On Thu, 11 Jul 2013, Andrew Morton wrote: > > PTR_ERR() may not imply IS_ERR(), > > Well why not. Are we saying that code can legitimately convert the > PTR_ERR() return value back into a pointer? If so that sounds nuts. >
ERR_PTR() is just delivering a payload that can be interpreted by PTR_ERR(), Rusty has spotted places in the kernel that do this without actual errno. The most obvious case for me is the ERR_PTR(-1UL) in mm/oom_kill.c. People delivering a non-errno payload shouldn't be using ERR_PTR(), but nothing enforces that. You could add a WARN_ON_ONCE(error >= MAX_ERRNO). But PTR_ERR() will still need to rely on IS_ERR(). I agree that these longs should be converted to ints, since errno is defined to be int by the C standard. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
