Re: [linux-usb-devel] Re: [OOPS, usbcore, releaseintf] 2.6.0-test10-mm1

[David Brownell]

> PS: Here is the patch that fixed the original usbfs Oops, but gained the new
> one Vince reported:

Good -- more locks vanishing from usbcore; it's about time!
This is a case where fewer locks are better.

My main patch feedback here would be that it should merge
most of the usbfs patch I sent (second URL below).  There's
a driver model locking requirement that you didn't know about,
it needs to bubble up (subsys.rwsem writelock must be held if
you're going to change driver bindings).  And there were a
few other rough spots, which I think you've mentioned (and
I don't think they were new issues).

The more I think about it, the more I like your idea of
changing device->serialize to be an rwsem.  Changing config,
or resetting the device, would get the writelock.  All other
uses should share, with readlocks -- that's the right model.

Likely not before 2.6.1 though ... ;)

- Dave

[1] http://marc.theaimsgroup.com/?l=linux-usb-devel&m=107100212612153&w=2
[2] http://marc.theaimsgroup.com/?l=linux-usb-devel&m=107102580404037&w=2


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/