diff options
| -rw-r--r-- | include/linux/rhashtable.h | 142 |
1 files changed, 71 insertions, 71 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 2711cbf01b64..c504cd820736 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -88,77 +88,6 @@ struct bucket_table { }; /* - * 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 bucket_table *tbl, - struct rhash_lock_head **bkt) -{ - local_bh_disable(); - bit_spin_lock(1, (unsigned long *)bkt); - lock_map_acquire(&tbl->dep_map); -} - -static inline void rht_lock_nested(struct bucket_table *tbl, - struct rhash_lock_head **bucket, - unsigned int subclass) -{ - local_bh_disable(); - bit_spin_lock(1, (unsigned long *)bucket); - lock_acquire_exclusive(&tbl->dep_map, subclass, 0, NULL, _THIS_IP_); -} - -static inline void rht_unlock(struct bucket_table *tbl, - struct rhash_lock_head **bkt) -{ - lock_map_release(&tbl->dep_map); - bit_spin_unlock(1, (unsigned long *)bkt); - local_bh_enable(); -} - -static inline void rht_assign_unlock(struct bucket_table *tbl, - struct rhash_lock_head __rcu **bkt, - struct rhash_head *obj) -{ - struct rhash_head __rcu **p = (struct rhash_head __rcu **)bkt; - - lock_map_release(&tbl->dep_map); - 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. @@ -372,6 +301,77 @@ static inline struct rhash_lock_head __rcu **rht_bucket_insert( &tbl->buckets[hash]; } +/* + * 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 bucket_table *tbl, + struct rhash_lock_head **bkt) +{ + local_bh_disable(); + bit_spin_lock(1, (unsigned long *)bkt); + lock_map_acquire(&tbl->dep_map); +} + +static inline void rht_lock_nested(struct bucket_table *tbl, + struct rhash_lock_head **bucket, + unsigned int subclass) +{ + local_bh_disable(); + bit_spin_lock(1, (unsigned long *)bucket); + lock_acquire_exclusive(&tbl->dep_map, subclass, 0, NULL, _THIS_IP_); +} + +static inline void rht_unlock(struct bucket_table *tbl, + struct rhash_lock_head **bkt) +{ + lock_map_release(&tbl->dep_map); + bit_spin_unlock(1, (unsigned long *)bkt); + 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)); +} + +static inline void rht_assign_unlock(struct bucket_table *tbl, + struct rhash_lock_head __rcu **bkt, + struct rhash_head *obj) +{ + struct rhash_head __rcu **p = (struct rhash_head __rcu **)bkt; + + lock_map_release(&tbl->dep_map); + rcu_assign_pointer(*p, obj); + preempt_enable(); + __release(bitlock); + local_bh_enable(); +} + /** * rht_for_each_from - iterate over hash chain from given head * @pos: the &struct rhash_head to use as a loop cursor. |