lockd: convert nsm_mutex to a spinlock

[linux-2.6-omap-h63xx.git] / fs / lockd / host.c

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index de0ffb6106c4c038d82cbbaf278fcfce7167773d..c7854791898f69b6c11b112515f91c44fa71d80a 100644 (file)
--- 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);
 }