From 58be8a583d8d316448bafa5926414cfb83c02dec Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 24 Mar 2015 14:18:16 +0100 Subject: rhashtable: Extend RCU read lock into rhashtable_insert_rehash() rhashtable_insert_rehash() requires RCU locks to be held in order to access ht->tbl and traverse to the last table. Fixes: ccd57b1bd324 ("rhashtable: Add immediate rehash during insertion") Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index d7be9cb0e91f..5976ab59b88f 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -585,8 +585,8 @@ restart: if (unlikely(rht_grow_above_100(ht, tbl))) { slow_path: spin_unlock_bh(lock); - rcu_read_unlock(); err = rhashtable_insert_rehash(ht); + rcu_read_unlock(); if (err) return err; -- cgit v1.2.3 From 299e5c32a37a6bca8175db177117467bd1ce970a Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 24 Mar 2015 14:18:17 +0100 Subject: rhashtable: Use 'unsigned int' consistently Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 5976ab59b88f..f89cda067cb9 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -208,13 +208,13 @@ static inline unsigned int rht_key_hashfn( struct rhashtable *ht, const struct bucket_table *tbl, const void *key, const struct rhashtable_params params) { - unsigned hash; + unsigned int hash; /* params must be equal to ht->p if it isn't constant. */ if (!__builtin_constant_p(params.key_len)) hash = ht->p.hashfn(key, ht->key_len, tbl->hash_rnd); else if (params.key_len) { - unsigned key_len = params.key_len; + unsigned int key_len = params.key_len; if (params.hashfn) hash = params.hashfn(key, key_len, tbl->hash_rnd); @@ -224,7 +224,7 @@ static inline unsigned int rht_key_hashfn( hash = jhash2(key, key_len / sizeof(u32), tbl->hash_rnd); } else { - unsigned key_len = ht->p.key_len; + unsigned int key_len = ht->p.key_len; if (params.hashfn) hash = params.hashfn(key, key_len, tbl->hash_rnd); @@ -512,7 +512,7 @@ static inline void *rhashtable_lookup_fast( }; const struct bucket_table *tbl; struct rhash_head *he; - unsigned hash; + unsigned int hash; rcu_read_lock(); @@ -550,8 +550,8 @@ static inline int __rhashtable_insert_fast( struct bucket_table *tbl, *new_tbl; struct rhash_head *head; spinlock_t *lock; - unsigned elasticity; - unsigned hash; + unsigned int elasticity; + unsigned int hash; int err; restart: @@ -718,7 +718,7 @@ static inline int __rhashtable_remove_fast( struct rhash_head __rcu **pprev; struct rhash_head *he; spinlock_t * lock; - unsigned hash; + unsigned int hash; int err = -ENOENT; hash = rht_head_hashfn(ht, tbl, obj, params); -- cgit v1.2.3 From ac833bddb591b9c7a0609f440f196375be184044 Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 24 Mar 2015 14:18:18 +0100 Subject: rhashtable: Mark internal/private inline functions as such Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index f89cda067cb9..0e1f975ad101 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -539,6 +539,7 @@ restart: return NULL; } +/* Internal function, please use rhashtable_insert_fast() instead */ static inline int __rhashtable_insert_fast( struct rhashtable *ht, const void *key, struct rhash_head *obj, const struct rhashtable_params params) @@ -711,6 +712,7 @@ static inline int rhashtable_lookup_insert_key( return __rhashtable_insert_fast(ht, key, obj, params); } +/* Internal function, please use rhashtable_remove_fast() instead */ static inline int __rhashtable_remove_fast( struct rhashtable *ht, struct bucket_table *tbl, struct rhash_head *obj, const struct rhashtable_params params) -- cgit v1.2.3 From b5e2c150ac914f28a28833b57397bec0b0a2bd5f Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 24 Mar 2015 20:42:19 +0000 Subject: rhashtable: Disable automatic shrinking by default Introduce a new bool automatic_shrinking to require the user to explicitly opt-in to automatic shrinking of tables. Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 0e1f975ad101..ae26c494e230 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -2,7 +2,7 @@ * Resizable, Scalable, Concurrent Hash Table * * Copyright (c) 2015 Herbert Xu - * Copyright (c) 2014 Thomas Graf + * Copyright (c) 2014-2015 Thomas Graf * Copyright (c) 2008-2014 Patrick McHardy * * Code partially derived from nft_hash @@ -104,6 +104,7 @@ struct rhashtable; * @min_size: Minimum size while shrinking * @nulls_base: Base value to generate nulls marker * @insecure_elasticity: Set to true to disable chain length checks + * @automatic_shrinking: Enable automatic shrinking of tables * @locks_mul: Number of bucket locks to allocate per cpu (default: 128) * @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash) * @obj_hashfn: Function to hash object @@ -118,6 +119,7 @@ struct rhashtable_params { unsigned int min_size; u32 nulls_base; bool insecure_elasticity; + bool automatic_shrinking; size_t locks_mul; rht_hashfn_t hashfn; rht_obj_hashfn_t obj_hashfn; @@ -784,7 +786,8 @@ static inline int rhashtable_remove_fast( goto out; atomic_dec(&ht->nelems); - if (rht_shrink_below_30(ht, tbl)) + if (unlikely(ht->p.automatic_shrinking && + rht_shrink_below_30(ht, tbl))) schedule_work(&ht->run_work); out: -- cgit v1.2.3 From 6b6f302ceda7a052dab545d6c69abf5f0d4a6cab Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 24 Mar 2015 14:18:20 +0100 Subject: rhashtable: Add rhashtable_free_and_destroy() rhashtable_destroy() variant which stops rehashes, iterates over the table and calls a callback to release resources. Avoids need for nft_hash to embed rhashtable internals and allows to get rid of the being_destroyed flag. It also saves a 2nd mutex lock upon destruction. Also fixes an RCU lockdep splash on nft set destruction due to calling rht_for_each_entry_safe() without holding bucket locks. Open code this loop as we need know that no mutations may occur in parallel. Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index ae26c494e230..99f2e49a8a07 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -136,12 +136,10 @@ struct rhashtable_params { * @run_work: Deferred worker to expand/shrink asynchronously * @mutex: Mutex to protect current/future table swapping * @lock: Spin lock to protect walker list - * @being_destroyed: True if table is set up for destruction */ struct rhashtable { struct bucket_table __rcu *tbl; atomic_t nelems; - bool being_destroyed; unsigned int key_len; unsigned int elasticity; struct rhashtable_params p; @@ -334,6 +332,9 @@ int rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU); void *rhashtable_walk_next(struct rhashtable_iter *iter); void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU); +void rhashtable_free_and_destroy(struct rhashtable *ht, + void (*free_fn)(void *ptr, void *arg), + void *arg); void rhashtable_destroy(struct rhashtable *ht); #define rht_dereference(p, ht) \ -- cgit v1.2.3