+/**
+ * write_ports - Pass a socket file descriptor or transport name to listen on
+ *
+ * Input:
+ * buf: ignored
+ * size: zero
+ * Output:
+ * On success: passed-in buffer filled with a '\n'-terminated C
+ * string containing a whitespace-separated list of
+ * named NFSD listeners;
+ * return code is the size in bytes of the string
+ * On error: return code is zero or a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ * buf: C string containing an unsigned
+ * integer value representing a bound
+ * but unconnected socket that is to be
+ * used as an NFSD listener
+ * size: non-zero length of C string in @buf
+ * Output:
+ * On success: NFS service is started;
+ * passed-in buffer filled with a '\n'-terminated C
+ * string containing a unique alphanumeric name of
+ * the listener;
+ * return code is the size in bytes of the string
+ * On error: return code is a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ * buf: C string containing a "-" followed
+ * by an integer value representing a
+ * previously passed in socket file
+ * descriptor
+ * size: non-zero length of C string in @buf
+ * Output:
+ * On success: NFS service no longer listens on that socket;
+ * passed-in buffer filled with a '\n'-terminated C
+ * string containing a unique name of the listener;
+ * return code is the size in bytes of the string
+ * On error: return code is a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ * buf: C string containing a transport
+ * name and an unsigned integer value
+ * representing the port to listen on,
+ * separated by whitespace
+ * size: non-zero length of C string in @buf
+ * Output:
+ * On success: returns zero; NFS service is started
+ * On error: return code is a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ * buf: C string containing a "-" followed
+ * by a transport name and an unsigned
+ * integer value representing the port
+ * to listen on, separated by whitespace
+ * size: non-zero length of C string in @buf
+ * Output:
+ * On success: returns zero; NFS service no longer listens
+ * on that transport
+ * On error: return code is a negative errno value
+ */
+static ssize_t write_ports(struct file *file, char *buf, size_t size)
+{
+ ssize_t rv;
+
+ mutex_lock(&nfsd_mutex);
+ rv = __write_ports(file, buf, size);
+ mutex_unlock(&nfsd_mutex);
+ return rv;
+}
+
+