how to add smart filter to adjustment layers or adjustment layer mask

Sorry, typo. Blank layer.

Sorry I am primitive in photoshop,I tried hard to follow your process,but still couldn't make through.You said "added a black layer",is it a normal layer? "Next I made a smart object of the layer with the noise.",this is where I am stucked,how to make a smart object of the layer with the noise?sorry for the naive question.

I just came up with a workaround, but it doesn't work with all filters. some like artistic brush stroke doesn't work with transparency, and you need to be able to have transparency to work. This is what I did:

In my screen shot, you'll notice that I applied a noise filter to the adjustment layer, but I turned it off. I did a ctrl-click on the mask thumbnail to create a selection of it. Then I inverted it.

Next I created a group and put the adjustment layer inside the group and added a black layer above the adjustment layer. I then fill that blank layer with black, from the selection that I made. It is the same as the layer mask, but only black and transparency - no white.

Next I made a smart object of the layer with the noise.

This is where the magic is: I opened the layer styles and set the fill opacity to 0 and the knockout to deep. This creates a mask from a layer. I could then apply motion blur. The area with the marching ants is what the original mask looked like. Outside of that is with the motion blur applied.

You can try different filters, but some may not work with transparency, as I mentioned above.

What type of filters do you want to apply to the layer mask, or what modification do you want to do?

Yea, you can't apply a smart object to an adjustment layer to retain the mask. Only workaround would be to keep an alpha channel of the original mask, so that if you needed to go back, you have the original.

Adjustment layers are non destructive, so I'm not sure why you would want to put them in a smart object.