Redesign scheduling points

kernel/proc/mutex.c

@@ -44,13 +44,15 @@ void proc_mutexes_cleanup (struct proc* proc) {
   spin_unlock (&proc->procgroup->lock, &ctxpg);
 }
 
-void proc_cleanup_resource_mutex (struct proc_resource* resource) {
+bool proc_cleanup_resource_mutex (struct proc_resource* resource) {
   struct proc_mutex* mutex = &resource->u.mutex;
   spin_lock_ctx_t ctxmt, ctxsq;
 
   spin_lock (&mutex->resource->lock, &ctxmt);
   spin_lock (&mutex->suspension_q.lock, &ctxsq);
 
+  bool reschedule = PROC_NO_RESCHEDULE;
+
   while (mutex->suspension_q.proc_list != NULL) {
     struct list_node_link* node = mutex->suspension_q.proc_list;
     struct proc_sq_entry* sq_entry = list_entry (node, struct proc_sq_entry, sq_link);
@@ -60,7 +62,7 @@ void proc_cleanup_resource_mutex (struct proc_resource* resource) {
     spin_unlock (&mutex->suspension_q.lock, &ctxsq);
     spin_unlock (&mutex->resource->lock, &ctxmt);
 
-    proc_sq_resume (suspended_proc, sq_entry);
+    reschedule = reschedule || proc_sq_resume (suspended_proc, sq_entry);
 
     /* reacquire */
     spin_lock (&mutex->resource->lock, &ctxmt);
@@ -72,23 +74,23 @@ void proc_cleanup_resource_mutex (struct proc_resource* resource) {
 
   spin_unlock (&mutex->suspension_q.lock, &ctxsq);
   spin_unlock (&mutex->resource->lock, &ctxmt);
+
+  return reschedule;
 }
 
-void proc_mutex_lock (struct proc* proc, struct proc_mutex* mutex) {
+bool proc_mutex_lock (struct proc* proc, struct proc_mutex* mutex) {
   spin_lock_ctx_t ctxmt;
 
-  for (;;) {
-    spin_lock (&mutex->resource->lock, &ctxmt);
+  spin_lock (&mutex->resource->lock, &ctxmt);
 
-    if (!mutex->locked || mutex->owner == proc) {
-      mutex->locked = true;
-      mutex->owner = proc;
-      spin_unlock (&mutex->resource->lock, &ctxmt);
-      return;
-    }
-
-    proc_sq_suspend (proc, &mutex->suspension_q, &mutex->resource->lock, &ctxmt);
+  if (!mutex->locked || mutex->owner == proc) {
+    mutex->locked = true;
+    mutex->owner = proc;
+    spin_unlock (&mutex->resource->lock, &ctxmt);
+    return PROC_NO_RESCHEDULE;
   }
+
+  return proc_sq_suspend (proc, &mutex->suspension_q, &mutex->resource->lock, &ctxmt);
 }
 
 bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex) {
@@ -98,7 +100,7 @@ bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex) {
 
   if (mutex->owner != proc) {
     spin_unlock (&mutex->resource->lock, &ctxmt);
-    return false;
+    return PROC_NO_RESCHEDULE;
   }
 
   spin_lock (&mutex->suspension_q.lock, &ctxsq);
@@ -115,9 +117,7 @@ bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex) {
     spin_unlock (&mutex->suspension_q.lock, &ctxsq);
     spin_unlock (&mutex->resource->lock, &ctxmt);
 
-    proc_sq_resume (resumed_proc, sq_entry);
-
-    return true;
+    return proc_sq_resume (resumed_proc, sq_entry);
   }
 
   mutex->locked = false;
@@ -126,5 +126,5 @@ bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex) {
   spin_unlock (&mutex->suspension_q.lock, &ctxsq);
   spin_unlock (&mutex->resource->lock, &ctxmt);
 
-  return true;
+  return PROC_NEED_RESCHEDULE;
 }