diff --git a/include/shm-directory.h b/include/shm-directory.h
index 1c0f9fcc89..8dc5befb96 100644
--- a/include/shm-directory.h
+++ b/include/shm-directory.h
@@ -28,8 +28,8 @@
 struct shmdir_name
 {
   /* The combined prefix/name.  The sizeof includes the terminating
-     NUL byte.  4 bytes are needed for the optional "sem." prefix.  */
-  char name[sizeof (SHMDIR) + 4 + NAME_MAX];
+     NUL byte.  */
+  char name[sizeof (SHMDIR) + NAME_MAX];
 };
 
 /* Sets RESULT->name to the constructed name and returns 0 on success,
diff --git a/posix/shm-directory.c b/posix/shm-directory.c
index c1e9c6c434..b578ada580 100644
--- a/posix/shm-directory.c
+++ b/posix/shm-directory.c
@@ -58,11 +58,7 @@ __shm_get_name (struct shmdir_name *result, const char *name, bool sem_prefix)
   if (namelen == 0 || memchr (name, '/', namelen) != NULL)
     return EINVAL;
   if (alloc_buffer_has_failed (&buffer))
-    {
-      if (namelen > NAME_MAX)
-        return ENAMETOOLONG;
-      return EINVAL;
-    }
+    return ENAMETOOLONG;
   return 0;
 }
 libc_hidden_def (__shm_get_name)