aboutsummaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
Diffstat (limited to 'lib')
-rw-r--r--lib/rhashtable.c141
-rw-r--r--lib/test_rhashtable.c2
2 files changed, 71 insertions, 72 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index b28fdd560ea9..c5d0974467ee 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -31,11 +31,10 @@
#define HASH_DEFAULT_SIZE 64UL
#define HASH_MIN_SIZE 4U
-#define BUCKET_LOCKS_PER_CPU 32UL
union nested_table {
union nested_table __rcu *table;
- struct rhash_head __rcu *bucket;
+ struct rhash_lock_head __rcu *bucket;
};
static u32 head_hashfn(struct rhashtable *ht,
@@ -56,9 +55,11 @@ EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash)
{
- spinlock_t *lock = rht_bucket_lock(tbl, hash);
-
- return (debug_locks) ? lockdep_is_held(lock) : 1;
+ if (!debug_locks)
+ return 1;
+ if (unlikely(tbl->nest))
+ return 1;
+ return bit_spin_is_locked(1, (unsigned long *)&tbl->buckets[hash]);
}
EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
#else
@@ -104,7 +105,6 @@ static void bucket_table_free(const struct bucket_table *tbl)
if (tbl->nest)
nested_bucket_table_free(tbl);
- free_bucket_spinlocks(tbl->locks);
kvfree(tbl);
}
@@ -171,7 +171,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
gfp_t gfp)
{
struct bucket_table *tbl = NULL;
- size_t size, max_locks;
+ size_t size;
int i;
size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
@@ -189,16 +189,6 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
tbl->size = size;
- max_locks = size >> 1;
- if (tbl->nest)
- max_locks = min_t(size_t, max_locks, 1U << tbl->nest);
-
- if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask, max_locks,
- ht->p.locks_mul, gfp) < 0) {
- bucket_table_free(tbl);
- return NULL;
- }
-
rcu_head_init(&tbl->rcu);
INIT_LIST_HEAD(&tbl->walkers);
@@ -223,24 +213,23 @@ static struct bucket_table *rhashtable_last_table(struct rhashtable *ht,
return new_tbl;
}
-static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
+static int rhashtable_rehash_one(struct rhashtable *ht,
+ struct rhash_lock_head __rcu **bkt,
+ unsigned int old_hash)
{
struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
struct bucket_table *new_tbl = rhashtable_last_table(ht, old_tbl);
- struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash);
int err = -EAGAIN;
struct rhash_head *head, *next, *entry;
- spinlock_t *new_bucket_lock;
+ struct rhash_head **pprev = NULL;
unsigned int new_hash;
if (new_tbl->nest)
goto out;
err = -ENOENT;
- if (!pprev)
- goto out;
- rht_for_each_from(entry, *pprev, old_tbl, old_hash) {
+ rht_for_each_from(entry, rht_ptr(*bkt), old_tbl, old_hash) {
err = 0;
next = rht_dereference_bucket(entry->next, old_tbl, old_hash);
@@ -255,18 +244,20 @@ static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
new_hash = head_hashfn(ht, new_tbl, entry);
- new_bucket_lock = rht_bucket_lock(new_tbl, new_hash);
+ rht_lock(&new_tbl->buckets[new_hash]);
- spin_lock_nested(new_bucket_lock, SINGLE_DEPTH_NESTING);
- head = rht_dereference_bucket(new_tbl->buckets[new_hash],
- new_tbl, new_hash);
+ head = rht_ptr(rht_dereference_bucket(new_tbl->buckets[new_hash],
+ new_tbl, new_hash));
RCU_INIT_POINTER(entry->next, head);
- rcu_assign_pointer(new_tbl->buckets[new_hash], entry);
- spin_unlock(new_bucket_lock);
+ rht_assign_unlock(&new_tbl->buckets[new_hash], entry);
- rcu_assign_pointer(*pprev, next);
+ if (pprev)
+ rcu_assign_pointer(*pprev, next);
+ else
+ /* Need to preserved the bit lock. */
+ rcu_assign_pointer(*bkt, rht_ptr_locked(next));
out:
return err;
@@ -276,19 +267,19 @@ static int rhashtable_rehash_chain(struct rhashtable *ht,
unsigned int old_hash)
{
struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
- spinlock_t *old_bucket_lock;
+ struct rhash_lock_head __rcu **bkt = rht_bucket_var(old_tbl, old_hash);
int err;
- old_bucket_lock = rht_bucket_lock(old_tbl, old_hash);
+ if (!bkt)
+ return 0;
+ rht_lock(bkt);
- spin_lock_bh(old_bucket_lock);
- while (!(err = rhashtable_rehash_one(ht, old_hash)))
+ while (!(err = rhashtable_rehash_one(ht, bkt, old_hash)))
;
if (err == -ENOENT)
err = 0;
-
- spin_unlock_bh(old_bucket_lock);
+ rht_unlock(bkt);
return err;
}
@@ -485,6 +476,7 @@ fail:
}
static void *rhashtable_lookup_one(struct rhashtable *ht,
+ struct rhash_lock_head __rcu **bkt,
struct bucket_table *tbl, unsigned int hash,
const void *key, struct rhash_head *obj)
{
@@ -492,15 +484,12 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
.ht = ht,
.key = key,
};
- struct rhash_head __rcu **pprev;
+ struct rhash_head **pprev = NULL;
struct rhash_head *head;
int elasticity;
elasticity = RHT_ELASTICITY;
- pprev = rht_bucket_var(tbl, hash);
- if (!pprev)
- return ERR_PTR(-ENOENT);
- rht_for_each_from(head, *pprev, tbl, hash) {
+ rht_for_each_from(head, rht_ptr(*bkt), tbl, hash) {
struct rhlist_head *list;
struct rhlist_head *plist;
@@ -522,7 +511,11 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
