Jens Axboe <axboe@xxxxxxxxx> writes: > On 10/30/20 4:22 PM, Al Viro wrote: >> On Fri, Oct 30, 2020 at 02:33:11PM -0600, Jens Axboe wrote: >>> On 10/30/20 12:49 PM, Al Viro wrote: >>>> On Fri, Oct 30, 2020 at 12:46:26PM -0600, Jens Axboe wrote: >>>> >>>>> See other reply, it's being posted soon, just haven't gotten there yet >>>>> and it wasn't ready. >>>>> >>>>> It's a prep patch so we can call do_renameat2 and pass in a filename >>>>> instead. The intent is not to have any functional changes in that prep >>>>> patch. But once we can pass in filenames instead of user pointers, it's >>>>> usable from io_uring. >>>> >>>> You do realize that pathname resolution is *NOT* offloadable to helper >>>> threads, I hope... >>> >>> How so? If we have all the necessary context assigned, what's preventing >>> it from working? >> >> Semantics of /proc/self/..., for starters (and things like /proc/mounts, etc. >> *do* pass through that, /dev/stdin included) > > Don't we just need ->thread_pid for that to work? No. You need ->signal. You need ->signal->pids[PIDTYPE_TGID]. It is only for /proc/thread-self that ->thread_pid is needed. Even more so than ->thread_pid, it is a kernel invariant that ->signal does not change. Eric
