rdma: export yield_until_fd_readable()

The RDMA event channel can be made non-blocking just like a TCP
socket. Exporting this function allows us to yield so that the
QEMU monitor remains available.

Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Chegu Vinod <chegu_vinod@hp.com>
Tested-by: Chegu Vinod <chegu_vinod@hp.com>
Tested-by: Michael R. Hines <mrhines@us.ibm.com>
Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

include/block/coroutine.h

@@ -209,4 +209,10 @@ void qemu_co_rwlock_unlock(CoRwlock *lock);
  */
 void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns);
 
+/**
+ * Yield until a file descriptor becomes readable
+ *
+ * Note that this function clobbers the handlers for the file descriptor.
+ */
+void coroutine_fn yield_until_fd_readable(int fd);
 #endif /* QEMU_COROUTINE_H */

qemu-coroutine-io.c

@@ -63,3 +63,26 @@ qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
     struct iovec iov = { .iov_base = buf, .iov_len = bytes };
     return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
 }
+
+typedef struct {
+    Coroutine *co;
+    int fd;
+} FDYieldUntilData;
+
+static void fd_coroutine_enter(void *opaque)
+{
+    FDYieldUntilData *data = opaque;
+    qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
+    qemu_coroutine_enter(data->co, NULL);
+}
+
+void coroutine_fn yield_until_fd_readable(int fd)
+{
+    FDYieldUntilData data;
+
+    assert(qemu_in_coroutine());
+    data.co = qemu_coroutine_self();
+    data.fd = fd;
+    qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
+    qemu_coroutine_yield();
+}

savevm.c

@@ -149,34 +149,6 @@ typedef struct QEMUFileSocket
     QEMUFile *file;
 } QEMUFileSocket;
 
-typedef struct {
-    Coroutine *co;
-    int fd;
-} FDYieldUntilData;
-
-static void fd_coroutine_enter(void *opaque)
-{
-    FDYieldUntilData *data = opaque;
-    qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
-    qemu_coroutine_enter(data->co, NULL);
-}
-
-/**
- * Yield until a file descriptor becomes readable
- *
- * Note that this function clobbers the handlers for the file descriptor.
- */
-static void coroutine_fn yield_until_fd_readable(int fd)
-{
-    FDYieldUntilData data;
-
-    assert(qemu_in_coroutine());
-    data.co = qemu_coroutine_self();
-    data.fd = fd;
-    qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
-    qemu_coroutine_yield();
-}
-
 static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
                                     int64_t pos)
 {