SUNRPC: Allow cache lookups to use RCU protection rather than the r/w spinlock

[linux-2.6-block.git] / include / linux / sunrpc / cache.h

diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 40d2822f0e2f1d1a6aa1a84e2ec820a8f9df392e..cf3e17ee278670e97c7dba9c1477de8feb3b5b63 100644 (file)
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -167,6 +167,9 @@ extern const struct file_operations cache_file_operations_pipefs;
 extern const struct file_operations content_file_operations_pipefs;
 extern const struct file_operations cache_flush_operations_pipefs;
 
+extern struct cache_head *
+sunrpc_cache_lookup_rcu(struct cache_detail *detail,
+                       struct cache_head *key, int hash);
 extern struct cache_head *
 sunrpc_cache_lookup(struct cache_detail *detail,
                    struct cache_head *key, int hash);
@@ -186,6 +189,12 @@ static inline struct cache_head  *cache_get(struct cache_head *h)
        return h;
 }
 
+static inline struct cache_head  *cache_get_rcu(struct cache_head *h)
+{
+       if (kref_get_unless_zero(&h->ref))
+               return h;
+       return NULL;
+}
 
 static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
 {
@@ -227,6 +236,9 @@ extern void sunrpc_cache_unhash(struct cache_detail *, struct cache_head *);
 extern void *cache_seq_start(struct seq_file *file, loff_t *pos);
 extern void *cache_seq_next(struct seq_file *file, void *p, loff_t *pos);
 extern void cache_seq_stop(struct seq_file *file, void *p);
+extern void *cache_seq_start_rcu(struct seq_file *file, loff_t *pos);
+extern void *cache_seq_next_rcu(struct seq_file *file, void *p, loff_t *pos);
+extern void cache_seq_stop_rcu(struct seq_file *file, void *p);
 
 extern void qword_add(char **bpp, int *lp, char *str);
 extern void qword_addhex(char **bpp, int *lp, char *buf, int blen);