Re: 26 ways to set a device driver variable from userland

Neil Brown
2005-10-19T23:51:11Z

On Wednesday October 19, cfriesen@nortel.com wrote:
> Kyle Moffett wrote:
>
> >> (4) sysfs
>
> > This is ideal for almost all device driver purposes.
>
> The one thing that I have yet to see a good solution for is
> transaction-based operations, where userspace passes in something (could
> be a command, a new value, a query, etc.) and expects some data in return.
>

knfsd does this sort of stuff with it's own tiny filesystem.

If you look in fs/libfs.c you will see a section headed
Transaction based IO
which is exactly for this sort of thing.

Currently I think you need to create your own tiny filesystem (which
isn't much effort if you use the stuff in libfs).

I think I'd like this sort of file to be a standard option for sysfs
attributes, but I haven't looked seriously into the possibility yet.

NeilBrown