diff --git a/mount/doc.go b/mount/doc.go
new file mode 100644
index 00000000..b8108d85
--- /dev/null
+++ b/mount/doc.go
@@ -0,0 +1,5 @@
+// Package mount provides a set of functions to mount and unmount mounts.
+//
+// Currently it supports Linux. For historical reasons, there is also some support for FreeBSD.
+
+package mount
diff --git a/mount/flags.go b/mount/flags_unix.go
similarity index 99%
rename from mount/flags.go
rename to mount/flags_unix.go
index d514a9d8..995d7280 100644
--- a/mount/flags.go
+++ b/mount/flags_unix.go
@@ -1,3 +1,5 @@
+// +build !darwin,!windows
+
 package mount
 
 import (
diff --git a/mount/flags_unsupported.go b/mount/flags_unsupported.go
deleted file mode 100644
index 3ec4a11e..00000000
--- a/mount/flags_unsupported.go
+++ /dev/null
@@ -1,30 +0,0 @@
-// +build !linux,!freebsd
-
-package mount
-
-// These flags are unsupported.
-const (
-	BIND        = 0
-	DIRSYNC     = 0
-	MANDLOCK    = 0
-	NOATIME     = 0
-	NODEV       = 0
-	NODIRATIME  = 0
-	NOEXEC      = 0
-	NOSUID      = 0
-	UNBINDABLE  = 0
-	RUNBINDABLE = 0
-	PRIVATE     = 0
-	RPRIVATE    = 0
-	SHARED      = 0
-	RSHARED     = 0
-	SLAVE       = 0
-	RSLAVE      = 0
-	RBIND       = 0
-	RELATIME    = 0
-	REMOUNT     = 0
-	STRICTATIME = 0
-	SYNCHRONOUS = 0
-	RDONLY      = 0
-	mntDetach   = 0
-)
diff --git a/mount/mount.go b/mount/mount_unix.go
similarity index 76%
rename from mount/mount.go
rename to mount/mount_unix.go
index 4a7bb27b..b47ab875 100644
--- a/mount/mount.go
+++ b/mount/mount_unix.go
@@ -1,4 +1,4 @@
-// +build go1.13
+// +build !darwin,!windows
 
 package mount
 
@@ -7,6 +7,7 @@ import (
 	"sort"
 
 	"github.com/moby/sys/mountinfo"
+	"golang.org/x/sys/unix"
 )
 
 // Mount will mount filesystem according to the specified configuration.
@@ -18,9 +19,22 @@ func Mount(device, target, mType, options string) error {
 }
 
 // Unmount lazily unmounts a filesystem on supported platforms, otherwise does
-// a normal unmount.  If target is not a mount point, no error is returned.
+// a normal unmount. If target is not a mount point, no error is returned.
 func Unmount(target string) error {
-	return unmount(target, mntDetach)
+	err := unix.Unmount(target, mntDetach)
+	if err == nil || err == unix.EINVAL {
+		// Ignore "not mounted" error here. Note the same error
+		// can be returned if flags are invalid, so this code
+		// assumes that the flags value is always correct.
+		return nil
+	}
+
+	return &mountError{
+		op:     "umount",
+		target: target,
+		flags:  uintptr(mntDetach),
+		err:    err,
+	}
 }
 
 // RecursiveUnmount unmounts the target and all mounts underneath, starting
@@ -32,7 +46,7 @@ func RecursiveUnmount(target string) error {
 	// platforms, if there are submounts, we'll get EBUSY (and fall back
 	// to the slow path). NOTE we do not ignore EINVAL here as target might
 	// not be a mount point itself (but there can be mounts underneath).
-	if err := unmountBare(target, mntDetach); err == nil {
+	if err := unix.Unmount(target, mntDetach); err == nil {
 		return nil
 	}
 
@@ -49,7 +63,7 @@ func RecursiveUnmount(target string) error {
 
 	var suberr error
 	for i, m := range mounts {
-		err = unmount(m.Mountpoint, mntDetach)
+		err = Unmount(m.Mountpoint)
 		if err != nil {
 			if i == len(mounts)-1 { // last mount
 				return fmt.Errorf("%w (possible cause: %s)", err, suberr)
diff --git a/mount/mounter_freebsd.go b/mount/mounter_freebsd.go
index 3964af4f..f4e2e0bb 100644
--- a/mount/mounter_freebsd.go
+++ b/mount/mounter_freebsd.go
@@ -1,3 +1,5 @@
+// +build freebsd cgo
+
 package mount
 
 /*
diff --git a/mount/mounter_unsupported.go b/mount/mounter_unsupported.go
index 15380671..41ac018a 100644
--- a/mount/mounter_unsupported.go
+++ b/mount/mounter_unsupported.go
@@ -1,7 +1,7 @@
-// +build !linux,!freebsd freebsd,!cgo
+// +build freebsd,!cgo
 
 package mount
 
 func mount(device, target, mType string, flag uintptr, data string) error {
-	panic("Not implemented")
+	panic("cgo required on freebsd")
 }
diff --git a/mount/sharedsubtree_linux_test.go b/mount/sharedsubtree_linux_test.go
index e950230a..1e2a053e 100644
--- a/mount/sharedsubtree_linux_test.go
+++ b/mount/sharedsubtree_linux_test.go
@@ -1,4 +1,4 @@
-// +build linux,go1.13
+// +build linux
 
 package mount
 
diff --git a/mount/unmount_unix.go b/mount/unmount_unix.go
deleted file mode 100644
index 924d059a..00000000
--- a/mount/unmount_unix.go
+++ /dev/null
@@ -1,26 +0,0 @@
-// +build !windows
-
-package mount
-
-import "golang.org/x/sys/unix"
-
-func unmountBare(target string, flags int) error {
-	return unix.Unmount(target, flags)
-}
-
-func unmount(target string, flags int) error {
-	err := unmountBare(target, flags)
-	if err == nil || err == unix.EINVAL {
-		// Ignore "not mounted" error here. Note the same error
-		// can be returned if flags are invalid, so this code
-		// assumes that the flags value is always correct.
-		return nil
-	}
-
-	return &mountError{
-		op:     "umount",
-		target: target,
-		flags:  uintptr(flags),
-		err:    err,
-	}
-}
diff --git a/mount/unmount_unsupported.go b/mount/unmount_unsupported.go
deleted file mode 100644
index 4d6073ec..00000000
--- a/mount/unmount_unsupported.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// +build windows
-
-package mount
-
-func unmountBare(_ string, _ int) error {
-	panic("Not implemented")
-}
-
-func unmount(_ string, _ int) error {
-	panic("Not implemented")
-}