On Thu 2014-11-06 10:57:48, Seth Jennings wrote: > On Thu, Nov 06, 2014 at 04:51:02PM +0100, Jiri Slaby wrote: > > On 11/06/2014, 03:39 PM, Seth Jennings wrote: > > > +/************************************* > > > + * Core structures > > > + ************************************/ > > > + > > > +/* > > > + * lp_ structs vs lpc_ structs > > > + * > > > + * For each element (patch, object, func) in the live-patching code, > > > + * there are two types with two different prefixes: lp_ and lpc_. > > > + * > > > + * Structures used by the live-patch modules to register with this core > > > module > > > + * are prefixed with lp_ (live patching). These structures are part of > > > the > > > + * registration API and are defined in livepatch.h. The structures used > > > + * internally by this core module are prefixed with lpc_ (live patching > > > core). > > > + */ > > > > I am not sure if the separation and the allocations/kobj handling are > > worth it. It makes the code really less understandable. Can we have just > > struct lip_function (don't unnecessarily abbreviate), lip_objectfile > > (object is too generic, like Java object) and lip_patch containing all > > the needed information? It would clean up the code a lot. (Yes, we would > > have profited from c++ here.) > > I looked at doing this and this is actually what we did in kpatch. We > made one structure that had "private" members that the user wasn't > suppose to access that were only used in the core. This was messy > though. Every time you wanted to add a "private" field to the struct so > the core could do something new, you were changing the API to the patch > modules as well. While copying the data into an internal structure does > add code and opportunity for errors, that functionality is localized > into functions that are specifically tasked with taking care of that. > So the risk is minimized and we gain flexibility within the core and > more self-documenting API structures.
I am not sure if the modified API is really such a big limit. The modules initialize the needed members using ".member = value". Also we do not need to take care of API/ABI backward compatibility because there is very strict dependency between patches and the patched kernel. Well, I have to think more about it. Best Regards, Petr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
