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-rw-r--r--include/linux/rhashtable-types.h2
-rw-r--r--include/linux/rhashtable.h261
-rw-r--r--ipc/util.c1
-rw-r--r--lib/rhashtable.c141
-rw-r--r--lib/test_rhashtable.c2
-rw-r--r--net/bridge/br_fdb.c1
-rw-r--r--net/bridge/br_multicast.c1
-rw-r--r--net/bridge/br_vlan.c1
-rw-r--r--net/bridge/br_vlan_tunnel.c1
-rw-r--r--net/ipv4/ipmr.c1
-rw-r--r--net/ipv6/ip6mr.c1
-rw-r--r--net/netfilter/nf_tables_api.c1
12 files changed, 236 insertions, 178 deletions
diff --git a/include/linux/rhashtable-types.h b/include/linux/rhashtable-types.h
index 763d613ce2c2..57467cbf4c5b 100644
--- a/include/linux/rhashtable-types.h
+++ b/include/linux/rhashtable-types.h
@@ -48,7 +48,6 @@ typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg,
* @head_offset: Offset of rhash_head in struct to be hashed
* @max_size: Maximum size while expanding
* @min_size: Minimum size while shrinking
- * @locks_mul: Number of bucket locks to allocate per cpu (default: 32)
* @automatic_shrinking: Enable automatic shrinking of tables
* @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash)
* @obj_hashfn: Function to hash object
@@ -62,7 +61,6 @@ struct rhashtable_params {
unsigned int max_size;
u16 min_size;
bool automatic_shrinking;
- u8 locks_mul;
rht_hashfn_t hashfn;
rht_obj_hashfn_t obj_hashfn;
rht_obj_cmpfn_t obj_cmpfn;
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 0c9175aeab8a..ccbbafdf5547 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -24,12 +24,27 @@
#include <linux/list_nulls.h>
#include <linux/workqueue.h>
#include <linux/rculist.h>
+#include <linux/bit_spinlock.h>
#include <linux/rhashtable-types.h>
/*
+ * Objects in an rhashtable have an embedded struct rhash_head
+ * which is linked into as hash chain from the hash table - or one
+ * of two or more hash tables when the rhashtable is being resized.
* The end of the chain is marked with a special nulls marks which has
- * the least significant bit set.
+ * the least significant bit set but otherwise stores the address of
+ * the hash bucket. This allows us to be be sure we've found the end
+ * of the right list.
+ * The value stored in the hash bucket has BIT(2) used as a lock bit.
+ * This bit must be atomically set before any changes are made to
+ * the chain. To avoid dereferencing this pointer without clearing
+ * the bit first, we use an opaque 'struct rhash_lock_head *' for the
+ * pointer stored in the bucket. This struct needs to be defined so
+ * that rcu_derefernce() works on it, but it has no content so a
+ * cast is needed for it to be useful. This ensures it isn't
+ * used by mistake with clearing the lock bit first.
*/
+struct rhash_lock_head {};
/* Maximum chain length before rehash
*
@@ -52,8 +67,6 @@
* @nest: Number of bits of first-level nested table.
* @rehash: Current bucket being rehashed
* @hash_rnd: Random seed to fold into hash
- * @locks_mask: Mask to apply before accessing locks[]
- * @locks: Array of spinlocks protecting individual buckets
* @walkers: List of active walkers
* @rcu: RCU structure for freeing the table
* @future_tbl: Table under construction during rehashing
@@ -64,17 +77,71 @@ struct bucket_table {
unsigned int size;
unsigned int nest;
u32 hash_rnd;
- unsigned int locks_mask;
- spinlock_t *locks;
struct list_head walkers;
struct rcu_head rcu;
struct bucket_table __rcu *future_tbl;
- struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp;
+ struct rhash_lock_head __rcu *buckets[] ____cacheline_aligned_in_smp;
};
/*
+ * We lock a bucket by setting BIT(1) in the pointer - this is always
+ * zero in real pointers and in the nulls marker.
