/*
- * Copyright (c) 2009 Nicira Networks.
+ * Copyright (c) 2009, 2010, 2011 Nicira Networks.
* Distributed under the terms of the GNU GPL version 2.
*
* Significant portions of this file may be copied from parts of the Linux
#include "flow.h"
#include "datapath.h"
+#include "table.h"
+#include <linux/genetlink.h>
#include <linux/gfp.h>
-#include <linux/jhash.h>
-#include <linux/random.h>
#include <linux/slab.h>
-#include <linux/vmalloc.h>
#include <linux/mm.h>
-#include <linux/highmem.h>
#include <asm/pgtable.h>
-static inline int bucket_size(int n_flows)
+/**
+ * struct tbl_bucket - single bucket within a hash table
+ * @rcu: RCU callback structure
+ * @n_objs: number of objects in @objs[] array
+ * @objs: array of @n_objs pointers to table nodes contained inside objects
+ *
+ * The expected number of objects per bucket is 1, but this allows for an
+ * arbitrary number of collisions.
+ */
+struct tbl_bucket {
+ struct rcu_head rcu;
+ unsigned int n_objs;
+ struct tbl_node *objs[];
+};
+
+static struct tbl_bucket *get_bucket(struct tbl_bucket __rcu *bucket)
{
- return sizeof(struct dp_bucket) + sizeof(struct sw_flow*) * n_flows;
+ return rcu_dereference_check(bucket, rcu_read_lock_held() ||
+ lockdep_genl_is_held());
}
-static struct dp_bucket *dp_bucket_alloc(int n_flows)
+static struct tbl_bucket *get_bucket_protected(struct tbl_bucket __rcu *bucket)
{
- return kmalloc(bucket_size(n_flows), GFP_KERNEL);
+ return rcu_dereference_protected(bucket, lockdep_genl_is_held());
}
-static void free_buckets(struct dp_bucket ***l1, unsigned int n_buckets,
- int free_flows)
+static inline int bucket_size(int n_objs)
+{
+ return sizeof(struct tbl_bucket) + sizeof(struct tbl_node *) * n_objs;
+}
+
+static struct tbl_bucket *bucket_alloc(int n_objs)
+{
+ return kmalloc(bucket_size(n_objs), GFP_KERNEL);
+}
+
+static void free_buckets(struct tbl_bucket __rcu ***l1,
+ unsigned int n_buckets,
+ void (*free_obj)(struct tbl_node *))
{
unsigned int i;
- for (i = 0; i < n_buckets >> DP_L1_BITS; i++) {
- struct dp_bucket **l2 = l1[i];
+ for (i = 0; i < n_buckets >> TBL_L1_SHIFT; i++) {
+ struct tbl_bucket __rcu **l2 = l1[i];
unsigned int j;
- for (j = 0; j < DP_L1_SIZE; j++) {
- struct dp_bucket *bucket = l2[j];
+ for (j = 0; j < TBL_L2_SIZE; j++) {
+ struct tbl_bucket *bucket = (struct tbl_bucket __force *)l2[j];
if (!bucket)
continue;
- if (free_flows) {
+ if (free_obj) {
unsigned int k;
- for (k = 0; k < bucket->n_flows; k++)
- flow_free(bucket->flows[k]);
+ for (k = 0; k < bucket->n_objs; k++)
+ free_obj(bucket->objs[k]);
}
kfree(bucket);
}
kfree(l1);
}
-static struct dp_bucket ***alloc_buckets(unsigned int n_buckets)
+static struct tbl_bucket __rcu ***alloc_buckets(unsigned int n_buckets)
{
- struct dp_bucket ***l1;
+ struct tbl_bucket __rcu ***l1;
unsigned int i;
- l1 = kmalloc((n_buckets >> DP_L1_BITS) * sizeof(struct dp_bucket**),
+ l1 = kmalloc((n_buckets >> TBL_L1_SHIFT) * sizeof(struct tbl_bucket **),
GFP_KERNEL);
if (!l1)
return NULL;
- for (i = 0; i < n_buckets >> DP_L1_BITS; i++) {
- l1[i] = (struct dp_bucket **)get_zeroed_page(GFP_KERNEL);
+ for (i = 0; i < n_buckets >> TBL_L1_SHIFT; i++) {
+ l1[i] = (struct tbl_bucket __rcu **)get_zeroed_page(GFP_KERNEL);
if (!l1[i]) {
- free_buckets(l1, i << DP_L1_BITS, 0);
+ free_buckets(l1, i << TBL_L1_SHIFT, NULL);
return NULL;
}
}
}
/**
- * dp_table_create - create and return a new flow table
+ * tbl_create - create and return a new hash table
* @n_buckets: number of buckets in the new table
*
- * Creates and returns a new flow table, or %NULL if memory cannot be
- * allocated. @n_buckets must be a power of 2 in the range %DP_L1_SIZE to
- * %DP_MAX_BUCKETS.
