nbd: switch to asynchronous operation

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/nbd.c b/nbd.c
index de880fe3c6..ff701d3dc8 100644
--- a/nbd.c
+++ b/nbd.c
@@ -81,6 +81,14 @@ size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
 {
     size_t offset = 0;
 
+    if (qemu_in_coroutine()) {
+        if (do_read) {
+            return qemu_co_recv(fd, buffer, size);
+        } else {
+            return qemu_co_send(fd, buffer, size);
+        }
+    }
+
     while (offset < size) {
         ssize_t len;