1 files changed, 19 insertions, 15 deletions

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index de0ffb6106c4..c7854791898f 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -457,7 +457,7 @@ nlm_gc_hosts(void)
  * Manage NSM handles
  */
 static LIST_HEAD(nsm_handles);
-static DEFINE_MUTEX(nsm_mutex);
+static DEFINE_SPINLOCK(nsm_lock);
 
 static struct nsm_handle *
 __nsm_find(const struct sockaddr_in *sin,
@@ -479,7 +479,8 @@ __nsm_find(const struct sockaddr_in *sin,
                 return NULL;
         }
 
-        mutex_lock(&nsm_mutex);
+retry:
+        spin_lock(&nsm_lock);
         list_for_each_entry(pos, &nsm_handles, sm_link) {
 
                 if (hostname && nsm_use_hostnames) {
@@ -489,28 +490,32 @@ __nsm_find(const struct sockaddr_in *sin,
                 } else if (!nlm_cmp_addr(&pos->sm_addr, sin))
                         continue;
                 atomic_inc(&pos->sm_count);
+                kfree(nsm);
                 nsm = pos;
-                goto out;
+                goto found;
         }
-
-        if (!create) {
-                nsm = NULL;
-                goto out;
+        if (nsm) {
+                list_add(&nsm->sm_link, &nsm_handles);
+                goto found;
         }
+        spin_unlock(&nsm_lock);
+
+        if (!create)
+                return NULL;
 
         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
         if (nsm == NULL)
-                goto out;
+                return NULL;
+
         nsm->sm_addr = *sin;
         nsm->sm_name = (char *) (nsm + 1);
         memcpy(nsm->sm_name, hostname, hostname_len);
         nsm->sm_name[hostname_len] = '\0';
         atomic_set(&nsm->sm_count, 1);
+        goto retry;
 
-        list_add(&nsm->sm_link, &nsm_handles);
-
-out:
-        mutex_unlock(&nsm_mutex);
+found:
+        spin_unlock(&nsm_lock);
         return nsm;
 }
 
@@ -529,10 +534,9 @@ nsm_release(struct nsm_handle *nsm)
 {
         if (!nsm)
                 return;
-        mutex_lock(&nsm_mutex);
-        if (atomic_dec_and_test(&nsm->sm_count)) {
+        if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
                 list_del(&nsm->sm_link);
+                spin_unlock(&nsm_lock);
                 kfree(nsm);
         }
-        mutex_unlock(&nsm_mutex);
 }