+ * Creates and returns a new hash table, or %NULL if memory cannot be
+ * allocated. @n_buckets must be a power of 2 in the range %TBL_MIN_BUCKETS to
+ * %TBL_MAX_BUCKETS.
*/
-struct dp_table *dp_table_create(unsigned int n_buckets)
+struct tbl *tbl_create(unsigned int n_buckets)
{
- struct dp_table *table;
+ struct tbl *table;
- table = kzalloc(sizeof *table, GFP_KERNEL);
+ table = kzalloc(sizeof(*table), GFP_KERNEL);
if (!table)
goto err;
table->buckets = alloc_buckets(n_buckets);
if (!table->buckets)
goto err_free_table;
- get_random_bytes(&table->hash_seed, sizeof table->hash_seed);
return table;
}
/**
- * dp_table_destroy - destroy flow table and optionally the flows it contains
- * @table: table to destroy (must not be %NULL)
- * @free_flows: whether to destroy the flows
+ * tbl_destroy - destroy hash table and optionally the objects it contains
+ * @table: table to destroy
+ * @destructor: function to be called on objects at destruction time
*
- * If @free_flows is zero, then the buckets in @table are destroyed but not the
- * flows within those buckets. This behavior is useful when a table is being
- * replaced by a larger or smaller one without destroying the flows.
+ * If a destructor is null, then the buckets in @table are destroyed
+ * but not the objects within those buckets. This behavior is useful when a
+ * table is being replaced by a larger or smaller one without destroying the
+ * objects.
*
- * If @free_flows is nonzero, then the flows in @table are destroyed as well as
- * the buckets.
+ * If a destructor is not null, then it is called on the objects in @table
+ * before destroying the buckets.
*/
-void dp_table_destroy(struct dp_table *table, int free_flows)
+void tbl_destroy(struct tbl *table, void (*destructor)(struct tbl_node *))
{
- free_buckets(table->buckets, table->n_buckets, free_flows);
+ if (!table)
+ return;
+
+ free_buckets(table->buckets, table->n_buckets, destructor);
kfree(table);
}
-static struct dp_bucket **find_bucket(struct dp_table *table, u32 hash)
+static void destroy_table_rcu(struct rcu_head *rcu)
+{
+ struct tbl *table = container_of(rcu, struct tbl, rcu);
+ tbl_destroy(table, table->obj_destructor);
+}
+
+/**
+ * tbl_deferred_destroy - destroy table after a RCU grace period
+ * @table: table to destroy
+ * @destructor: function to be called on objects at destruction time
+ *
+ * Calls tbl_destroy() on @table after an RCU grace period. If @destructor is
+ * not null it is called on every element before the table is destroyed. */
+void tbl_deferred_destroy(struct tbl *table, void (*destructor)(struct tbl_node *))
+{
+ if (!table)
+ return;
+
+ table->obj_destructor = destructor;
+ call_rcu(&table->rcu, destroy_table_rcu);
+}
+
+static struct tbl_bucket __rcu **find_bucket(struct tbl *table, u32 hash)
{
- unsigned int l1 = (hash & (table->n_buckets - 1)) >> DP_L1_SHIFT;
- unsigned int l2 = hash & ((1 << DP_L2_BITS) - 1);
+ unsigned int l1 = (hash & (table->n_buckets - 1)) >> TBL_L1_SHIFT;
+ unsigned int l2 = hash & ((1 << TBL_L2_BITS) - 1);
return &table->buckets[l1][l2];
}
-static int search_bucket(const struct dp_bucket *bucket, const struct odp_flow_key *key)
