rhashtable: Rip out obsolete out-of-line interface (dc0ee268) · Commits · e / devices / android_kernel_xiaomi_nabu

include/linux/rhashtable.h

+3 −16

Original line number	Diff line number	Diff line
		/*
		* Resizable, Scalable, Concurrent Hash Table
		*
		* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
		* Copyright (c) 2014 Thomas Graf <tgraf@suug.ch>
		* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
		*
		* Based on the following paper by Josh Triplett, Paul E. McKenney
		* and Jonathan Walpole:
		* https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf
		*
		* Code partially derived from nft_hash
		* Rewritten with rehash code from br_multicast plus single list
		* pointer as suggested by Josh Triplett
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		@@ -282,22 +281,10 @@ int rhashtable_init(struct rhashtable *ht,
		int rhashtable_insert_slow(struct rhashtable ht, const void key,
		struct rhash_head *obj,
		struct bucket_table *old_tbl);
		void rhashtable_insert(struct rhashtable ht, struct rhash_head node);
		bool rhashtable_remove(struct rhashtable ht, struct rhash_head node);

		int rhashtable_expand(struct rhashtable *ht);
		int rhashtable_shrink(struct rhashtable *ht);

		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);

		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);

lib/rhashtable.c

+0 −284

Original line number	Diff line number	Diff line
		@@ -339,290 +339,6 @@ int rhashtable_insert_slow(struct rhashtable ht, const void key,
		}
		EXPORT_SYMBOL_GPL(rhashtable_insert_slow);

		static bool __rhashtable_insert(struct rhashtable ht, struct rhash_head obj,
		bool (compare)(void , void ), void arg)
		{
		struct bucket_table tbl, old_tbl;
		struct rhash_head *head;
		bool no_resize_running;
		unsigned hash;
		spinlock_t *old_lock;
		bool success = true;

		rcu_read_lock();

		old_tbl = rht_dereference_rcu(ht->tbl, ht);
		hash = head_hashfn(ht, old_tbl, obj);
		old_lock = rht_bucket_lock(old_tbl, hash);

		spin_lock_bh(old_lock);

		/* Because we have already taken the bucket lock in old_tbl,
		* if we find that future_tbl is not yet visible then that
		* guarantees all other insertions of the same entry will
		* also grab the bucket lock in old_tbl because until the
		* rehash completes ht->tbl won't be changed.
		*/
		tbl = rht_dereference_rcu(old_tbl->future_tbl, ht) ?: old_tbl;
		if (tbl != old_tbl) {
		hash = head_hashfn(ht, tbl, obj);
		spin_lock_nested(rht_bucket_lock(tbl, hash),
		SINGLE_DEPTH_NESTING);
		}

		if (compare &&
		rhashtable_lookup_compare(ht, rht_obj(ht, obj) + ht->p.key_offset,
		compare, arg)) {
		success = false;
		goto exit;
		}

		no_resize_running = tbl == old_tbl;

		head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);

		if (rht_is_a_nulls(head))
		INIT_RHT_NULLS_HEAD(obj->next, ht, hash);
		else
		RCU_INIT_POINTER(obj->next, head);

		rcu_assign_pointer(tbl->buckets[hash], obj);

		atomic_inc(&ht->nelems);
		if (no_resize_running && rht_grow_above_75(ht, tbl))
		schedule_work(&ht->run_work);

		exit:
		if (tbl != old_tbl)
		spin_unlock(rht_bucket_lock(tbl, hash));

		spin_unlock_bh(old_lock);

		rcu_read_unlock();

		return success;
		}

		/**
		* rhashtable_insert - insert object into hash table
		* @ht: hash table
		* @obj: pointer to hash head inside object
		*
		* Will take a per bucket spinlock to protect against mutual mutations
		* on the same bucket. Multiple insertions may occur in parallel unless
		* they map to the same bucket lock.
		*
		* It is safe to call this function from atomic context.
		*
		* Will trigger an automatic deferred table resizing if the size grows
		* beyond the watermark indicated by grow_decision() which can be passed
		* to rhashtable_init().
		*/
		void rhashtable_insert(struct rhashtable ht, struct rhash_head obj)
		{
		__rhashtable_insert(ht, obj, NULL, NULL);
		}
		EXPORT_SYMBOL_GPL(rhashtable_insert);

		static bool __rhashtable_remove(struct rhashtable *ht,
		struct bucket_table *tbl,
		struct rhash_head *obj)
		{
		struct rhash_head __rcu **pprev;
		struct rhash_head *he;
		spinlock_t * lock;
		unsigned hash;
		bool ret = false;

		hash = head_hashfn(ht, tbl, obj);
		lock = rht_bucket_lock(tbl, hash);

		spin_lock_bh(lock);

		pprev = &tbl->buckets[hash];
		rht_for_each(he, tbl, hash) {
		if (he != obj) {
		pprev = &he->next;
		continue;
		}

		rcu_assign_pointer(*pprev, obj->next);
		ret = true;
		break;
		}

		spin_unlock_bh(lock);

		return ret;
		}

		/**
		* rhashtable_remove - remove object from hash table
		* @ht: hash table
		* @obj: pointer to hash head inside object
		*
		* Since the hash chain is single linked, the removal operation needs to
		* walk the bucket chain upon removal. The removal operation is thus
		* considerable slow if the hash table is not correctly sized.
		*
		* Will automatically shrink the table via rhashtable_expand() if the
		* shrink_decision function specified at rhashtable_init() returns true.
		*
		* The caller must ensure that no concurrent table mutations occur. It is
		* however valid to have concurrent lookups if they are RCU protected.
		*/
		bool rhashtable_remove(struct rhashtable ht, struct rhash_head obj)
		{
		struct bucket_table *tbl;
		bool ret;

		rcu_read_lock();

		tbl = rht_dereference_rcu(ht->tbl, ht);

