diff --git a/sys_util/src/guest_memory.rs b/sys_util/src/guest_memory.rs
index ae96eadb37..e9a33f6193 100644
--- a/sys_util/src/guest_memory.rs
+++ b/sys_util/src/guest_memory.rs
@@ -118,7 +118,7 @@ impl GuestMemory {
     }
 
     /// Writes a slice to guest memory at the specified guest address.
-    /// Returns Ok(<number of bytes written>).  The number of bytes written can
+    /// Returns the number of bytes written.  The number of bytes written can
     /// be less than the length of the slice if there isn't enough room in the
     /// memory region.
     ///
diff --git a/sys_util/src/mmap.rs b/sys_util/src/mmap.rs
index 57627f8644..732c4f0648 100644
--- a/sys_util/src/mmap.rs
+++ b/sys_util/src/mmap.rs
@@ -105,7 +105,7 @@ impl MemoryMapping {
     }
 
     /// Writes a slice to the memory region at the specified offset.
-    /// Returns Ok(<number of bytes written>).  The number of bytes written can
+    /// Returns the number of bytes written.  The number of bytes written can
     /// be less than the length of the slice if there isn't enough room in the
     /// memory region.
     ///