From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subhash Jadavani Subject: Re: [PATCH 1/2] mmc: core: fix permanent sleep of mmcqd during card removal Date: Tue, 05 Feb 2013 13:02:11 +0530 Message-ID: <5110B57B.1040903@codeaurora.org> 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> <5110AF4E.5040207@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=EUC-KR Content-Transfer-Encoding: 7bit Return-path: Received: from wolverine01.qualcomm.com ([199.106.114.254]:56710 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751595Ab3BEHcQ (ORCPT ); Tue, 5 Feb 2013 02:32:16 -0500 In-Reply-To: <5110AF4E.5040207@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Jaehoon Chung Cc: Seungwon Jeon , 'Konstantin Dorfman' , 'Chris Ball' , linux-mmc@vger.kernel.org On 2/5/2013 12:35 PM, Jaehoon Chung wrote: > Hi Subhash, > > As Mr. Seungwon mentioned, your patch didn't solve the dead-lock issue. > I'm prefered to the seungwon's patch. Yes, i got the problem with the patch. I guess it's better to g ahead with Seungwon's patch. Looks good to me. Reviewed-by: Subhash Jadavani > > 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 >>