Merge tag 'fscache-fixes-20141013' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / include / linux / dynamic_queue_limits.h

diff --git a/include/linux/dynamic_queue_limits.h b/include/linux/dynamic_queue_limits.h
index 5621547d631bf47db8056b64e79bb09bd7018ad5..a4be70398ce1b2cb192a7b3bed9477439b2e3c57 100644 (file)
--- a/include/linux/dynamic_queue_limits.h
+++ b/include/linux/dynamic_queue_limits.h
@@ -73,14 +73,22 @@ static inline void dql_queued(struct dql *dql, unsigned int count)
 {
        BUG_ON(count > DQL_MAX_OBJECT);
 
-       dql->num_queued += count;
        dql->last_obj_cnt = count;
+
+       /* We want to force a write first, so that cpu do not attempt
+        * to get cache line containing last_obj_cnt, num_queued, adj_limit
+        * in Shared state, but directly does a Request For Ownership
+        * It is only a hint, we use barrier() only.
+        */
+       barrier();
+
+       dql->num_queued += count;
 }
 
 /* Returns how many objects can be queued, < 0 indicates over limit. */
 static inline int dql_avail(const struct dql *dql)
 {
-       return dql->adj_limit - dql->num_queued;
+       return ACCESS_ONCE(dql->adj_limit) - ACCESS_ONCE(dql->num_queued);
 }
 
 /* Record number of completed objects and recalculate the limit. */