From 42d0fe3f784524224a5a2ff725f974ed08abfe30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cenk=20G=C3=BCndo=C4=9Fan?= <cnkgndgn@gmail.com>
Date: Fri, 5 Dec 2014 16:31:41 +0100
Subject: [PATCH] rpl: removing unnecessary recv_mutex

In the main function of RPL (rpl_process thread)
a mutex is used after receiving a message via msg_recv.
However, this mutex is never used in another thread and thus is rendered
obsolete.
---
 sys/net/include/rpl.h     | 3 ---
 sys/net/routing/rpl/rpl.c | 8 --------
 2 files changed, 11 deletions(-)

diff --git a/sys/net/include/rpl.h b/sys/net/include/rpl.h
index c06be848d1..f580ad34f9 100644
--- a/sys/net/include/rpl.h
+++ b/sys/net/include/rpl.h
@@ -47,9 +47,6 @@ extern "C" {
 extern kernel_pid_t rpl_process_pid;
 extern uint8_t rpl_max_routing_entries;
 
-/* needed for receiving messages with ICMP-code 155. Received via IPC from ipv6.c */
-extern mutex_t rpl_recv_mutex;
-
 /* needed for sending RPL-messages */
 extern mutex_t rpl_send_mutex;
 
diff --git a/sys/net/routing/rpl/rpl.c b/sys/net/routing/rpl/rpl.c
index b8cd815be2..0a2814e48b 100644
--- a/sys/net/routing/rpl/rpl.c
+++ b/sys/net/routing/rpl/rpl.c
@@ -54,7 +54,6 @@ char addr_str[IPV6_MAX_ADDR_STR_LEN];
 
 /* global variables */
 kernel_pid_t rpl_process_pid = KERNEL_PID_UNDEF;
-mutex_t rpl_recv_mutex = MUTEX_INIT;
 mutex_t rpl_send_mutex = MUTEX_INIT;
 msg_t rpl_msg_queue[RPL_PKT_RECV_BUF_SIZE];
 char rpl_process_buf[RPL_PROCESS_STACKSIZE];
@@ -163,7 +162,6 @@ void *rpl_process(void *arg)
 
     while (1) {
         msg_receive(&m_recv);
-        mutex_lock(&rpl_recv_mutex);
 
         /* differentiate packet types */
         ipv6_buf = ((ipv6_hdr_t *)m_recv.content.ptr);
@@ -179,30 +177,25 @@ void *rpl_process(void *arg)
             switch (icmp_buf->code) {
                 case (ICMP_CODE_DIS): {
                     rpl_recv_DIS();
-                    mutex_unlock(&rpl_recv_mutex);
                     break;
                 }
 
                 case (ICMP_CODE_DIO): {
                     rpl_recv_DIO();
-                    mutex_unlock(&rpl_recv_mutex);
                     break;
                 }
 
                 case (ICMP_CODE_DAO): {
                     rpl_recv_DAO();
-                    mutex_unlock(&rpl_recv_mutex);
                     break;
                 }
 
                 case (ICMP_CODE_DAO_ACK): {
                     rpl_recv_DAO_ACK();
-                    mutex_unlock(&rpl_recv_mutex);
                     break;
                 }
 
                 default:
-                    mutex_unlock(&rpl_recv_mutex);
                     break;
             }
         }
@@ -238,7 +231,6 @@ void *rpl_process(void *arg)
                 }
             }
 
-            mutex_unlock(&rpl_recv_mutex);
         }
 
 #endif