drbd: Remove unnecessary/unused code

Get rid of dump_stack() debug statements.

There is no point whatsoever in registering and unregistering a reboot
notifier that doesn't do anything.

The intention was to switch to an "emergency read-only" mode,
so we won't have to resync the full activity log just because
we had been Primary before the reboot.

Once we have that implemented, we may re-introduce the reboot notifier.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -1468,7 +1468,6 @@ static inline void drbd_generic_make_request(struct drbd_device *device,
 		printk(KERN_ERR "drbd%d: drbd_generic_make_request: "
 				"bio->bi_bdev == NULL\n",
 		       device_to_minor(device));
-		dump_stack();
 		bio_endio(bio, -ENODEV);
 		return;
 	}

drivers/block/drbd/drbd_main.c

@@ -2125,20 +2125,6 @@ static int drbd_create_mempools(void)
 	return -ENOMEM;
 }
 
-static int drbd_notify_sys(struct notifier_block *this, unsigned long code,
-	void *unused)
-{
-	/* just so we have it.  you never know what interesting things we
-	 * might want to do here some day...
-	 */
-
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block drbd_notifier = {
-	.notifier_call = drbd_notify_sys,
-};
-
 static void drbd_release_all_peer_reqs(struct drbd_device *device)
 {
 	int rr;
@@ -2314,8 +2300,6 @@ static void drbd_cleanup(void)
 	struct drbd_device *device;
 	struct drbd_resource *resource, *tmp;
 
-	unregister_reboot_notifier(&drbd_notifier);
-
 	/* first remove proc,
 	 * drbdsetup uses it's presence to detect
 	 * whether DRBD is loaded.
@@ -2899,8 +2883,6 @@ static int __init drbd_init(void)
 		return err;
 	}
 
-	register_reboot_notifier(&drbd_notifier);
-
 	/*
 	 * allocate all necessary structs
 	 */

drivers/block/drbd/drbd_proc.c

@@ -299,7 +299,7 @@ static int drbd_proc_open(struct inode *inode, struct file *file)
 	int err;
 
 	if (try_module_get(THIS_MODULE)) {
-		err = single_open(file, drbd_seq_show, PDE_DATA(inode));
+		err = single_open(file, drbd_seq_show, NULL);
 		if (err)
 			module_put(THIS_MODULE);
 		return err;