From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCH 1/2] mmc: core: fix permanent sleep of mmcqd during card removal Date: Tue, 05 Feb 2013 16:05:50 +0900 Message-ID: <5110AF4E.5040207@samsung.com> References: <1356513966-24945-1-git-send-email-kdorfman@codeaurora.org> <001201cdfeb3$3e628ee0$bb27aca0$%jun@samsung.com> <510F9ED6.2030402@codeaurora.org> <001f01ce0365$a7e7f560$f7b7e020$%jun@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=EUC-KR Content-Transfer-Encoding: 7bit Return-path: Received: from mailout1.samsung.com ([203.254.224.24]:43973 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750842Ab3BEHFy (ORCPT ); Tue, 5 Feb 2013 02:05:54 -0500 Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MHQ00KFBJOFGQ30@mailout1.samsung.com> for linux-mmc@vger.kernel.org; Tue, 05 Feb 2013 16:05:52 +0900 (KST) Received: from [10.90.51.55] by mmp1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MHQ006SZJPQRV10@mmp1.samsung.com> for linux-mmc@vger.kernel.org; Tue, 05 Feb 2013 16:05:50 +0900 (KST) In-reply-to: <001f01ce0365$a7e7f560$f7b7e020$%jun@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Seungwon Jeon Cc: 'Subhash Jadavani' , 'Konstantin Dorfman' , 'Chris Ball' , linux-mmc@vger.kernel.org Hi Subhash, As Mr. Seungwon mentioned, your patch didn't solve the dead-lock issue. I'm prefered to the seungwon's patch. Best Regards, Jaehoon Chung On 02/05/2013 02:57 PM, Seungwon Jeon wrote: > On Monday, February 04, 2013, Subhash Jadavani wrote: >> On 1/30/2013 12:00 PM, Seungwon Jeon wrote: >>> Hi Konstantin. >>> >>> Could you check this patch with [2/2]? >>> [PATCH 2/2] mmc: block: don't start new request when the card is removed >>> >>> mmcqd is often sleeping with acquiring the claim(mmc_claim_host) when a card is removed. >>> As a result, mmc_rescan can be blocked for the insertion of a card newly. It's a dead lock. >>> >>> Thanks, >>> Seungwon Jeon >>> >>> On Tuesday, January 22, 2013, Seungwon Jeon wrote: >>>> This patch is derived from 'mmc: fix async request mechanism ...'. >>>> According as async transfer, a request is handled with twice mmc_start_req. >>>> When the card is removed, the request is actually not issued in the first >>>> mmc_start_req [__mmc_start_data_req]. And then mmc_wait_for_data_req_done >>>> will come in the next mmc_start_req. But there is no event for completions. >>>> wake_up_interruptible is needed in __mmc_start_data_req for the case of >>>> removed card. >> >> Hi Seungwon, >> >> I looked at this again and i guess there is something wrong with >> mmc_start_req() itself. >> As per your commit text, first call to mmc_start_req() calls the >> __mmc_start_data_req() function and __mmc_start_data_req() returns the >> -ENOMEDIUM error (as card is removed) without starting the request on >> host controller. so now in mmc_start_req(), "start_err" should be set. >> But currently mmc_start_req() incorrectly marks the "host->areq" to >> "areq" in even if the start_err is set which i guess is wrong. what do >> you think about it? >> >> So how about this fix? I guess this is better and it should fix the >> deadlock issue as well. Do let me know you thoughts on this. If it looks >> reasonable, i can post the formal patch. > > Hi Subhash, > > I tested your fix, but there is still problem. > I didn't look into the reason. > > Thanks, > Seungwon Jeon >> >> >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c >> index 39f28af..1aa7dbe 100644 >> --- a/drivers/mmc/core/core.c >> +++ b/drivers/mmc/core/core.c >> @@ -546,7 +546,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host >> *host, >> if ((err || start_err) && areq) >> mmc_post_req(host, areq->mrq, -EINVAL); >> >> - if (err) >> + if (err || start_err) >> host->areq = NULL; >> else >> host->areq = areq; >> >> Regards, >> Subhash >> >>>> >>>> Signed-off-by: Seungwon Jeon >>>> --- >>>> drivers/mmc/core/core.c | 1 + >>>> 1 files changed, 1 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c >>>> index 8b3a122..997b257 100644 >>>> --- a/drivers/mmc/core/core.c >>>> +++ b/drivers/mmc/core/core.c >>>> @@ -350,6 +350,7 @@ static int __mmc_start_data_req(struct mmc_host *host, struct mmc_request *mrq) >>>> mrq->host = host; >>>> if (mmc_card_removed(host->card)) { >>>> mrq->cmd->error = -ENOMEDIUM; >>>> + mmc_wait_data_done(mrq); >>>> return -ENOMEDIUM; >>>> } >>>> mmc_start_request(host, mrq); >>>> -- >>>> 1.7.0.4 >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >