Gen 17 is P

Gen 17:1-27 is assigned to P on grounds of its consistent use of P's nomenclature. Examples are p'ru ur'vu (17:2, 6, 20) Kel Shakai (17:1), and "becoming a nation" (17:6, 17:16, 17:20), and the word הוֹלִיד
(17:20), "fell on his face" (17:3, 17:17).

Also, this section generaly uses the divine names of P (17:1, 3, 7, 8, 9, 15, 18, 19, 22)

Gen 17 can also be assigned to P based on contradictions between it and chapter 18 which is JE

The major weakness in this argument is that Gen 17:1 uses the Holy name of God which is not usual associated with P before Exodus. This is indeed a problem.