+ * bit_spin_locks do not handle contention well, but the whole point
+ * of the hashtable design is to achieve minimum per-bucket contention.
+ * A nested hash table might not have a bucket pointer. In that case
+ * we cannot get a lock. For remove and replace the bucket cannot be
+ * interesting and doesn't need locking.
+ * For insert we allocate the bucket if this is the last bucket_table,
+ * and then take the lock.
+ * Sometimes we unlock a bucket by writing a new pointer there. In that
+ * case we don't need to unlock, but we do need to reset state such as
+ * local_bh. For that we have rht_assign_unlock(). As rcu_assign_pointer()
+ * provides the same release semantics that bit_spin_unlock() provides,
+ * this is safe.
+ */
+
+static inline void rht_lock(struct rhash_lock_head **bkt)
+{
+ local_bh_disable();
+ bit_spin_lock(1, (unsigned long *)bkt);
+}
+
+static inline void rht_unlock(struct rhash_lock_head **bkt)
+{
+ bit_spin_unlock(1, (unsigned long *)bkt);
+ local_bh_enable();
+}
+
+static inline void rht_assign_unlock(struct rhash_lock_head **bkt,
+ struct rhash_head *obj)
+{
+ struct rhash_head **p = (struct rhash_head **)bkt;
+
+ rcu_assign_pointer(*p, obj);
+ preempt_enable();
+ __release(bitlock);
+ local_bh_enable();
+}
+
+/*
+ * If 'p' is a bucket head and might be locked:
+ * rht_ptr() returns the address without the lock bit.
+ * rht_ptr_locked() returns the address WITH the lock bit.
+ */
+static inline struct rhash_head __rcu *rht_ptr(const struct rhash_lock_head *p)
+{
+ return (void *)(((unsigned long)p) & ~BIT(1));
+}
+
+static inline struct rhash_lock_head __rcu *rht_ptr_locked(const
+ struct rhash_head *p)
+{
+ return (void *)(((unsigned long)p) | BIT(1));
+}
+
+/*
* NULLS_MARKER() expects a hash value with the low
* bits mostly likely to be significant, and it discards
* the msb.
@@ -206,25 +273,6 @@ static inline bool rht_grow_above_max(const struct rhashtable *ht,
return atomic_read(&ht->nelems) >= ht->max_elems;
}
-/* The bucket lock is selected based on the hash and protects mutations
- * on a group of hash buckets.
- *
- * A maximum of tbl->size/2 bucket locks is allocated. This ensures that
- * a single lock always covers both buckets which may both contains
- * entries which link to the same bucket of the old table during resizing.
- * This allows to simplify the locking as locking the bucket in both
- * tables during resize always guarantee protection.
- *
- * IMPORTANT: When holding the bucket lock of both the old and new table
- * during expansions and shrinking, the old bucket lock must always be
- * acquired first.
- */
-static inline spinlock_t *rht_bucket_lock(const struct bucket_table *tbl,
- unsigned int hash)
-{
- return &tbl->locks[hash & tbl->locks_mask];
-}
-
#ifdef CONFIG_PROVE_LOCKING
int lockdep_rht_mutex_is_held(struct rhashtable *ht);
int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash);
@@ -263,13 +311,13 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
void *arg);
void rhashtable_destroy(struct rhashtable *ht);
-struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash);
-struct rhash_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash);
-struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
- struct bucket_table *tbl,
+struct rhash_lock_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);
+struct rhash_lock_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
+ struct bucket_table *tbl,
+ unsigned int hash);
#define rht_dereference(p, ht) \
rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht))
@@ -286,21 +334,21 @@ struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
#define rht_entry(tpos, pos, member) \
({ tpos = container_of(pos, typeof(*tpos), member); 1; })
-static inline struct rhash_head __rcu *const *rht_bucket(
+static inline struct rhash_lock_head __rcu *const *rht_bucket(
const struct bucket_table *tbl, unsigned int hash)
{
return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) :
&tbl->buckets[hash];
}
-static inline struct rhash_head __rcu **rht_bucket_var(
+static inline struct rhash_lock_head __rcu **rht_bucket_var(
struct bucket_table *tbl, unsigned int hash)
{
return unlikely(tbl->nest) ? __rht_bucket_nested(tbl, hash) :
&tbl->buckets[hash];
}
-static inline struct rhash_head __rcu **rht_bucket_insert(
+static inline struct rhash_lock_head __rcu **rht_bucket_insert(
struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash)
{
return unlikely(tbl->nest) ? rht_bucket_nested_insert(ht, tbl, hash) :
@@ -326,7 +374,7 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
* @hash: the hash value / bucket index
*/
#define rht_for_each(pos, tbl, hash) \
- rht_for_each_from(pos, *rht_bucket(tbl, hash), tbl, hash)
+ rht_for_each_from(pos, rht_ptr(*rht_bucket(tbl, hash)), tbl, hash)
/**
* rht_for_each_entry_from - iterate over hash chain from given head
@@ -351,7 +399,7 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
* @member: name of the &struct rhash_head within the hashable struct.
