Messages in this thread | | | Date | Mon, 29 Nov 2010 21:54:10 +0100 (CET) | From | Guennadi Liakhovetski <> | Subject | Re: [PATCH/RFC] core: add a function to safely try to get device driver owner |
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Hi Jon
On Mon, 29 Nov 2010, Jonathan Corbet wrote:
> On Mon, 29 Nov 2010 20:43:28 +0100 (CET) > Guennadi Liakhovetski <g.liakhovetski@gmx.de> wrote: > > > When two drivers interoperate without an explicit dependency, it is often > > required to prevent one of them from being unloaded safely by dereferencing > > dev->driver->owner. This patch provides a generic function to do this in a > > race-free way. > > I must ask: why not, instead, make the dependency explicit? In > particular, this looks like an application for the proposed media > controller code, which is meant to model the connections between otherwise > independent devices. The fact that your example comes from V4L2 (which is > the current domain of the media controller) also argues that way.
Sorry, don't see a good way to do this. This function is for a general dependency, where you don't have that driver, we are checking for register with us, so, the only way to get to it is via dev->driver->owner. And I also don't want to move registering the device into the dependant driver and then wait (with a timeout) for a driver to probe with it... I just want to verify, whether a driver has attached to that device and whether I can lock it down.
Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/
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