diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index 580c62febe42..dce0b2e686eb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -624,6 +624,14 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, if (is_zero_pfn(pfn)) return NULL; if (pte_devmap(pte)) + /* + * NOTE: New users of ZONE_DEVICE will not set pte_devmap() + * and will have refcounts incremented on their struct pages + * when they are inserted into PTEs, thus they are safe to + * return here. Legacy ZONE_DEVICE pages that set pte_devmap() + * do not have refcounts. Example of legacy ZONE_DEVICE is + * MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers. + */ return NULL; print_bad_pte(vma, addr, pte, NULL); @@ -4693,7 +4701,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) pte = pte_modify(old_pte, vma->vm_page_prot); page = vm_normal_page(vma, vmf->address, pte); - if (!page) + if (!page || is_zone_device_page(page)) goto out_map; /* TODO: handle PTE-mapped THP */ |