Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752163Ab0FDLUY (ORCPT ); Fri, 4 Jun 2010 07:20:24 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:49976 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751344Ab0FDLUX (ORCPT ); Fri, 4 Jun 2010 07:20:23 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=vAiK0wVQZXhu0z/AyrM9t5UojUMHJYV645j4BTi5zMppMS7a67tAkXcov5y8irJx0D OGQF7UseYGbNdbCOBPM1aaUfU+sM+rqJSIdosZvZogv5znK6+5ZMCIGrKmn1TfqCCe3S yU5r0VfablSkOr78KaTOIjLd3oCQxjKP5G8DU= Subject: Re: [linux-pm] Is it supposed to be ok to call del_gendisk while userspace is frozen? From: Maxim Levitsky To: Pavel Machek Cc: Alan Stern , Jens Axboe , "Rafael J. Wysocki" , linux-pm , linux-kernel , Andrew Morton In-Reply-To: <20100304135337.GC12191@atrey.karlin.mff.cuni.cz> References: <20100303215056.GB2579@ucw.cz> <20100304135337.GC12191@atrey.karlin.mff.cuni.cz> Content-Type: text/plain; charset="UTF-8" Date: Fri, 04 Jun 2010 14:20:16 +0300 Message-ID: <1275650416.3403.5.camel@maxim-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1547 Lines: 42 On Thu, 2010-03-04 at 14:53 +0100, Pavel Machek wrote: > Hi! > > > > journalling assumptions broken: commit block is there, but previous > > > blocks are not intact. Data loss. > > > > > > ...and that was the first I could think about. Lets not do > > > this. Barriers were invented for a reason. > > > > Very well. Then we still need a solution to the original problem: > > Devices sometimes need to be unregistered during resume, but > > del_gendisk() blocks on the writeback thread, which is frozen until > > after the resume finishes. How do you suggest this be fixed? > > Avoid unregistering device during resume. Instead, return errors until > resume is done and you can call del_gendisk? This won't help ether. The same driver needs to unregister perfectly working device on suspend, because the user might replace the card during suspend and fool the os. There is a setting, CONFIG_MMC_UNSAFE_RESUME and I use it, but it isn't default. Anyway to revive that old thread, how about introducing new del_gendisk_no_sync? A less safe version of del_gendisk, but which won't sync the filesystem. Since driver knows that card is gone, there is no point of syncing it. (the sync is done by invalidate_partition, so some flag should be propagated to it). Best regards, Maxim Levitsky -- 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/