migration: introduce set_blocking function in QEMUFileOps

Remove the assumption that every QEMUFile implementation has
a file descriptor available by introducing a new function
in QEMUFileOps to change the blocking state of a QEMUFile.

If not set, it will fallback to the original code using
the get_fd method.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <1461751518-12128-7-git-send-email-berrange@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index b480b7270c..2b25decd5b 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -684,9 +684,13 @@ size_t qemu_get_counted_string(QEMUFile *f, char buf[256])
  */
 void qemu_file_set_blocking(QEMUFile *f, bool block)
 {
-    if (block) {
-        qemu_set_block(qemu_get_fd(f));
+    if (f->ops->set_blocking) {
+        f->ops->set_blocking(f->opaque, block);
     } else {
-        qemu_set_nonblock(qemu_get_fd(f));
+        if (block) {
+            qemu_set_block(qemu_get_fd(f));
+        } else {
+            qemu_set_nonblock(qemu_get_fd(f));
+        }
     }
 }