Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757348AbZKKLvL (ORCPT ); Wed, 11 Nov 2009 06:51:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756802AbZKKLvK (ORCPT ); Wed, 11 Nov 2009 06:51:10 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:56714 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753097AbZKKLvJ (ORCPT ); Wed, 11 Nov 2009 06:51:09 -0500 Subject: Re: [PATCH 1/1]: Thaws refrigerated bdi flusher threads before invoking kthread_stop on them From: Romit Dasgupta Reply-To: romit@ti.com To: "Rafael J. Wysocki" Cc: Pavel Machek , "jens.axboe@oracle.com" , "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" , "linux-pm@lists.linux-foundation.org" In-Reply-To: <200911111230.58479.rjw@sisk.pl> References: <1257928216.15415.57.camel@boson> <20091111103444.GD26423@elf.ucw.cz> <200911111230.58479.rjw@sisk.pl> Content-Type: text/plain; charset="UTF-8" Organization: Texas Instruments Date: Wed, 11 Nov 2009 17:20:31 +0530 Message-ID: <1257940231.28810.2.camel@boson> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1752 Lines: 47 Hello Rafael, As suggested I have added the relevant information in the changelog. The patch is below: > For completness, below is the information from the Romit's introductory message > (Romit, I really think that should go into the chagelog): Kicks out frozen bdi flusher task out of the refrigerator when the said task needs to exit. Steps to reproduce this. 1) Mount a file system from MMC/SD card. 2) Unmount the file system. This creates a flusher task. 3) Attempt suspend to RAM. System is unresponsive. This is because the bdi flusher thread is already in the refrigerator and will remain so until it is thawed. The MMC driver suspend routine ultimately will issue a 'kthread_stop' on the bdi flusher thread and will block until the flusher thread is exited. Since the bdi flusher thread is in the refrigerator it never cleans up until thawed. Signed-off-by: Romit Dasgupta --- diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 5a37e20..c757b05 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -606,8 +606,11 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi) * Finally, kill the kernel threads. We don't need to be RCU * safe anymore, since the bdi is gone from visibility. */ - list_for_each_entry(wb, &bdi->wb_list, list) + list_for_each_entry(wb, &bdi->wb_list, list) { + if (unlikely(frozen(wb->task))) + wb->task->flags &= ~PF_FROZEN; kthread_stop(wb->task); + } } void bdi_unregister(struct backing_dev_info *bdi) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/