Index: sys/compat/linuxkpi/common/src/linux_page.c
===================================================================
--- sys/compat/linuxkpi/common/src/linux_page.c
+++ sys/compat/linuxkpi/common/src/linux_page.c
@@ -288,29 +288,11 @@
 		panic("GFP_NOWAIT is unimplemented");
 
 	VM_OBJECT_WLOCK(obj);
-	page = vm_page_grab(obj, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY |
-	    VM_ALLOC_WIRED);
-	if (page->valid != VM_PAGE_BITS_ALL) {
-		vm_page_xbusy(page);
-		if (vm_pager_has_page(obj, pindex, NULL, NULL)) {
-			rv = vm_pager_get_pages(obj, &page, 1, NULL, NULL);
-			if (rv != VM_PAGER_OK) {
-				vm_page_lock(page);
-				vm_page_unwire_noq(page);
-				vm_page_free(page);
-				vm_page_unlock(page);
-				VM_OBJECT_WUNLOCK(obj);
-				return (ERR_PTR(-EINVAL));
-			}
-			MPASS(page->valid == VM_PAGE_BITS_ALL);
-		} else {
-			pmap_zero_page(page);
-			page->valid = VM_PAGE_BITS_ALL;
-			page->dirty = 0;
-		}
-		vm_page_xunbusy(page);
-	}
+	rv = vm_page_grab_valid(&page, obj, pindex, VM_ALLOC_NORMAL |
+	    VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
 	VM_OBJECT_WUNLOCK(obj);
+	if (rv != VM_PAGER_OK)
+		return (ERR_PTR(-EINVAL));
 	return (page);
 }
 
Index: sys/dev/drm2/ttm/ttm_tt.c
===================================================================
--- sys/dev/drm2/ttm/ttm_tt.c
+++ sys/dev/drm2/ttm/ttm_tt.c
@@ -288,22 +288,12 @@
 	VM_OBJECT_WLOCK(obj);
 	vm_object_pip_add(obj, 1);
 	for (i = 0; i < ttm->num_pages; ++i) {
-		from_page = vm_page_grab(obj, i, VM_ALLOC_NORMAL);
-		if (from_page->valid != VM_PAGE_BITS_ALL) {
-			if (vm_pager_has_page(obj, i, NULL, NULL)) {
-				rv = vm_pager_get_pages(obj, &from_page, 1,
-				    NULL, NULL);
-				if (rv != VM_PAGER_OK) {
-					vm_page_lock(from_page);
-					vm_page_free(from_page);
-					vm_page_unlock(from_page);
-					ret = -EIO;
-					goto err_ret;
-				}
-			} else
-				vm_page_zero_invalid(from_page, TRUE);
+		rv = vm_page_grab_valid(&from_page, obj, i,
+		    VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
+		if (rv != VM_PAGER_OK) {
+			ret = -EIO;
+			goto err_ret;
 		}
-		vm_page_xunbusy(from_page);
 		to_page = ttm->pages[i];
 		if (unlikely(to_page == NULL)) {
 			ret = -ENOMEM;
Index: sys/kern/uipc_shm.c
===================================================================
--- sys/kern/uipc_shm.c
+++ sys/kern/uipc_shm.c
@@ -188,24 +188,13 @@
 	 * lock to page out tobj's pages because tobj is a OBJT_SWAP
 	 * type object.
 	 */
-	m = vm_page_grab(obj, idx, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
-	if (m->valid != VM_PAGE_BITS_ALL) {
-		vm_page_xbusy(m);
-		if (vm_pager_has_page(obj, idx, NULL, NULL)) {
-			rv = vm_pager_get_pages(obj, &m, 1, NULL, NULL);
-			if (rv != VM_PAGER_OK) {
-				printf(
-	    "uiomove_object: vm_obj %p idx %jd valid %x pager error %d\n",
-				    obj, idx, m->valid, rv);
-				vm_page_lock(m);
-				vm_page_free(m);
-				vm_page_unlock(m);
-				VM_OBJECT_WUNLOCK(obj);
-				return (EIO);
-			}
-		} else
-			vm_page_zero_invalid(m, TRUE);
-		vm_page_xunbusy(m);
+	rv = vm_page_grab_valid(&m, obj, idx,
+	    VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
+	if (rv != VM_PAGER_OK) {
+		VM_OBJECT_WUNLOCK(obj);
+		printf("uiomove_object: vm_obj %p idx %jd pager error %d\n",
+		    obj, idx, rv);
+		return (EIO);
 	}
 	vm_page_lock(m);
 	vm_page_wire(m);
Index: sys/vm/vm_glue.c
===================================================================
--- sys/vm/vm_glue.c
+++ sys/vm/vm_glue.c
@@ -219,26 +219,11 @@
 {
 	vm_page_t m;
 	vm_pindex_t pindex;
-	int rv;
 
-	VM_OBJECT_WLOCK(object);
 	pindex = OFF_TO_IDX(offset);
-	m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY |
-	    VM_ALLOC_WIRED);
-	if (m->valid != VM_PAGE_BITS_ALL) {
-		vm_page_xbusy(m);
-		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
-		if (rv != VM_PAGER_OK) {
-			vm_page_lock(m);
-			vm_page_unwire(m, PQ_NONE);
-			vm_page_free(m);
-			vm_page_unlock(m);
-			m = NULL;
-			goto out;
-		}
-		vm_page_xunbusy(m);
-	}
-out:
+	VM_OBJECT_WLOCK(object);
+	(void) vm_page_grab_valid(&m, object, pindex,
+	    VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
 	VM_OBJECT_WUNLOCK(object);
 	return (m);
 }
Index: sys/vm/vm_object.c
===================================================================
--- sys/vm/vm_object.c
+++ sys/vm/vm_object.c
@@ -2030,16 +2030,9 @@
 
