diff --git a/fs/mmap/Make.defs b/fs/mmap/Make.defs
index 09428e55675..f7d0a3c90c1 100644
--- a/fs/mmap/Make.defs
+++ b/fs/mmap/Make.defs
@@ -33,10 +33,10 @@
 #
 ############################################################################
 
-CSRCS += fs_mmap.c
+CSRCS += fs_mmap.c fs_munmap.c
 
 ifeq ($(CONFIG_FS_RAMMAP),y)
-CSRCS += fs_munmap.c fs_rammap.c
+CSRCS += fs_rammap.c
 endif
 
 # Include MMAP build support
diff --git a/fs/mmap/fs_munmap.c b/fs/mmap/fs_munmap.c
index bd3d18e0194..722e9619531 100644
--- a/fs/mmap/fs_munmap.c
+++ b/fs/mmap/fs_munmap.c
@@ -52,8 +52,6 @@
 #include "inode/inode.h"
 #include "fs_rammap.h"
 
-#ifdef CONFIG_FS_RAMMAP
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -110,6 +108,7 @@
 
 int munmap(FAR void *start, size_t length)
 {
+#ifdef CONFIG_FS_RAMMAP
   FAR struct fs_rammap_s *prev;
   FAR struct fs_rammap_s *curr;
   FAR void *newaddr;
@@ -129,7 +128,8 @@ int munmap(FAR void *start, size_t length)
 
   /* Search the list of regions */
 
-  for (prev = NULL, curr = g_rammaps.head; curr; prev = curr, curr = curr->flink)
+  for (prev = NULL, curr = g_rammaps.head; curr;
+       prev = curr, curr = curr->flink)
     {
       /* Does this region include any part of the specified range? */
 
@@ -196,7 +196,8 @@ int munmap(FAR void *start, size_t length)
 
   else
     {
-      newaddr = kumm_realloc(curr->addr, sizeof(struct fs_rammap_s) + length);
+      newaddr = kumm_realloc(curr->addr,
+                             sizeof(struct fs_rammap_s) + length);
       DEBUGASSERT(newaddr == (FAR void *)(curr->addr));
       UNUSED(newaddr); /* May not be used */
       curr->length = length;
@@ -211,6 +212,7 @@ errout_with_semaphore:
 errout:
   set_errno(errcode);
   return ERROR;
-}
-
+#else
+  return OK;
 #endif /* CONFIG_FS_RAMMAP */
+}
diff --git a/include/sys/mman.h b/include/sys/mman.h
index 9c748f54980..4d8b0e053e4 100644
--- a/include/sys/mman.h
+++ b/include/sys/mman.h
@@ -174,16 +174,13 @@ int msync(FAR void *addr, size_t len, int flags);
 int munlock(FAR const void *addr, size_t len);
 int munlockall(void);
 
-#ifdef CONFIG_FS_RAMMAP
 int munmap(FAR void *start, size_t length);
-#else
-#  define munmap(start, length)
-#endif
 
 int posix_madvise(FAR void *addr, size_t len, int advice);
 int posix_mem_offset(FAR const void *addr, size_t len, FAR off_t *off,
                      FAR size_t *contig_len, FAR int *fildes);
-int posix_typed_mem_get_info(int fildes, FAR struct posix_typed_mem_info *info);
+int posix_typed_mem_get_info(int fildes,
+                             FAR struct posix_typed_mem_info *info);
 int posix_typed_mem_open(FAR const char *name, int oflag, int tflag);
 int shm_open(FAR const char *name, int oflag, mode_t mode);
 int shm_unlink(FAR const char *name);