#include <urcu/arch.h>
#include <assert.h>
#include <urcu-pointer.h>
+#include <stdlib.h>
+#include <time.h>
#include "rcuja-internal.h"
#include "bitfield.h"
+static unsigned long hash_seed;
+
+/*
+ * Hash function
+ * Source: http://burtleburtle.net/bob/c/lookup3.c
+ * Originally Public Domain
+ */
+
+#define rot(x, k) (((x) << (k)) | ((x) >> (32 - (k))))
+
+#define mix(a, b, c) \
+do { \
+ a -= c; a ^= rot(c, 4); c += b; \
+ b -= a; b ^= rot(a, 6); a += c; \
+ c -= b; c ^= rot(b, 8); b += a; \
+ a -= c; a ^= rot(c, 16); c += b; \
+ b -= a; b ^= rot(a, 19); a += c; \
+ c -= b; c ^= rot(b, 4); b += a; \
+} while (0)
+
+#define final(a, b, c) \
+{ \
+ c ^= b; c -= rot(b, 14); \
+ a ^= c; a -= rot(c, 11); \
+ b ^= a; b -= rot(a, 25); \
+ c ^= b; c -= rot(b, 16); \
+ a ^= c; a -= rot(c, 4);\
+ b ^= a; b -= rot(a, 14); \
+ c ^= b; c -= rot(b, 24); \
+}
+
+static inline __attribute__((unused))
+uint32_t hash_u32(
+ const uint32_t *k, /* the key, an array of uint32_t values */
+ size_t length, /* the length of the key, in uint32_ts */
+ uint32_t initval) /* the previous hash, or an arbitrary value */
+{
+ uint32_t a, b, c;
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + (((uint32_t) length) << 2) + initval;
+
+ /*----------------------------------------- handle most of the key */
+ while (length > 3) {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a, b, c);
+ length -= 3;
+ k += 3;
+ }
+
+ /*----------------------------------- handle the last 3 uint32_t's */
+ switch (length) { /* all the case statements fall through */
+ case 3: c += k[2];
+ case 2: b += k[1];
+ case 1: a += k[0];
+ final(a, b, c);
+ case 0: /* case 0: nothing left to add */
+ break;
+ }
+ /*---------------------------------------------- report the result */
+ return c;
+}
+
+static inline
+void hashword2(
+ const uint32_t *k, /* the key, an array of uint32_t values */
+ size_t length, /* the length of the key, in uint32_ts */
+ uint32_t *pc, /* IN: seed OUT: primary hash value */
+ uint32_t *pb) /* IN: more seed OUT: secondary hash value */
+{
+ uint32_t a, b, c;
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + ((uint32_t) (length << 2)) + *pc;
+ c += *pb;
+
+ /*----------------------------------------- handle most of the key */
+ while (length > 3) {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a, b, c);
+ length -= 3;
+ k += 3;
+ }
+
+ /*----------------------------------- handle the last 3 uint32_t's */
+ switch (length) { /* all the case statements fall through */
+ case 3: c += k[2];
+ case 2: b += k[1];
+ case 1: a += k[0];
+ final(a, b, c);
+ case 0: /* case 0: nothing left to add */
+ break;
+ }
+ /*---------------------------------------------- report the result */
+ *pc = c;
+ *pb = b;
+}
+
+#if (CAA_BITS_PER_LONG == 32)
+static
+unsigned long hash_pointer(const void *_key, unsigned long seed)
+{
+ unsigned int key = (unsigned int) _key;
+
+ return hash_u32(&key, 1, seed);
+}
+#else
+static
+unsigned long hash_pointer(const void *_key, unsigned long seed)
+{
+ union {
+ uint64_t v64;
+ uint32_t v32[2];
+ } v;
+ union {
+ uint64_t v64;
+ uint32_t v32[2];
+ } key;
+
+ v.v64 = (uint64_t) seed;
+ key.v64 = (uint64_t) _key;
+ hashword2(key.v32, 2, &v.v32[0], &v.v32[1]);
+ return v.v64;
+}
+#endif
+
+static
+int match_pointer(struct cds_lfht_node *node, const void *key)
