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Date: Wed, 25 Jun 2003 18:56:49 +0100
From: viro@parcelfarce.linux.theplanet.co.uk
To: Paul.Clements@steeleye.com
Cc: Lou Langholtz <ldl@aros.net>, linux-kernel@vger.kernel.org,
       Andrew Morton <akpm@digeo.com>, Pavel Machek <pavel@ucw.cz>
Subject: Re: [RFC][PATCH] nbd driver for 2.5+: fix locking issues with ioctl UI
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References: <3EF94672.3030201@aros.net> <Pine.LNX.4.10.10306251251410.11076-100000@clements.sc.steeleye.com>
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On Wed, Jun 25, 2003 at 01:48:16PM -0400, Paul Clements wrote:

> This patch introduces a locking hierarchy between the lo->tx_lock and
> lo->queue_lock. The existing driver does not have this limitation.
> I would feel a lot better about this patch if you were to recode it
> to avoid this.

?????

One of them is a semaphore, another - a spinlock.  Of course there always
had been a hierarchy - you can't call down() under a spinlock, the damn
thing can schedule.