#include <stdint.h>
#include <errno.h>
#include <limits.h>
+#include <string.h>
#include <urcu/rcuja.h>
#include <urcu/compiler.h>
#include <urcu/arch.h>
#include "rcuja-internal.h"
#include "bitfield.h"
+#ifndef abs
+#define abs_int(a) ((int) (a) > 0 ? (int) (a) : -((int) (a)))
+#endif
+
enum cds_ja_type_class {
RCU_JA_LINEAR = 0, /* Type A */
/* 32-bit: 1 to 25 children, 8 to 128 bytes */
{ .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
- * filled beyond capacity, we need to roll back to pigeon.
+ * Upon node removal below min_child, if child pool is filled
+ * beyond capacity, we roll back to pigeon.
*/
{ .type_class = RCU_JA_PIGEON, .min_child = 89, .max_child = ja_type_7_max_child, .order = 10, },
{ .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
- * filled beyond capacity, we need to roll back to pigeon.
+ * Upon node removal below min_child, if child pool is filled
+ * beyond capacity, we roll back to pigeon.
*/
{ .type_class = RCU_JA_PIGEON, .min_child = 101, .max_child = ja_type_7_max_child, .order = 11, },
JA_RECOMPACT_DEL,
};
+static
+struct cds_ja_inode *_ja_node_mask_ptr(struct cds_ja_inode_flag *node)
+{
+ return (struct cds_ja_inode *) (((unsigned long) node) & JA_PTR_MASK);
+}
+
+unsigned long ja_node_type(struct cds_ja_inode_flag *node)
+{
+ unsigned long type;
+
+ if (_ja_node_mask_ptr(node) == NULL) {
+ return NODE_INDEX_NULL;
+ }
+ type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
+ assert(type < (1UL << JA_TYPE_BITS));
+ return type;
+}
+
+struct cds_ja_inode *ja_node_ptr(struct cds_ja_inode_flag *node)
+{
+ unsigned long type_index = ja_node_type(node);
+ const struct cds_ja_type *type;
+
+ type = &ja_types[type_index];
+ switch (type->type_class) {
+ case RCU_JA_LINEAR:
+ case RCU_JA_PIGEON: /* fall-through */
+ case RCU_JA_NULL: /* fall-through */
+ default: /* fall-through */
+ return _ja_node_mask_ptr(node);
+ case RCU_JA_POOL:
+ switch (type->nr_pool_order) {
+ case 1:
+ return (struct cds_ja_inode *) (((unsigned long) node) & ~(JA_POOL_1D_MASK | JA_TYPE_MASK));
+ case 2:
+ return (struct cds_ja_inode *) (((unsigned long) node) & ~(JA_POOL_2D_MASK | JA_POOL_1D_MASK | JA_TYPE_MASK));
+ default:
+ assert(0);
+ }
+ }
+}
+
struct cds_ja_inode *alloc_cds_ja_node(const struct cds_ja_type *ja_type)
{
- return calloc(1U << ja_type->order, sizeof(char));
+ size_t len = 1U << ja_type->order;
+ void *p;
+ int ret;
+
+ ret = posix_memalign(&p, len, len);
+ if (ret || !p) {
+ return NULL;
+ }
+ memset(p, 0, len);
+ return p;
}
void free_cds_ja_node(struct cds_ja_inode *node)
struct cds_ja_inode_flag *ja_linear_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
struct cds_ja_inode_flag ***child_node_flag_ptr,
+ struct cds_ja_inode_flag **child_node_flag_v,
struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
ptr = rcu_dereference(pointers[i]);
if (caa_unlikely(child_node_flag_ptr) && ptr)
*child_node_flag_ptr = &pointers[i];
+ if (caa_unlikely(child_node_flag_v) && ptr)
+ *child_node_flag_v = ptr;
if (caa_unlikely(node_flag_ptr))
*node_flag_ptr = &pointers[i];
return ptr;
static
struct cds_ja_inode_flag *ja_pool_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag *node_flag,
struct cds_ja_inode_flag ***child_node_flag_ptr,
+ struct cds_ja_inode_flag **child_node_flag_v,
struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
struct cds_ja_inode *linear;
assert(type->type_class == RCU_JA_POOL);
- /*
- * TODO: currently, we select the pool by highest bits. We
- * should support various encodings.
