Messages in this thread |  | | From | "Dunlap, Randy" <> | Subject | RE: Updated Linux 2.4 issues page | Date | Mon, 21 Aug 2000 16:13:00 -0700 |
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> > > > 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).
Thanks, ~Randy
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