diff options
Diffstat (limited to 'include/linux/rhashtable.h')
| -rw-r--r-- | include/linux/rhashtable.h | 308 |
1 files changed, 231 insertions, 77 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index b93fd89b2e5e..58851275fed9 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -18,16 +18,45 @@ #ifndef _LINUX_RHASHTABLE_H #define _LINUX_RHASHTABLE_H -#include <linux/rculist.h> +#include <linux/compiler.h> +#include <linux/list_nulls.h> +#include <linux/workqueue.h> +#include <linux/mutex.h> + +/* + * The end of the chain is marked with a special nulls marks which has + * the following format: + * + * +-------+-----------------------------------------------------+-+ + * | Base | Hash |1| + * +-------+-----------------------------------------------------+-+ + * + * Base (4 bits) : Reserved to distinguish between multiple tables. + * Specified via &struct rhashtable_params.nulls_base. + * Hash (27 bits): Full hash (unmasked) of first element added to bucket + * 1 (1 bit) : Nulls marker (always set) + * + * The remaining bits of the next pointer remain unused for now. + */ +#define RHT_BASE_BITS 4 +#define RHT_HASH_BITS 27 +#define RHT_BASE_SHIFT RHT_HASH_BITS struct rhash_head { struct rhash_head __rcu *next; }; -#define INIT_HASH_HEAD(ptr) ((ptr)->next = NULL) - +/** + * struct bucket_table - Table of hash buckets + * @size: Number of hash buckets + * @locks_mask: Mask to apply before accessing locks[] + * @locks: Array of spinlocks protecting individual buckets + * @buckets: size * hash buckets + */ struct bucket_table { size_t size; + unsigned int locks_mask; + spinlock_t *locks; struct rhash_head __rcu *buckets[]; }; @@ -45,11 +74,16 @@ struct rhashtable; * @hash_rnd: Seed to use while hashing * @max_shift: Maximum number of shifts while expanding * @min_shift: Minimum number of shifts while shrinking + * @nulls_base: Base value to generate nulls marker + * @locks_mul: Number of bucket locks to allocate per cpu (default: 128) * @hashfn: Function to hash key * @obj_hashfn: Function to hash object * @grow_decision: If defined, may return true if table should expand * @shrink_decision: If defined, may return true if table should shrink - * @mutex_is_held: Must return true if protecting mutex is held + * + * Note: when implementing the grow and shrink decision function, min/max + * shift must be enforced, otherwise, resizing watermarks they set may be + * useless. */ struct rhashtable_params { size_t nelem_hint; @@ -59,36 +93,95 @@ struct rhashtable_params { u32 hash_rnd; size_t max_shift; size_t min_shift; + u32 nulls_base; + size_t locks_mul; rht_hashfn_t hashfn; rht_obj_hashfn_t obj_hashfn; bool (*grow_decision)(const struct rhashtable *ht, size_t new_size); bool (*shrink_decision)(const struct rhashtable *ht, size_t new_size); -#ifdef CONFIG_PROVE_LOCKING - int (*mutex_is_held)(void *parent); - void *parent; -#endif }; /** * struct rhashtable - Hash table handle * @tbl: Bucket table + * @future_tbl: Table under construction during expansion/shrinking * @nelems: Number of elements in table * @shift: Current size (1 << shift) * @p: Configuration parameters + * @run_work: Deferred worker to expand/shrink asynchronously + * @mutex: Mutex to protect current/future table swapping + * @walkers: List of active walkers + * @being_destroyed: True if table is set up for destruction */ struct rhashtable { struct bucket_table __rcu *tbl; - size_t nelems; - size_t shift; + struct bucket_table __rcu *future_tbl; + atomic_t nelems; + atomic_t shift; struct rhashtable_params p; + struct work_struct run_work; + struct mutex mutex; + struct list_head walkers; + bool being_destroyed; +}; + +/** + * struct rhashtable_walker - Hash table walker + * @list: List entry on list of walkers + * @resize: Resize event occured + */ +struct rhashtable_walker { + struct list_head list; + bool resize; }; +/** + * struct rhashtable_iter - Hash table iterator, fits into netlink cb + * @ht: Table to iterate through + * @p: Current pointer + * @walker: Associated rhashtable walker + * @slot: Current slot + * @skip: Number of entries to skip in slot + */ +struct rhashtable_iter { + struct rhashtable *ht; + struct rhash_head *p; + struct rhashtable_walker *walker; + unsigned int slot; + unsigned int skip; +}; + +static inline unsigned long rht_marker(const struct rhashtable *ht, u32 hash) +{ + return NULLS_MARKER(ht->p.nulls_base + hash); +} + +#define INIT_RHT_NULLS_HEAD(ptr, ht, hash) \ + ((ptr) = (typeof(ptr)) rht_marker(ht, hash)) + +static inline bool rht_is_a_nulls(const struct rhash_head *ptr) +{ + return ((unsigned long) ptr & 1); +} + +static inline unsigned long rht_get_nulls_value(const struct rhash_head *ptr) +{ + return ((unsigned long) ptr) >> 1; +} + #ifdef CONFIG_PROVE_LOCKING -int lockdep_rht_mutex_is_held(const struct rhashtable *ht); +int lockdep_rht_mutex_is_held(struct rhashtable *ht); +int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash); #else -static inline int lockdep_rht_mutex_is_held(const struct rhashtable *ht) +static inline int lockdep_rht_mutex_is_held(struct rhashtable *ht) +{ + return 1; +} + +static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, + u32 hash) { return 1; } @@ -96,13 +189,8 @@ static inline int lockdep_rht_mutex_is_held(const struct rhashtable *ht) int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params); -u32 rhashtable_hashfn(const struct rhashtable *ht, const void *key, u32 len); -u32 rhashtable_obj_hashfn(const struct rhashtable *ht, void *ptr); - void rhashtable_insert(struct rhashtable *ht, struct rhash_head *node); bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *node); -void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj, - struct rhash_head __rcu **pprev); bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size); bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size); @@ -110,11 +198,23 @@ bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size); int rhashtable_expand(struct rhashtable *ht); int rhashtable_shrink(struct rhashtable *ht); -void *rhashtable_lookup(const struct rhashtable *ht, const void *key); -void *rhashtable_lookup_compare(const struct rhashtable *ht, u32 hash, +void *rhashtable_lookup(struct rhashtable *ht, const void *key); +void *rhashtable_lookup_compare(struct rhashtable *ht, const void *key, bool (*compare)(void *, void *), void *arg); -void rhashtable_destroy(const struct rhashtable *ht); +bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj); +bool rhashtable_lookup_compare_insert(struct rhashtable *ht, + struct rhash_head *obj, + bool (*compare)(void *, void *), + void *arg); + +int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter); +void rhashtable_walk_exit(struct rhashtable_iter *iter); +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_destroy(struct rhashtable *ht); #define rht_dereference(p, ht) \ rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht)) @@ -122,92 +222,146 @@ void rhashtable_destroy(const struct rhashtable *ht); #define rht_dereference_rcu(p, ht) \ rcu_dereference_check(p, lockdep_rht_mutex_is_held(ht)) -#define rht_entry(ptr, type, member) container_of(ptr, type, member) -#define rht_entry_safe(ptr, type, member) \ -({ \ - typeof(ptr) __ptr = (ptr); \ - __ptr ? rht_entry(__ptr, type, member) : NULL; \ -}) +#define rht_dereference_bucket(p, tbl, hash) \ + rcu_dereference_protected(p, lockdep_rht_bucket_is_held(tbl, hash)) + +#define rht_dereference_bucket_rcu(p, tbl, hash) \ + rcu_dereference_check(p, lockdep_rht_bucket_is_held(tbl, hash)) -#define rht_next_entry_safe(pos, ht, member) \ -({ \ - pos ? rht_entry_safe(rht_dereference((pos)->member.next, ht), \ - typeof(*(pos)), member) : NULL; \ -}) +#define rht_entry(tpos, pos, member) \ + ({ tpos = container_of(pos, typeof(*tpos), member); 1; }) + +/** + * rht_for_each_continue - continue iterating over hash chain + * @pos: the &struct rhash_head to use as a loop cursor. + * @head: the previous &struct rhash_head to continue from + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + */ +#define rht_for_each_continue(pos, head, tbl, hash) \ + for (pos = rht_dereference_bucket(head, tbl, hash); \ + !rht_is_a_nulls(pos); \ + pos = rht_dereference_bucket((pos)->next, tbl, hash)) /** * rht_for_each - iterate over hash chain - * @pos: &struct rhash_head to use as a loop cursor. - * @head: head of the hash chain (struct rhash_head *) - * @ht: pointer to your struct rhashtable + * @pos: the &struct rhash_head to use as a loop cursor. + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index */ -#define rht_for_each(pos, head, ht) \ - for (pos = rht_dereference(head, ht); \ - pos; \ - pos = rht_dereference((pos)->next, ht)) +#define rht_for_each(pos, tbl, hash) \ + rht_for_each_continue(pos, (tbl)->buckets[hash], tbl, hash) + +/** + * rht_for_each_entry_continue - continue iterating over hash chain + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct rhash_head to use as a loop cursor. + * @head: the previous &struct rhash_head to continue from + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * @member: name of the &struct rhash_head within the hashable struct. + */ +#define rht_for_each_entry_continue(tpos, pos, head, tbl, hash, member) \ + for (pos = rht_dereference_bucket(head, tbl, hash); \ + (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ + pos = rht_dereference_bucket((pos)->next, tbl, hash)) /** * rht_for_each_entry - iterate over hash chain of given type - * @pos: type * to use as a loop cursor. - * @head: head of the hash chain (struct rhash_head *) - * @ht: pointer to your struct rhashtable - * @member: name of the rhash_head within the hashable struct. + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct rhash_head to use as a loop cursor. + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * @member: name of the &struct rhash_head within the hashable