- */
- linear = (struct cds_ja_inode *)
- &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
+
+ switch (type->nr_pool_order) {
+ case 1:
+ {
+ unsigned long bitsel, index;
+
+ bitsel = ja_node_pool_1d_bitsel(node_flag);
+ assert(bitsel < CHAR_BIT);
+ index = ((unsigned long) n >> bitsel) & type->nr_pool_order;
+ linear = (struct cds_ja_inode *) &node->u.data[index << type->pool_size_order];
+ break;
+ }
+ case 2:
+ {
+ /*
+ * TODO: currently, we select the pool by highest bits. We
+ * should support various encodings.
+ */
+ linear = (struct cds_ja_inode *)
+ &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
+ break;
+ }
+ default:
+ linear = NULL;
+ assert(0);
+ }
return ja_linear_node_get_nth(type, linear, child_node_flag_ptr,
- node_flag_ptr, n);
+ child_node_flag_v, node_flag_ptr, n);
}
static
struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
struct cds_ja_inode_flag ***child_node_flag_ptr,
+ struct cds_ja_inode_flag **child_node_flag_v,
struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
struct cds_ja_inode_flag **child_node_flag;
+ struct cds_ja_inode_flag *child_node_flag_read;
assert(type->type_class == RCU_JA_PIGEON);
child_node_flag = &((struct cds_ja_inode_flag **) node->u.data)[n];
+ child_node_flag_read = rcu_dereference(*child_node_flag);
dbg_printf("ja_pigeon_node_get_nth child_node_flag_ptr %p\n",
child_node_flag);
- if (caa_unlikely(child_node_flag_ptr) && *child_node_flag)
+ if (caa_unlikely(child_node_flag_ptr) && child_node_flag_read)
*child_node_flag_ptr = child_node_flag;
+ if (caa_unlikely(child_node_flag_v) && child_node_flag_read)
+ *child_node_flag_v = child_node_flag_read;
if (caa_unlikely(node_flag_ptr))
*node_flag_ptr = child_node_flag;
- return rcu_dereference(*child_node_flag);
+ return child_node_flag_read;
}
static
struct cds_ja_inode *node,
uint8_t i)
{
- return ja_pigeon_node_get_nth(type, node, NULL, NULL, i);
+ return ja_pigeon_node_get_nth(type, node, NULL, NULL, NULL, i);
}
/*
* node_flag is already rcu_dereference'd.
*/
static
-struct cds_ja_inode_flag * ja_node_get_nth(struct cds_ja_inode_flag *node_flag,
+struct cds_ja_inode_flag *ja_node_get_nth(struct cds_ja_inode_flag *node_flag,
struct cds_ja_inode_flag ***child_node_flag_ptr,
+ struct cds_ja_inode_flag **child_node_flag,
struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
switch (type->type_class) {
case RCU_JA_LINEAR:
return ja_linear_node_get_nth(type, node,
- child_node_flag_ptr, node_flag_ptr, n);
+ child_node_flag_ptr, child_node_flag,
+ node_flag_ptr, n);
case RCU_JA_POOL:
- return ja_pool_node_get_nth(type, node,
- child_node_flag_ptr, node_flag_ptr, n);
+ return ja_pool_node_get_nth(type, node, node_flag,
+ child_node_flag_ptr, child_node_flag,
+ node_flag_ptr, n);
case RCU_JA_PIGEON:
return ja_pigeon_node_get_nth(type, node,
- child_node_flag_ptr, node_flag_ptr, n);
+ child_node_flag_ptr, child_node_flag,
+ node_flag_ptr, n);
default:
assert(0);
return (void *) -1UL;
static
int ja_pool_node_set_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag *node_flag,
struct cds_ja_shadow_node *shadow_node,
uint8_t n,
struct cds_ja_inode_flag *child_node_flag)
struct cds_ja_inode *linear;
assert(type->type_class == RCU_JA_POOL);
- linear = (struct cds_ja_inode *)
- &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
+
+ switch (type->nr_pool_order) {
+ case 1:
+ {
+ unsigned long bitsel, index;
+
+ bitsel = ja_node_pool_1d_bitsel(node_flag);
+ assert(bitsel < CHAR_BIT);
+ index = ((unsigned long) n >> bitsel) & type->nr_pool_order;
+ linear = (struct cds_ja_inode *) &node->u.data[index << type->pool_size_order];
+ break;
+ }
+ case 2:
+ {
+ /*
+ * TODO: currently, we select the pool by highest bits. We
+ * should support various encodings.
