There’s growing anger toward the LAPD for not arresting Will Smith on the spot even after Chris Rock said he didn’t want Will busted — but fact is, there were only 2 ways cops could have taken Will out of the Dolby Theater in cuffs.

LAPD sources with firsthand knowledge tell us only one officer was inside the auditorium, and he was backstage and didn’t see the slap. Since it was misdemeanor battery, the only way a cop could arrest Will on his/her own is if it was committed in their presence, and it was not.

We’re told the officer backstage heard what happened and then beelined it for Chris’ dressing room, where he waited outside for a while and then asked Chris if he wanted to press charges. We’re told Chris was clear he did not, and our LAPD sources dispute what Oscar producer Will Packer claimed … that Chris was asked if he wanted Will removed.

So there was one other way Will could have been arrested. Someone in the crowd — and there were several thousand — could have gone up to a cop and asked to make a citizen’s arrest. Under California law, “a private person may arrest another for a public offense committed or attempted in his presence.” No one in the crowd asked to do that.

Now we’ve also learned there was a flood of angry folks — people who either called LAPD or actually went to one of the divisions — and asked to arrest Will for battery. Thing is … they didn’t witness the slap in person — watching it on TV doesn’t count — so LAPD could do nothing.