Sushi bar supply (4)
I believe the answer is:
rice
'sushi bar supply' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for rice that I've seen before include "Asian staple food" , "Staple food -- English lyricist, b. 1944" , "Grains used as food" , "Edible grains of grass" , "Basmati, for example" .)