SUNRPC: Ensure we initialise the cache_detail before creating procfs files

Also ensure that we destroy those files before we destroy the cache_detail.
Otherwise, user processes might attempt to write into uninitialised caches.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 20 insertions, 10 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 8ede4a6f384b..062d4f4307eb 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -347,13 +347,8 @@ static int create_cache_proc_entries(struct cache_detail *cd)
 }
 #endif
 
-int cache_register(struct cache_detail *cd)
+static void sunrpc_init_cache_detail(struct cache_detail *cd)
 {
-        int ret;
-
-        ret = create_cache_proc_entries(cd);
-        if (ret)
-                return ret;
         rwlock_init(&cd->hash_lock);
         INIT_LIST_HEAD(&cd->queue);
         spin_lock(&cache_list_lock);
@@ -367,11 +362,9 @@ int cache_register(struct cache_detail *cd)
 
         /* start the cleaning process */
         schedule_delayed_work(&cache_cleaner, 0);
-        return 0;
 }
-EXPORT_SYMBOL_GPL(cache_register);
 
-void cache_unregister(struct cache_detail *cd)
+static void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 {
         cache_purge(cd);
         spin_lock(&cache_list_lock);
@@ -386,7 +379,6 @@ void cache_unregister(struct cache_detail *cd)
         list_del_init(&cd->others);
         write_unlock(&cd->hash_lock);
         spin_unlock(&cache_list_lock);
-        remove_cache_proc_entries(cd);
         if (list_empty(&cache_list)) {
                 /* module must be being unloaded so its safe to kill the worker */
                 cancel_delayed_work_sync(&cache_cleaner);
@@ -395,6 +387,24 @@ void cache_unregister(struct cache_detail *cd)
 out:
         printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
 }
+
+int cache_register(struct cache_detail *cd)
+{
+        int ret;
+
+        sunrpc_init_cache_detail(cd);
+        ret = create_cache_proc_entries(cd);
+        if (ret)
+                sunrpc_destroy_cache_detail(cd);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cache_register);
+
+void cache_unregister(struct cache_detail *cd)
+{
+        remove_cache_proc_entries(cd);
+        sunrpc_destroy_cache_detail(cd);
+}
 EXPORT_SYMBOL_GPL(cache_unregister);
 
 /* clean cache tries to find something to clean