diff --git a/mm/memory.c b/mm/memory.c
index 93897f2..f09cdb8 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -63,6 +63,7 @@
 #include <linux/dma-debug.h>
 #include <linux/debugfs.h>
 #include <linux/userfaultfd_k.h>
+#include <linux/dax.h>
 
 #include <asm/io.h>
 #include <asm/mmu_context.h>
@@ -2785,7 +2786,8 @@
  */
 static int __do_fault(struct vm_area_struct *vma, unsigned long address,
 			pgoff_t pgoff, unsigned int flags,
-			struct page *cow_page, struct page **page)
+			struct page *cow_page, struct page **page,
+			void **entry)
 {
 	struct vm_fault vmf;
 	int ret;
@@ -2800,8 +2802,10 @@
 	ret = vma->vm_ops->fault(vma, &vmf);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;
-	if (!vmf.page)
-		goto out;
+	if (ret & VM_FAULT_DAX_LOCKED) {
+		*entry = vmf.entry;
+		return ret;
+	}
 
 	if (unlikely(PageHWPoison(vmf.page))) {
 		if (ret & VM_FAULT_LOCKED)
@@ -2815,7 +2819,6 @@
 	else
 		VM_BUG_ON_PAGE(!PageLocked(vmf.page), vmf.page);
 
- out:
 	*page = vmf.page;
 	return ret;
 }
@@ -2987,7 +2990,7 @@
 		pte_unmap_unlock(pte, ptl);
 	}
 
-	ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page);
+	ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page, NULL);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;
 
@@ -3010,6 +3013,7 @@
 		pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
 {
 	struct page *fault_page, *new_page;
+	void *fault_entry;
 	struct mem_cgroup *memcg;
 	spinlock_t *ptl;
 	pte_t *pte;
@@ -3027,26 +3031,24 @@
 		return VM_FAULT_OOM;
 	}
 
-	ret = __do_fault(vma, address, pgoff, flags, new_page, &fault_page);
+	ret = __do_fault(vma, address, pgoff, flags, new_page, &fault_page,
+			 &fault_entry);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		goto uncharge_out;
 
-	if (fault_page)
+	if (!(ret & VM_FAULT_DAX_LOCKED))
 		copy_user_highpage(new_page, fault_page, address, vma);
 	__SetPageUptodate(new_page);
 
 	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
 	if (unlikely(!pte_same(*pte, orig_pte))) {
 		pte_unmap_unlock(pte, ptl);
-		if (fault_page) {
+		if (!(ret & VM_FAULT_DAX_LOCKED)) {
 			unlock_page(fault_page);
 			put_page(fault_page);
 		} else {
-			/*
-			 * The fault handler has no page to lock, so it holds
-			 * i_mmap_lock for read to protect against truncate.
-			 */
-			i_mmap_unlock_read(vma->vm_file->f_mapping);
+			dax_unlock_mapping_entry(vma->vm_file->f_mapping,
+						 pgoff);
 		}
 		goto uncharge_out;
 	}
@@ -3054,15 +3056,11 @@
 	mem_cgroup_commit_charge(new_page, memcg, false, false);
 	lru_cache_add_active_or_unevictable(new_page, vma);
 	pte_unmap_unlock(pte, ptl);
-	if (fault_page) {
+	if (!(ret & VM_FAULT_DAX_LOCKED)) {
 		unlock_page(fault_page);
 		put_page(fault_page);
 	} else {
-		/*
-		 * The fault handler has no page to lock, so it holds
-		 * i_mmap_lock for read to protect against truncate.
-		 */
-		i_mmap_unlock_read(vma->vm_file->f_mapping);
+		dax_unlock_mapping_entry(vma->vm_file->f_mapping, pgoff);
 	}
 	return ret;
 uncharge_out:
@@ -3082,7 +3080,7 @@
 	int dirtied = 0;
 	int ret, tmp;
 
-	ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page);
+	ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page, NULL);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;