Visiting China from HK with HKSAR Re-entry Permit

I hold Canadian Passport. I am a permanent resident of Hong Kong. I have HKSAR Re-entry Permit, do I need a China Visa to travel to China from Canada? If I enter China from Hong Kong with my HKSAR Re-entry Permit, can I fly right back to Canada from China? Please help. It is my pleasure to visit China after my retirement.

Harry from Canada