+static int search_bucket(const struct tbl_bucket *bucket, void *target, int len, u32 hash,
+ int (*cmp)(const struct tbl_node *, void *, int len))
{
int i;
- for (i = 0; i < bucket->n_flows; i++) {
- struct sw_flow *flow = rcu_dereference(bucket->flows[i]);
- if (!memcmp(&flow->key, key, sizeof(struct odp_flow_key)))
+ for (i = 0; i < bucket->n_objs; i++) {
+ struct tbl_node *obj = bucket->objs[i];
+ if (obj->hash == hash && likely(cmp(obj, target, len)))
return i;
}
return -1;
}
-static struct sw_flow *lookup_flow(struct dp_table *table, u32 hash,
- const struct odp_flow_key *key)
+/**
+ * tbl_lookup - searches hash table for a matching object
+ * @table: hash table to search
+ * @target: identifier for the object that is being searched for, will be
+ * provided as an argument to @cmp when making comparisions
+ * @len: length of @target in bytes, will be provided as an argument to @cmp
+ * when making comparisons
+ * @hash: hash of @target
+ * @cmp: comparision function to match objects with the given hash, returns
+ * nonzero if the objects match, zero otherwise
+ *
+ * Searches @table for an object identified by @target. Returns the tbl_node
+ * contained in the object if successful, otherwise %NULL.
+ */
+struct tbl_node *tbl_lookup(struct tbl *table, void *target, int len, u32 hash,
+ int (*cmp)(const struct tbl_node *, void *, int))
{
- struct dp_bucket **bucketp = find_bucket(table, hash);
- struct dp_bucket *bucket = rcu_dereference(*bucketp);
+ struct tbl_bucket __rcu **bucketp = find_bucket(table, hash);
+ struct tbl_bucket *bucket = get_bucket(*bucketp);
int index;
if (!bucket)
return NULL;
- index = search_bucket(bucket, key);
+ index = search_bucket(bucket, target, len, hash, cmp);
if (index < 0)
return NULL;
- return bucket->flows[index];
-}
-
-static u32 flow_hash(const struct dp_table *table,
- const struct odp_flow_key *key)
-{
- return jhash2((u32*)key, sizeof *key / sizeof(u32), table->hash_seed);
-}
-
-/**
- * dp_table_lookup - searches flow table for a matching flow
- * @table: flow table to search
- * @key: flow key for which to search
- *
- * Searches @table for a flow whose key is equal to @key. Returns the flow if
- * successful, otherwise %NULL.
- */
-struct sw_flow *dp_table_lookup(struct dp_table *table,
- const struct odp_flow_key *key)
-{
- return lookup_flow(table, flow_hash(table, key), key);
+ return bucket->objs[index];
}
/**
- * dp_table_foreach - iterate through flow table
+ * tbl_foreach - iterate through hash table
* @table: table to iterate
- * @callback: function to call for each flow entry
+ * @callback: function to call for each entry
* @aux: Extra data to pass to @callback
*
- * Iterates through all of the flows in @table in hash order, passing each of
+ * Iterates through all of the objects in @table in hash order, passing each of
* them in turn to @callback. If @callback returns nonzero, this terminates
- * the iteration and dp_table_foreach() returns the same value. Returns 0 if
+ * the iteration and tbl_foreach() returns the same value. Returns 0 if
* @callback never returns nonzero.
