NSM: More clean up of nsm_get_handle()

Clean up: refactor nsm_get_handle() so it is organized the same way that
nsm_reboot_lookup() is.

There is an additional micro-optimization here.  This change moves the
"hostname & nsm_use_hostnames" test out of the list_for_each_entry()
clause in nsm_get_handle(), since it is loop-invariant.

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

1 files changed, 35 insertions, 27 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 315ca07715c7..99aec744474c 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -213,6 +213,16 @@ static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
         return NULL;
 }
 
+static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
+{
+        struct nsm_handle *nsm;
+
+        list_for_each_entry(nsm, &nsm_handles, sm_link)
+                if (nlm_cmp_addr(nsm_addr(nsm), sap))
+                        return nsm;
+        return NULL;
+}
+
 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
 {
         struct nsm_handle *nsm;
@@ -281,8 +291,7 @@ struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
                                   const size_t salen, const char *hostname,
                                   const size_t hostname_len)
 {
-        struct nsm_handle *nsm = NULL;
-        struct nsm_handle *pos;
+        struct nsm_handle *cached, *new = NULL;
 
         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
                 if (printk_ratelimit()) {
@@ -295,38 +304,37 @@ struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
 
 retry:
         spin_lock(&nsm_lock);
-        list_for_each_entry(pos, &nsm_handles, sm_link) {
-
-                if (hostname && nsm_use_hostnames) {
-                        if (strlen(pos->sm_name) != hostname_len
-                         || memcmp(pos->sm_name, hostname, hostname_len))
-                                continue;
-                } else if (!nlm_cmp_addr(nsm_addr(pos), sap))
-                        continue;
-                atomic_inc(&pos->sm_count);
-                kfree(nsm);
-                nsm = pos;
-                dprintk("lockd: found nsm_handle for %s (%s), cnt %d\n",
-                                pos->sm_name, pos->sm_addrbuf,
-                                atomic_read(&pos->sm_count));
-                goto found;
+
+        if (nsm_use_hostnames && hostname != NULL)
+                cached = nsm_lookup_hostname(hostname, hostname_len);
+        else
+                cached = nsm_lookup_addr(sap);
+
+        if (cached != NULL) {
+                atomic_inc(&cached->sm_count);
+                spin_unlock(&nsm_lock);
+                kfree(new);
+                dprintk("lockd: found nsm_handle for %s (%s), "
+                                "cnt %d\n", cached->sm_name,
+                                cached->sm_addrbuf,
+                                atomic_read(&cached->sm_count));
+                return cached;
         }
-        if (nsm) {
-                list_add(&nsm->sm_link, &nsm_handles);
+
+        if (new != NULL) {
+                list_add(&new->sm_link, &nsm_handles);
+                spin_unlock(&nsm_lock);
                 dprintk("lockd: created nsm_handle for %s (%s)\n",
-                                nsm->sm_name, nsm->sm_addrbuf);
-                goto found;
+                                new->sm_name, new->sm_addrbuf);
+                return new;
         }
+
         spin_unlock(&nsm_lock);
 
-        nsm = nsm_create_handle(sap, salen, hostname, hostname_len);
-        if (unlikely(nsm == NULL))
+        new = nsm_create_handle(sap, salen, hostname, hostname_len);
+        if (unlikely(new == NULL))
                 return NULL;
         goto retry;
-
-found:
-        spin_unlock(&nsm_lock);
-        return nsm;
 }
 
 /**