xen/9pfs: introduce Xen 9pfs transport driver

Introduce the Xen 9pfs transport driver: add struct xenbus_driver to
register as a xenbus driver and add struct p9_trans_module to register
as v9fs driver.

All functions are empty stubs for now.

CC: groug@kaod.org
CC: jgross@suse.com
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

1 files changed, 125 insertions, 0 deletions

diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
new file mode 100644
index 000000000000..3d072605e6a1
--- /dev/null
+++ b/net/9p/trans_xen.c
@@ -0,0 +1,125 @@
+/*
+ * linux/fs/9p/trans_xen
+ *
+ * Xen transport layer.
+ *
+ * Copyright (C) 2017 by Stefano Stabellini <stefano@aporeto.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/9pfs.h>
+
+#include <linux/module.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <net/9p/transport.h>
+
+static int p9_xen_cancel(struct p9_client *client, struct p9_req_t *req)
+{
+        return 0;
+}
+
+static int p9_xen_create(struct p9_client *client, const char *addr, char *args)
+{
+        return 0;
+}
+
+static void p9_xen_close(struct p9_client *client)
+{
+}
+
+static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
+{
+        return 0;
+}
+
+static struct p9_trans_module p9_xen_trans = {
+        .name = "xen",
+        .maxsize = 1 << (XEN_9PFS_RING_ORDER + XEN_PAGE_SHIFT),
+        .def = 1,
+        .create = p9_xen_create,
+        .close = p9_xen_close,
+        .request = p9_xen_request,
+        .cancel = p9_xen_cancel,
+        .owner = THIS_MODULE,
+};
+
+static const struct xenbus_device_id xen_9pfs_front_ids[] = {
+        { "9pfs" },
+        { "" }
+};
+
+static int xen_9pfs_front_remove(struct xenbus_device *dev)
+{
+        return 0;
+}
+
+static int xen_9pfs_front_probe(struct xenbus_device *dev,
+                                const struct xenbus_device_id *id)
+{
+        return 0;
+}
+
+static int xen_9pfs_front_resume(struct xenbus_device *dev)
+{
+        return 0;
+}
+
+static void xen_9pfs_front_changed(struct xenbus_device *dev,
+                                   enum xenbus_state backend_state)
+{
+}
+
+static struct xenbus_driver xen_9pfs_front_driver = {
+        .ids = xen_9pfs_front_ids,
+        .probe = xen_9pfs_front_probe,
+        .remove = xen_9pfs_front_remove,
+        .resume = xen_9pfs_front_resume,
+        .otherend_changed = xen_9pfs_front_changed,
+};
+
+int p9_trans_xen_init(void)
+{
+        if (!xen_domain())
+                return -ENODEV;
+
+        pr_info("Initialising Xen transport for 9pfs\n");
+
+        v9fs_register_trans(&p9_xen_trans);
+        return xenbus_register_frontend(&xen_9pfs_front_driver);
+}
+module_init(p9_trans_xen_init);
+
+void p9_trans_xen_exit(void)
+{
+        v9fs_unregister_trans(&p9_xen_trans);
+        return xenbus_unregister_driver(&xen_9pfs_front_driver);
+}
+module_exit(p9_trans_xen_exit);