On Wed, Mar 11, 2020 at 03:34:58PM -0300, Jason Gunthorpe wrote: > From: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > > The hmm_range_fault() flow is fairly complicated. The scheme allows the > caller to specify if it needs a usable result for each page, or if it only > needs the current page table status filled in. This mixture of behavior is > useful for a caller that wants to build a 'prefetch around fault' > algorithm. > > Although we have no in-tree users of this capability, I am working on > having RDMA ODP work in this manner, and removing these bugs from > hmm_range_fault() is a necessary step. > > The basic principles are: > > - If the caller did not ask for a VA to be valid then hmm_range_fault() > should not fail because of that VA > > - If 0 is returned from hmm_range_fault() then the entire pfns array > contains valid data > > - HMM_PFN_ERROR is set if faulting fails, or if asking for faulting > would fail > > - A 0 return from hmm_range_fault() does not have HMM_PFN_ERROR in any > VA's the caller asked to be valid > > This series does not get there completely, I have a followup series > closing some more complex cases. > > I tested this series using Ralph's hmm tester he posted a while back, > other testing would be appreciated. > > Jason Gunthorpe (8): > mm/hmm: add missing unmaps of the ptep during hmm_vma_handle_pte() > mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock > mm/hmm: add missing pfns set to hmm_vma_walk_pmd() > mm/hmm: add missing call to hmm_range_need_fault() before returning > EFAULT > mm/hmm: reorganize how !pte_present is handled in hmm_vma_handle_pte() > mm/hmm: return -EFAULT when setting HMM_PFN_ERROR on requested valid > pages > mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL > handling > mm/hmm: do not check pmd_protnone twice in hmm_vma_handle_pmd() I moved these toward linux-next, if others have remarks or tags please feel free to continue. > mm/hmm: don't free the cached pgmap while scanning I will respin Thank you all for the reviews! Regards, Jason _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
