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SubjectRE: Updated Linux 2.4 issues page
> > > >                o usbpl_{read,write}(): on UP concurrent 
> read/write
> > > > operations could corrupt the urb structures if
> > > > copy_to_user sleeps, on SMP it's worse.
> > >
> > > Again, what does this refer to? What functions, and in what
> > > files? There
> > > is no usbpl_ functions and I can't find any past
> references to them.
> > > Does anyone know what this means?
> >
> > Could these be usblp_{read,write}() instead? (in usb/printer.c)
> >
> > Not that that helps me understand the problem...
> Actually that does make more sense. And yes, this could be a problem.
> But if we are going to call out every SMP problem in the USB
> drivers, we
> would have a long list :)
> David Brownell's recent patch for the dc2xx driver shows what needs to
> be done to the drivers that don't have mechanisms to protect their
> internal data structures and urbs from reentrancy. Do you
> want me to go
> through the driver code to get a feel of which drivers have problems?

Sure, please do.

usblp_read() and usblp_write() already use separate urbs
for read vs. write and for each instance of the lp (minor).
Can you give me a brief explanation of the problem?
(and I'll look at David's dc2xx patch).


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