Improve readability of EDF comparisons.

Restructured the EDF task comparison code to improve readability.
Recoded chained logical expression embedded in return statement
into a series of if/else blocks.

1 files changed, 26 insertions, 16 deletions

diff --git a/litmus/edf_common.c b/litmus/edf_common.c
index 9b44dc2d8d1e..1ea0f31f35fb 100644
--- a/litmus/edf_common.c
+++ b/litmus/edf_common.c
@@ -63,25 +63,35 @@ int edf_higher_prio(struct task_struct* first,
 
 #endif
 
-
-        return !is_realtime(second_task)  ||
-
-                /* is the deadline of the first task earlier?
+        /* Determine the task with earliest deadline, with
+         * tie-break logic.
+         */
+        if (unlikely(!is_realtime(second_task))) {
+                return 1;
+        }
+        else if (earlier_deadline(first_task, second_task)) {
+                /* Is the deadline of the first task earlier?
                  * Then it has higher priority.
                  */
-                earlier_deadline(first_task, second_task) ||
-
-                /* Do we have a deadline tie?
-                 * Then break by PID.
-                 */
-                (get_deadline(first_task) == get_deadline(second_task) &&
-                (first_task->pid < second_task->pid ||
+                return 1;
+        }
+        else if (get_deadline(first_task) == get_deadline(second_task)) {
+                /* Need to tie break */
 
-                /* If the PIDs are the same then the task with the inherited
-                 * priority wins.
-                 */
-                (first_task->pid == second_task->pid &&
-                 !second->rt_param.inh_task)));
+                /* Tie break by pid */
+                if (first_task->pid < second_task->pid) {
+                        return 1;
+                }
+                else if (first_task->pid == second_task->pid) {
+                        /* If the PIDs are the same then the task with the
+                         * inherited priority wins.
+                         */
+                        if (!second->rt_param.inh_task) {
+                                return 1;
+                        }
+                }
+        }
+        return 0; /* fall-through. prio(second_task) > prio(first_task) */
 }
 
 int edf_ready_order(struct bheap_node* a, struct bheap_node* b)