+ */
+ linear = (struct cds_ja_inode *)
+ &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
+ break;
+ }
+ default:
+ linear = NULL;
+ assert(0);
+ }
+
return ja_linear_node_set_nth(type, linear, shadow_node,
n, child_node_flag);
}
static
int _ja_node_set_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag *node_flag,
struct cds_ja_shadow_node *shadow_node,
uint8_t n,
struct cds_ja_inode_flag *child_node_flag)
return ja_linear_node_set_nth(type, node, shadow_node, n,
child_node_flag);
case RCU_JA_POOL:
- return ja_pool_node_set_nth(type, node, shadow_node, n,
+ return ja_pool_node_set_nth(type, node, node_flag, shadow_node, n,
child_node_flag);
case RCU_JA_PIGEON:
return ja_pigeon_node_set_nth(type, node, shadow_node, n,
return 0;
}
+/*
+ * Calculate bit distribution. Returns the bit (0 to 7) that splits the
+ * distribution in two sub-distributions containing as much elements one
+ * compared to the other.
+ */
+static
+unsigned int ja_node_sum_distribution_1d(enum ja_recompact mode,
+ struct cds_ja *ja,
+ unsigned int type_index,
+ const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ uint8_t n,
+ struct cds_ja_inode_flag *child_node_flag,
+ struct cds_ja_inode_flag **nullify_node_flag_ptr)
+{
+ uint8_t nr_one[JA_BITS_PER_BYTE];
+ unsigned int bitsel = 0, bit_i, overall_best_distance = UINT_MAX;
+ unsigned int distrib_nr_child = 0;
+
+ memset(nr_one, 0, sizeof(nr_one));
+
+ switch (type->type_class) {
+ case RCU_JA_LINEAR:
+ {
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(type, node);
+ unsigned int i;
+
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+ unsigned int bit;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, node, i, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit = 0; bit < JA_BITS_PER_BYTE; bit++) {
+ if (v & (1U << bit))
+ nr_one[bit]++;
+ }
+ distrib_nr_child++;
+ }
+ break;
+ }
+ case RCU_JA_POOL:
+ {
+ unsigned int pool_nr;
+
+ for (pool_nr = 0; pool_nr < (1U << type->nr_pool_order); pool_nr++) {
+ struct cds_ja_inode *pool =
+ ja_pool_node_get_ith_pool(type,
+ node, pool_nr);
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(type, pool);
+ unsigned int j;
+
+ for (j = 0; j < nr_child; j++) {
+ struct cds_ja_inode_flag *iter;
+ unsigned int bit;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit = 0; bit < JA_BITS_PER_BYTE; bit++) {
+ if (v & (1U << bit))
+ nr_one[bit]++;
+ }
+ distrib_nr_child++;
+ }
+ }
+ break;
+ }
+ case RCU_JA_PIGEON:
+ {
+ uint8_t nr_child;
+ unsigned int i;
+
+ assert(mode == JA_RECOMPACT_DEL);
+ nr_child = shadow_node->nr_child;
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+ unsigned int bit;
+
+ iter = ja_pigeon_node_get_ith_pos(type, node, i);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit = 0; bit < JA_BITS_PER_BYTE; bit++) {
+ if (i & (1U << bit))
+ nr_one[bit]++;
+ }
+ distrib_nr_child++;
+ }
+ break;
+ }
+ case RCU_JA_NULL:
+ assert(mode == JA_RECOMPACT_ADD);
+ break;
+ default:
+ assert(0);
+ break;
+ }
+
+ if (mode == JA_RECOMPACT_ADD) {
+ unsigned int bit;
+
+ for (bit = 0; bit < JA_BITS_PER_BYTE; bit++) {
+ if (n & (1U << bit))
+ nr_one[bit]++;
+ }
+ distrib_nr_child++;
+ }
+
+ /*
+ * The best bit selector is that for which the number of ones is
+ * closest to half of the number of children in the
+ * distribution.
+ */
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ unsigned int distance_to_best;
+
+ distance_to_best = abs_int(nr_one[bit_i] - (distrib_nr_child >> 1U));
+ if (distance_to_best < overall_best_distance) {
+ overall_best_distance = distance_to_best;
+ bitsel = bit_i;
+ }
+ }
+ dbg_printf("1 dimension pool bit selection: (%u)\n", bitsel);
+ return bitsel;
+}
+
/*
* ja_node_recompact_add: recompact a node, adding a new child.
