From: Tejun Heo <tj@kernel.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com,
linux-kernel@vger.kernel.org, Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: [PATCH 14/16] blkcg: don't allow or retain configuration of missing devices
Date: Tue, 24 Jan 2012 07:53:09 -0800 [thread overview]
Message-ID: <20120124155309.GA12906@google.com> (raw)
In-Reply-To: <20120124154224.GA17291@redhat.com>
On Tue, Jan 24, 2012 at 10:42:24AM -0500, Vivek Goyal wrote:
> On Mon, Jan 23, 2012 at 03:09:51PM -0800, Tejun Heo wrote:
> > + disk = get_gendisk(dev, &part);
> > +
> > + if ((!disk || part) && temp) {
> > + ret = -ENODEV;
> > + goto out;
> > + }
> > +
> > + rcu_read_lock();
> > +
> > + if (disk && !part) {
> > + spin_lock_irq(disk->queue->queue_lock);
> > + blkg = blkg_lookup_create(blkcg, disk->queue, plid);
> > + spin_unlock_irq(disk->queue->queue_lock);
>
> If queue is in bypass mode, is group creation and linking allowed when
> somebody is trying to set per device rules. (/me is thinking if there are
> any potential races between elevator switch and rule setting in cgroup).
Yeap, there is. Nice catch. blkg_lookup_create() should be testing
blk_queue_bypass() instead of blk_queue_dead() and parse_and_set
should probably retry after a bit. Will update.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-01-24 15:53 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-23 23:09 [PATCHSET] blkcg: kill policy node and blkg->dev, take#3 Tejun Heo
2012-01-23 23:09 ` [PATCH 01/16] blkcg: make CONFIG_BLK_CGROUP bool Tejun Heo
2012-01-23 23:09 ` [PATCH 02/16] cfq: don't register propio policy if !CONFIG_CFQ_GROUP_IOSCHED Tejun Heo
2012-01-23 23:09 ` [PATCH 03/16] elevator: clear auxiliary data earlier during elevator switch Tejun Heo
2012-01-23 23:09 ` [PATCH 04/16] elevator: make elevator_init_fn() return 0/-errno Tejun Heo
2012-01-23 23:09 ` [PATCH 05/16] block: implement blk_queue_bypass_start/end() Tejun Heo
2012-01-23 23:09 ` [PATCH 06/16] block: extend queue bypassing to cover blkcg policies Tejun Heo
2012-01-23 23:09 ` [PATCH 07/16] blkcg: shoot down blkio_groups on elevator switch Tejun Heo
2012-01-23 23:09 ` [PATCH 08/16] blkcg: move rcu_read_lock() outside of blkio_group get functions Tejun Heo
2012-01-23 23:09 ` [PATCH 09/16] blkcg: update blkg get functions take blkio_cgroup as parameter Tejun Heo
2012-01-23 23:09 ` [PATCH 10/16] blkcg: use q and plid instead of opaque void * for blkio_group association Tejun Heo
2012-01-23 23:09 ` [PATCH 11/16] blkcg: add blkio_policy[] array and allow one policy per policy ID Tejun Heo
2012-01-23 23:09 ` [PATCH 12/16] blkcg: use the usual get blkg path for root blkio_group Tejun Heo
2012-01-23 23:09 ` [PATCH 13/16] blkcg: factor out blkio_group creation Tejun Heo
2012-01-24 16:23 ` [PATCH UPDATED " Tejun Heo
2012-01-24 16:25 ` Tejun Heo
2012-01-23 23:09 ` [PATCH 14/16] blkcg: don't allow or retain configuration of missing devices Tejun Heo
2012-01-24 15:42 ` Vivek Goyal
2012-01-24 15:53 ` Tejun Heo [this message]
2012-01-24 16:32 ` Vivek Goyal
2012-01-24 16:34 ` Tejun Heo
2012-01-24 19:30 ` [PATCH UPDATED " Tejun Heo
2012-01-24 19:46 ` Vivek Goyal
2012-01-23 23:09 ` [PATCH 15/16] blkcg: kill blkio_policy_node Tejun Heo
2012-01-23 23:09 ` [PATCH 16/16] blkcg: kill the mind-bending blkg->dev Tejun Heo
2012-01-24 19:29 ` [PATCH 13.5] blkcg: make blkg_lookup_create() return ERR_PTR value on failure Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2012-02-01 20:50 [PATCHSET] blkcg: kill policy node and blkg->dev, take#4 Tejun Heo
2012-02-01 20:50 ` [PATCH 14/16] blkcg: don't allow or retain configuration of missing devices Tejun Heo
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