bugfix: don't use stale linked flag

When a job completion occured at the end of real-time mode  it was possible
for unlink to be called with entry->linked == NULL. As a solution, don't
use a flag for linked, since it becomes stale too easily.

1 files changed, 3 insertions, 9 deletions

diff --git a/kernel/sched_gsn_edf.c b/kernel/sched_gsn_edf.c
index fc05daf114..25f21a7505 100644
--- a/kernel/sched_gsn_edf.c
+++ b/kernel/sched_gsn_edf.c
@@ -427,8 +427,7 @@ static int gsnedf_schedule(struct task_struct * prev,
                          runqueue_t * rq)
 {
         cpu_entry_t*    entry = &__get_cpu_var(gsnedf_cpu_entries);
-        int             out_of_time, sleep, preempt, np, exists, rt, linked, 
-                        blocks;
+        int             out_of_time, sleep, preempt, np, exists, rt, blocks;
 
         /* Will be released in finish_switch. */
         queue_lock(&gsnedf_lock);
@@ -440,7 +439,6 @@ static int gsnedf_schedule(struct task_struct * prev,
 
         /* (0) Determine state */       
         exists      = entry->scheduled != NULL;
-        linked      = entry->linked != NULL;
         blocks      = exists && !is_running(entry->scheduled);
         out_of_time = exists && !entry->scheduled->time_slice;
         np          = exists && is_np(entry->scheduled);
@@ -472,19 +470,15 @@ static int gsnedf_schedule(struct task_struct * prev,
         
         /* Stop real-time tasks when we leave real-time mode 
          */
-        if (!rt && linked)
+        if (!rt && entry->linked)
                 /* task will be preempted once it is preemptable 
                  * (which it may be now already)
                  */
                 unlink(entry->linked);  
 
-        /* Reevaluate linked in case we changed it.
-         */
-        linked = entry->linked != NULL;
-
         /* Link pending task if we became unlinked.
          */
-        if (rt && !linked)
+        if (rt && !entry->linked)
                 link_task_to_cpu(__take_ready(&gsnedf), entry); 
 
         /* The final scheduling decision. Do we need to switch for some reason?