*
* This function does not try to intelligently handle the case where @callback
* adds or removes flows in @table.
*/
-int dp_table_foreach(struct dp_table *table,
- int (*callback)(struct sw_flow *flow, void *aux),
- void *aux)
+int tbl_foreach(struct tbl *table,
+ int (*callback)(struct tbl_node *, void *aux), void *aux)
{
- unsigned int i, j, k;
- for (i = 0; i < table->n_buckets >> DP_L1_BITS; i++) {
- struct dp_bucket **l2 = table->buckets[i];
- for (j = 0; j < DP_L1_SIZE; j++) {
- struct dp_bucket *bucket = rcu_dereference(l2[j]);
+ unsigned int n_l1 = table->n_buckets >> TBL_L1_SHIFT;
+ unsigned int l1_idx;
+
+ for (l1_idx = 0; l1_idx < n_l1; l1_idx++) {
+ struct tbl_bucket __rcu **l2 = table->buckets[l1_idx];
+ unsigned int l2_idx;
+
+ for (l2_idx = 0; l2_idx < TBL_L2_SIZE; l2_idx++) {
+ struct tbl_bucket *bucket;
+ unsigned int i;
+
+ bucket = get_bucket(l2[l2_idx]);
if (!bucket)
continue;
- for (k = 0; k < bucket->n_flows; k++) {
- int error = (*callback)(bucket->flows[k], aux);
+ for (i = 0; i < bucket->n_objs; i++) {
+ int error = (*callback)(bucket->objs[i], aux);
if (error)
return error;
}
return 0;
}
-static int insert_flow(struct sw_flow *flow, void *new_table_)
+/**
+ * tbl_next - find next node in hash table
+ * @table: table to iterate
+ * @bucketp: On entry, hash value of bucket to start from. On exit, updated
+ * to bucket to start from on next call.
+ * @objp: On entry, index to start from within first bucket. On exit, updated
+ * to index to start from on next call.
+ *
+ * Returns the next node in @table in hash order, or %NULL when no nodes remain
+ * in the hash table.
+ *
+ * On entry, uses the values that @bucketp and @objp reference to determine
+ * where to begin iteration. Use 0 for both values to begin a new iteration.
+ * On exit, stores the values to pass on the next iteration into @bucketp and
+ * @objp's referents.
+ */
+struct tbl_node *tbl_next(struct tbl *table, u32 *bucketp, u32 *objp)
{
- struct dp_table *new_table = new_table_;
- return dp_table_insert(new_table, flow);
+ unsigned int n_l1 = table->n_buckets >> TBL_L1_SHIFT;
+ u32 s_l1_idx = *bucketp >> TBL_L1_SHIFT;
+ u32 s_l2_idx = *bucketp & (TBL_L2_SIZE - 1);
+ u32 s_obj = *objp;
+ unsigned int l1_idx;
+
+ for (l1_idx = s_l1_idx; l1_idx < n_l1; l1_idx++) {
+ struct tbl_bucket __rcu **l2 = table->buckets[l1_idx];
+ unsigned int l2_idx;
+
+ for (l2_idx = s_l2_idx; l2_idx < TBL_L2_SIZE; l2_idx++) {
+ struct tbl_bucket *bucket;
+
+ bucket = get_bucket_protected(l2[l2_idx]);
+ if (bucket && s_obj < bucket->n_objs) {
+ *bucketp = (l1_idx << TBL_L1_SHIFT) + l2_idx;
+ *objp = s_obj + 1;
+ return bucket->objs[s_obj];
+ }
+
+ s_obj = 0;
+ }
+ s_l2_idx = 0;
+ }
+ *bucketp = 0;
+ *objp = 0;
+ return NULL;
}
-static void dp_free_table_rcu(struct rcu_head *rcu)
+static int insert_table_flow(struct tbl_node *node, void *new_table_)
{
- struct dp_table *table = container_of(rcu, struct dp_table, rcu);
- dp_table_destroy(table, 0);
+ struct tbl *new_table = new_table_;
+ return tbl_insert(new_table, node, node->hash);
}
/**
- * dp_table_expand - replace datapath's flow table by one with more buckets
- * @dp: datapath to expand
+ * tbl_expand - create a hash table with more buckets
+ * @table: table to expand
*
- * Replaces @dp's flow table by one that has twice as many buckets. All of the
- * flows in @dp's flow table are moved to the new flow table. Returns 0 if
- * successful, otherwise a negative error.