*/
#define rht_for_each_entry(tpos, pos, tbl, hash, member) \
- rht_for_each_entry_from(tpos, pos, *rht_bucket(tbl, hash), \
+ rht_for_each_entry_from(tpos, pos, rht_ptr(*rht_bucket(tbl, hash)), \
tbl, hash, member)
/**
@@ -367,7 +415,8 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
* remove the loop cursor from the list.
*/
#define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member) \
- for (pos = rht_dereference_bucket(*rht_bucket(tbl, hash), tbl, hash), \
+ for (pos = rht_dereference_bucket(rht_ptr(*rht_bucket(tbl, hash)), \
+ tbl, hash), \
next = !rht_is_a_nulls(pos) ? \
rht_dereference_bucket(pos->next, tbl, hash) : NULL; \
(!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \
@@ -402,8 +451,12 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
* the _rcu mutation primitives such as rhashtable_insert() as long as the
* traversal is guarded by rcu_read_lock().
*/
-#define rht_for_each_rcu(pos, tbl, hash) \
- rht_for_each_rcu_from(pos, *rht_bucket(tbl, hash), tbl, hash)
+#define rht_for_each_rcu(pos, tbl, hash) \
+ for (({barrier(); }), \
+ pos = rht_ptr(rht_dereference_bucket_rcu( \
+ *rht_bucket(tbl, hash), tbl, hash)); \
+ !rht_is_a_nulls(pos); \
+ pos = rcu_dereference_raw(pos->next))
/**
* rht_for_each_entry_rcu_from - iterated over rcu hash chain from given head
@@ -437,7 +490,8 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
* traversal is guarded by rcu_read_lock().
*/
#define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member) \
- rht_for_each_entry_rcu_from(tpos, pos, *rht_bucket(tbl, hash), \
+ rht_for_each_entry_rcu_from(tpos, pos, \
+ rht_ptr(*rht_bucket(tbl, hash)), \
tbl, hash, member)
/**
@@ -483,7 +537,7 @@ static inline struct rhash_head *__rhashtable_lookup(
.ht = ht,
.key = key,
};
- struct rhash_head __rcu * const *head;
+ struct rhash_lock_head __rcu * const *bkt;
struct bucket_table *tbl;
struct rhash_head *he;
unsigned int hash;
@@ -491,9 +545,10 @@ static inline struct rhash_head *__rhashtable_lookup(
tbl = rht_dereference_rcu(ht->tbl, ht);
restart:
hash = rht_key_hashfn(ht, tbl, key, params);
- head = rht_bucket(tbl, hash);
+ bkt = rht_bucket(tbl, hash);
do {
- rht_for_each_rcu_from(he, *head, tbl, hash) {
+ he = rht_ptr(rht_dereference_bucket_rcu(*bkt, tbl, hash));
+ rht_for_each_rcu_from(he, he, tbl, hash) {
if (params.obj_cmpfn ?
params.obj_cmpfn(&arg, rht_obj(ht, he)) :
rhashtable_compare(&arg, rht_obj(ht, he)))
@@ -503,7 +558,7 @@ restart:
/* An object might have been moved to a different hash chain,
* while we walk along it - better check and retry.
