code review 12418043: net: add special netFD mutex

src/pkg/net/sockoptip_bsd.go

 // Copyright 2011 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // +build darwin freebsd netbsd openbsd
 
 package net
 
 import (
         "os"
         "syscall"
 )
 
 func setIPv4MulticastInterface(fd *netFD, ifi *Interface) error {
         ip, err := interfaceToIPv4Addr(ifi)
         if err != nil {
                 return os.NewSyscallError("setsockopt", err)
         }
         var a [4]byte
         copy(a[:], ip.To4())
-        if err := fd.incref(false); err != nil {
+        if err := fd.incref(); err != nil {
                 return err
         }
         defer fd.decref()
         return os.NewSyscallError("setsockopt", syscall.SetsockoptInet4Addr(fd.sysfd, syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF, a))
 }
 
 func setIPv4MulticastLoopback(fd *netFD, v bool) error {
-        if err := fd.incref(false); err != nil {
+        if err := fd.incref(); err != nil {
                 return err
         }
         defer fd.decref()
         return os.NewSyscallError("setsockopt", syscall.SetsockoptByte(fd.sysfd, syscall.IPPROTO_IP, syscall.IP_MULTICAST_LOOP, byte(boolint(v))))
 }