feat: input device subsystem to resolve race condition on polling input

[lunaix-os.git] / lunaix-os / kernel / ds / waitq.c

diff --git a/lunaix-os/kernel/ds/waitq.c b/lunaix-os/kernel/ds/waitq.c
new file mode 100644 (file)
index 0000000..5241a4e
--- /dev/null
+++ b/lunaix-os/kernel/ds/waitq.c
@@ -0,0 +1,50 @@
+#include <lunaix/ds/waitq.h>
+#include <lunaix/process.h>
+#include <lunaix/sched.h>
+#include <lunaix/spike.h>
+
+void
+pwait(waitq_t* queue)
+{
+    waitq_t* current_wq = &__current->waitqueue;
+    assert(llist_empty(&current_wq->waiters));
+
+    llist_append(&queue->waiters, &current_wq->waiters);
+
+    // FIXME centralize the state change.
+    __current->state = PS_BLOCKED;
+    sched_yieldk();
+}
+
+void
+pwake_one(waitq_t* queue)
+{
+    if (llist_empty(&queue->waiters)) {
+        return;
+    }
+
+    waitq_t* wq = list_entry(queue->waiters.next, waitq_t, waiters);
+    struct proc_info* proc = container_of(wq, struct proc_info, waitqueue);
+
+    assert(proc->state == PS_BLOCKED);
+    proc->state = PS_READY;
+    llist_delete(&wq->waiters);
+}
+
+void
+pwake_all(waitq_t* queue)
+{
+    if (llist_empty(&queue->waiters)) {
+        return;
+    }
+
+    struct proc_info* proc;
+    waitq_t *pos, *n;
+    llist_for_each(pos, n, &queue->waiters, waiters)
+    {
+        proc = container_of(pos, struct proc_info, waitqueue);
+
+        proc->state = PS_READY;
+        llist_delete(&pos->waiters);
+    }
+}
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