Re: [PATCH] Store the relevant miscdevice in file->private_data inmisc_open()

[Greg KH]

On Fri, Nov 14, 2008 at 01:50:52PM +1100, Michael Ellerman wrote:
> On Thu, 2008-11-13 at 16:18 -0800, Greg KH wrote:
> > On Fri, Nov 14, 2008 at 10:54:41AM +1100, Michael Ellerman wrote:
> > > On Thu, 2008-11-13 at 09:31 -0800, Greg KH wrote: 
> > > > On Thu, Nov 13, 2008 at 03:49:50PM +1100, Michael Ellerman wrote:
> > > > > Currently it's not easy to share file_operations between multiple
> > > > > instances of a miscdevice. In order to do this, the device code needs to
> > > > > store a list of all it's miscdevice instances, and when fops->open() is
> > > > > called, search the list and find the right device based on the minor
> > > > > number.
> > > > > 
> > > > > However the generic miscdevice code already has a list of miscdevices,
> > > > > and uses this to find the right device in misc_open(). If misc_open()
> > > > > would store the miscdevice it found in file->private_data, then the
> > > > > device code wouldn't need to worry about storing it's own separate list
> > > > > and searching that as well.
> > > > > 
> > > > > The rest of the miscdevice code does not use file->private_data, so the
> > > > > device code is still free to use file->private_data for something else
> > > > > if it wants to.
> > > > > 
> > > > > Signed-off-by: Michael Ellerman <michael@xxxxxxxxxxxxxx>
> > > > 
> > > > Do you have a follow-on patch for some misc device using code that would
> > > > take advantage of this change?
> > > 
> > > Ah, good point. I do, but not for upstream :/
> > 
> > Hm, then I have to ask why should we take this change?
> 
> Because it's seems like a good idea.

You know we don't make changes to core code for drivers that aren't in
the main tree, this is not a new thing...

> > And why would the driver not be availble for upstream to take?
> 
> Because it's a hacky pile of crud, and it's for unreleased and
> non-existent hardware.

That's what the drivers/staging/ tree is for, send it on over to me and
I'll add it to that location.

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/