smc91c111: Fix receive starvation

[qemu.git] / qemu-coroutine-lock.c

diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
index 6b58160058c26737786248854bde9c8edaa5d9d1..aeb33b9118a7fec8bade8a385a7923db0efe4cd4 100644 (file)
--- a/qemu-coroutine-lock.c
+++ b/qemu-coroutine-lock.c
@@ -23,57 +23,95 @@
  */
 
 #include "qemu-common.h"
-#include "qemu-coroutine.h"
-#include "qemu-coroutine-int.h"
-#include "qemu-queue.h"
-#include "main-loop.h"
+#include "block/coroutine.h"
+#include "block/coroutine_int.h"
+#include "qemu/queue.h"
 #include "trace.h"
 
-static QTAILQ_HEAD(, Coroutine) unlock_bh_queue =
-    QTAILQ_HEAD_INITIALIZER(unlock_bh_queue);
-static QEMUBH* unlock_bh;
+void qemu_co_queue_init(CoQueue *queue)
+{
+    QTAILQ_INIT(&queue->entries);
+}
 
-static void qemu_co_queue_next_bh(void *opaque)
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
+{
+    Coroutine *self = qemu_coroutine_self();
+    QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
+    qemu_coroutine_yield();
+    assert(qemu_in_coroutine());
+}
+
+void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue)
+{
+    Coroutine *self = qemu_coroutine_self();
+    QTAILQ_INSERT_HEAD(&queue->entries, self, co_queue_next);
+    qemu_coroutine_yield();
+    assert(qemu_in_coroutine());
+}
+
+/**
+ * qemu_co_queue_run_restart:
+ *
+ * Enter each coroutine that was previously marked for restart by
+ * qemu_co_queue_next() or qemu_co_queue_restart_all().  This function is
+ * invoked by the core coroutine code when the current coroutine yields or
+ * terminates.
+ */
+void qemu_co_queue_run_restart(Coroutine *co)
 {
     Coroutine *next;
 
-    trace_qemu_co_queue_next_bh();
-    while ((next = QTAILQ_FIRST(&unlock_bh_queue))) {
-        QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next);
+    trace_qemu_co_queue_run_restart(co);
+    while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
+        QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next);
         qemu_coroutine_enter(next, NULL);
     }
 }
 
-void qemu_co_queue_init(CoQueue *queue)
+static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
 {
-    QTAILQ_INIT(&queue->entries);
+    Coroutine *self = qemu_coroutine_self();
+    Coroutine *next;
+
+    if (QTAILQ_EMPTY(&queue->entries)) {
+        return false;
+    }
 
-    if (!unlock_bh) {
-        unlock_bh = qemu_bh_new(qemu_co_queue_next_bh, NULL);
+    while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) {
+        QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
+        QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
+        trace_qemu_co_queue_next(next);
+        if (single) {
+            break;
+        }
     }
+    return true;
 }
 
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
+bool coroutine_fn qemu_co_queue_next(CoQueue *queue)
+{
+    assert(qemu_in_coroutine());
+    return qemu_co_queue_do_restart(queue, true);
+}
+
+void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
 {
-    Coroutine *self = qemu_coroutine_self();
-    QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
-    qemu_coroutine_yield();
     assert(qemu_in_coroutine());
+    qemu_co_queue_do_restart(queue, false);
 }
 
-bool qemu_co_queue_next(CoQueue *queue)
+bool qemu_co_enter_next(CoQueue *queue)
 {
     Coroutine *next;
 
     next = QTAILQ_FIRST(&queue->entries);
-    if (next) {
-        QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
-        QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next);
-        trace_qemu_co_queue_next(next);
-        qemu_bh_schedule(unlock_bh);
+    if (!next) {
+        return false;
     }
 
-    return (next != NULL);
+    QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
+    qemu_coroutine_enter(next, NULL);
+    return true;
 }
 
 bool qemu_co_queue_empty(CoQueue *queue)
@@ -136,13 +174,7 @@ void qemu_co_rwlock_unlock(CoRwlock *lock)
     assert(qemu_in_coroutine());
     if (lock->writer) {
         lock->writer = false;
-        while (!qemu_co_queue_empty(&lock->queue)) {
-            /*
-             * Wakeup every body. This will include some
-             * writers too.
-             */
-            qemu_co_queue_next(&lock->queue);
-        }
+        qemu_co_queue_restart_all(&lock->queue);
     } else {
         lock->reader--;
         assert(lock->reader >= 0);