 	VM_OBJECT_ASSERT_WLOCKED(object);
 	for (pindex = start; pindex < end; pindex++) {
-		m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL);
-		if (m->valid != VM_PAGE_BITS_ALL) {
-			rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
-			if (rv != VM_PAGER_OK) {
-				vm_page_lock(m);
-				vm_page_free(m);
-				vm_page_unlock(m);
-				break;
-			}
-		}
+		rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL);
+		if (rv != VM_PAGER_OK)
+			break;
 		/*
 		 * Keep "m" busy because a subsequent iteration may unlock
 		 * the object.
Index: sys/vm/vm_page.h
===================================================================
--- sys/vm/vm_page.h
+++ sys/vm/vm_page.h
@@ -537,6 +537,8 @@
 vm_page_t vm_page_grab (vm_object_t, vm_pindex_t, int);
 int vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
     vm_page_t *ma, int count);
+int vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex,
+    int allocflags);
 void vm_page_deactivate(vm_page_t);
 void vm_page_deactivate_noreuse(vm_page_t);
 void vm_page_dequeue(vm_page_t m);
Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c
+++ sys/vm/vm_page.c
@@ -3878,6 +3878,103 @@
 	return (m);
 }
 
+/*
+ * Grab a page and make it valid, paging in if necessary.  Pages missing from
+ * their pager are zero filled and validated.
+ */
+int
+vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex, int allocflags)
+{
+	vm_page_t m;
+	bool sleep, xbusy;
+	int pflags;
+	int rv;
+
+	KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
+	    (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
+	    ("vm_page_grab_valid: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
+	KASSERT((allocflags & (VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL |
+	    VM_ALLOC_NOCREAT | VM_ALLOC_VALID | VM_ALLOC_ZERO)) == 0,
+	    ("vm_page_grab_valid: Invalid flags 0x%X", allocflags));
+	VM_OBJECT_ASSERT_WLOCKED(object);
+	pflags = allocflags & ~(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY);
+	pflags |= VM_ALLOC_WAITFAIL;
+
+retrylookup:
+	xbusy = false;
+	if ((m = vm_page_lookup(object, pindex)) != NULL) {
+		/*
+		 * If the page is fully valid it can only become invalid
+		 * with the object lock held.  If it is not valid it can
+		 * become valid with the busy lock held.  Therefore, we
+		 * may unnecessarily lock the exclusive busy here if we
+		 * race with I/O completion not using the object lock.
+		 * However, we will not end up with an invalid page and a
+		 * shared lock.
+		 */
+		if (m->valid != VM_PAGE_BITS_ALL ||
+		    (allocflags & (VM_ALLOC_IGN_SBUSY | VM_ALLOC_SBUSY)) == 0) {
+			sleep = !vm_page_tryxbusy(m);
+			xbusy = true;
+		} else
+			sleep = !vm_page_trysbusy(m);
+		if (sleep) {
+			/*
+			 * Reference the page before unlocking and
+			 * sleeping so that the page daemon is less
+			 * likely to reclaim it.
+			 */
+			vm_page_aflag_set(m, PGA_REFERENCED);
+			VM_OBJECT_WUNLOCK(object);
+			vm_page_busy_sleep(m, "pgrbwt", (allocflags &
+			    VM_ALLOC_IGN_SBUSY) != 0);
+			VM_OBJECT_WLOCK(object);
+			goto retrylookup;
+		}
+		if ((allocflags & VM_ALLOC_WIRED) != 0) {
+			vm_page_lock(m);
+			vm_page_wire(m);
+			vm_page_unlock(m);
+		}
+		if (m->valid == VM_PAGE_BITS_ALL)
+			goto out;
+	} else if ((m = vm_page_alloc(object, pindex, pflags)) != NULL) {
+		xbusy = true;
+	} else {
+		goto retrylookup;
+	}
+
+	vm_page_assert_xbusied(m);
+	MPASS(xbusy);
+	if (vm_pager_has_page(object, pindex, NULL, NULL)) {
+		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
+		if (rv != VM_PAGER_OK) {
+			vm_page_lock(m);
+			if (allocflags & VM_ALLOC_WIRED)
+				vm_page_unwire_noq(m);
+			vm_page_free(m);
+			vm_page_unlock(m);
+			*mp = NULL;
+			return (rv);
+		}
+		MPASS(m->valid == VM_PAGE_BITS_ALL);
+	} else {
+		vm_page_zero_invalid(m, TRUE);
+		vm_page_undirty(m);	/* XXX ? */
+	}
+out:
+	if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
+		if (xbusy)
+			vm_page_xunbusy(m);
+		else
+			vm_page_sunbusy(m);
+	}
+	if ((allocflags & VM_ALLOC_SBUSY) != 0 && xbusy)
+		vm_page_busy_downgrade(m);
+	*mp = m;
+	return (VM_PAGER_OK);
+}
+
 /*
  * Return the specified range of pages from the given object.  For each
  * page offset within the range, if a page already exists within the object