From patchwork Thu Apr 12 15:24:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 10338849 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5B379604D4 for ; Thu, 12 Apr 2018 15:24:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4EA2D27CEE for ; Thu, 12 Apr 2018 15:24:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 40AF427E01; Thu, 12 Apr 2018 15:24:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D87F327CEE for ; Thu, 12 Apr 2018 15:24:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753948AbeDLPYa (ORCPT ); Thu, 12 Apr 2018 11:24:30 -0400 Received: from osg.samsung.com ([64.30.133.232]:59748 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753210AbeDLPY3 (ORCPT ); Thu, 12 Apr 2018 11:24:29 -0400 Received: from localhost (localhost [127.0.0.1]) by osg.samsung.com (Postfix) with ESMTP id B1C571CFC6; Thu, 12 Apr 2018 08:24:28 -0700 (PDT) X-Virus-Scanned: Debian amavisd-new at dev.s-opensource.com X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" Received: from osg.samsung.com ([127.0.0.1]) by localhost (localhost [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id hlAoMf4uQ5VA; Thu, 12 Apr 2018 08:24:27 -0700 (PDT) Received: from smtp.s-opensource.com (unknown [179.179.40.138]) by osg.samsung.com (Postfix) with ESMTPSA id 640761CF44; Thu, 12 Apr 2018 08:24:13 -0700 (PDT) Received: from mchehab by smtp.s-opensource.com with local (Exim 4.90_1) (envelope-from ) id 1f6e55-0005St-BO; Thu, 12 Apr 2018 11:24:11 -0400 From: Mauro Carvalho Chehab Cc: Mauro Carvalho Chehab , Linux Media Mailing List , Mauro Carvalho Chehab , Patrice Chotard , linux-arm-kernel@lists.infradead.org Subject: [PATCH 15/17] media: st_rc: Don't stay on an IRQ handler forever Date: Thu, 12 Apr 2018 11:24:07 -0400 Message-Id: <16b1993cde965edc096f0833091002dd05d4da7f.1523546545.git.mchehab@s-opensource.com> X-Mailer: git-send-email 2.14.3 In-Reply-To: References: In-Reply-To: References: To: unlisted-recipients:; (no To-header on input) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP As warned by smatch: drivers/media/rc/st_rc.c:110 st_rc_rx_interrupt() warn: this loop depends on readl() succeeding If something goes wrong at readl(), the logic will stay there inside an IRQ code forever. This is not the nicest thing to do :-) So, add a timeout there, preventing staying inside the IRQ for more than 10ms. Signed-off-by: Mauro Carvalho Chehab Acked-by: Patrice Chotard --- drivers/media/rc/st_rc.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/media/rc/st_rc.c b/drivers/media/rc/st_rc.c index d2efd7b2c3bc..c855b177103c 100644 --- a/drivers/media/rc/st_rc.c +++ b/drivers/media/rc/st_rc.c @@ -96,19 +96,24 @@ static void st_rc_send_lirc_timeout(struct rc_dev *rdev) static irqreturn_t st_rc_rx_interrupt(int irq, void *data) { + unsigned long timeout; unsigned int symbol, mark = 0; struct st_rc_device *dev = data; int last_symbol = 0; - u32 status; + u32 status, int_status; DEFINE_IR_RAW_EVENT(ev); if (dev->irq_wake) pm_wakeup_event(dev->dev, 0); - status = readl(dev->rx_base + IRB_RX_STATUS); + /* FIXME: is 10ms good enough ? */ + timeout = jiffies + msecs_to_jiffies(10); + do { + status = readl(dev->rx_base + IRB_RX_STATUS); + if (!(status & (IRB_FIFO_NOT_EMPTY | IRB_OVERFLOW))) + break; - while (status & (IRB_FIFO_NOT_EMPTY | IRB_OVERFLOW)) { - u32 int_status = readl(dev->rx_base + IRB_RX_INT_STATUS); + int_status = readl(dev->rx_base + IRB_RX_INT_STATUS); if (unlikely(int_status & IRB_RX_OVERRUN_INT)) { /* discard the entire collection in case of errors! */ ir_raw_event_reset(dev->rdev); @@ -148,8 +153,7 @@ static irqreturn_t st_rc_rx_interrupt(int irq, void *data) } last_symbol = 0; - status = readl(dev->rx_base + IRB_RX_STATUS); - } + } while (time_is_after_jiffies(timeout)); writel(IRB_RX_INTS, dev->rx_base + IRB_RX_INT_CLEAR);