From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751849AbeBUTYq (ORCPT ); Wed, 21 Feb 2018 14:24:46 -0500 Received: from us01smtprelay-2.synopsys.com ([198.182.60.111]:39780 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751752AbeBUTYm (ORCPT ); Wed, 21 Feb 2018 14:24:42 -0500 Subject: Re: [PATCH] mmc: dw_mmc: Fix the DTO timeout overflow calculation for 32-bit systems To: Evgeniy Didin , CC: Ulf Hansson , Alexey Brodkin , Douglas Anderson , , , "andy.shevchenko@gmail.com >> Andy Shevchenko" Newsgroups: gmane.linux.kernel.arc,gmane.linux.kernel.mmc,gmane.linux.kernel References: <20180221175734.39114-1-Evgeniy.Didin@synopsys.com> From: Vineet Gupta Message-ID: Date: Wed, 21 Feb 2018 11:24:32 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180221175734.39114-1-Evgeniy.Didin@synopsys.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.10.161.84] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Evgeniy On 02/21/2018 09:57 AM, Evgeniy Didin wrote: > In commit 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation") have been made > changes which can cause multiply overflow for 32-bit systems. Awesome, thx for quickly narrowing it down. I tried the fix and it cures my issue. It was caught on arc/hsdk board > when "drto_ms" should be 671, but it was 70 and that caused a flow of stack-traces just copying > file from mmc. IMHO, the fragment above could be improved. "The broken timeout calculations caused false interrupt latency warnings and stacktrace splat (such as below) when accessing the SD Card." | Running : 4M-check-reassembly-tcp-cmykw2-rotatew2.out -v0 -w1 | - Info: Finished target initialization. | mmcblk0: error -110 transferring data, sector 320544, nr 2048, cmd response | 0x900, card status 0x0 | mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 400000Hz, actual | 396825HZ div = 63) | mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 25000000Hz, actual | 25000000HZ div = 1) | ------------[ cut here ]------------ | softirq: huh, entered softirq 6 TASKLET 6f6a9412 with preempt_count 00000101, | exited with 00000100? | WARNING: CPU: 2 PID: 0 at ../lib/scatterlist.c:652 sg_miter_next+0x28/0x20c | Modules linked in: | CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.15.0 #57 | | Stack Trace: | arc_unwind_core.constprop.1+0xd0/0xf4 | dump_stack+0x68/0x80 | warn_slowpath_null+0x4e/0xec | sg_miter_next+0x28/0x20c | dw_mci_read_data_pio+0x44/0x190 | dw_mmc f000a000.mmc: Unexpected interrupt latency | dw_mci_interrupt+0x3ee/0x530 | __handle_irq_event_percpu+0x56/0x150 | handle_irq_event+0x34/0x78 | handle_level_irq+0x8e/0x120 | generic_handle_irq+0x1c/0x2c | idu_cascade_isr+0x30/0x6c | __handle_domain_irq+0x72/0xc8 | ret_from_exception+0x0/0x8 |---[ end trace 2a58c9af6c25fe51 ]--- > > Lets cast this multiply to long long int which prevents overflow. > > Signed-off-by: Evgeniy Didin > CC: Alexey Brodkin > CC: Douglas Anderson > CC: Ulf Hansson > CC: linux-kernel@vger.kernel.org > CC: linux-snps-arc@lists.infradead.org Tested-by: Vineet Gupta Fixes: ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files > --- > drivers/mmc/host/dw_mmc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 0aa39975f33b..1a0b9751c67c 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1944,7 +1944,7 @@ static void dw_mci_set_drto(struct dw_mci *host) > drto_div = (mci_readl(host, CLKDIV) & 0xff) * 2; > if (drto_div == 0) > drto_div = 1; > - drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div, > + drto_ms = DIV_ROUND_UP((uint64_t)MSEC_PER_SEC * drto_clks * drto_div, > host->bus_hz); > > /* add a bit spare time */ >