From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sujit Reddy Thumma Subject: Re: [PATCH] mmc: core: Fix deadlock when the CONFIG_MMC_UNSAFE_RESUME is not defined Date: Wed, 23 Nov 2011 08:43:38 +0530 Message-ID: <4ECC64E2.4050207@codeaurora.org> References: <1321961437-27130-1-git-send-email-sthumma@codeaurora.org> <4ECBC332.9090407@stericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wolverine02.qualcomm.com ([199.106.114.251]:28218 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753956Ab1KWDNm (ORCPT ); Tue, 22 Nov 2011 22:13:42 -0500 In-Reply-To: <4ECBC332.9090407@stericsson.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson Cc: "linux-mmc@vger.kernel.org" , "cjb@laptop.org" On 11/22/2011 9:13 PM, Ulf Hansson wrote: > Sujit Reddy Thumma wrote: >> mmc_suspend_host() tries to claim host during suspend >> and release it only when the bus suspend operation is >> compeleted. If CONFIG_MMC_UNSAFE_RESUME is defined and >> the host is flagged as removable, mmc_suspend_host() >> tries to remove the card. In this process, the file system >> sync can get blocked trying to acquire host which is already >> claimed by mmc_suspend_host() causing deadlock. >> >> Fix this deadlock by releasing host before ->remove() is called. >> >> Signed-off-by: Sujit Reddy Thumma >> --- >> drivers/mmc/core/core.c | 4 +++- >> 1 files changed, 3 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c >> index 271efea..8adbadf 100644 >> --- a/drivers/mmc/core/core.c >> +++ b/drivers/mmc/core/core.c >> @@ -2338,6 +2338,7 @@ int mmc_suspend_host(struct mmc_host *host) >> * We simply "remove" the card in this case. >> * It will be redetected on resume. >> */ >> + mmc_do_release_host(host); > > Instead of having an "else" below move mmc_do_release_host to be done > before "if (err == -ENOSYS || !host->bus_ops->resume)" Sure. > >> if (host->bus_ops->remove) >> host->bus_ops->remove(host); >> mmc_claim_host(host); >> @@ -2346,8 +2347,9 @@ int mmc_suspend_host(struct mmc_host *host) >> mmc_release_host(host); >> host->pm_flags = 0; >> err = 0; >> + } else { >> + mmc_do_release_host(host); >> } > > Remove else statement entirely. Okay. Will do it. Thanks, Sujit