- * TODO: for pool type, take selection bit(s) into account.
* Return 0 on success, -EAGAIN if need to retry, or other negative
* error value otherwise.
*/
new_node = alloc_cds_ja_node(new_type);
if (!new_node)
return -ENOMEM;
- new_node_flag = ja_node_flag(new_node, new_type_index);
+
+ if (new_type->type_class == RCU_JA_POOL) {
+ switch (new_type->nr_pool_order) {
+ case 1:
+ {
+ unsigned int node_distrib_bitsel = 0;
+ node_distrib_bitsel =
+ ja_node_sum_distribution_1d(mode, ja,
+ old_type_index, old_type,
+ old_node, shadow_node,
+ n, child_node_flag,
+ nullify_node_flag_ptr);
+ assert(!((unsigned long) new_node & JA_POOL_1D_MASK));
+ new_node_flag = ja_node_flag_pool_1d(new_node,
+ new_type_index, node_distrib_bitsel);
+ break;
+ }
+ case 2:
+ {
+ /* TODO: pool order 2 in 2d */
+ assert(!((unsigned long) new_node & JA_POOL_1D_MASK));
+ assert(!((unsigned long) new_node & JA_POOL_2D_MASK));
+ new_node_flag = ja_node_flag(new_node, new_type_index);
+ break;
+ }
+ default:
+ assert(0);
+ }
+ } else {
+ new_node_flag = ja_node_flag(new_node, new_type_index);
+ }
+
dbg_printf("Recompact inherit lock from %p\n", shadow_node);
new_shadow_node = rcuja_shadow_set(ja->ht, new_node_flag, shadow_node, ja);
if (!new_shadow_node) {
continue;
if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
continue;
- ret = _ja_node_set_nth(new_type, new_node,
+ ret = _ja_node_set_nth(new_type, new_node, new_node_flag,
new_shadow_node,
v, iter);
if (new_type->type_class == RCU_JA_POOL && ret) {
continue;
if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
continue;
- ret = _ja_node_set_nth(new_type, new_node,
+ ret = _ja_node_set_nth(new_type, new_node, new_node_flag,
new_shadow_node,
v, iter);
if (new_type->type_class == RCU_JA_POOL
continue;
if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
continue;
- ret = _ja_node_set_nth(new_type, new_node,
+ ret = _ja_node_set_nth(new_type, new_node, new_node_flag,
new_shadow_node,
i, iter);
if (new_type->type_class == RCU_JA_POOL && ret) {
if (mode == JA_RECOMPACT_ADD) {
/* add node */
- ret = _ja_node_set_nth(new_type, new_node,
+ ret = _ja_node_set_nth(new_type, new_node, new_node_flag,
new_shadow_node,
n, child_node_flag);
+ if (new_type->type_class == RCU_JA_POOL && ret) {
+ goto fallback_toosmall;
+ }
assert(!ret);
}
/* Return pointer to new recompacted node through old_node_flag_ptr */
node = ja_node_ptr(*node_flag);
type_index = ja_node_type(*node_flag);
type = &ja_types[type_index];
- ret = _ja_node_set_nth(type, node, shadow_node,
+ ret = _ja_node_set_nth(type, node, *node_flag, shadow_node,
n, child_node_flag);
switch (ret) {
case -ENOSPC:
uint8_t iter_key;
iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1)));
- node_flag = ja_node_get_nth(node_flag, NULL, NULL,
+ node_flag = ja_node_get_nth(node_flag, NULL, NULL, NULL,
iter_key);
dbg_printf("cds_ja_lookup iter key lookup %u finds node_flag %p\n",
(unsigned int) iter_key, node_flag);
static
int ja_attach_node(struct cds_ja *ja,
struct cds_ja_inode_flag **attach_node_flag_ptr,
+ struct cds_ja_inode_flag *attach_node_flag,
struct cds_ja_inode_flag **node_flag_ptr,
struct cds_ja_inode_flag *node_flag,
struct cds_ja_inode_flag *parent_node_flag,
if (node_flag_ptr && ja_node_ptr(*node_flag_ptr)) {
/*
- * Target node is non-NULL: it has been updated between
- * RCU lookup and lock acquisition. We need to re-try
- * lookup and attach.
