Photoshop: non-destructive mask editing using adjustments (curves)

There is workaround how to do that. Sory for non-english tutorial but this maybe is not everywhere in English: http://graficketipy.cz/sedmero-vrstev-4/ You should be able aplly adjustemt layer on Smart Object mask. You can also save "Blend if presset" into layer styles panel and then aplly with single click.

I came here to suggest just the same. Nice to see, that I am not alone 🙂

This would be very helpful. Great idea.

Great suggestion David.

As you may be aware, to some extend the MASK Dialog box offers some limited, nondestructive options to modify the layer Mask, but I agree - more flexibility would be useful here.

»Even better would be the ability to use the luminosity of a layer group or a smart object as a layer mask.«
Utilizing a Clipping Mask and the Blend If-settings of a Layer/SO that is possible to some (fairly limited) extent now.
Edit: A very limited extent actually ... it’s a fairly uncomfortable work-around with the Blend If-settings set in the SO, so previewing is not instantaneous.

And in my opinion your request does not go far enough: full Smart Object functionality for Layer Masks (including Layers, Masks etc.) would seem preferable to me.

Here is a mock-up of what I'd really like to see. It would give the same options for editing masks as we currently have for luma/chroma channels. The inset area is the set of layers that is applied to the layer mask of the layer under it.

Image is not available