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From: Pete Zaitcev <zaitcev@redhat.com>
To: Daniel Walker <dwalker@mvista.com>
Cc: akpm@linux-foundation.org, mingo@elte.hu,
	linux-kernel@vger.kernel.org, linux@bohmer.net,
	jonathan@jonmasters.org, matthias.kaehlcke@gmail.com,
	kjwinchester@gmail.com
Subject: Re: [PATCH 4/4] usb: libusual: locking cleanup
Date: Mon, 24 Dec 2007 06:12:20 -0800	[thread overview]
Message-ID: <20071224061220.ceed2bf8.zaitcev@redhat.com> (raw)
In-Reply-To: <1198428397.2742.20.camel@imap.mvista.com>

On Sun, 23 Dec 2007 08:46:37 -0800, Daniel Walker <dwalker@mvista.com> wrote:

> I noticed you also have a spinlock held in usu_probe_thread(), the
> usu_lock.. That spinlock would preclude anything inside request_module()
> from sleeping..

The usu_lock is not held across request_module. In fact, it can be
easily taken from inside request_module, when it invokes modprobe.
Stop scaring me :-)

> One thing that has bothered me is that I don't see a reason why this
> couldn't become a complete, yet you have a comment which says that it
> can't be a complete.. I honestly didn't understand the comment.. I would
> imagine that you tried a complete , and it didn't work?

Yes, it was a completition initially. But suppose you have two storage
devices, plugged in across a reboot. Two threads are created and have to
wait until the libusual's init function ends. Since we post one completion,
only one thread continues.

-- Pete

  reply	other threads:[~2007-12-24 14:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20071221205848.989157559@mvista.com>
2007-12-21  8:00 ` [PATCH 1/4] usb microtek: remove unused semaphore Daniel Walker
2007-12-21  8:00 ` [PATCH 2/4] prism54: remove questionable down_interruptible usage Daniel Walker
2007-12-21  8:00 ` [PATCH 3/4] docs: convert kref semaphore to mutex Daniel Walker
2007-12-21 21:33   ` Corey Minyard
2007-12-21  8:00 ` [PATCH 4/4] usb: libusual: locking cleanup Daniel Walker
2007-12-22  4:22   ` Andrew Morton
2007-12-22  6:24   ` Pete Zaitcev
2007-12-22  6:31     ` Andrew Morton
2007-12-22 17:01     ` Daniel Walker
2007-12-23  7:37       ` Pete Zaitcev
2007-12-23 16:46         ` Daniel Walker
2007-12-24 14:12           ` Pete Zaitcev [this message]
2007-12-24 16:04             ` Daniel Walker

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