On Thu, Mar 11, 2021, Ben Gardon wrote: > In tdp_mmu_iter_cond_resched there is a call to tdp_iter_start which > causes the iterator to continue its walk over the paging structure from > the root. This is needed after a yield as paging structure could have > been freed in the interim. > > The tdp_iter_start call is not very clear and something of a hack. It > requires exposing tdp_iter fields not used elsewhere in tdp_mmu.c and > the effect is not obvious from the function name. Factor a more aptly > named function out of tdp_iter_start and call it from > tdp_mmu_iter_cond_resched and tdp_iter_start. What about calling it tdp_iter_restart()? Or tdp_iter_resume()? Or something like tdp_iter_restart_at_next() if we want it to give a hint that the next_last thing is where it restarts. I think I like tdp_iter_restart() the best. It'd be easy enough to add a function comment clarifying from where it restarts, and IMO the resulting code in tdp_mmu_iter_cond_resched() is the most intutive, e.g. it makes it very clear that the walk is being restarted in some capacity after yielding.
