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From: Oliver Neukum <oliver@neukum.org>
To: Duncan Sands <baldrick@free.fr>, Greg KH <greg@kroah.com>
Cc: linux-usb-devel@lists.sourceforge.net,
	linux-kernel@vger.kernel.org, Frederic Detienne <fd@cisco.com>
Subject: Re: [linux-usb-devel] [PATCH 1/9] USB usbfs: take a reference to the usb device
Date: Sat, 17 Apr 2004 22:33:03 +0200	[thread overview]
Message-ID: <200404172233.03552.oliver@neukum.org> (raw)
In-Reply-To: <200404172217.10994.baldrick@free.fr>


> riddled with races of this kind.  The simplest solution is to
> systematically take ps->dev->serialize when entering the usbfs routines,
> which is what my patches do.  This should be regarded as a first step: it

What is the alternative?

> gives correctness, but at the cost of a probable performance hit.  In later
> steps we can (1) turn dev->serialize into a rwsem

Rwsems are _slower_ in the normal case of no contention.

> (2) push the acquisition of dev->serialize down to the lower levels as they
> are fixed up.

Why?

	Regards
		Oliver


  reply	other threads:[~2004-04-17 20:33 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-14 10:29 [PATCH 1/9] USB usbfs: take a reference to the usb device Duncan Sands
2004-04-17 20:17 ` [linux-usb-devel] " Duncan Sands
2004-04-17 20:33   ` Oliver Neukum [this message]
2004-04-18  9:35     ` Duncan Sands
2004-04-18 13:57       ` Oliver Neukum
2004-04-18 14:08         ` Duncan Sands
2004-04-18 14:40       ` Alan Stern
2004-04-19 17:25   ` David Brownell
2004-04-23 23:18 ` Greg KH
2004-04-26 14:05   ` Duncan Sands
2004-04-26 22:14     ` Greg KH
2004-04-27  8:58       ` [linux-usb-devel] " Oliver Neukum
2004-04-30  9:04         ` Duncan Sands
2004-05-01 23:01           ` Greg KH

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