Re: upcalls from kernel code to user space daemons

From: Oliver Neukum
Date: Mon Jun 14 2004 - 16:42:32 EST


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> > 1) getHostByName: when the kernel cifs code detects a server crashes
> > and fails reconnecting the socket and the kernel code wants to see if
> > the hostname now has a new ip address.

Is that possible at all? It looks like that might deadlock in the page
out code path.

> > 2) package a kerberos ticket ala RFC2478 (SPNEGO)
>
> One way to do it (or is this what you meant by captive ioctl?)
>
> userspace daemon loops on ioctl()
> kernel portion of ioctl call goes to sleep until something to do
> when needed, fill in data and return to userspace
> userspace does stuff, then passes data back down via ioctl()
> ioctl() puts userspace back to sleep and continues on with other work

You could just as well implement an ordinary read()

Regards
Oliver
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