Gracenote.com lists recordings with all the following titles:

JUST PASSIN' THROUGH
JUST PASSIN' THRU
JUST PASSING THROUGH
JUST'A PASSIN' THROUGH
PASSIN' THROUGH
PASSIN' THRU
PASSING THROUGH
PASSING THRU

I don't know how many of these are actually different songs.

Performers who have recorded these songs include Aim; Augie March; Bobby Bare; Bridget St John; Bruce Hornsby; Chico Hamilton; Chris Rea; Dale Ann Bradley; Earl Scruggs; Eve Selis; Frederick Knight; George Thorogood & The Destroyers; Jackie Wilson; Kick Axe; Leonard Cohen; Lumidee; Rae & Christian; Randy Scruggs; Reckless Kelly; Rice, Rice, Hillmann & Pedersen; String Cheese Incident; The Picketts; and Vocal Union.