[PATCH] knfsd: Unexport cache_fresh and fix a small race

Cache_fresh is now only used in cache.c, so unexport it.

Part of cache_fresh (setting CACHE_VALID) should really be done under the
lock, while part (calling cache_revisit_request etc) must be done outside the
lock.  So we split it up appropriately.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 30 insertions, 22 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index b242f491cea9..edcda4fd88e8 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -96,6 +96,27 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
 }
 EXPORT_SYMBOL(sunrpc_cache_lookup);
 
+
+static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
+
+static int cache_fresh_locked(struct cache_head *head, time_t expiry)
+{
+        head->expiry_time = expiry;
+        head->last_refresh = get_seconds();
+        return !test_and_set_bit(CACHE_VALID, &head->flags);
+}
+
+static void cache_fresh_unlocked(struct cache_head *head,
+                        struct cache_detail *detail, int new)
+{
+        if (new)
+                cache_revisit_request(head);
+        if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
+                cache_revisit_request(head);
+                queue_loose(detail, head);
+        }
+}
+
 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
                                        struct cache_head *new, struct cache_head *old, int hash)
 {
@@ -105,6 +126,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
          */
         struct cache_head **head;
         struct cache_head *tmp;
+        int is_new;
 
         if (!test_bit(CACHE_VALID, &old->flags)) {
                 write_lock(&detail->hash_lock);
@@ -113,9 +135,9 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
                                 set_bit(CACHE_NEGATIVE, &old->flags);
                         else
                                 detail->update(old, new);
-                        /* FIXME cache_fresh should come first */
+                        is_new = cache_fresh_locked(old, new->expiry_time);
                         write_unlock(&detail->hash_lock);
-                        cache_fresh(detail, old, new->expiry_time);
+                        cache_fresh_unlocked(old, detail, is_new);
                         return old;
                 }
                 write_unlock(&detail->hash_lock);
@@ -138,9 +160,11 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
         tmp->next = *head;
         *head = tmp;
         cache_get(tmp);
+        is_new = cache_fresh_locked(tmp, new->expiry_time);
+        cache_fresh_locked(old, 0);
         write_unlock(&detail->hash_lock);
-        cache_fresh(detail, tmp, new->expiry_time);
-        cache_fresh(detail, old, 0);
+        cache_fresh_unlocked(tmp, detail, is_new);
+        cache_fresh_unlocked(old, detail, 0);
         detail->cache_put(old, detail);
         return tmp;
 }
@@ -192,7 +216,8 @@ int cache_check(struct cache_detail *detail,
                                 clear_bit(CACHE_PENDING, &h->flags);
                                 if (rv == -EAGAIN) {
                                         set_bit(CACHE_NEGATIVE, &h->flags);
-                                        cache_fresh(detail, h, get_seconds()+CACHE_NEW_EXPIRY);
+                                        cache_fresh_unlocked(h, detail,
+                                             cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY));
                                         rv = -ENOENT;
                                 }
                                 break;
@@ -213,22 +238,6 @@ int cache_check(struct cache_detail *detail,
         return rv;
 }
 
-static void queue_loose(struct cache_detail *detail, struct cache_head *ch);
-
-void cache_fresh(struct cache_detail *detail,
-                 struct cache_head *head, time_t expiry)
-{
-
-        head->expiry_time = expiry;
-        head->last_refresh = get_seconds();
-        if (!test_and_set_bit(CACHE_VALID, &head->flags))
-                cache_revisit_request(head);
-        if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
-                cache_revisit_request(head);
-                queue_loose(detail, head);
-        }
-}
-
 /*
  * caches need to be periodically cleaned.
  * For this we maintain a list of cache_detail and
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index 40401196e7de..69b8238f3d10 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -105,7 +105,6 @@ EXPORT_SYMBOL(auth_unix_lookup);
 EXPORT_SYMBOL(cache_check);
 EXPORT_SYMBOL(cache_flush);
 EXPORT_SYMBOL(cache_purge);
-EXPORT_SYMBOL(cache_fresh);
 EXPORT_SYMBOL(cache_init);
 EXPORT_SYMBOL(cache_register);
 EXPORT_SYMBOL(cache_unregister);