*/
- } while (he != RHT_NULLS_MARKER(head));
+ } while (he != RHT_NULLS_MARKER(bkt));
/* Ensure we see any new tables. */
smp_rmb();
@@ -599,10 +654,10 @@ static inline void *__rhashtable_insert_fast(
.ht = ht,
.key = key,
};
+ struct rhash_lock_head __rcu **bkt;
struct rhash_head __rcu **pprev;
struct bucket_table *tbl;
struct rhash_head *head;
- spinlock_t *lock;
unsigned int hash;
int elasticity;
void *data;
@@ -611,23 +666,22 @@ static inline void *__rhashtable_insert_fast(
tbl = rht_dereference_rcu(ht->tbl, ht);
hash = rht_head_hashfn(ht, tbl, obj, params);
- lock = rht_bucket_lock(tbl, hash);
- spin_lock_bh(lock);
+ elasticity = RHT_ELASTICITY;
+ bkt = rht_bucket_insert(ht, tbl, hash);
+ data = ERR_PTR(-ENOMEM);
+ if (!bkt)
+ goto out;
+ pprev = NULL;
+ rht_lock(bkt);
if (unlikely(rcu_access_pointer(tbl->future_tbl))) {
slow_path:
- spin_unlock_bh(lock);
+ rht_unlock(bkt);
rcu_read_unlock();
return rhashtable_insert_slow(ht, key, obj);
}
- elasticity = RHT_ELASTICITY;
- pprev = rht_bucket_insert(ht, tbl, hash);
- data = ERR_PTR(-ENOMEM);
- if (!pprev)
- goto out;
-
- rht_for_each_from(head, *pprev, tbl, hash) {
+ rht_for_each_from(head, rht_ptr(*bkt), tbl, hash) {
struct rhlist_head *plist;
struct rhlist_head *list;
@@ -643,7 +697,7 @@ slow_path:
data = rht_obj(ht, head);
if (!rhlist)
- goto out;
+ goto out_unlock;
list = container_of(obj, struct rhlist_head, rhead);
@@ -652,9 +706,13 @@ slow_path:
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);
-
- goto good;
+ if (pprev) {
+ rcu_assign_pointer(*pprev, obj);
+ rht_unlock(bkt);
+ } else
+ rht_assign_unlock(bkt, obj);
+ data = NULL;
+ goto out;
}
if (elasticity <= 0)
@@ -662,12 +720,13 @@ slow_path:
data = ERR_PTR(-E2BIG);
if (unlikely(rht_grow_above_max(ht, tbl)))
- goto out;
+ goto out_unlock;
if (unlikely(rht_grow_above_100(ht, tbl)))
goto slow_path;
- head = rht_dereference_bucket(*pprev, tbl, hash);
+ /* Inserting at head of list makes unlocking free. */
+ head = rht_ptr(rht_dereference_bucket(*bkt, tbl, hash));
RCU_INIT_POINTER(obj->next, head);
if (rhlist) {
@@ -677,20 +736,21 @@ slow_path:
RCU_INIT_POINTER(list->next, NULL);
}
- rcu_assign_pointer(*pprev, obj);
-
atomic_inc(&ht->nelems);
+ rht_assign_unlock(bkt, obj);
+
if (rht_grow_above_75(ht, tbl))
schedule_work(&ht->run_work);
-good:
data = NULL;
-
out:
- spin_unlock_bh(lock);
rcu_read_unlock();
return data;
+
+out_unlock:
+ rht_unlock(bkt);
+ goto out;
}
/**
@@ -699,9 +759,9 @@ out:
* @obj: pointer to hash head inside object
* @params: hash table parameters
*
- * Will take a per bucket spinlock to protect against mutual mutations
+ * Will take the per bucket bitlock to protect against mutual mutations
* on the same bucket. Multiple insertions may occur in parallel unless
- * they map to the same bucket lock.