struct. */ -#define rht_for_each_entry(pos, head, ht, member) \ - for (pos = rht_entry_safe(rht_dereference(head, ht), \ - typeof(*(pos)), member); \ - pos; \ - pos = rht_next_entry_safe(pos, ht, member)) +#define rht_for_each_entry(tpos, pos, tbl, hash, member) \ + rht_for_each_entry_continue(tpos, pos, (tbl)->buckets[hash], \ + tbl, hash, member) /** * rht_for_each_entry_safe - safely iterate over hash chain of given type - * @pos: type * to use as a loop cursor. - * @n: type * to use for temporary next object storage - * @head: head of the hash chain (struct rhash_head *) - * @ht: pointer to your struct rhashtable - * @member: name of the rhash_head within the hashable struct. + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct rhash_head to use as a loop cursor. + * @next: the &struct rhash_head to use as next in loop cursor. + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * @member: name of the &struct rhash_head within the hashable struct. * * This hash chain list-traversal primitive allows for the looped code to * remove the loop cursor from the list. */ -#define rht_for_each_entry_safe(pos, n, head, ht, member) \ - for (pos = rht_entry_safe(rht_dereference(head, ht), \ - typeof(*(pos)), member), \ - n = rht_next_entry_safe(pos, ht, member); \ - pos; \ - pos = n, \ - n = rht_next_entry_safe(pos, ht, member)) +#define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member) \ + for (pos = rht_dereference_bucket((tbl)->buckets[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); \ + pos = next, \ + next = !rht_is_a_nulls(pos) ? \ + rht_dereference_bucket(pos->next, tbl, hash) : NULL) + +/** + * rht_for_each_rcu_continue - continue iterating over rcu hash chain + * @pos: the &struct rhash_head to use as a loop cursor. + * @head: the previous &struct rhash_head to continue from + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * + * This hash chain list-traversal primitive may safely run concurrently with + * the _rcu mutation primitives such as rhashtable_insert() as long as the + * traversal is guarded by rcu_read_lock(). + */ +#define rht_for_each_rcu_continue(pos, head, tbl, hash) \ + for (({barrier(); }), \ + pos = rht_dereference_bucket_rcu(head, tbl, hash); \ + !rht_is_a_nulls(pos); \ + pos = rcu_dereference_raw(pos->next)) /** * rht_for_each_rcu - iterate over rcu hash chain - * @pos: &struct rhash_head to use as a loop cursor. - * @head: head of the hash chain (struct rhash_head *) - * @ht: pointer to your struct rhashtable + * @pos: the &struct rhash_head to use as a loop cursor. + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * + * This hash chain list-traversal primitive may safely run concurrently with + * 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_continue(pos, (tbl)->buckets[hash], tbl, hash) + +/** + * rht_for_each_entry_rcu_continue - continue iterating over rcu hash chain + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct rhash_head to use as a loop cursor. + * @head: the previous &struct rhash_head to continue from + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * @member: name of the &struct rhash_head within the hashable struct. * * This hash chain list-traversal primitive may safely run concurrently with - * the _rcu fkht mutation primitives such as rht_insert() as long as the + * 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, head, ht) \ - for (pos = rht_dereference_rcu(head, ht); \ - pos; \ - pos = rht_dereference_rcu((pos)->next, ht)) +#define rht_for_each_entry_rcu_continue(tpos, pos, head, tbl, hash, member) \ + for (({barrier(); }), \ + pos = rht_dereference_bucket_rcu(head, tbl, hash); \ + (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ + pos = rht_dereference_bucket_rcu(pos->next, tbl, hash)) /** * rht_for_each_entry_rcu - iterate over rcu hash chain of given type - * @pos: type * to use as a loop cursor. - * @head: head of the hash chain (struct rhash_head *) - * @member: name of the rhash_head within the hashable struct. + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct rhash_head to use as a loop cursor. + * @tbl: the &struct bucket_table + * @hash: the hash value / bucket index + * @member: name of the &struct rhash_head within the hashable struct. * * This hash chain list-traversal primitive may safely run concurrently with - * the _rcu fkht mutation primitives such as rht_insert() as long as the + * the _rcu mutation primitives such as rhashtable_insert() as long as the * traversal is guarded by rcu_read_lock(). */ -#define rht_for_each_entry_rcu(pos, head, member) \ - for (pos = rht_entry_safe(rcu_dereference_raw(head), \ - typeof(*(pos)), member); \ - pos; \ - pos = rht_entry_safe(rcu_dereference_raw((pos)->member.next), \ - typeof(*(pos)), member)) +#define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member) \ + rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\ + tbl, hash, member) #endif /* _LINUX_RHASHTABLE_H */ |