libceph: make DEFINE_RB_* helpers more general

Initially for ceph_pg_mapping, ceph_spg_mapping and ceph_hobject_id,
compared with ceph_pg_compare(), ceph_spg_compare() and hoid_compare()
respectively.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index 3229ae6c78469019f0eb747c4e09a10137e26b0f..8a79587e1317e6d1a6a31b6fe64cedf8bc429484 100644 (file)
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -184,10 +184,11 @@ static inline int calc_pages_for(u64 off, u64 len)
                (off >> PAGE_SHIFT);
 }
 
-/*
- * These are not meant to be generic - an integer key is assumed.
- */
-#define DEFINE_RB_INSDEL_FUNCS(name, type, keyfld, nodefld)            \
+#define RB_BYVAL(a)      (a)
+#define RB_BYPTR(a)      (&(a))
+#define RB_CMP3WAY(a, b) ((a) < (b) ? -1 : (a) > (b))
+
+#define DEFINE_RB_INSDEL_FUNCS2(name, type, keyfld, cmpexp, keyexp, nodefld) \
 static void insert_##name(struct rb_root *root, type *t)               \
 {                                                                      \
        struct rb_node **n = &root->rb_node;                            \
@@ -197,11 +198,13 @@ static void insert_##name(struct rb_root *root, type *t)          \
                                                                        \
        while (*n) {                                                    \
                type *cur = rb_entry(*n, type, nodefld);                \
+               int cmp;                                                \
                                                                        \
                parent = *n;                                            \
-               if (t->keyfld < cur->keyfld)                            \
+               cmp = cmpexp(keyexp(t->keyfld), keyexp(cur->keyfld));   \
+               if (cmp < 0)                                            \
                        n = &(*n)->rb_left;                             \
-               else if (t->keyfld > cur->keyfld)                       \
+               else if (cmp > 0)                                       \
                        n = &(*n)->rb_right;                            \
                else                                                    \
                        BUG();                                          \
@@ -217,19 +220,24 @@ static void erase_##name(struct rb_root *root, type *t)                   \
        RB_CLEAR_NODE(&t->nodefld);                                     \
 }
 
-#define DEFINE_RB_LOOKUP_FUNC(name, type, keyfld, nodefld)             \
-extern type __lookup_##name##_key;                                     \
-static type *lookup_##name(struct rb_root *root,                       \
-                          typeof(__lookup_##name##_key.keyfld) key)    \
+/*
+ * @lookup_param_type is a parameter and not constructed from (@type,
+ * @keyfld) with typeof() because adding const is too unwieldy.
+ */
+#define DEFINE_RB_LOOKUP_FUNC2(name, type, keyfld, cmpexp, keyexp,     \
+                              lookup_param_type, nodefld)              \
+static type *lookup_##name(struct rb_root *root, lookup_param_type key)        \
 {                                                                      \
        struct rb_node *n = root->rb_node;                              \
                                                                        \
        while (n) {                                                     \
                type *cur = rb_entry(n, type, nodefld);                 \
+               int cmp;                                                \
                                                                        \
-               if (key < cur->keyfld)                                  \
+               cmp = cmpexp(key, keyexp(cur->keyfld));                 \
+               if (cmp < 0)                                            \
                        n = n->rb_left;                                 \
-               else if (key > cur->keyfld)                             \
+               else if (cmp > 0)                                       \
                        n = n->rb_right;                                \
                else                                                    \
                        return cur;                                     \
@@ -238,6 +246,23 @@ static type *lookup_##name(struct rb_root *root,                   \
        return NULL;                                                    \
 }
 
+#define DEFINE_RB_FUNCS2(name, type, keyfld, cmpexp, keyexp,           \
+                        lookup_param_type, nodefld)                    \
+DEFINE_RB_INSDEL_FUNCS2(name, type, keyfld, cmpexp, keyexp, nodefld)   \
+DEFINE_RB_LOOKUP_FUNC2(name, type, keyfld, cmpexp, keyexp,             \
+                      lookup_param_type, nodefld)
+
+/*
+ * Shorthands for integer keys.
+ */
+#define DEFINE_RB_INSDEL_FUNCS(name, type, keyfld, nodefld)            \
+DEFINE_RB_INSDEL_FUNCS2(name, type, keyfld, RB_CMP3WAY, RB_BYVAL, nodefld)
+
+#define DEFINE_RB_LOOKUP_FUNC(name, type, keyfld, nodefld)             \
+extern type __lookup_##name##_key;                                     \
+DEFINE_RB_LOOKUP_FUNC2(name, type, keyfld, RB_CMP3WAY, RB_BYVAL,       \
+                      typeof(__lookup_##name##_key.keyfld), nodefld)
+
 #define DEFINE_RB_FUNCS(name, type, keyfld, nodefld)                   \
 DEFINE_RB_INSDEL_FUNCS(name, type, keyfld, nodefld)                    \
 DEFINE_RB_LOOKUP_FUNC(name, type, keyfld, nodefld)