RCU_INIT_POINTER(list->next, plist);
head = rht_dereference_bucket(head->next, tbl, hash);
RCU_INIT_POINTER(list->rhead.next, head);
- rcu_assign_pointer(*pprev, obj);
+ if (pprev)
+ rcu_assign_pointer(*pprev, obj);
+ else
+ /* Need to preserve the bit lock */
+ rcu_assign_pointer(*bkt, rht_ptr_locked(obj));
return NULL;
}
@@ -534,12 +527,12 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
}
static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
+ struct rhash_lock_head __rcu **bkt,
struct bucket_table *tbl,
unsigned int hash,
struct rhash_head *obj,
void *data)
{
- struct rhash_head __rcu **pprev;
struct bucket_table *new_tbl;
struct rhash_head *head;
@@ -562,11 +555,7 @@ static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
if (unlikely(rht_grow_above_100(ht, tbl)))
return ERR_PTR(-EAGAIN);
- pprev = rht_bucket_insert(ht, tbl, hash);
- if (!pprev)
- return ERR_PTR(-ENOMEM);
-
- head = rht_dereference_bucket(*pprev, tbl, hash);
+ head = rht_ptr(rht_dereference_bucket(*bkt, tbl, hash));
RCU_INIT_POINTER(obj->next, head);
if (ht->rhlist) {
@@ -576,7 +565,10 @@ static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
RCU_INIT_POINTER(list->next, NULL);
}
- rcu_assign_pointer(*pprev, obj);
+ /* bkt is always the head of the list, so it holds
+ * the lock, which we need to preserve
+ */
+ rcu_assign_pointer(*bkt, rht_ptr_locked(obj));
atomic_inc(&ht->nelems);
if (rht_grow_above_75(ht, tbl))
@@ -590,6 +582,7 @@ static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
{
struct bucket_table *new_tbl;
struct bucket_table *tbl;
+ struct rhash_lock_head __rcu **bkt;
unsigned int hash;
void *data;
@@ -598,14 +591,25 @@ static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
do {
tbl = new_tbl;
hash = rht_head_hashfn(ht, tbl, obj, ht->p);
- spin_lock_bh(rht_bucket_lock(tbl, hash));
-
- data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
- new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
- if (PTR_ERR(new_tbl) != -EEXIST)
- data = ERR_CAST(new_tbl);
-
- spin_unlock_bh(rht_bucket_lock(tbl, hash));
+ if (rcu_access_pointer(tbl->future_tbl))
+ /* Failure is OK */
+ bkt = rht_bucket_var(tbl, hash);
+ else
+ bkt = rht_bucket_insert(ht, tbl, hash);
+ if (bkt == NULL) {
+ new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+ data = ERR_PTR(-EAGAIN);
+ } else {
+ rht_lock(bkt);
+ data = rhashtable_lookup_one(ht, bkt, tbl,
+ hash, key, obj);
+ new_tbl = rhashtable_insert_one(ht, bkt, tbl,
+ hash, obj, data);
+ if (PTR_ERR(new_tbl) != -EEXIST)
+ data = ERR_CAST(new_tbl);
+
+ rht_unlock(bkt);
+ }
} while (!IS_ERR_OR_NULL(new_tbl));
if (PTR_ERR(data) == -EAGAIN)
@@ -1032,11 +1036,6 @@ int rhashtable_init(struct rhashtable *ht,
size = rounded_hashtable_size(&ht->p);
- if (params->locks_mul)
- ht->p.locks_mul = roundup_pow_of_two(params->locks_mul);
- else
- ht->p.locks_mul = BUCKET_LOCKS_PER_CPU;
-
ht->key_len = ht->p.key_len;
if (!params->hashfn) {
ht->p.hashfn = jhash;
@@ -1138,7 +1137,7 @@ restart:
struct rhash_head *pos, *next;
cond_resched();
- for (pos = rht_dereference(*rht_bucket(tbl, i), ht),
+ for (pos = rht_ptr(rht_dereference(*rht_bucket(tbl, i), ht)),
next = !rht_is_a_nulls(pos) ?
rht_dereference(pos->next, ht) : NULL;
!rht_is_a_nulls(pos);
@@ -1165,8 +1164,8 @@ void rhashtable_destroy(struct rhashtable *ht)
}
EXPORT_SYMBOL_GPL(rhashtable_destroy);
-struct rhash_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash)
+struct rhash_lock_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
+ unsigned int hash)
{
const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
unsigned int index = hash & ((1 << tbl->nest) - 1);
@@ -1194,10 +1193,10 @@ struct rhash_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
}
EXPORT_SYMBOL_GPL(__rht_bucket_nested);
-struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash)
+struct rhash_lock_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
+ unsigned int hash)
{
- static struct rhash_head __rcu *rhnull;
+ static struct rhash_lock_head __rcu *rhnull;
if (!rhnull)
INIT_RHT_NULLS_HEAD(rhnull);
@@ -1205,9 +1204,9 @@ struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
}
EXPORT_SYMBOL_GPL(rht_bucket_nested);
-struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
- struct bucket_table *tbl,
- unsigned int hash)
+struct rhash_lock_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
+ struct bucket_table *tbl,
+ unsigned int hash)
{
const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
unsigned int index = hash & ((1 << tbl->nest) - 1);
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 3bd2e91bfc29..02592c2a249c 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -500,7 +500,7 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
struct rhash_head *pos, *next;
struct test_obj_rhl *p;
- pos = rht_dereference(tbl->buckets[i], ht);
+ pos = rht_ptr(rht_dereference(tbl->buckets[i], ht));
next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;
if (!rht_is_a_nulls(pos)) {