From: James Bottomley <James.Bottomley@SteelEye.com>
To: Greg KH <greg@kroah.com>
Cc: Andrew Morton <akpm@osdl.org>,
linux-scsi@vger.kernel.org, Olaf Hering <olh@suse.de>
Subject: Re: Fw: blk_cleanup_queue, sleep in invalid context
Date: Thu, 05 Jan 2006 12:08:15 -0500 [thread overview]
Message-ID: <1136480895.3288.26.camel@mulgrave> (raw)
In-Reply-To: <20060105005609.GA17604@kroah.com>
On Wed, 2006-01-04 at 16:56 -0800, Greg KH wrote:
> You mean, put a might_sleep() in put_device()? Yes, I can do that, as
> that function might sleep. SCSI is the culprit here, and I thought that
> the scsi developers had fixed this up already.
No .. I identified one clear culprit which was fixed, but I also said we
have exposure to this all over the place. Our basic problem is that we
have a complex refcounted model for hosts, devices and commands. Since
the I/O paths are all accessible from either user or softirq context,
most of these puts will be in potentially illegal places.
We could get out of this by dumping device refcounting and implementing
our own instead, but that really doesn't sound to be the right thing to
do. Conversely, putting workqueues everywhere to get around this, like
I did for the target handling, is going to get very messy.
James
prev parent reply other threads:[~2006-01-05 17:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-05 0:53 Fw: blk_cleanup_queue, sleep in invalid context Andrew Morton
2006-01-05 0:56 ` Greg KH
2006-01-05 1:12 ` Andrew Morton
2006-01-05 12:52 ` Olaf Hering
2006-01-05 17:08 ` James Bottomley [this message]
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