nfs: move nfs_set_events out of the while loops

nfs_set_events only needs to be called once before entering the
while loop; afterwards, nfs_process_read and nfs_process_write
take care of it.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-9-git-send-email-pbonzini@redhat.com>
Signed-off-by: NFam Zheng <famz@redhat.com>

block/nfs.c

@@ -149,8 +149,8 @@ static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
         return -ENOMEM;
     }
 
-    while (!task.complete) {
     nfs_set_events(client);
+    while (!task.complete) {
         qemu_coroutine_yield();
     }
 
@@ -191,8 +191,8 @@ static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
         return -ENOMEM;
     }
 
-    while (!task.complete) {
     nfs_set_events(client);
+    while (!task.complete) {
         qemu_coroutine_yield();
     }
 
@@ -217,8 +217,8 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
         return -ENOMEM;
     }
 
-    while (!task.complete) {
     nfs_set_events(client);
+    while (!task.complete) {
         qemu_coroutine_yield();
     }
 
@@ -513,8 +513,8 @@ static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
         return -ENOMEM;
     }
 
-    while (!task.complete) {
     nfs_set_events(client);
+    while (!task.complete) {
         aio_poll(client->aio_context, true);
     }