ipmi: Rework SMI registration failure

There were certain situations where ipmi_register_smi() would
return a failure, but the interface would still be registered
and would need to be unregistered.  This is obviously a bad
design and resulted in an oops in certain failure cases.

If the interface is started up in ipmi_register_smi(), then
an error occurs, shut down the interface there so the
cleanup can be done properly.

Fix the various smi users, too.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reported-by: Justin Ernst <justin.ernst@hpe.com>
Tested-by: Justin Ernst <justin.ernst@hpe.com>
Cc: Andrew Banman <abanman@hpe.com>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: <stable@vger.kernel.org> # 4.18.x

1 files changed, 30 insertions, 23 deletions

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 51832b8a2c62..7fc9612070a1 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -3381,39 +3381,45 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
 
 	rv = handlers->start_processing(send_info, intf);
 	if (rv)
-		goto out;
+		goto out_err;
 
 	rv = __bmc_get_device_id(intf, NULL, &id, NULL, NULL, i);
 	if (rv) {
 		dev_err(si_dev, "Unable to get the device id: %d\n", rv);
-		goto out;
+		goto out_err_started;
 	}
 
 	mutex_lock(&intf->bmc_reg_mutex);
 	rv = __scan_channels(intf, &id);
 	mutex_unlock(&intf->bmc_reg_mutex);
+	if (rv)
+		goto out_err_bmc_reg;
 
- out:
-	if (rv) {
-		ipmi_bmc_unregister(intf);
-		list_del_rcu(&intf->link);
-		mutex_unlock(&ipmi_interfaces_mutex);
-		synchronize_srcu(&ipmi_interfaces_srcu);
-		cleanup_srcu_struct(&intf->users_srcu);
-		kref_put(&intf->refcount, intf_free);
-	} else {
-		/*
-		 * Keep memory order straight for RCU readers.  Make
-		 * sure everything else is committed to memory before
-		 * setting intf_num to mark the interface valid.
-		 */
-		smp_wmb();
-		intf->intf_num = i;
-		mutex_unlock(&ipmi_interfaces_mutex);
+	/*
+	 * Keep memory order straight for RCU readers.  Make
+	 * sure everything else is committed to memory before
+	 * setting intf_num to mark the interface valid.
+	 */
+	smp_wmb();
+	intf->intf_num = i;
+	mutex_unlock(&ipmi_interfaces_mutex);
 
-		/* After this point the interface is legal to use. */
-		call_smi_watchers(i, intf->si_dev);
-	}
+	/* After this point the interface is legal to use. */
+	call_smi_watchers(i, intf->si_dev);
+
+	return 0;
+
+ out_err_bmc_reg:
+	ipmi_bmc_unregister(intf);
+ out_err_started:
+	if (intf->handlers->shutdown)
+		intf->handlers->shutdown(intf->send_info);
+ out_err:
+	list_del_rcu(&intf->link);
+	mutex_unlock(&ipmi_interfaces_mutex);
+	synchronize_srcu(&ipmi_interfaces_srcu);
+	cleanup_srcu_struct(&intf->users_srcu);
+	kref_put(&intf->refcount, intf_free);
 
 	return rv;
 }
@@ -3504,7 +3510,8 @@ void ipmi_unregister_smi(struct ipmi_smi *intf)
 	}
 	srcu_read_unlock(&intf->users_srcu, index);
 
-	intf->handlers->shutdown(intf->send_info);
+	if (intf->handlers->shutdown)
+		intf->handlers->shutdown(intf->send_info);
 
 	cleanup_smi_msgs(intf);