+ * Creates a new table containing the same objects as @table but with twice
+ * as many buckets. Returns 0 if successful, otherwise a negative error. The
+ * caller should free @table upon success (probably using
+ * tbl_deferred_destroy()).
*/
-int dp_table_expand(struct datapath *dp)
+struct tbl *tbl_expand(struct tbl *table)
{
- struct dp_table *old_table = rcu_dereference(dp->table);
- struct dp_table *new_table;
+ int err;
+ int n_buckets = table->n_buckets * 2;
+ struct tbl *new_table;
- new_table = dp_table_create(old_table->n_buckets * 2);
+ if (n_buckets > TBL_MAX_BUCKETS) {
+ err = -ENOSPC;
+ goto error;
+ }
+
+ err = -ENOMEM;
+ new_table = tbl_create(n_buckets);
if (!new_table)
goto error;
- if (dp_table_foreach(old_table, insert_flow, new_table))
+ if (tbl_foreach(table, insert_table_flow, new_table))
goto error_free_new_table;
- rcu_assign_pointer(dp->table, new_table);
- call_rcu(&old_table->rcu, dp_free_table_rcu);
- return 0;
+ return new_table;
error_free_new_table:
- dp_table_destroy(new_table, 0);
+ tbl_destroy(new_table, NULL);
error:
- return -ENOMEM;
-}
-
-static void dp_free_table_and_flows_rcu(struct rcu_head *rcu)
-{
- struct dp_table *table = container_of(rcu, struct dp_table, rcu);
- dp_table_destroy(table, 1);
+ return ERR_PTR(err);
}
/**
- * dp_table_flush - clear datapath's flow table
- * @dp: datapath to clear
+ * tbl_n_buckets - returns the number of buckets
+ * @table: table to examine
*
- * Replaces @dp's flow table by an empty flow table, destroying all the flows
- * in the old table (after a suitable RCU grace period).
+ * Returns the number of buckets currently allocated in @table, useful when
+ * deciding whether to expand.
*/
-int dp_table_flush(struct datapath *dp)
+int tbl_n_buckets(struct tbl *table)
{
- struct dp_table *old_table = rcu_dereference(dp->table);
- struct dp_table *new_table = dp_table_create(DP_L1_SIZE);
- if (!new_table)
- return -ENOMEM;
- rcu_assign_pointer(dp->table, new_table);
- call_rcu(&old_table->rcu, dp_free_table_and_flows_rcu);
- return 0;
+ return table->n_buckets;
}
-static void dp_free_bucket_rcu(struct rcu_head *rcu)
+static void free_bucket_rcu(struct rcu_head *rcu)
{
- struct dp_bucket *bucket = container_of(rcu, struct dp_bucket, rcu);
+ struct tbl_bucket *bucket = container_of(rcu, struct tbl_bucket, rcu);
kfree(bucket);
}
/**
- * dp_table_insert - insert flow into table
- * @table: table in which to insert flow
- * @target: flow to insert
+ * tbl_insert - insert object into table
+ * @table: table in which to insert object
+ * @target: tbl_node contained in object to insert
+ * @hash: hash of object to insert
*
- * The caller must ensure that no flow with key identical to @target->key
+ * The caller must ensure that no object considered to be identical to @target
* already exists in @table. Returns 0 or a negative error (currently just
* -ENOMEM).
- *
- * The caller is responsible for updating &struct datapath's n_flows member.
