Re: Right way to configure a driver? (sysfs, ioctl, proc, configfs,....)

[Greg KH <greg@kroah.com>]

On Mon, Jan 30, 2006 at 12:23:14PM +0100, Aritz Bastida wrote:
> Thank you Antonio and Greg
> But I still have one question pending:
> 
> > >
> > > 3.- Actually the most difficult config I must do is to pass three
> > > values from userspace to my module. Specifically two integers and a
> > > long (it's an offset to a memory zone I've previously defined)
> > >
> > > struct meminfo {
> > >         unsigned int      id;         /* segment identifier */
> > >         unsigned int      size;     /* size of the memory area */
> > >         unsigned long   offset;   /* offset to the information */
> > > };
> > >
> > > How would you pass this information in sysfs? Three values in the same
> > > file? Note that using three different files wouldn't be atomic, and I
> > > need atomicity.
> > >
> 
> I guess I could pass three values on the same file, like this:
> $ echo "5  1000  500" > meminfo
> 
> I know that breaks the sysfs golden-rule, but how can I pass those
> values _atomically_ then? Having three different files wouldn't be
> atomic...

That's what configfs was created for.  I suggest using that for things
like this, as sysfs is not intended for it.

thanks,

greg k-h