+{
+ struct rcu_ja_shadow_node *shadow =
+ caa_container_of(node, struct rcu_ja_shadow_node, ht_node);
+
+ return (key == shadow->node);
+}
+
+__attribute__((visibility("protected")))
+struct rcu_ja_shadow_node *rcuja_shadow_lookup_lock(struct cds_lfht *ht,
+ struct rcu_ja_node *node)
+{
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *lookup_node;
+ struct rcu_ja_shadow_node *shadow_node;
+ int ret;
+
+ rcu_read_lock();
+ cds_lfht_lookup(ht, hash_pointer(node, hash_seed),
+ match_pointer, node, &iter);
+
+ lookup_node = cds_lfht_iter_get_node(&iter);
+ if (!lookup_node) {
+ shadow_node = NULL;
+ goto rcu_unlock;
+ }
+ shadow_node = caa_container_of(lookup_node,
+ struct rcu_ja_shadow_node, ht_node);
+ ret = pthread_mutex_lock(&shadow_node->lock);
+ assert(!ret);
+ if (cds_lfht_is_node_deleted(lookup_node)) {
+ ret = pthread_mutex_unlock(&shadow_node->lock);
+ assert(!ret);
+ shadow_node = NULL;
+ }
+rcu_unlock:
+ rcu_read_unlock();
+ return shadow_node;
+}
+
+void rcuja_shadow_unlock(struct rcu_ja_shadow_node *shadow_node)
+{
+ int ret;
+
+ ret = pthread_mutex_unlock(&shadow_node->lock);
+ assert(!ret);
+}
+
+__attribute__((visibility("protected")))
+int rcuja_shadow_set(struct cds_lfht *ht,
+ struct rcu_ja_node *node)
+{
+ struct rcu_ja_shadow_node *shadow_node;
+ struct cds_lfht_node *ret_node;
+
+ shadow_node = calloc(sizeof(*shadow_node), 1);
+ if (!shadow_node)
+ return -ENOMEM;
+
+ shadow_node->node = node;
+ pthread_mutex_init(&shadow_node->lock, NULL);
+
+ rcu_read_lock();
+ ret_node = cds_lfht_add_unique(ht,
+ hash_pointer(node, hash_seed),
+ match_pointer,
+ node,
+ &shadow_node->ht_node);
+ rcu_read_unlock();
+
+ if (ret_node != &shadow_node->ht_node) {
+ free(shadow_node);
+ return -EEXIST;
+ }
+ return 0;
+}
+
+static
+void free_shadow_node(struct rcu_head *head)
+{
+ struct rcu_ja_shadow_node *shadow_node =
+ caa_container_of(head, struct rcu_ja_shadow_node, head);
+ free(shadow_node);
+}
+
+__attribute__((visibility("protected")))
+int rcuja_shadow_clear(struct cds_lfht *ht,
+ struct rcu_ja_node *node)
+{
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *lookup_node;
+ struct rcu_ja_shadow_node *shadow_node;
+ int ret, lockret;
+
+ rcu_read_lock();
+ cds_lfht_lookup(ht, hash_pointer(node, hash_seed),
+ match_pointer, node, &iter);
+ lookup_node = cds_lfht_iter_get_node(&iter);
+ if (!lookup_node) {
+ ret = -ENOENT;
+ goto rcu_unlock;
+ }
+ shadow_node = caa_container_of(lookup_node,
+ struct rcu_ja_shadow_node, ht_node);
+ lockret = pthread_mutex_lock(&shadow_node->lock);
+ assert(!lockret);
+
+ /*
+ * Holding the mutex across deletion, and by also re-checking if
+ * the node is deleted with mutex held at lookup ensure that we
+ * don't let RCU JA use a node being removed.
+ */
+ ret = cds_lfht_del(ht, lookup_node);
+ if (!ret) {
+ call_rcu(&shadow_node->head, free_shadow_node);
+ }
+ lockret = pthread_mutex_unlock(&shadow_node->lock);
+ assert(!lockret);
+rcu_unlock:
+ rcu_read_unlock();
+
+ return ret;
+}
+
__attribute__((visibility("protected")))
struct cds_lfht *rcuja_create_ht(void)
{
ret = cds_lfht_destroy(ht, NULL);
assert(!ret);
}
+
+__attribute__((constructor))
+void rcuja_ht_init(void)
+{
+ hash_seed = (unsigned long) time(NULL);
+}
projects / userspace-rcu.git / commitdiff
