[PATCH 01/13] io: Add qio_channel_wait_cond() helper

[Peter Xu <peterx@redhat.com>]

Add the helper to wait for QIO channel's IO availability in any
context (coroutine, or non-coroutine).  Use it tree-wide for three
occurences.

Cc: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/io/channel.h  | 15 +++++++++++++++
 io/channel.c          | 21 +++++++++++----------
 migration/qemu-file.c |  6 +-----
 3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/include/io/channel.h b/include/io/channel.h
index 0f25ae0069..d6d5bf2b5f 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -871,6 +871,21 @@ void qio_channel_wake_read(QIOChannel *ioc);
 void qio_channel_wait(QIOChannel *ioc,
                       GIOCondition condition);
 
+/**
+ * qio_channel_wait_cond:
+ * @ioc: the channel object
+ * @condition: the I/O condition to wait for
+ *
+ * Block execution from the current thread until
+ * the condition indicated by @condition becomes
+ * available.
+ *
+ * This will work with/without a coroutine context, by automatically select
+ * the proper API to wait.
+ */
+void qio_channel_wait_cond(QIOChannel *ioc,
+                           GIOCondition condition);
+
 /**
  * qio_channel_set_aio_fd_handler:
  * @ioc: the channel object
diff --git a/io/channel.c b/io/channel.c
index 852e684938..b18fc346ff 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -159,11 +159,7 @@ int coroutine_mixed_fn qio_channel_readv_full_all_eof(QIOChannel *ioc,
         len = qio_channel_readv_full(ioc, local_iov, nlocal_iov, local_fds,
                                      local_nfds, flags, errp);
         if (len == QIO_CHANNEL_ERR_BLOCK) {
-            if (qemu_in_coroutine()) {
-                qio_channel_yield(ioc, G_IO_IN);
-            } else {
-                qio_channel_wait(ioc, G_IO_IN);
-            }
+            qio_channel_wait_cond(ioc, G_IO_IN);
             continue;
         }
 
@@ -268,11 +264,7 @@ int coroutine_mixed_fn qio_channel_writev_full_all(QIOChannel *ioc,
                                             nfds, flags, errp);
 
         if (len == QIO_CHANNEL_ERR_BLOCK) {
-            if (qemu_in_coroutine()) {
-                qio_channel_yield(ioc, G_IO_OUT);
-            } else {
-                qio_channel_wait(ioc, G_IO_OUT);
-            }
+            qio_channel_wait_cond(ioc, G_IO_OUT);
             continue;
         }
         if (len < 0) {
@@ -774,6 +766,15 @@ void qio_channel_wait(QIOChannel *ioc,
     g_main_context_unref(ctxt);
 }
 
+void qio_channel_wait_cond(QIOChannel *ioc,
+                           GIOCondition condition)
+{
+    if (qemu_in_coroutine()) {
+        qio_channel_yield(ioc, condition);
+    } else {
+        qio_channel_wait(ioc, condition);
+    }
+}
 
 static void qio_channel_finalize(Object *obj)
 {
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 2d4ce174a5..4b5a409a80 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -343,11 +343,7 @@ static ssize_t coroutine_mixed_fn qemu_fill_buffer(QEMUFile *f)
                                      QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING,
                                      &local_error);
         if (len == QIO_CHANNEL_ERR_BLOCK) {
-            if (qemu_in_coroutine()) {
-                qio_channel_yield(f->ioc, G_IO_IN);
-            } else {
-                qio_channel_wait(f->ioc, G_IO_IN);
-            }
+            qio_channel_wait_cond(f->ioc, G_IO_IN);
         }
     } while (len == QIO_CHANNEL_ERR_BLOCK);
 
-- 
2.50.1