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

[Neil Brown]

On Wednesday October 19, cfriesen@xxxxxxxxxx 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
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