> Is there concrete architecture where it breaks? I'd expect i386/x86-64 > to be safe, and pretty much everyone to be safe as long as that long > is aligned.... or that was the result of arch-maintainers > discussion... It'll break on x86 if gcc decides to cache the value and you don't have explicit barriers. If the long is not aligned it's not safe on x86 at all. > I'd really like to document if it is right or not, so that I can point > people to documentation... We should always tell people to use atomic/set_bit etc. There *are* cases you can get away with it but it is far far better that the default is the safe one because most driver writers do not have a detailed knowledge of gcc code generation, processor quirks and barriers. If in a specific case its a performance hit then its worth optimising that case. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
