You are between a rock and a hard thing.
In most cites a law has been past that prevent smoking in rental units.Since this is a law of the city, many landlords no longer include in their lease or rental contracts that no smoking is allowed. The also do not advertise that their rental unit is a smoke free unit.
Since this is a city law it is like making noise in an apartment unit. You may call the police and inform them of your problem, however, a call about smoking or noise compliant is not high the police list to go directly to.
Telling the landlord that someone is breaking a law is not the landlords problem. The landlord is not a law enforcement agent.
You might inform the landlord that you are encountering a problem that is of a financial nature that require you to have your clothing cleaned, since the tenants above you are smoking. Since this is the case you will be suing the landlord as well as the tenant in small claims court for the cleaning of your clothing.
Your other option is to inform your landlord that the conditions you are currently living under with the smoke that is creeping into your rental unit would be cause for you to move.
Make sure you keep a record of the times you informed your landlord. You will need this proof in court if you move and your landlord file a claim against you for extra rent or damages.
Without proof, you would be like any other defendant in court, saying the famous lines "I did not know" I did not know is not a defense an ignorance of the law is not a defense either.
It takes time and is pain staking to have the proper proof to support your claim.
I hope this has been of some benefit to you, good luck.
"FIGHT ON"