+ * Target node has been updated between RCU lookup and
+ * lock acquisition. We need to re-try lookup and
+ * attach.
+ */
+ ret = -EAGAIN;
+ goto unlock_parent;
+ }
+
+ if (attach_node_flag_ptr && ja_node_ptr(*attach_node_flag_ptr) !=
+ ja_node_ptr(attach_node_flag)) {
+ /*
+ * Target node has been updated between RCU lookup and
+ * lock acquisition. We need to re-try lookup and
+ * attach.
*/
ret = -EAGAIN;
goto unlock_parent;
int ja_chain_node(struct cds_ja *ja,
struct cds_ja_inode_flag *parent_node_flag,
struct cds_ja_inode_flag **node_flag_ptr,
+ struct cds_ja_inode_flag *node_flag,
struct cds_hlist_head *head,
struct cds_ja_node *node)
{
if (!shadow_node) {
return -EAGAIN;
}
- if (!ja_node_ptr(*node_flag_ptr)) {
+ if (ja_node_ptr(*node_flag_ptr) != ja_node_ptr(node_flag)) {
ret = -EAGAIN;
goto end;
}
**node_flag_ptr;
struct cds_ja_inode_flag *node_flag,
*parent_node_flag,
- *parent2_node_flag;
+ *parent2_node_flag,
+ *attach_node_flag;
int ret;
if (caa_unlikely(key > ja->key_max)) {
parent_node_flag =
(struct cds_ja_inode_flag *) &ja->root; /* Use root ptr address as key for mutex */
attach_node_flag_ptr = &ja->root;
+ attach_node_flag = rcu_dereference(ja->root);
node_flag_ptr = &ja->root;
node_flag = rcu_dereference(ja->root);
uint8_t iter_key;
dbg_printf("cds_ja_add iter attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
- *attach_node_flag_ptr, *node_flag_ptr, node_flag);
+ attach_node_flag_ptr, node_flag_ptr, node_flag);
if (!ja_node_ptr(node_flag)) {
ret = ja_attach_node(ja, attach_node_flag_ptr,
+ attach_node_flag,
node_flag_ptr,
- parent_node_flag, parent2_node_flag,
+ parent_node_flag,
+ parent2_node_flag,
key, i, new_node);
if (ret == -EAGAIN || ret == -EEXIST)
goto retry;
parent_node_flag = node_flag;
node_flag = ja_node_get_nth(node_flag,
&attach_node_flag_ptr,
+ &attach_node_flag,
&node_flag_ptr,
iter_key);
dbg_printf("cds_ja_add iter key lookup %u finds node_flag %p attach_node_flag_ptr %p node_flag_ptr %p\n",
(unsigned int) iter_key, node_flag,
- *attach_node_flag_ptr,
- *node_flag_ptr);
+ attach_node_flag_ptr,
+ node_flag_ptr);
}
/*
* level, or chain it if key is already present.
*/
if (!ja_node_ptr(node_flag)) {
- dbg_printf("cds_ja_add last attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
- *attach_node_flag_ptr, *node_flag_ptr, node_flag);
+ dbg_printf("cds_ja_add attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
+ attach_node_flag_ptr, node_flag_ptr, node_flag);
ret = ja_attach_node(ja, attach_node_flag_ptr,
+ attach_node_flag,
node_flag_ptr, parent_node_flag,
parent2_node_flag, key, i, new_node);
} else {
ret = ja_chain_node(ja,
parent_node_flag,
node_flag_ptr,
+ node_flag,
(struct cds_hlist_head *) attach_node_flag_ptr,
new_node);
}
ret = -EAGAIN;
goto end;
}
- assert(shadow_node->nr_child > 0);
shadow_nodes[nr_shadow++] = shadow_node;
+
+ /*
+ * Check if node has been removed between RCU
+ * lookup and lock acquisition.
+ */
+ assert(snapshot_ptr[i + 1]);
+ if (ja_node_ptr(*snapshot_ptr[i + 1])
+ != ja_node_ptr(snapshot[i + 1])) {
+ ret = -ENOENT;
+ goto end;
+ }
+
+ assert(shadow_node->nr_child > 0);
if (shadow_node->nr_child == 1 && i > 1)
nr_clear++;
nr_branch++;
goto end;
}
shadow_nodes[nr_shadow++] = shadow_node;
+
+ /*
+ * Check if node has been removed between RCU
+ * lookup and lock acquisition.
