kern: sched: Add function to dequeue processes

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 23 insertions, 0 deletions

diff --git a/sys/inc/os/sched.h b/sys/inc/os/sched.h
index 1caf1d6..948c95b 100644
--- a/sys/inc/os/sched.h
+++ b/sys/inc/os/sched.h
@@ -42,4 +42,9 @@
  */
 struct cpu_info *sched_enqueue_proc(struct process *proc);
 
+/*
+ * Dequeue a process from the current core
+ */
+struct process *sched_dequeue_proc(void);
+
 #endif  /* !_OS_SCHED_H_ */
diff --git a/sys/os/os_sched.c b/sys/os/os_sched.c
index e0dfc98..7d3b485 100644
--- a/sys/os/os_sched.c
+++ b/sys/os/os_sched.c
@@ -64,3 +64,21 @@ sched_enqueue_proc(struct process *proc)
     TAILQ_INSERT_TAIL(&core->pqueue, proc, link);
     return core;
 }
+
+struct process *
+sched_dequeue_proc(void)
+{
+    struct cpu_info *core;
+    struct process *proc;
+
+    core = cpu_self();
+    if (core == NULL) {
+        return NULL;
+    }
+
+    proc = TAILQ_FIRST(&core->pqueue);
+    if (proc != NULL) {
+        TAILQ_REMOVE(&core->pqueue, proc, link);
+    }
+    return proc;
+}