1 files changed, 62 insertions, 0 deletions

diff --git a/include/linux/ceph/string_table.h b/include/linux/ceph/string_table.h
new file mode 100644
index 000000000000..1b02c96daf75
--- /dev/null
+++ b/include/linux/ceph/string_table.h
@@ -0,0 +1,62 @@
+#ifndef _FS_CEPH_STRING_TABLE_H
+#define _FS_CEPH_STRING_TABLE_H
+
+#include <linux/types.h>
+#include <linux/kref.h>
+#include <linux/rbtree.h>
+#include <linux/rcupdate.h>
+
+struct ceph_string {
+        struct kref kref;
+        union {
+                struct rb_node node;
+                struct rcu_head rcu;
+        };
+        size_t len;
+        char str[];
+};
+
+extern void ceph_release_string(struct kref *ref);
+extern struct ceph_string *ceph_find_or_create_string(const char *str,
+                                                      size_t len);
+extern bool ceph_strings_empty(void);
+
+static inline struct ceph_string *ceph_get_string(struct ceph_string *str)
+{
+        kref_get(&str->kref);
+        return str;
+}
+
+static inline void ceph_put_string(struct ceph_string *str)
+{
+        if (!str)
+                return;
+        kref_put(&str->kref, ceph_release_string);
+}
+
+static inline int ceph_compare_string(struct ceph_string *cs,
+                                      const char* str, size_t len)
+{
+        size_t cs_len = cs ? cs->len : 0;
+        if (cs_len != len)
+                return cs_len - len;
+        if (len == 0)
+                return 0;
+        return strncmp(cs->str, str, len);
+}
+
+#define ceph_try_get_string(x)                                  \
+({                                                              \
+        struct ceph_string *___str;                             \
+        rcu_read_lock();                                        \
+        for (;;) {                                              \
+                ___str = rcu_dereference(x);                    \
+                if (!___str ||                                  \
+                    kref_get_unless_zero(&___str->kref))        \
+                        break;                                  \
+        }                                                       \
+        rcu_read_unlock();                                      \
+        (___str);                                               \
+})
+
+#endif