Rashi on Genesis 47:22/רש"י על בראשית מ״ז:כ״ב

1הכהנים mean THE PRIESTS. The term כהן always means one who ministers to Deity except in those cases where it denotes one of high rank, e.g. (Exodus 2:16) “Jethro the chief of (כהן) Midian” and (Genesis 41:45) “the chief of (כהן) On”).

2חק לכהנים [FOR] THE PRIESTS HAD A PORTION — an assigned portion of a definite quantity of bread daily.