coroutine: add co_aio_sleep_ns() to allow sleep in block drivers

This helper function behaves similarly to co_sleep_ns(), but the
sleeping coroutine will be resumed when using qemu_aio_wait().

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Tested-by: Liu Yuan <namei.unix@gmail.com>
Reviewed-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

include/block/coroutine.h

@@ -215,6 +215,15 @@ void qemu_co_rwlock_unlock(CoRwlock *lock);
  */
 void coroutine_fn co_sleep_ns(QEMUClockType type, int64_t ns);
 
+/**
+ * Yield the coroutine for a given duration
+ *
+ * Behaves similarly to co_sleep_ns(), but the sleeping coroutine will be
+ * resumed when using qemu_aio_wait().
+ */
+void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type,
+                                  int64_t ns);
+
 /**
  * Yield until a file descriptor becomes readable
  *

qemu-coroutine-sleep.c

@@ -13,6 +13,7 @@
 
 #include "block/coroutine.h"
 #include "qemu/timer.h"
+#include "block/aio.h"
 
 typedef struct CoSleepCB {
     QEMUTimer *ts;
@@ -37,3 +38,16 @@ void coroutine_fn co_sleep_ns(QEMUClockType type, int64_t ns)
     timer_del(sleep_cb.ts);
     timer_free(sleep_cb.ts);
 }
+
+void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type,
+                                  int64_t ns)
+{
+    CoSleepCB sleep_cb = {
+        .co = qemu_coroutine_self(),
+    };
+    sleep_cb.ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, &sleep_cb);
+    timer_mod(sleep_cb.ts, qemu_clock_get_ns(type) + ns);
+    qemu_coroutine_yield();
+    timer_del(sleep_cb.ts);
+    timer_free(sleep_cb.ts);
+}