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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4695C54FD0 for ; Fri, 24 Apr 2020 12:31:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 954FC20700 for ; Fri, 24 Apr 2020 12:31:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587731498; bh=AiHZMRGZN++JkczioNXBdzkyrnsdGgspzRfy4nft0mg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VsaS+bn7DK/R3vdtktucxmZbi28WKdDhWjaAc8Ni6KmfUAPaM1mdUWDuWe+jf8g7j fyH48F+MfY30e3rX2MKspa0g/OygbO9hDxZm9ZTi52oQFMEbo1erktUYkzbNTAuK/O 1WaVv+kArbIhNU7DNSg/lo2kU4o94yg5PLOcej/8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728353AbgDXMbi (ORCPT ); Fri, 24 Apr 2020 08:31:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:52776 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727864AbgDXMXM (ORCPT ); Fri, 24 Apr 2020 08:23:12 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85A2621582; Fri, 24 Apr 2020 12:23:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587730992; bh=AiHZMRGZN++JkczioNXBdzkyrnsdGgspzRfy4nft0mg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KDYxHJ//hrlq75jPlPKbi1+rFZubZFD6BlX4Ds59z3He/5aa/MFJiO/lgblG/4CvB k+n2bsIwYOJlodCK/O8O+7ekWoBUBe7sh8d1MV6HtH60E0hM3Vze/+oNwaeZgYmtVY 1fJ78Dg/+5kyVTyr2YSmeHmcj6fnd81Cur1gDCHI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dmitry Osipenko , Wolfram Sang , Sasha Levin , linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 30/38] i2c: tegra: Better handle case where CPU0 is busy for a long time Date: Fri, 24 Apr 2020 08:22:28 -0400 Message-Id: <20200424122237.9831-30-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200424122237.9831-1-sashal@kernel.org> References: <20200424122237.9831-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitry Osipenko [ Upstream commit a900aeac253729411cf33c6cb598c152e9e4137f ] Boot CPU0 always handle I2C interrupt and under some rare circumstances (like running KASAN + NFS root) it may stuck in uninterruptible state for a significant time. In this case we will get timeout if I2C transfer is running on a sibling CPU, despite of IRQ being raised. In order to handle this rare condition, the IRQ status needs to be checked after completion timeout. Signed-off-by: Dmitry Osipenko Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-tegra.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index cbc2ad49043e4..0daa863fb26f2 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -1000,14 +1000,13 @@ tegra_i2c_poll_completion_timeout(struct tegra_i2c_dev *i2c_dev, do { u32 status = i2c_readl(i2c_dev, I2C_INT_STATUS); - if (status) { + if (status) tegra_i2c_isr(i2c_dev->irq, i2c_dev); - if (completion_done(complete)) { - s64 delta = ktime_ms_delta(ktimeout, ktime); + if (completion_done(complete)) { + s64 delta = ktime_ms_delta(ktimeout, ktime); - return msecs_to_jiffies(delta) ?: 1; - } + return msecs_to_jiffies(delta) ?: 1; } ktime = ktime_get(); @@ -1034,14 +1033,18 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev, disable_irq(i2c_dev->irq); /* - * There is a chance that completion may happen after IRQ - * synchronization, which is done by disable_irq(). + * Under some rare circumstances (like running KASAN + + * NFS root) CPU, which handles interrupt, may stuck in + * uninterruptible state for a significant time. In this + * case we will get timeout if I2C transfer is running on + * a sibling CPU, despite of IRQ being raised. + * + * In order to handle this rare condition, the IRQ status + * needs to be checked after timeout. */ - if (ret == 0 && completion_done(complete)) { - dev_warn(i2c_dev->dev, - "completion done after timeout\n"); - ret = 1; - } + if (ret == 0) + ret = tegra_i2c_poll_completion_timeout(i2c_dev, + complete, 0); } return ret; -- 2.20.1