Allow the roast to stand at room temperature for 30 to 45 minutes.
Put the garlic, rosemary, thyme, salt, and pepper in a food processor and pulse until finely minced. Add the mustard and olive oil and process to form a paste. Smear the paste all over the top and sides of the roast.
Oil the grill racks. Set up your grill for indirect heat. Preheat your gas grill or light a charcoal fire. You want to have a temperature of about 200-225 degrees. Put the roast on a rack, bone side down, and place the rack inside a disposable aluminum pan large enough to accommodate the rack.
Add your wood chips or chunks to the charcoal, or follow your grill’s instructions on setting up for smoking. For a gas grill, the simplest thing is to use a smoke box or wrap the wood in aluminum foil and poke holes in the foil. Allow the smoke to build, then add the pan with the roast over the indirect area of the grill. Close the lid and cook to your desired doneness, 1 1/2 to 2 hours for medium-rare (the meat will register 135°F to 140°F on an instant-read thermometer).
Transfer the roast to a cutting board and remove the bones. Loosely cover the roast with foil and let rest for 20 to 30 minutes. The internal temperature will rise 5°F to 10°F.
Carve the meat into slices and serve.