[+Philip] Hi Jason, I'm out of the office this week. Hi Philip, can you give this a go? Not sure how much you've been following this patch series review. Message or call me on Skype to discuss any questions. Thanks, Felix On 2019-06-11 12:48, Jason Gunthorpe wrote: > On Thu, Jun 06, 2019 at 03:44:27PM -0300, Jason Gunthorpe wrote: >> From: Jason Gunthorpe <jgg@xxxxxxxxxxxx> >> >> For hmm.git: >> >> This patch series arised out of discussions with Jerome when looking at the >> ODP changes, particularly informed by use after free races we have already >> found and fixed in the ODP code (thanks to syzkaller) working with mmu >> notifiers, and the discussion with Ralph on how to resolve the lifetime model. >> >> Overall this brings in a simplified locking scheme and easy to explain >> lifetime model: >> >> If a hmm_range is valid, then the hmm is valid, if a hmm is valid then the mm >> is allocated memory. >> >> If the mm needs to still be alive (ie to lock the mmap_sem, find a vma, etc) >> then the mmget must be obtained via mmget_not_zero(). >> >> Locking of mm->hmm is shifted to use the mmap_sem consistently for all >> read/write and unlocked accesses are removed. >> >> The use unlocked reads on 'hmm->dead' are also eliminated in favour of using >> standard mmget() locking to prevent the mm from being released. Many of the >> debugging checks of !range->hmm and !hmm->mm are dropped in favour of poison - >> which is much clearer as to the lifetime intent. >> >> The trailing patches are just some random cleanups I noticed when reviewing >> this code. >> >> This v2 incorporates alot of the good off list changes & feedback Jerome had, >> and all the on-list comments too. However, now that we have the shared git I >> have kept the one line change to nouveau_svm.c rather than the compat >> funtions. >> >> I believe we can resolve this merge in the DRM tree now and keep the core >> mm/hmm.c clean. DRM maintainers, please correct me if I'm wrong. >> >> It is on top of hmm.git, and I have a git tree of this series to ease testing >> here: >> >> https://github.com/jgunthorpe/linux/tree/hmm >> >> There are still some open locking issues, as I think this remains unaddressed: >> >> https://lore.kernel.org/linux-mm/20190527195829.GB18019@xxxxxxxxxxxx/ >> >> I'm looking for some more acks, reviews and tests so this can move ahead to >> hmm.git. > AMD Folks, this is looking pretty good now, can you please give at > least a Tested-by for the new driver code using this that I see in > linux-next? > > Thanks, > Jason
