1 files changed, 27 insertions, 0 deletions
diff --git a/mm/internal.h b/mm/internal.h
index 16c1f3cd599e5..4eab2961e69ce 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -108,6 +108,33 @@ static inline void *folio_raw_mapping(const struct folio *folio)
 	return (void *)(mapping & ~PAGE_MAPPING_FLAGS);
 }
 
+/*
+ * This is a file-backed mapping, and is about to be memory mapped - invoke its
+ * mmap hook and safely handle error conditions. On error, VMA hooks will be
+ * mutated.
+ *
+ * @file: File which backs the mapping.
+ * @vma:  VMA which we are mapping.
+ *
+ * Returns: 0 if success, error otherwise.
+ */
+static inline int mmap_file(struct file *file, struct vm_area_struct *vma)
+{
+	int err = call_mmap(file, vma);
+
+	if (likely(!err))
+		return 0;
+
+	/*
+	 * OK, we tried to call the file hook for mmap(), but an error
+	 * arose. The mapping is in an inconsistent state and we most not invoke
+	 * any further hooks on it.
+	 */
+	vma->vm_ops = &vma_dummy_vm_ops;
+
+	return err;
+}
+
 #ifdef CONFIG_MMU
 
 /* Flags for folio_pte_batch(). */