From: Pavel Machek <pavel@ucw.cz>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Jens Axboe <jens.axboe@oracle.com>,
linux-pm <linux-pm@lists.linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: Is it supposed to be ok to call del_gendisk while userspace is frozen?
Date: Thu, 4 Mar 2010 21:15:48 +0100 [thread overview]
Message-ID: <20100304201548.GA1341@elf.ucw.cz> (raw)
In-Reply-To: <201003042026.30303.rjw@sisk.pl>
Hi!
> > My thought exactly. This is the only approach that also solves the
> > following race:
> >
> > A driver is unloaded at the same time as a suspend starts.
> >
> > The writeback thread gets frozen.
> >
> > Then before the rmmod thread is frozen, it calls del_gendisk.
> >
> > Delaying things by means of a workqueue (or the equivalent) might also
> > work, but it doesn't seem as safe. For example, some important
> > writebacks might end up getting delayed until too late.
Delaying writebacks during sleep should be ok... That's why we do
sync() after userspace is frozen -- nothing really important should be
waiting for writeback after that point.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2010-03-04 20:15 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.LNX.4.44L0.1003032142580.6963-100000@netrider.rowland.org>
2010-03-04 19:26 ` Is it supposed to be ok to call del_gendisk while userspace is frozen? Rafael J. Wysocki
[not found] ` <201003042026.30303.rjw@sisk.pl>
2010-03-04 19:36 ` Alan Stern
2010-03-04 20:04 ` Rafael J. Wysocki
2010-03-04 20:15 ` Pavel Machek [this message]
2010-04-22 23:40 ` Matt Reimer
[not found] ` <y2yf383264b1004221640rd1fca614zfa15d7e7984ab3ba@mail.gmail.com>
2010-04-23 5:17 ` Rafael J. Wysocki
[not found] ` <201004230717.07086.rjw@sisk.pl>
2010-05-11 23:55 ` Matt Reimer
[not found] <1275664778.4596.1.camel@maxim-laptop>
2010-06-04 17:52 ` Alan Stern
[not found] <Pine.LNX.4.44L0.1006041052570.1794-100000@iolanthe.rowland.org>
2010-06-04 15:19 ` Maxim Levitsky
[not found] <1275650416.3403.5.camel@maxim-laptop>
2010-06-04 14:59 ` Alan Stern
[not found] <201005182143.28004.rjw@sisk.pl>
2010-05-18 20:06 ` Alan Stern
[not found] <Pine.LNX.4.44L0.1005162219330.24400-100000@netrider.rowland.org>
2010-05-17 7:45 ` Nigel Cunningham
[not found] ` <4BF0F3FF.2010603@crca.org.au>
2010-05-17 20:35 ` Rafael J. Wysocki
[not found] ` <201005172235.37824.rjw@sisk.pl>
2010-05-17 22:51 ` Nigel Cunningham
[not found] ` <4BF1C86B.8000203@crca.org.au>
2010-05-18 19:43 ` Rafael J. Wysocki
2010-05-24 19:02 ` Pavel Machek
[not found] ` <20100524190206.GL1292@ucw.cz>
2010-05-24 21:21 ` Nigel Cunningham
[not found] <4BF06489.1050200@crca.org.au>
2010-05-17 2:22 ` Alan Stern
[not found] <Pine.LNX.4.44L0.1005142231390.11498-100000@netrider.rowland.org>
2010-05-15 20:30 ` Rafael J. Wysocki
[not found] ` <201005152230.10230.rjw@sisk.pl>
2010-05-16 7:49 ` Nigel Cunningham
[not found] ` <4BEFA375.7030404@crca.org.au>
2010-05-16 19:38 ` Rafael J. Wysocki
[not found] ` <201005162138.07105.rjw@sisk.pl>
2010-05-16 21:32 ` Nigel Cunningham
[not found] <Pine.LNX.4.44L0.1005142235580.11498-100000@netrider.rowland.org>
2010-05-15 2:53 ` Nigel Cunningham
[not found] ` <4BEE0CC5.60804@crca.org.au>
2010-05-16 19:35 ` Rafael J. Wysocki
[not found] <4BEC8173.4070500@crca.org.au>
2010-05-15 2:37 ` Alan Stern
[not found] <AANLkTimW3wLEt-DIRirHic1ZN1Z0k1t3TavwaCxTh_QL@mail.gmail.com>
2010-05-13 21:54 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1005131752160.1731-100000@iolanthe.rowland.org>
2010-05-13 22:20 ` Matt Reimer
[not found] ` <AANLkTimBxoCCeT_ns30JTIGKqgkiRIvKTf4LfE3mopkS@mail.gmail.com>
2010-05-13 22:47 ` Nigel Cunningham
2010-05-15 2:32 ` Alan Stern
[not found] <AANLkTikH7DvizJ9340SiksoIWU5KU2n-OCqWc4f_-z9v@mail.gmail.com>
2010-05-12 14:50 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1005121048420.1962-100000@iolanthe.rowland.org>
2010-05-13 21:44 ` Matt Reimer
[not found] <201003040123.13617.rjw@sisk.pl>
2010-03-04 2:48 ` Alan Stern
[not found] <20100303215056.GB2579@ucw.cz>
2010-03-03 22:23 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1003031720530.1380-100000@iolanthe.rowland.org>
2010-03-04 0:23 ` Rafael J. Wysocki
2010-03-04 13:53 ` Pavel Machek
[not found] ` <20100304135337.GC12191@atrey.karlin.mff.cuni.cz>
2010-06-04 11:20 ` Maxim Levitsky
[not found] <20100301063508.GA1455@ucw.cz>
2010-03-01 15:23 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1003011021440.1645-100000@iolanthe.rowland.org>
2010-03-03 21:50 ` Pavel Machek
[not found] <20100224191213.GH1025@kernel.dk>
2010-02-24 20:19 ` Alan Stern
[not found] <20100223221635.GP1025@kernel.dk>
2010-02-24 15:59 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1002241051470.2436-100000@iolanthe.rowland.org>
2010-02-24 19:12 ` Jens Axboe
[not found] <20100223155803.GN1025@kernel.dk>
2010-02-23 16:33 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1002231115510.1308-100000@iolanthe.rowland.org>
2010-02-23 22:16 ` Jens Axboe
[not found] <20100223123321.GA1025@kernel.dk>
2010-02-23 15:29 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1002231016500.1507-100000@iolanthe.rowland.org>
2010-02-23 15:58 ` Jens Axboe
2010-03-01 6:35 ` Pavel Machek
[not found] <201002152204.04148.rjw@sisk.pl>
2010-02-16 16:27 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1002161126340.1281-100000@iolanthe.rowland.org>
2010-02-20 22:22 ` Maxim Levitsky
2010-02-23 12:33 ` Jens Axboe
2010-02-13 13:29 Maxim Levitsky
2010-02-15 16:00 ` Maxim Levitsky
[not found] ` <1266249634.10662.6.camel@maxim-laptop>
2010-02-15 21:04 ` Rafael J. Wysocki
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