		/* Because we have already taken (and released) the bucket
		* lock in old_tbl, if we find that future_tbl is not yet
		* visible then that guarantees the entry to still be in
		* the old tbl if it exists.
		*/
		while (!(ret = __rhashtable_remove(ht, tbl, obj)) &&
		(tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
		;

		if (ret) {
		atomic_dec(&ht->nelems);
		if (rht_shrink_below_30(ht, tbl))
		schedule_work(&ht->run_work);
		}

		rcu_read_unlock();

		return ret;
		}
		EXPORT_SYMBOL_GPL(rhashtable_remove);

		/**
		* rhashtable_lookup - lookup key in hash table
		* @ht: hash table
		* @key: pointer to key
		*
		* Computes the hash value for the key and traverses the bucket chain looking
		* for a entry with an identical key. The first matching entry is returned.
		*
		* This lookup function may only be used for fixed key hash table (key_len
		* parameter set). It will BUG() if used inappropriately.
		*
		* Lookups may occur in parallel with hashtable mutations and resizing.
		*/
		void rhashtable_lookup(struct rhashtable ht, const void *key)
		{
		return rhashtable_lookup_fast(ht, key, ht->p);
		}
		EXPORT_SYMBOL_GPL(rhashtable_lookup);

		/**
		* rhashtable_lookup_compare - search hash table with compare function
		* @ht: hash table
		* @key: the pointer to the key
		* @compare: compare function, must return true on match
		* @arg: argument passed on to compare function
		*
		* Traverses the bucket chain behind the provided hash value and calls the
		* specified compare function for each entry.
		*
		* Lookups may occur in parallel with hashtable mutations and resizing.
		*
		* Returns the first entry on which the compare function returned true.
		*/
		void rhashtable_lookup_compare(struct rhashtable ht, const void *key,
		bool (compare)(void , void *),
		void *arg)
		{
		const struct bucket_table *tbl;
		struct rhash_head *he;
		u32 hash;

		rcu_read_lock();

		tbl = rht_dereference_rcu(ht->tbl, ht);
		restart:
		hash = rht_key_hashfn(ht, tbl, key, ht->p);
		rht_for_each_rcu(he, tbl, hash) {
		if (!compare(rht_obj(ht, he), arg))
		continue;
		rcu_read_unlock();
		return rht_obj(ht, he);
		}

		/* Ensure we see any new tables. */
		smp_rmb();

		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
		if (unlikely(tbl))
		goto restart;
		rcu_read_unlock();

		return NULL;
		}
		EXPORT_SYMBOL_GPL(rhashtable_lookup_compare);

		/**
		* rhashtable_lookup_insert - lookup and insert object into hash table
		* @ht: hash table
		* @obj: pointer to hash head inside object
		*
		* Locks down the bucket chain in both the old and new table if a resize
		* is in progress to ensure that writers can't remove from the old table
		* and can't insert to the new table during the atomic operation of search
		* and insertion. Searches for duplicates in both the old and new table if
		* a resize is in progress.
		*
		* This lookup function may only be used for fixed key hash table (key_len
		* parameter set). It will BUG() if used inappropriately.
		*
		* It is safe to call this function from atomic context.
		*
		* Will trigger an automatic deferred table resizing if the size grows
		* beyond the watermark indicated by grow_decision() which can be passed
		* to rhashtable_init().
		*/
		bool rhashtable_lookup_insert(struct rhashtable ht, struct rhash_head obj)
		{
		return rhashtable_lookup_insert_fast(ht, obj, ht->p);
		}
		EXPORT_SYMBOL_GPL(rhashtable_lookup_insert);

		/**
		* rhashtable_lookup_compare_insert - search and insert object to hash table
		* with compare function
		* @ht: hash table
		* @obj: pointer to hash head inside object
		* @compare: compare function, must return true on match
		* @arg: argument passed on to compare function
		*
		* Locks down the bucket chain in both the old and new table if a resize
		* is in progress to ensure that writers can't remove from the old table
		* and can't insert to the new table during the atomic operation of search
		* and insertion. Searches for duplicates in both the old and new table if
		* a resize is in progress.
		*
		* Lookups may occur in parallel with hashtable mutations and resizing.
		*
		* Will trigger an automatic deferred table resizing if the size grows
		* beyond the watermark indicated by grow_decision() which can be passed
		* to rhashtable_init().
		*/
		bool rhashtable_lookup_compare_insert(struct rhashtable *ht,
		struct rhash_head *obj,
		bool (compare)(void , void *),
		void *arg)
		{
		BUG_ON(!ht->p.key_len);

		return __rhashtable_insert(ht, obj, compare, arg);
		}
		EXPORT_SYMBOL_GPL(rhashtable_lookup_compare_insert);

		/**
		* rhashtable_walk_init - Initialise an iterator
		* @ht: Table to walk over