Messages in this thread | | | Date | Wed, 06 Oct 1999 13:28:46 +0200 | From | Marcin Dalecki <> | Subject | Re: USB device allocation |
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Nathan Hand wrote: > > On Tue, Oct 05, 1999 at 04:03:34PM -0700, H. Peter Anvin wrote: > > David Weinehall wrote: > > > > > > > That is one way of doing it; IMO a very good way because it lets you > > > > have policy in user space. > > > > > > Oh? And what kind of image of how devfs does things do you have then? > > > > > > This is how devfs works. The kernel part of devfs informs devfsd of the > > > changes (what devices need to be created/removed), and devfsd nicely > > > carries out its chores. User-space policy and persistent access-rights are > > > there for you. > > > > > > > ... in which case you don't need devfs at all. > > > > -hpa > > Agreed. Getting rid of devfs (the dynamic filesystem) makes devfs (the > concept of dynamic /dev) more acceptable to more punters, and honestly > doesn't lose all that much functionality. Modules contact devfsd when > they need a node. The daemon creates/deletes nodes as needed on a real > filesystem using the policy laid out via /etc/devfsd.conf. > > - The /dev directory is updated in user space, not kernel space. > > - You can just turn off the daemon, old behaviour is restored. > > - Kernel modifications are minimal (changes to init/cleanup_module). > > - Major/minors can be assigned dynamically by drivers, avoids GUID. > > - Topology rules for USB can be over-engineered totally in user space. > > - The policy for naming nodes moves to user space, hpa is happy. > > - Persistence of nodes is maintained by the filesystem, tso is happy. > > - Devfs gets into the kernel, everyone else in the world is happy. > > You lose the ability to run a Linux system without a filesystem which > knows about major/minor numbers. Only a tiny number of people are going > to complain about this (David?).
What about just passing something along the lines of request_module("/dev/sdd4") to the kernel module loader instead of the request_module("k-major-2") or for example request_module("net_alias-2").
Or even better just provice a request_device("sdd", 'c', major_nr, minor_nr) istead and let the modprobe do anything appriopriate about it? This would be the way as it should had been done since even the beginning of modularization...
--Marcin
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