- Fix EFD_SEMAPHORE missing for kernel version < 2.6.30

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4641 818b1a75-f10b-46b9-bf7c-635c3b92a50f

common/utils/itti/intertask_interface.c

@@ -83,6 +83,10 @@ const int itti_debug_poll = 0;
 /* Global message size */
 #define MESSAGE_SIZE(mESSAGEiD) (sizeof(MessageHeader) + itti_desc.messages_info[mESSAGEiD].size)
 
+#if !defined(EFD_SEMAPHORE)
+# define KERNEL_VERSION_PRE_2_6_30 1
+#endif
+
 typedef enum task_state_s {
     TASK_STATE_NOT_CONFIGURED, TASK_STATE_STARTING, TASK_STATE_READY, TASK_STATE_ENDED, TASK_STATE_MAX,
 } task_state_t;
@@ -111,6 +115,10 @@ typedef struct thread_desc_s {
     /* Number of events to monitor */
     uint16_t nb_events;
 
+#if defined(KERNEL_VERSION_PRE_2_6_30)
+    uint64_t sem_counter;
+#endif
+
     /* Array of events monitored by the task.
      * By default only one fd is monitored (the one used to received messages
      * from other tasks).
@@ -136,7 +144,7 @@ typedef struct task_desc_s {
 
 typedef struct itti_desc_s {
     thread_desc_t *threads;
-    task_desc_t *tasks;
+    task_desc_t   *tasks;
 
     /* Current message number. Incremented every call to send_msg_to_task */
     message_number_t message_number __attribute__((aligned(8)));
@@ -525,7 +533,7 @@ static inline void itti_receive_msg_internal_event_fd(task_id_t task_id, uint8_t
         if ((itti_desc.threads[thread_id].events[i].events & EPOLLIN) &&
             (itti_desc.threads[thread_id].events[i].data.fd == itti_desc.threads[thread_id].task_event_fd))
         {
-            struct message_list_s *message;
+            struct message_list_s *message = NULL;
             uint64_t sem_counter;
             ssize_t  read_ret;
 
@@ -533,10 +541,16 @@ static inline void itti_receive_msg_internal_event_fd(task_id_t task_id, uint8_t
             read_ret = read (itti_desc.threads[thread_id].task_event_fd, &sem_counter, sizeof(sem_counter));
             DevCheck(read_ret == sizeof(sem_counter), read_ret, sizeof(sem_counter), 0);
 
+#if defined(KERNEL_VERSION_PRE_2_6_30)
+            /* Store the value of the semaphore counter */
+            itti_desc.tasks[task_id].sem_counter = sem_counter - 1;
+#endif
+
             if (lfds611_queue_dequeue (itti_desc.tasks[task_id].message_queue, (void **) &message) == 0) {
                 /* No element in list -> this should not happen */
                 DevParam(task_id, epoll_ret, 0);
             }
+            DevAssert(message != NULL);
             *received_msg = message->msg;
             free (message);
             return;
@@ -550,6 +564,21 @@ void itti_receive_msg(task_id_t task_id, MessageDef **received_msg)
     vcd_signal_dumper_dump_variable_by_name(VCD_SIGNAL_DUMPER_VARIABLE_ITTI_RECV_MSG,
                                             __sync_and_and_fetch (&itti_desc.vcd_receive_msg, ~(1L << task_id)));
 #endif
+
+#if defined(KERNEL_VERSION_PRE_2_6_30)
+    /* Store the value of the semaphore counter */
+    if (itti_desc.tasks[task_id].sem_counter > 0) {
+        if (lfds611_queue_dequeue (itti_desc.tasks[task_id].message_queue, (void **) &message) == 0) {
+            /* No element in list -> this should not happen */
+            DevParam(task_id, itti_desc.tasks[task_id].sem_counter, 0);
+        }
+        DevAssert(message != NULL);
+        *received_msg = message->msg;
+        free (message);
+
+        itti_desc.tasks[task_id].sem_counter--;
+    } else
+#endif
     itti_receive_msg_internal_event_fd(task_id, 0, received_msg);
 
 #if defined(OAI_EMU) || defined(RTAI)
@@ -769,7 +798,14 @@ int itti_init(task_id_t task_max, thread_id_t thread_max, MessagesIds messages_i
             DevAssert(0 == 1);
         }
 
+# if defined(KERNEL_VERSION_PRE_2_6_30)
+        /* SR: for kernel versions < 2.6.30 EFD_SEMAPHORE is not defined.
+         * A read operation on the event fd will return the 8 byte value.
+         */
+        itti_desc.threads[thread_id].task_event_fd = eventfd(0, 0);
+# else
         itti_desc.threads[thread_id].task_event_fd = eventfd(0, EFD_SEMAPHORE);
+# endif
         if (itti_desc.threads[thread_id].task_event_fd == -1)
         {
             ITTI_ERROR("eventfd failed: %s\n", strerror(errno));