On Tue, 23 Mar 2004 19:23:07 -0800 Greg KH <greg@xxxxxxxxx> wrote: > On Tue, Mar 23, 2004 at 02:31:53PM -0800, Pete Zaitcev wrote: > > > > If everything goes well, I will push this to Marcelo for 2.4.27. > > Wait, aren't I still the USB serial maintainer? :) Oh duh, that's right. I just forgot :-) > > I held back hoping for a backport, but now that I looked even more > > at it, I think 2.6 gets it wrong, too. It will be a separate work. > > How does 2.6 get it wrong? That's how: I didn't agree with this paragraph: > > However, what about the port->open_count? > > It is manipulated without any locking, it seems. > > Actually it can be gotten rid of entirely I think. The reference count > of the object is now handled properly, so open_count is pretty much > pointless. Now we are still relying on the fact that open() can't race > with disconnect() from the USB bus, which in real-life is probably ok, You cannot just get rid of it if you still want to call component driver's ->open only once. Something has to count, and reference counts do not match open counts, so you have to keep a counter for it. An alternative would be to pass all upper level opens through to component drivers, which would just push open counts down a level. IIRC, we did it before, but migrated to the current scheme. So, the open count stays. Since it stays, it has to be protected. > How about a patch against a clean 2.4 tree? This is against the latest > fedora 2.4 kernel, right? I was going to send it out after 2.4.26, but I can send it now if you want. -- Pete
