On Wed, Dec 24, 2008 at 03:26, Derek M Jones <derek@xxxxxxxxxxxx> wrote: > Alexey, > > I have been looking through the source to look at the contexts > in which arithmetic is performed on void pointers. > >>> 1) Are the arguments really chars of one sort or another and >>> therefore the parameter ought to be declared as such? >> >> You mean, if address arithmetics is performed on a void * cast result, >> check that the casted type too has sizeof 1? > > I was thinking more along the lines of pointer to a character type being > converted to void * for no obvious reason, or a value being converted to > void * having an arithmetic operation performed and then converted to > a pointer to character type. > For an example see line 156 of arch/x86/kernel/module_64. > > I would expect the void * to come from/go to a type that had a > size greater than 1. > >>> 4) Other possible fault issues, people? > > I have found an instance (arch/x86/kernel/kprobes.c:834) that > effectively does: > > (void *)long_val + an_int_calculation > > when it should have done: > > (void *)(long_val + an_int_calculation) > > hardly an earth shattering misuse. There is nothing wrong here. Just depends on the way you think about it. In the first case you convert a long to a pointer, and add an int, the the second, you convert the sum. The result is of course the same. And this has nothing to do with void*, it would be the same with char*. So far the only concern with void* is that not everyone knows the it is sizeof 1. So if you propose repulsing void* with char* when we don't really need a void*, that's probably fine. But don't you think there are more useful ways to spend your time? With open issues like the Global Warming, World Hunger and standing 2.6.28 regressions, I don't see anyone bothered with replacing unnecessary void* casts. -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
