rcuja: implement node set nth

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c
index 586b29b6d368b49c36b9a85ab9f619db8b2afbad..c86173b42325c985f8301d1db47fa15e43652bec 100644 (file)
--- a/rcuja/rcuja.c
+++ b/rcuja/rcuja.c
@@ -21,11 +21,14 @@
  */
 
 #include <stdint.h>
+#include <errno.h>
 #include <limits.h>
 #include <urcu/rcuja.h>
 #include <urcu/compiler.h>
 #include <urcu/arch.h>
 #include <assert.h>
+#include <urcu-pointer.h>
+
 #include "rcuja-internal.h"
 #include "bitfield.h"
 
@@ -45,9 +48,10 @@ enum rcu_ja_type_class {
 
 struct rcu_ja_type {
        enum rcu_ja_type_class type_class;
-       uint16_t min_child;     /* minimum number of children: 1 to 256 */
-       uint16_t max_child;     /* maximum number of children: 1 to 256 */
-       uint16_t order;         /* node size is (1 << order), in bytes */
+       uint16_t min_child;             /* minimum number of children: 1 to 256 */
+       uint16_t max_child;             /* maximum number of children: 1 to 256 */
+       uint16_t max_linear_child;      /* per-pool max nr. children: 1 to 256 */
+       uint16_t order;                 /* node size is (1 << order), in bytes */
        uint16_t nr_pool_order;         /* number of pools */
        uint16_t pool_size_order;       /* pool size */
 };
@@ -94,21 +98,31 @@ enum {
        ja_type_7_max_child = 256,
 };
 
+enum {
+       ja_type_0_max_linear_child = 1,
+       ja_type_1_max_linear_child = 3,
+       ja_type_2_max_linear_child = 6,
+       ja_type_3_max_linear_child = 12,
+       ja_type_4_max_linear_child = 25,
+       ja_type_5_max_linear_child = 24,
+       ja_type_6_max_linear_child = 23,
+};
+
 enum {
        ja_type_5_nr_pool_order = 1,
        ja_type_6_nr_pool_order = 2,
 };
 
 const struct rcu_ja_type ja_types[] = {
-       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 3, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 4, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 5, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = ja_type_3_max_child, .order = 6, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 7, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .max_linear_child = ja_type_0_max_linear_child, .order = 3, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .max_linear_child = ja_type_1_max_linear_child, .order = 4, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .max_linear_child = ja_type_2_max_linear_child, .order = 5, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = ja_type_3_max_child, .max_linear_child = ja_type_3_max_linear_child, .order = 6, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .max_linear_child = ja_type_4_max_linear_child, .order = 7, },
 
        /* Pools may fill sooner than max_child */
-       { .type_class = RCU_JA_POOL, .min_child = 20, .max_child = ja_type_5_max_child, .order = 8, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 7, },
-       { .type_class = RCU_JA_POOL, .min_child = 45, .max_child = ja_type_6_max_child, .order = 9, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 7, },
+       { .type_class = RCU_JA_POOL, .min_child = 20, .max_child = ja_type_5_max_child, .max_linear_child = ja_type_5_max_linear_child, .order = 8, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 7, },
+       { .type_class = RCU_JA_POOL, .min_child = 45, .max_child = ja_type_6_max_child, .max_linear_child = ja_type_6_max_linear_child, .order = 9, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 7, },
 
        /*
         * TODO: Upon node removal below min_child, if child pool is
@@ -129,21 +143,31 @@ enum {
        ja_type_7_max_child = 256,
 };
 
+enum {
+       ja_type_0_max_linear_child = 1,
+       ja_type_1_max_linear_child = 3,
+       ja_type_2_max_linear_child = 7,
+       ja_type_3_max_linear_child = 14,
+       ja_type_4_max_linear_child = 28,
+       ja_type_5_max_linear_child = 27,
+       ja_type_6_max_linear_child = 26,
+};
+
 enum {
        ja_type_5_nr_pool_order = 1,
        ja_type_6_nr_pool_order = 2,
 };
 
 const struct rcu_ja_type ja_types[] = {
-       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 4, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 5, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 6, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = ja_type_3_max_child, .order = 7, },
-       { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 8, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .max_linear_child = ja_type_0_max_linear_child, .order = 4, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .max_linear_child = ja_type_1_max_linear_child, .order = 5, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .max_linear_child = ja_type_2_max_linear_child, .order = 6, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = ja_type_3_max_child, .max_linear_child = ja_type_3_max_linear_child, .order = 7, },
+       { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .max_linear_child = ja_type_4_max_linear_child, .order = 8, },
 
