[PATCH] powerpc/pseries: Hold reference and fix refcount leak bugs

[Liang He]

In pseries_cpuhp_cache_use_count() and pseries_cpuhp_detach_nodes(),
we need carefully hold the reference returned by
of_find_next_cache_node() and use it to call of_node_put() to keep
refcount balance.

Signed-off-by: Liang He <win...@126.com>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c 
b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 0f8cd8b06432..e0a7ac5db15d 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -619,17 +619,21 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
 static unsigned int pseries_cpuhp_cache_use_count(const struct device_node 
*cachedn)
 {
        unsigned int use_count = 0;
-       struct device_node *dn;
+       struct device_node *dn, *tn;
 
        WARN_ON(!of_node_is_type(cachedn, "cache"));
 
        for_each_of_cpu_node(dn) {
-               if (of_find_next_cache_node(dn) == cachedn)
+               tn = of_find_next_cache_node(dn);
+               of_node_put(tn);
+               if (tn == cachedn)
                        use_count++;
        }
 
        for_each_node_by_type(dn, "cache") {
-               if (of_find_next_cache_node(dn) == cachedn)
+               tn = of_find_next_cache_node(dn);
+               of_node_put(tn);
+               if (tn == cachedn)
                        use_count++;
        }
 
@@ -649,10 +653,13 @@ static int pseries_cpuhp_detach_nodes(struct device_node 
*cpudn)
 
        dn = cpudn;
        while ((dn = of_find_next_cache_node(dn))) {
-               if (pseries_cpuhp_cache_use_count(dn) > 1)
+               if (pseries_cpuhp_cache_use_count(dn) > 1) {
+                       of_node_put(dn);
                        break;
+               }
 
                ret = of_changeset_detach_node(&cs, dn);
+               of_node_put(dn);
                if (ret)
                        goto out;
        }
-- 
2.25.1