Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: How to tell whether a struct file is held by a process? | Date | Fri, 22 May 2009 15:38:08 +0200 |
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Am Freitag, 22. Mai 2009 15:30:20 schrieb Pantelis Koukousoulas: > The only problem I find with leaving mutual exclusion 100% to userspace and > burdening the kernel only with the decision of whether a port should be > handled by kernel or userspace is this: > > Suppose a device needs a reset as part of its init sequence (a whole lot > of them do, this is not purely hypothetical). Then a different process may > get to operate the device before and after the reset and hilarity may > result from that.
If you leave the locking against user space to user space this can happen any time, not just due to a reset. What is so special about reset? You just need a user space locking scheme operating on port numbers, not device addresses.
Regards Oliver
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