Here in Austria, there are no restaurants and no bars, with the exception of McDonalds, that ban smoking completely. As a consequence, my wife and I go out very rarely - less than we would if Austria, like Italy, had a smoking ban.
What smells funny (ha ha) in terms of market failure to me is that I know that there are plenty of people like ourselves who don't smoke, and prefer not to have to bear the costs of other people's smoking habit (beyond health, if you choose not to believe in that, simply having to wash everything to get the awful smell out). You would think that there might be one or two places that would cater to that segment of the market. But there are none.
Consider a different element: loud music. The market provides a wide range of places to go, from the silent to the dull-roar where you can't hear yourself think. Don't like loud music? Don't go to those bars, then - everything works out just fine with no regulations.
Smoking doesn't work that way, though - perhaps the business of non-smokers might not be enough to keep a few bars alive, or the pressure of smokers in a mixed group of smoker/non smoker friends would keep them from going there, so restaurants/bars are afraid to even try. With a blanket ban, though, everyone is on a level playing field, and the smokers just go outside.
It's sort of like helmet regulations in sports like hockey or cycling: some people wore helmets beforehand, but since they hinder you in certain conditions, they were the exception rather than the rule. By making everyone wear them, they're all safer, and those who care about taking reasonable measures to keep themselves safe aren't at a disadvantage compared to those who are willing to take that risk, and thus the difference is, as it should be, athletic ability.