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rhashtable: Rip out obsolete out-of-line interface
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Now that all rhashtable users have been converted over to the
inline interface, this patch removes the unused out-of-line
interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Herbert Xu authored and David S. Miller committed Mar 20, 2015
1 parent 6cca728 commit dc0ee26
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Showing 2 changed files with 3 additions and 300 deletions.
19 changes: 3 additions & 16 deletions include/linux/rhashtable.h
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Original file line number Diff line number Diff line change
@@ -1,14 +1,13 @@
/*
* 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
Expand Down Expand Up @@ -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);
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284 changes: 0 additions & 284 deletions lib/rhashtable.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
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