[PATCH 4.16 168/272] powerpc/vas: Fix cleanup when VAS is not configured

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>

[ Upstream commit 45ddea8a73a25461387eb8e87f3e0ecca084799b ]

When VAS is not configured, unregister the platform driver. Also simplify
cleanup by delaying vas debugfs init until we know VAS is configured.

Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/powerpc/platforms/powernv/vas-debug.c |   11 +++++++++++
 arch/powerpc/platforms/powernv/vas.c       |    6 +++---
 2 files changed, 14 insertions(+), 3 deletions(-)

--- a/arch/powerpc/platforms/powernv/vas-debug.c
+++ b/arch/powerpc/platforms/powernv/vas-debug.c
@@ -179,6 +179,7 @@ void vas_instance_init_dbgdir(struct vas
 {
        struct dentry *d;
 
+       vas_init_dbgdir();
        if (!vas_debugfs)
                return;
 
@@ -201,8 +202,18 @@ free_name:
        vinst->dbgdir = NULL;
 }
 
+/*
+ * Set up the "root" VAS debugfs dir. Return if we already set it up
+ * (or failed to) in an earlier instance of VAS.
+ */
 void vas_init_dbgdir(void)
 {
+       static bool first_time = true;
+
+       if (!first_time)
+               return;
+
+       first_time = false;
        vas_debugfs = debugfs_create_dir("vas", NULL);
        if (IS_ERR(vas_debugfs))
                vas_debugfs = NULL;
--- a/arch/powerpc/platforms/powernv/vas.c
+++ b/arch/powerpc/platforms/powernv/vas.c
@@ -160,8 +160,6 @@ static int __init vas_init(void)
        int found = 0;
        struct device_node *dn;
 
-       vas_init_dbgdir();
-
        platform_driver_register(&vas_driver);
 
        for_each_compatible_node(dn, NULL, "ibm,vas") {
@@ -169,8 +167,10 @@ static int __init vas_init(void)
                found++;
        }
 
-       if (!found)
+       if (!found) {
+               platform_driver_unregister(&vas_driver);
                return -ENODEV;
+       }
 
        pr_devel("Found %d instances\n", found);