        /* Pools may fill sooner than max_child. */
-       { .type_class = RCU_JA_POOL, .min_child = 22, .max_child = ja_type_5_max_child, .order = 9, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 8, },
-       { .type_class = RCU_JA_POOL, .min_child = 51, .max_child = ja_type_6_max_child, .order = 10, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 8, },
+       { .type_class = RCU_JA_POOL, .min_child = 22, .max_child = ja_type_5_max_child, .max_linear_child = ja_type_5_max_linear_child, .order = 9, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 8, },
+       { .type_class = RCU_JA_POOL, .min_child = 51, .max_child = ja_type_6_max_child, .max_linear_child = ja_type_6_max_linear_child, .order = 10, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 8, },
 
        /*
         * TODO: Upon node removal below min_child, if child pool is
@@ -177,16 +201,16 @@ struct rcu_ja_node_flag;
 #define DECLARE_LINEAR_NODE(index)                                                                     \
                struct {                                                                                \
                        uint8_t nr_child;                                                               \
-                       uint8_t child_value[ja_type_## index ##_max_child];                             \
-                       struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child];                      \
+                       uint8_t child_value[ja_type_## index ##_max_linear_child];                      \
+                       struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_linear_child];       \
                }
 
 #define DECLARE_POOL_NODE(index)                                                                       \
                struct {                                                                                \
                        struct {                                                                        \
                                uint8_t nr_child;                                                       \
-                               uint8_t child_value[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \
-                               struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \
+                               uint8_t child_value[ja_type_## index ##_max_linear_child]; \
+                               struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
                        } linear[1U << ja_type_## index ##_nr_pool_order];                              \
                }
 
@@ -213,7 +237,8 @@ struct rcu_ja_node {
 };
 
 static
-struct rcu_ja_node_flag *ja_node_flag(struct rcu_ja_node *node, unsigned int type)
+struct rcu_ja_node_flag *ja_node_flag(struct rcu_ja_node *node,
+               unsigned int type)
 {
        assert(type < RCU_JA_NR_TYPES);
        return (struct rcu_ja_node_flag *) (((unsigned long) node) | type);
@@ -258,8 +283,8 @@ uint8_t *align_ptr_size(uint8_t *ptr)
 
 static
 struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
-                                       struct rcu_ja_node *node,
-                                       uint8_t n)
+               struct rcu_ja_node *node,
+               uint8_t n)
 {
        uint8_t nr_child;
        uint8_t *values;
@@ -267,12 +292,12 @@ struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
        struct rcu_ja_node_flag *ptr;
        unsigned int i;
 
-       assert(!type || type->type_class == RCU_JA_LINEAR);
+       assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
 
        nr_child = node->u.data[0];
        cmm_smp_rmb();  /* read nr_child before values */
-       assert(!type || nr_child <= type->max_child);
-       assert(!type || nr_child >= type->min_child);
+       assert(nr_child <= type->max_linear_child);
+       assert(type->type_class != RCU_JA_LINEAR || nr_child >= type->min_child);
 
        values = &node->u.data[1];
        for (i = 0; i < nr_child; i++) {
@@ -282,7 +307,7 @@ struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
        if (i >= nr_child)
                return NULL;
        cmm_smp_rmb();  /* read values before pointer */
-       pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[nr_child]);
+       pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]);
        ptr = pointers[i];
        assert(ja_node_ptr(ptr) != NULL);
        return ptr;
@@ -290,21 +315,21 @@ struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
 
 static
 struct rcu_ja_node_flag *ja_pool_node_get_nth(const struct rcu_ja_type *type,
-                                       struct rcu_ja_node *node,
-                                       uint8_t n)
+               struct rcu_ja_node *node,
+               uint8_t n)
 {
        struct rcu_ja_node *linear;
 
        assert(type->type_class == RCU_JA_POOL);
        linear = (struct rcu_ja_node *)
                &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
-       return ja_linear_node_get_nth(NULL, linear, n);
+       return ja_linear_node_get_nth(type, linear, n);
 }
 
