Xen: consolidate and simplify struct xenbus_driver instantiation

The 'name', 'owner', and 'mod_name' members are redundant with the
identically named fields in the 'driver' sub-structure. Rather than
switching each instance to specify these fields explicitly, introduce
a macro to simplify this.

Eliminate further redundancy by allowing the drvname argument to
DEFINE_XENBUS_DRIVER() to be blank (in which case the first entry from
the ID table will be used for .driver.name).

Also eliminate the questionable xenbus_register_{back,front}end()
wrappers - their sole remaining purpose was the checking of the
'owner' field, proper setting of which shouldn't be an issue anymore
when the macro gets used.

v2: Restore DRV_NAME for the driver name in xen-pciback.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

5 files changed, 13 insertions, 27 deletions

diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 075525945e36..c80f9c84d08e 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -707,19 +707,16 @@ static int xen_pcibk_xenbus_remove(struct xenbus_device *dev)
         return 0;
 }
 
-static const struct xenbus_device_id xenpci_ids[] = {
+static const struct xenbus_device_id xen_pcibk_ids[] = {
         {"pci"},
         {""},
 };
 
-static struct xenbus_driver xenbus_xen_pcibk_driver = {
-        .name                   = DRV_NAME,
-        .owner                  = THIS_MODULE,
-        .ids                    = xenpci_ids,
+static DEFINE_XENBUS_DRIVER(xen_pcibk, DRV_NAME,
         .probe                  = xen_pcibk_xenbus_probe,
         .remove                 = xen_pcibk_xenbus_remove,
         .otherend_changed       = xen_pcibk_frontend_changed,
-};
+);
 
 const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
 
@@ -735,11 +732,11 @@ int __init xen_pcibk_xenbus_register(void)
         if (passthrough)
                 xen_pcibk_backend = &xen_pcibk_passthrough_backend;
         pr_info(DRV_NAME ": backend is %s\n", xen_pcibk_backend->name);
-        return xenbus_register_backend(&xenbus_xen_pcibk_driver);
+        return xenbus_register_backend(&xen_pcibk_driver);
 }
 
 void __exit xen_pcibk_xenbus_unregister(void)
 {
         destroy_workqueue(xen_pcibk_wq);
-        xenbus_unregister_driver(&xenbus_xen_pcibk_driver);
+        xenbus_unregister_driver(&xen_pcibk_driver);
 }
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 1c05b2508ae8..3864967202b5 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -291,14 +291,9 @@ void xenbus_dev_shutdown(struct device *_dev)
 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
 
 int xenbus_register_driver_common(struct xenbus_driver *drv,
-                                  struct xen_bus_type *bus,
-                                  struct module *owner,
-                                  const char *mod_name)
+                                  struct xen_bus_type *bus)
 {
-        drv->driver.name = drv->name;
         drv->driver.bus = &bus->bus;
-        drv->driver.owner = owner;
-        drv->driver.mod_name = mod_name;
 
         return driver_register(&drv->driver);
 }
diff --git a/drivers/xen/xenbus/xenbus_probe.h b/drivers/xen/xenbus/xenbus_probe.h
index 460d784a769a..bb4f92ed8730 100644
--- a/drivers/xen/xenbus/xenbus_probe.h
+++ b/drivers/xen/xenbus/xenbus_probe.h
@@ -53,9 +53,7 @@ extern int xenbus_match(struct device *_dev, struct device_driver *_drv);
 extern int xenbus_dev_probe(struct device *_dev);
 extern int xenbus_dev_remove(struct device *_dev);
 extern int xenbus_register_driver_common(struct xenbus_driver *drv,
-                                         struct xen_bus_type *bus,
-                                         struct module *owner,
-                                         const char *mod_name);
+                                         struct xen_bus_type *bus);
 extern int xenbus_probe_node(struct xen_bus_type *bus,
                              const char *type,
                              const char *nodename);
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index c3c7cd195c11..257be37d9091 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -232,15 +232,13 @@ int xenbus_dev_is_online(struct xenbus_device *dev)
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
 
-int __xenbus_register_backend(struct xenbus_driver *drv,
-                              struct module *owner, const char *mod_name)
+int xenbus_register_backend(struct xenbus_driver *drv)
 {
         drv->read_otherend_details = read_frontend_details;
 
-        return xenbus_register_driver_common(drv, &xenbus_backend,
-                                             owner, mod_name);
+        return xenbus_register_driver_common(drv, &xenbus_backend);
 }
-EXPORT_SYMBOL_GPL(__xenbus_register_backend);
+EXPORT_SYMBOL_GPL(xenbus_register_backend);
 
 static int backend_probe_and_watch(struct notifier_block *notifier,
                                    unsigned long event,
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 2f73195512b4..9c57819df51a 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -230,15 +230,13 @@ static void wait_for_devices(struct xenbus_driver *xendrv)
                          print_device_status);
 }
 
-int __xenbus_register_frontend(struct xenbus_driver *drv,
-                               struct module *owner, const char *mod_name)
+int xenbus_register_frontend(struct xenbus_driver *drv)
 {
         int ret;
 
         drv->read_otherend_details = read_backend_details;
 
-        ret = xenbus_register_driver_common(drv, &xenbus_frontend,
-                                            owner, mod_name);
+        ret = xenbus_register_driver_common(drv, &xenbus_frontend);
         if (ret)
                 return ret;
 
@@ -247,7 +245,7 @@ int __xenbus_register_frontend(struct xenbus_driver *drv,
 
         return 0;
 }
-EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
+EXPORT_SYMBOL_GPL(xenbus_register_frontend);
 
 static DECLARE_WAIT_QUEUE_HEAD(backend_state_wq);
 static int backend_state;