NSM: Release nsmhandle in nlm_destroy_host

The nsm_handle's reference count is bumped in nlm_lookup_host().  It
should be decremented in nlm_destroy_host() to make it easier to see
the balance of these two operations.

Move the nsm_release() call to fs/lockd/host.c.

The h_nsmhandle pointer is set in nlm_lookup_host(), and never cleared.
The nlm_destroy_host() function is never called for the same nlm_host
twice, so h_nsmhandle won't ever be NULL when nsm_unmonitor() is
called.

All references to the nlm_host are gone before it is freed.  We can
skip making h_nsmhandle NULL just before the nlm_host is deallocated.

It's also likely we can remove the h_nsmhandle NULL check in
nlmsvc_is_client() as well, but we can do that later when rearchitect-
ing the nlm_host cache.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

2 files changed, 3 insertions, 10 deletions

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index 780918acd6f4..1d523c1a7b62 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -37,6 +37,7 @@ static struct nsm_handle	*nsm_find(const struct sockaddr *sap,
                                                 const char *hostname,
                                                 const size_t hostname_len,
                                                 const int create);
+static void                     nsm_release(struct nsm_handle *nsm);
 
 struct nlm_lookup_host_info {
         const int               server;         /* search for server|client */
@@ -263,10 +264,8 @@ nlm_destroy_host(struct nlm_host *host)
         BUG_ON(!list_empty(&host->h_lockowners));
         BUG_ON(atomic_read(&host->h_count));
 
-        /*
-         * Release NSM handle and unmonitor host.
-         */
         nsm_unmonitor(host);
+        nsm_release(host->h_nsmhandle);
 
         clnt = host->h_rpcclnt;
         if (clnt != NULL)
@@ -711,8 +710,7 @@ found:
 /*
  * Release an NSM handle
  */
-void
-nsm_release(struct nsm_handle *nsm)
+static void nsm_release(struct nsm_handle *nsm)
 {
         if (!nsm)
                 return;
diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index aaaa08e7ae7a..15fab22db028 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -117,10 +117,6 @@ nsm_unmonitor(struct nlm_host *host)
         struct nsm_res  res;
         int             status = 0;
 
-        if (nsm == NULL)
-                return 0;
-        host->h_nsmhandle = NULL;
-
         if (atomic_read(&nsm->sm_count) == 1
          && nsm->sm_monitored && !nsm->sm_sticky) {
                 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
@@ -132,7 +128,6 @@ nsm_unmonitor(struct nlm_host *host)
                 else
                         nsm->sm_monitored = 0;
         }
-        nsm_release(nsm);
         return status;
 }