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>

2 files changed, 7 insertions, 13 deletions

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index f759ad4584c3..edbb69ebdf20 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -787,17 +787,14 @@ static const struct xenbus_device_id xen_blkbk_ids[] = {
 };
 
 
-static struct xenbus_driver xen_blkbk = {
-	.name = "vbd",
-	.owner = THIS_MODULE,
-	.ids = xen_blkbk_ids,
+static DEFINE_XENBUS_DRIVER(xen_blkbk, ,
 	.probe = xen_blkbk_probe,
 	.remove = xen_blkbk_remove,
 	.otherend_changed = frontend_changed
-};
+);
 
 
 int xen_blkif_xenbus_init(void)
 {
-	return xenbus_register_backend(&xen_blkbk);
+	return xenbus_register_backend(&xen_blkbk_driver);
 }
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 7b2ec5908413..9fd3ee203b1e 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1437,16 +1437,13 @@ static const struct xenbus_device_id blkfront_ids[] = {
 	{ "" }
 };
 
-static struct xenbus_driver blkfront = {
-	.name = "vbd",
-	.owner = THIS_MODULE,
-	.ids = blkfront_ids,
+static DEFINE_XENBUS_DRIVER(blkfront, ,
 	.probe = blkfront_probe,
 	.remove = blkfront_remove,
 	.resume = blkfront_resume,
 	.otherend_changed = blkback_changed,
 	.is_ready = blkfront_is_ready,
-};
+);
 
 static int __init xlblk_init(void)
 {
@@ -1461,7 +1458,7 @@ static int __init xlblk_init(void)
 		return -ENODEV;
 	}
 
-	ret = xenbus_register_frontend(&blkfront);
+	ret = xenbus_register_frontend(&blkfront_driver);
 	if (ret) {
 		unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
 		return ret;
@@ -1474,7 +1471,7 @@ module_init(xlblk_init);
 
 static void __exit xlblk_exit(void)
 {
-	return xenbus_unregister_driver(&blkfront);
+	return xenbus_unregister_driver(&blkfront_driver);
 }
 module_exit(xlblk_exit);