Re: klists and struct device semaphores

From: Dmitry Torokhov
Date: Tue Mar 29 2005 - 11:28:38 EST


On Tue, 29 Mar 2005 11:18:13 -0500 (EST), Alan Stern
<stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> With that change in place we can guarantee that every time a USB driver's
> probe() is called, both the interface and the parent device are locked.
>
> I don't know how cleanly this can be implemented. You probably don't want
> to lock dev->parent->sem every time, only when needed. Maybe the simplest
> approach would be to add a flag in struct bus_type, which could be set for
> the USB bus_type and clear for everything else.
>

I think it is fine to lock parent unconditionally. After all
device/driver matching is not the most performance-critical part of
the kernel.

--
Dmitry
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