s->lock, flags); mod = readl(i2s->addr + I2SMOD); /* * Don't change the I2S mode if any controller is active on this @@ -657,7 +659,7 @@ static int i2s_set_fmt(struct snd_soc_dai *dai, */ if (any_active(i2s) && ((mod & (sdf_mask | lrp_rlow | mod_slave)) != tmp)) { - spin_unlock(i2s->lock); + spin_unlock_irqrestore(i2s->lock, flags); dev_err(&i2s->pdev->dev, "%s:%d Other DAI busy\n", __func__, __LINE__); return -EAGAIN; @@ -666,7 +668,7 @@ static int i2s_set_fmt(struct snd_soc_dai *dai, mod &= ~(sdf_mask | lrp_rlow | mod_slave); mod |= tmp; writel(mod, i2s->addr + I2SMOD); - spin_unlock(i2s->lock); + spin_unlock_irqrestore(i2s->lock, flags); return 0; } @@ -676,6 +678,7 @@ static int i2s_hw_params(struct snd_pcm_substream *substream, { struct i2s_dai *i2s = to_info(dai); u32 mod, mask = 0, val = 0; + unsigned long flags; if (!is_secondary(i2s)) mask |= (MOD_DC2_EN | MOD_DC1_EN); @@ -744,11 +747,11 @@ static int i2s_hw_params(struct snd_pcm_substream *substream, return -EINVAL; } - spin_lock(i2s->lock); + spin_lock_irqsave(i2s->lock, flags); mod = readl(i2s->addr + I2SMOD); mod = (mod & ~mask) | val; writel(mod, i2s->addr + I2SMOD); - spin_unlock(i2s->lock); + spin_unlock_irqrestore(i2s->lock, flags); samsung_asoc_init_dma_data(dai, &i2s->dma_playback, &i2s->dma_capture);