diff options
| -rw-r--r-- | include/linux/rhashtable.h | 19 | ||||
| -rw-r--r-- | lib/rhashtable.c | 11 |
2 files changed, 30 insertions, 0 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index dbcbcc59aa92..843ceca9a21e 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -17,6 +17,7 @@ #ifndef _LINUX_RHASHTABLE_H #define _LINUX_RHASHTABLE_H +#include <linux/atomic.h> #include <linux/compiler.h> #include <linux/errno.h> #include <linux/jhash.h> @@ -100,6 +101,7 @@ struct rhashtable; * @key_len: Length of key * @key_offset: Offset of key in struct to be hashed * @head_offset: Offset of rhash_head in struct to be hashed + * @insecure_max_entries: Maximum number of entries (may be exceeded) * @max_size: Maximum size while expanding * @min_size: Minimum size while shrinking * @nulls_base: Base value to generate nulls marker @@ -115,6 +117,7 @@ struct rhashtable_params { size_t key_len; size_t key_offset; size_t head_offset; + unsigned int insecure_max_entries; unsigned int max_size; unsigned int min_size; u32 nulls_base; @@ -286,6 +289,18 @@ static inline bool rht_grow_above_100(const struct rhashtable *ht, (!ht->p.max_size || tbl->size < ht->p.max_size); } +/** + * rht_grow_above_max - returns true if table is above maximum + * @ht: hash table + * @tbl: current table + */ +static inline bool rht_grow_above_max(const struct rhashtable *ht, + const struct bucket_table *tbl) +{ + return ht->p.insecure_max_entries && + atomic_read(&ht->nelems) >= ht->p.insecure_max_entries; +} + /* The bucket lock is selected based on the hash and protects mutations * on a group of hash buckets. * @@ -589,6 +604,10 @@ restart: goto out; } + err = -E2BIG; + if (unlikely(rht_grow_above_max(ht, tbl))) + goto out; + if (unlikely(rht_grow_above_100(ht, tbl))) { slow_path: spin_unlock_bh(lock); diff --git a/lib/rhashtable.c b/lib/rhashtable.c index b28df4019ade..4396434e4715 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -14,6 +14,7 @@ * published by the Free Software Foundation. */ +#include <linux/atomic.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/log2.h> @@ -446,6 +447,10 @@ int rhashtable_insert_slow(struct rhashtable *ht, const void *key, if (key && rhashtable_lookup_fast(ht, key, ht->p)) goto exit; + err = -E2BIG; + if (unlikely(rht_grow_above_max(ht, tbl))) + goto exit; + err = -EAGAIN; if (rhashtable_check_elasticity(ht, tbl, hash) || rht_grow_above_100(ht, tbl)) @@ -738,6 +743,12 @@ int rhashtable_init(struct rhashtable *ht, if (params->max_size) ht->p.max_size = rounddown_pow_of_two(params->max_size); + if (params->insecure_max_entries) + ht->p.insecure_max_entries = + rounddown_pow_of_two(params->insecure_max_entries); + else + ht->p.insecure_max_entries = ht->p.max_size * 2; + ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE); /* The maximum (not average) chain length grows with the |