> > > > + bit = ftrace_test_recursion_trylock(); > > > > + if (bit < 0) > > > > + return; > > > > > > This means that the original function will be called in case of recursion. > > > That's probably fair, but I'm wondering if we should at least WARN about > > > it. > > > > Yeah, the early return might break the consistency model and > > unexpected things might happen. We should be aware of it. > > Please use: > > > > if (WARN_ON_ONCE(bit < 0)) > > return; > > > > WARN_ON_ONCE() might be part of the recursion. But it should happen > > only once. IMHO, it is worth the risk. > > > > Otherwise it looks good. > > Perhaps we can add that as a separate patch, because this patch doesn't add > any real functionality change. It only moves the recursion testing from the > helper function (which ftrace wraps all callbacks that do not have the > RECURSION flags set, including this one) down to your callback. > > In keeping with one patch to do one thing principle, the added of > WARN_ON_ONCE() should be a separate patch, as that will change the > functionality. > > If that WARN_ON_ONCE() breaks things, I'd like it to be bisected to another > patch other than this one. Works for me. Miroslav
