On Wed, 24 Oct 2018, Petr Mladek wrote: > On Thu 2018-10-18 07:58:24, Josh Poimboeuf wrote: > > On Thu, Oct 18, 2018 at 01:11:53PM +0200, Petr Mladek wrote: > > > On Wed 2018-10-17 13:17:56, Josh Poimboeuf wrote: > > > > On Mon, Oct 15, 2018 at 02:37:03PM +0200, Petr Mladek wrote: > > > > > The definition of struct klp_func might be a bit confusing. > > > > > The original function is defined by name as a string. > > > > > The new function is defined by name as a function pointer > > > > > casted to unsigned long. > > > > > > > > > > This patch adds helper macros that hide the different types. > > > > > The functions are defined just by the name. For example: > > > > > > > > On one hand, these macros are kind of nice, because they do the function > > > > pointer casting for the user. > > > > > > > > On the other hand, they hide the field names, which hurts readability a > > > > bit. For example, it would be easy to accidentally assign the wrong > > > > callback function. > > > > > > I am not a big fan of the macros either. > > > > > > > > > > Also, it's unfortunate that these macros are needed in the first place. > > > > > > > > What if we just change new_addr (and old_addr) to be 'void *'? Then the > > > > macros wouldn't be as useful, and we could just get rid of them. > > > > > > Hmm, I wonder if any change make sense then. The above proposal might > > > just exchange one confusion with another one: > > > > > > + I would expect that a variable called addr is of the type > > > unsigned long > > > > > > + we would need casting when calling ftrace API > > > > > > + .new_addr = function_xxx looks a bit weird and it will > > > be used many times in all livepatch sources. > > > > Fair points. Instead of changing new_func to new_addr, how about we > > leave it alone, and instead change 'unsigned long old_addr' to 'void > > *old_func'? > > > > That would give us consistent naming internally, while making the > > external interface more sensible and cast-free. > > > > We'd still have to cast when passing to the ftrace API, but IMO it would > > be worth it. > > I am fine with this. I will do this in v14 unless anyone complains ;-) I agree. I don't like the change from 1/12 much as it exposes casting to user. Macros introduced here do not make any better and I go along with Josh. Miroslav