+ * they map to the same bucket.
*
* It is safe to call this function from atomic context.
*
@@ -728,9 +788,9 @@ static inline int rhashtable_insert_fast(
* @list: pointer to hash list head inside object
* @params: hash table parameters
*
- * Will take a per bucket spinlock to protect against mutual mutations
+ * Will take the per bucket bitlock to protect against mutual mutations
* on the same bucket. Multiple insertions may occur in parallel unless
- * they map to the same bucket lock.
+ * they map to the same bucket.
*
* It is safe to call this function from atomic context.
*
@@ -751,9 +811,9 @@ static inline int rhltable_insert_key(
* @list: pointer to hash list head inside object
* @params: hash table parameters
*
- * Will take a per bucket spinlock to protect against mutual mutations
+ * Will take the per bucket bitlock to protect against mutual mutations
* on the same bucket. Multiple insertions may occur in parallel unless
- * they map to the same bucket lock.
+ * they map to the same bucket.
*
* It is safe to call this function from atomic context.
*
@@ -880,21 +940,20 @@ static inline int __rhashtable_remove_fast_one(
struct rhash_head *obj, const struct rhashtable_params params,
bool rhlist)
{
+ struct rhash_lock_head __rcu **bkt;
struct rhash_head __rcu **pprev;
struct rhash_head *he;
- spinlock_t * lock;
unsigned int hash;
int err = -ENOENT;
hash = rht_head_hashfn(ht, tbl, obj, params);
- lock = rht_bucket_lock(tbl, hash);
+ bkt = rht_bucket_var(tbl, hash);
+ if (!bkt)
+ return -ENOENT;
+ pprev = NULL;
+ rht_lock(bkt);
- spin_lock_bh(lock);
-
- pprev = rht_bucket_var(tbl, hash);
- if (!pprev)
- goto out;
- rht_for_each_from(he, *pprev, tbl, hash) {
+ rht_for_each_from(he, rht_ptr(*bkt), tbl, hash) {
struct rhlist_head *list;
list = container_of(he, struct rhlist_head, rhead);
@@ -934,13 +993,17 @@ static inline int __rhashtable_remove_fast_one(
}
}
- rcu_assign_pointer(*pprev, obj);
- break;
+ if (pprev) {
+ rcu_assign_pointer(*pprev, obj);
+ rht_unlock(bkt);
+ } else {
+ rht_assign_unlock(bkt, obj);
+ }
+ goto unlocked;
}
-out:
- spin_unlock_bh(lock);
-
+ rht_unlock(bkt);
+unlocked:
if (err > 0) {
atomic_dec(&ht->nelems);
if (unlikely(ht->p.automatic_shrinking &&
@@ -1029,9 +1092,9 @@ static inline int __rhashtable_replace_fast(
struct rhash_head *obj_old, struct rhash_head *obj_new,
const struct rhashtable_params params)
{
+ struct rhash_lock_head __rcu **bkt;
struct rhash_head __rcu **pprev;
struct rhash_head *he;
- spinlock_t *lock;
unsigned int hash;
int err = -ENOENT;
@@ -1042,27 +1105,33 @@ static inline int __rhashtable_replace_fast(
if (hash != rht_head_hashfn(ht, tbl, obj_new, params))
return -EINVAL;
- lock = rht_bucket_lock(tbl, hash);
+ bkt = rht_bucket_var(tbl, hash);
+ if (!bkt)
+ return -ENOENT;
- spin_lock_bh(lock);
+ pprev = NULL;
+ rht_lock(bkt);
- pprev = rht_bucket_var(tbl, hash);
- if (!pprev)
- goto out;
- rht_for_each_from(he, *pprev, tbl, hash) {
+ rht_for_each_from(he, rht_ptr(*bkt), tbl, hash) {
if (he != obj_old) {
pprev = &he->next;
continue;
}
rcu_assign_pointer(obj_new->next, obj_old->next);
- rcu_assign_pointer(*pprev, obj_new);
+ if (pprev) {
+ rcu_assign_pointer(*pprev, obj_new);
+ rht_unlock(bkt);
+ } else {
+ rht_assign_unlock(bkt, obj_new);
+ }
err = 0;
- break;
+ goto unlocked;
}
-out:
- spin_unlock_bh(lock);
+ rht_unlock(bkt);
+
+unlocked:
return err;
