On Mon 2018-10-15 18:01:43, Miroslav Benes wrote: > On Fri, 12 Oct 2018, Petr Mladek wrote: > > > On Wed 2018-09-05 11:34:06, Miroslav Benes wrote: > > > On Tue, 28 Aug 2018, Petr Mladek wrote: > > > > Also the API and logic is much easier. It is enough to call > > > > klp_enable_patch() in module_init() call. The patch patch can be disabled > > > > by writing '0' into /sys/kernel/livepatch/<patch>/enabled. Then the module > > > > can be removed once the transition finishes and sysfs interface is freed. > > > > > > I think it would be good to discuss our sysfs interface here as well. > > > > > > Writing '1' to enabled attribute now makes sense only when you need to > > > reverse an unpatching transition. Writing '0' means "disable" or a > > > reversion again. > > > > > > Wouldn't be better to split it to two different attributes? Something like > > > "disable" and "reverse"? It could be more intuitive. > > > > > > Maybe we'd also find out that even patch->enabled member is not useful > > > anymore in such case. > > > > I though about this as well. I kept "enabled" because: > > > > + It keeps the public interface the same as before. Most people > > would not notice any change in the behavior except maybe that > > the interface disappears when the patch gets disabled. > > Well our sysfs interface is still in a testing phase as far as ABI is > involved. Moreover, each live patch is bound to its base kernel by > definition anyway. So we can change this without remorse, I think. > > > + The reverse operation makes most sense when the transition > > cannot get finished. In theory, it might be problem to > > finish even the reversed one. People might want to > > reverse once again and force it. Then "reverse" file > > might be confusing. They might not know in which direction > > they do the reverse. > > I still think it would be better to have a less confusing interface and it > would outweigh the second remark. OK, what about having just "disable" in sysfs. I agree that it makes much more sense than "enable" now. It might be used also for the reverse operation the same way as "enable" was used before. I think that standalone "reverse" might be confusing when we allow to reverse the operation in both directions. Best Regards, Petr