+ */
+ assert(snapshot_ptr[i]);
+ if (ja_node_ptr(*snapshot_ptr[i])
+ != ja_node_ptr(snapshot[i])) {
+ ret = -ENOENT;
+ goto end;
+ }
+
node_flag_ptr = snapshot_ptr[i + 1];
n = snapshot_n[i + 1];
parent_node_flag_ptr = snapshot_ptr[i];
parent_node_flag = snapshot[i];
+
if (i > 1) {
/*
* Lock parent's parent, in case we need
goto end;
}
shadow_nodes[nr_shadow++] = shadow_node;
+
+ /*
+ * Check if node has been removed between RCU
+ * lookup and lock acquisition.
+ */
+ assert(snapshot_ptr[i - 1]);
+ if (ja_node_ptr(*snapshot_ptr[i - 1])
+ != ja_node_ptr(snapshot[i - 1])) {
+ ret = -ENOENT;
+ goto end;
+ }
}
+
break;
}
}
- /*
- * Check if node has been removed between RCU lookup and lock
- * acquisition.
- */
- assert(node_flag_ptr);
- if (!ja_node_ptr(*node_flag_ptr)) {
- ret = -ENOENT;
- goto end;
- }
-
/*
* At this point, we want to delete all nodes that are about to
* be removed from shadow_nodes (except the last one, which is
* either the root or the parent of the upmost node with 1
- * child). OK to as to free lock here, because RCU read lock is
- * held, and free only performed in call_rcu.
+ * child). OK to free lock here, because RCU read lock is held,
+ * and free only performed in call_rcu.
*/
for (i = 0; i < nr_clear; i++) {
int ja_unchain_node(struct cds_ja *ja,
struct cds_ja_inode_flag *parent_node_flag,
struct cds_ja_inode_flag **node_flag_ptr,
- struct cds_hlist_head *head,
+ struct cds_ja_inode_flag *node_flag,
struct cds_ja_node *node)
{
struct cds_ja_shadow_node *shadow_node;
struct cds_hlist_node *hlist_node;
- int ret = 0, count = 0;
+ struct cds_hlist_head hlist_head;
+ int ret = 0, count = 0, found = 0;
shadow_node = rcuja_shadow_lookup_lock(ja->ht, parent_node_flag);
if (!shadow_node)
return -EAGAIN;
- if (!ja_node_ptr(*node_flag_ptr)) {
+ if (ja_node_ptr(*node_flag_ptr) != ja_node_ptr(node_flag)) {
ret = -EAGAIN;
goto end;
}
+ hlist_head.next = (struct cds_hlist_node *) ja_node_ptr(node_flag);
/*
* Retry if another thread removed all but one of duplicates
* since check (this check was performed without lock).
+ * Ensure that the node we are about to remove is still in the
+ * list (while holding lock).
*/
- cds_hlist_for_each_rcu(hlist_node, head, list) {
+ cds_hlist_for_each_rcu(hlist_node, &hlist_head) {
+ if (count == 0) {
+ /* FIXME: currently a work-around */
+ hlist_node->prev = (struct cds_hlist_node *) node_flag_ptr;
+ }
count++;
+ if (hlist_node == &node->list)
+ found++;
}
-
- if (count == 1) {
+ assert(found <= 1);
+ if (!found || count == 1) {
ret = -EAGAIN;
goto end;
}
cds_hlist_del_rcu(&node->list);
+ /*
+ * Validate that we indeed removed the node from linked list.
+ */
+ assert(ja_node_ptr(*node_flag_ptr) != (struct cds_ja_inode *) node);
end:
rcuja_shadow_unlock(shadow_node);
return ret;
snapshot[nr_snapshot++] = node_flag;
node_flag = ja_node_get_nth(node_flag,
&prev_node_flag_ptr,
+ NULL,
&node_flag_ptr,
iter_key);
dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p, prev_node_flag_ptr %p\n",
(unsigned int) iter_key, node_flag,
prev_node_flag_ptr);
}
-
/*
* We reached bottom of tree, try to find the node we are trying
* to remove. Fail if we cannot find it.
snapshot_n, nr_snapshot, key, node);
} else {
ret = ja_unchain_node(ja, snapshot[nr_snapshot - 1],
- node_flag_ptr, &hlist_head, match);
+ node_flag_ptr, node_flag, match);
}
}
/*
projects / urcu.git / blobdiff