[sheepdog] [PATCH v2 6/9] coroutine: add co_aio_sleep_ns() to allow sleep in block drivers

[MORITA Kazutaka]

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 at lab.ntt.co.jp>
---
 include/block/coroutine.h |  8 ++++++++
 qemu-coroutine-sleep.c    | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/include/block/coroutine.h b/include/block/coroutine.h
index 377805a..23ea6e9 100644
--- a/include/block/coroutine.h
+++ b/include/block/coroutine.h
@@ -210,6 +210,14 @@ void qemu_co_rwlock_unlock(CoRwlock *lock);
 void coroutine_fn co_sleep_ns(QEMUClock *clock, 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(int64_t ns);
+
+/**
  * Yield until a file descriptor becomes readable
  *
  * Note that this function clobbers the handlers for the file descriptor.
diff --git a/qemu-coroutine-sleep.c b/qemu-coroutine-sleep.c
index 169ce5c..3955347 100644
--- a/qemu-coroutine-sleep.c
+++ b/qemu-coroutine-sleep.c
@@ -13,6 +13,7 @@
 
 #include "block/coroutine.h"
 #include "qemu/timer.h"
+#include "qemu/thread.h"
 
 typedef struct CoSleepCB {
     QEMUTimer *ts;
@@ -37,3 +38,49 @@ void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns)
     qemu_del_timer(sleep_cb.ts);
     qemu_free_timer(sleep_cb.ts);
 }
+
+typedef struct CoAioSleepCB {
+    QEMUBH *bh;
+    int64_t ns;
+    Coroutine *co;
+} CoAioSleepCB;
+
+static void co_aio_sleep_cb(void *opaque)
+{
+    CoAioSleepCB *aio_sleep_cb = opaque;
+
+    qemu_coroutine_enter(aio_sleep_cb->co, NULL);
+}
+
+static void *sleep_thread(void *opaque)
+{
+    CoAioSleepCB *aio_sleep_cb = opaque;
+    struct timespec req = {
+        .tv_sec = aio_sleep_cb->ns / 1000000000,
+        .tv_nsec = aio_sleep_cb->ns % 1000000000,
+    };
+    struct timespec rem;
+
+    while (nanosleep(&req, &rem) < 0 && errno == EINTR) {
+        req = rem;
+    }
+
+    qemu_bh_schedule(aio_sleep_cb->bh);
+
+    return NULL;
+}
+
+void coroutine_fn co_aio_sleep_ns(int64_t ns)
+{
+    CoAioSleepCB aio_sleep_cb = {
+        .ns = ns,
+        .co = qemu_coroutine_self(),
+    };
+    QemuThread thread;
+
+    aio_sleep_cb.bh = qemu_bh_new(co_aio_sleep_cb, &aio_sleep_cb);
+    qemu_thread_create(&thread, sleep_thread, &aio_sleep_cb,
+                       QEMU_THREAD_DETACHED);
+    qemu_coroutine_yield();
+    qemu_bh_delete(aio_sleep_cb.bh);
+}
-- 
1.8.1.3.566.gaa39828