 static
 struct rcu_ja_node_flag *ja_pigeon_node_get_nth(const struct rcu_ja_type *type,
-                                       struct rcu_ja_node *node,
-                                       uint8_t n)
+               struct rcu_ja_node *node,
+               uint8_t n)
 {
        assert(type->type_class == RCU_JA_PIGEON);
        return ((struct rcu_ja_node_flag **) node->u.data)[n];
@@ -313,7 +338,7 @@ struct rcu_ja_node_flag *ja_pigeon_node_get_nth(const struct rcu_ja_type *type,
 /* ja_node_get_nth: get nth item from a node */
 static
 struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag,
-                                       uint8_t n)
+               uint8_t n)
 {
        unsigned int type_index;
        struct rcu_ja_node *node;
@@ -338,8 +363,101 @@ struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag,
        }
 }
 
+static
+int ja_linear_node_set_nth(const struct rcu_ja_type *type,
+               struct rcu_ja_node *node,
+               uint8_t n,
+               struct rcu_ja_node_flag *child_node_flag)
+{
+       uint8_t nr_child;
+       uint8_t *values, *nr_child_ptr;
+       struct rcu_ja_node_flag **pointers;
+       unsigned int i;
+
+       assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+
+       nr_child_ptr = &node->u.data[0];
+       nr_child = *nr_child_ptr;
+       assert(nr_child <= type->max_linear_child);
+       assert(type->type_class != RCU_JA_LINEAR || nr_child >= type->min_child);
+
+       values = &node->u.data[1];
+       for (i = 0; i < nr_child; i++) {
+               if (values[i] == n)
+                       return -EEXIST;
+       }
+       if (nr_child >= type->max_linear_child) {
+               /* No space left in this node type */
+               return -ENOSPC;
+       }
+       pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]);
+       pointers[nr_child] = child_node_flag;
+       (*nr_child_ptr)++;
+       return 0;
+}
+
+static
+int ja_pool_node_set_nth(const struct rcu_ja_type *type,
+               struct rcu_ja_node *node,
+               uint8_t n,
+               struct rcu_ja_node_flag *child_node_flag)
+{
+       struct rcu_ja_node *linear;
+
+       assert(type->type_class == RCU_JA_POOL);
+       linear = (struct rcu_ja_node *)
+               &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
+       return ja_linear_node_set_nth(type, linear, n, child_node_flag);
+}
+
+static
+int ja_pigeon_node_set_nth(const struct rcu_ja_type *type,
+               struct rcu_ja_node *node,
+               uint8_t n,
+               struct rcu_ja_node_flag *child_node_flag)
+{
+       struct rcu_ja_node_flag **ptr;
+
+       assert(type->type_class == RCU_JA_PIGEON);
+       ptr = &((struct rcu_ja_node_flag **) node->u.data)[n];
+       if (*ptr != NULL)
+               return -EEXIST;
+       rcu_assign_pointer(*ptr, child_node_flag);
+       return 0;
+}
+
 /*
- * ja_node_set_nth: set nth item within a node. asserts that it is not
- * there yet.
+ * ja_node_set_nth: set nth item within a node. Return an error
+ * (negative error value) if it is already there.
+ * TODO: exclusive access on node.
  */
+static
+int ja_node_set_nth(struct rcu_ja_node_flag *node_flag, uint8_t n,
+               struct rcu_ja_node_flag *child_node_flag)
+{
+       unsigned int type_index;
+       struct rcu_ja_node *node;
+       const struct rcu_ja_type *type;
 
+       node = ja_node_ptr(node_flag);
+       assert(node != NULL);
+       type_index = ja_node_type(node_flag);
+       type = &ja_types[type_index];
+
+       switch (type->type_class) {
+       case RCU_JA_LINEAR:
+               return ja_linear_node_set_nth(type, node, n,
+                               child_node_flag);
+       case RCU_JA_POOL:
+               return ja_pool_node_set_nth(type, node, n,
+                               child_node_flag);
+       case RCU_JA_PIGEON:
+               return ja_pigeon_node_set_nth(type, node, n,
+                               child_node_flag);
+       default:
+               assert(0);
+               return -EINVAL;
+       }
+
+       return 0;
+}