*/
-int dp_table_insert(struct dp_table *table, struct sw_flow *target)
+int tbl_insert(struct tbl *table, struct tbl_node *target, u32 hash)
{
- u32 hash = flow_hash(table, &target->key);
- struct dp_bucket **oldp = find_bucket(table, hash);
- struct dp_bucket *old = *rcu_dereference(oldp);
- unsigned int n = old ? old->n_flows : 0;
- struct dp_bucket *new = dp_bucket_alloc(n + 1);
+ struct tbl_bucket __rcu **oldp = find_bucket(table, hash);
+ struct tbl_bucket *old = get_bucket_protected(*oldp);
+ unsigned int n = old ? old->n_objs : 0;
+ struct tbl_bucket *new = bucket_alloc(n + 1);
if (!new)
return -ENOMEM;
- new->n_flows = n + 1;
+ target->hash = hash;
+
+ new->n_objs = n + 1;
if (old)
- memcpy(new->flows, old->flows, n * sizeof(struct sw_flow*));
- new->flows[n] = target;
+ memcpy(new->objs, old->objs, n * sizeof(struct tbl_node *));
+ new->objs[n] = target;
rcu_assign_pointer(*oldp, new);
if (old)
- call_rcu(&old->rcu, dp_free_bucket_rcu);
+ call_rcu(&old->rcu, free_bucket_rcu);
+
+ table->count++;
return 0;
}
/**
- * dp_table_delete - remove flow from table
- * @table: table from which to remove flow
- * @target: flow to remove
+ * tbl_remove - remove object from table
+ * @table: table from which to remove object
+ * @target: tbl_node inside of object to remove
*
* The caller must ensure that @target itself is in @table. (It is not
- * good enough for @table to contain a different flow with a key equal to
- * @target's key.)
+ * good enough for @table to contain a different object considered identical
+ * @target.)
*
* Returns 0 or a negative error (currently just -ENOMEM). Yes, it *is*
- * possible for a flow deletion to fail due to lack of memory.
- *
- * The caller is responsible for updating &struct datapath's n_flows member.
+ * possible for object deletion to fail due to lack of memory.
*/
-int dp_table_delete(struct dp_table *table, struct sw_flow *target)
+int tbl_remove(struct tbl *table, struct tbl_node *target)
{
- u32 hash = flow_hash(table, &target->key);
- struct dp_bucket **oldp = find_bucket(table, hash);
- struct dp_bucket *old = *rcu_dereference(oldp);
- unsigned int n = old->n_flows;
- struct dp_bucket *new;
+ struct tbl_bucket __rcu **oldp = find_bucket(table, target->hash);
+ struct tbl_bucket *old = get_bucket_protected(*oldp);
+ unsigned int n = old->n_objs;
+ struct tbl_bucket *new;
if (n > 1) {
unsigned int i;
- new = dp_bucket_alloc(n - 1);
+ new = bucket_alloc(n - 1);
if (!new)
return -ENOMEM;
- new->n_flows = 0;
+ new->n_objs = 0;
for (i = 0; i < n; i++) {
- struct sw_flow *flow = old->flows[i];
- if (flow != target)
- new->flows[new->n_flows++] = flow;
+ struct tbl_node *obj = old->objs[i];
+ if (obj != target)
+ new->objs[new->n_objs++] = obj;
}
- WARN_ON_ONCE(new->n_flows != n - 1);
+ WARN_ON_ONCE(new->n_objs != n - 1);
} else {
new = NULL;
}
rcu_assign_pointer(*oldp, new);
- call_rcu(&old->rcu, dp_free_bucket_rcu);
+ call_rcu(&old->rcu, free_bucket_rcu);
+
+ table->count--;
return 0;
}
+
+/**
+ * tbl_count - retrieves the number of stored objects
+ * @table: table to count
+ *
+ * Returns the number of objects that have been inserted into the hash table.
+ */
+unsigned int tbl_count(struct tbl *table)
+{
+ return table->count;
+}
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