[virtio-9p] Add infrastructure to support glib threads and coroutines.

This patch is originally made by Arun Bharadwaj for glib support.
Later Harsh Prateek Bora added coroutines support.
This version implemented with suggestions from
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>.

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri "<jvrao@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/hw/9pfs/virtio-9p-coth.h b/hw/9pfs/virtio-9p-coth.h
new file mode 100644
index 0000000000..8445d29bc4
--- /dev/null
+++ b/hw/9pfs/virtio-9p-coth.h
@@ -0,0 +1,58 @@
+/*
+ * Virtio 9p backend
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
+ *  Venkateswararao Jujjuri(JV) <jvrao@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef _QEMU_VIRTIO_9P_COTH_H
+#define _QEMU_VIRTIO_9P_COTH_H
+
+#include "qemu-thread.h"
+#include "qemu-coroutine.h"
+#include <glib.h>
+
+typedef struct V9fsThPool {
+    int rfd;
+    int wfd;
+    GThreadPool *pool;
+    GAsyncQueue *completed;
+} V9fsThPool;
+
+/*
+ * we want to use bottom half because we want to make sure the below
+ * sequence of events.
+ *
+ *   1. Yield the coroutine in the QEMU thread.
+ *   2. Submit the coroutine to a worker thread.
+ *   3. Enter the coroutine in the worker thread.
+ * we cannot swap step 1 and 2, because that would imply worker thread
+ * can enter coroutine while step1 is still running
+ */
+#define v9fs_co_run_in_worker(code_block)                               \
+    do {                                                                \
+        QEMUBH *co_bh;                                                  \
+        co_bh = qemu_bh_new(co_run_in_worker_bh,                        \
+                            qemu_coroutine_self());                     \
+        qemu_bh_schedule(co_bh);                                        \
+        /*                                                              \
+         * yeild in qemu thread and re-enter back                       \
+         * in glib worker thread                                        \
+         */                                                             \
+        qemu_coroutine_yield();                                         \
+        qemu_bh_delete(co_bh);                                          \
+        code_block;                                                     \
+        /* re-enter back to qemu thread */                              \
+        qemu_coroutine_yield();                                         \
+    } while (0)
+
+extern void co_run_in_worker_bh(void *);
+extern int v9fs_init_worker_threads(void);
+#endif