Re: [linux-usb-devel] [PATCH 1/9] USB usbfs: take a reference to the usb device

[Oliver Neukum]

> 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

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