}
diff --git a/ipc/util.c b/ipc/util.c
index 0af05752969f..095274a871f8 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -101,7 +101,6 @@ static const struct rhashtable_params ipc_kht_params = {
.head_offset = offsetof(struct kern_ipc_perm, khtnode),
.key_offset = offsetof(struct kern_ipc_perm, key),
.key_len = FIELD_SIZEOF(struct kern_ipc_perm, key),
- .locks_mul = 1,
.automatic_shrinking = true,
};
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)) {
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 00573cc46c98..b1c91f66d79c 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -33,7 +33,6 @@ static const struct rhashtable_params br_fdb_rht_params = {
.key_offset = offsetof(struct net_bridge_fdb_entry, key),
.key_len = sizeof(struct net_bridge_fdb_key),
.automatic_shrinking = true,
- .locks_mul = 1,
};
static struct kmem_cache *br_fdb_cache __read_mostly;
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 8d82107c6419..812560d7f7a2 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -44,7 +44,6 @@ static const struct rhashtable_params br_mdb_rht_params = {
.key_offset = offsetof(struct net_bridge_mdb_entry, addr),
.key_len = sizeof(struct br_ip),
.automatic_shrinking = true,
- .locks_mul = 1,
};
static void br_multicast_start_querier(struct net_bridge *br,
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 96abf8feb9dc..0a02822b5667 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -21,7 +21,6 @@ static const struct rhashtable_params br_vlan_rht_params = {
.key_offset = offsetof(struct net_bridge_vlan, vid),
.key_len = sizeof(u16),
.nelem_hint = 3,
- .locks_mul = 1,
.max_size = VLAN_N_VID,
.obj_cmpfn = br_vlan_cmp,
.automatic_shrinking = true,
diff --git a/net/bridge/br_vlan_tunnel.c b/net/bridge/br_vlan_tunnel.c
index 6d2c4eed2dc8..758151863669 100644
--- a/net/bridge/br_vlan_tunnel.c
+++ b/net/bridge/br_vlan_tunnel.c
@@ -34,7 +34,6 @@ static const struct rhashtable_params br_vlan_tunnel_rht_params = {
.key_offset = offsetof(struct net_bridge_vlan, tinfo.tunnel_id),
.key_len = sizeof(__be64),
.nelem_hint = 3,
- .locks_mul = 1,
.obj_cmpfn = br_vlan_tunid_cmp,
.automatic_shrinking = true,
};
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 2c931120c494..9a3f13edc98e 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -373,7 +373,6 @@ static const struct rhashtable_params ipmr_rht_params = {
.key_offset = offsetof(struct mfc_cache, cmparg),
.key_len = sizeof(struct mfc_cache_cmp_arg),
.nelem_hint = 3,
- .locks_mul = 1,
.obj_cmpfn = ipmr_hash_cmp,
.automatic_shrinking = true,
};
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index e4dd57976737..4e69847ed5be 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -355,7 +355,6 @@ static const struct rhashtable_params ip6mr_rht_params = {
.key_offset = offsetof(struct mfc6_cache, cmparg),
.key_len = sizeof(struct mfc6_cache_cmp_arg),
.nelem_hint = 3,
- .locks_mul = 1,
.obj_cmpfn = ip6mr_hash_cmp,
.automatic_shrinking = true,
};
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ef7772e976cc..90e6b09ef2af 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -53,7 +53,6 @@ static const struct rhashtable_params nft_chain_ht_params = {
.hashfn = nft_chain_hash,
.obj_hashfn = nft_chain_hash_obj,
.obj_cmpfn = nft_chain_hash_cmp,
- .locks_mul = 1,
.automatic_shrinking = true,
};
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