Commit 6eba8224 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

rhashtable: Drop gfp_flags arg in insert/remove functions 



Reallocation is only required for shrinking and expanding and both rely
on a mutex for synchronization and callers of rhashtable_init() are in
non atomic context. Therefore, no reason to continue passing allocation
hints through the API.

Instead, use GFP_KERNEL and add __GFP_NOWARN | __GFP_NORETRY to allow
for silent fall back to vzalloc() without the OOM killer jumping in as
pointed out by Eric Dumazet and Eric W. Biederman.

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 64bb7e99

include/linux/rhashtable.h

+5 −5
Original line number Diff line number Diff line
@@ -99,16 +99,16 @@ 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, gfp_t);

bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *node, gfp_t);

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, gfp_t flags);

			     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);



int rhashtable_expand(struct rhashtable *ht, gfp_t flags);

int rhashtable_shrink(struct rhashtable *ht, gfp_t flags);

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,

lib/rhashtable.c

+17 −24
Original line number Diff line number Diff line
@@ -107,13 +107,13 @@ static u32 head_hashfn(const struct rhashtable *ht, 
	return obj_hashfn(ht, rht_obj(ht, he), hsize);

}



static struct bucket_table *bucket_table_alloc(size_t nbuckets, gfp_t flags)

static struct bucket_table *bucket_table_alloc(size_t nbuckets)

{

	struct bucket_table *tbl;

	size_t size;



	size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);

	tbl = kzalloc(size, flags);

	tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);

	if (tbl == NULL)

		tbl = vzalloc(size);
@@ -200,7 +200,6 @@ static void hashtable_chain_unzip(const struct rhashtable *ht, 
/**

 * rhashtable_expand - Expand hash table while allowing concurrent lookups

 * @ht:		the hash table to expand

 * @flags:	allocation flags

 *

 * A secondary bucket array is allocated and the hash entries are migrated

 * while keeping them on both lists until the end of the RCU grace period.
@@ -211,7 +210,7 @@ static void hashtable_chain_unzip(const struct rhashtable *ht, 
 * The caller must ensure that no concurrent table mutations take place.

 * It is however valid to have concurrent lookups if they are RCU protected.

 */

int rhashtable_expand(struct rhashtable *ht, gfp_t flags)

int rhashtable_expand(struct rhashtable *ht)

{

	struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);

	struct rhash_head *he;
@@ -223,7 +222,7 @@ int rhashtable_expand(struct rhashtable *ht, gfp_t flags) 
	if (ht->p.max_shift && ht->shift >= ht->p.max_shift)

		return 0;



	new_tbl = bucket_table_alloc(old_tbl->size * 2, flags);

	new_tbl = bucket_table_alloc(old_tbl->size * 2);

	if (new_tbl == NULL)

		return -ENOMEM;
@@ -281,7 +280,6 @@ EXPORT_SYMBOL_GPL(rhashtable_expand); 
/**

 * rhashtable_shrink - Shrink hash table while allowing concurrent lookups

 * @ht:		the hash table to shrink

 * @flags:	allocation flags

 *

 * This function may only be called in a context where it is safe to call

 * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
@@ -289,7 +287,7 @@ EXPORT_SYMBOL_GPL(rhashtable_expand); 
 * The caller must ensure that no concurrent table mutations take place.

 * It is however valid to have concurrent lookups if they are RCU protected.

 */

int rhashtable_shrink(struct rhashtable *ht, gfp_t flags)

int rhashtable_shrink(struct rhashtable *ht)

{

	struct bucket_table *ntbl, *tbl = rht_dereference(ht->tbl, ht);

	struct rhash_head __rcu **pprev;
@@ -300,7 +298,7 @@ int rhashtable_shrink(struct rhashtable *ht, gfp_t flags) 
	if (ht->shift <= ht->p.min_shift)

		return 0;



	ntbl = bucket_table_alloc(tbl->size / 2, flags);

	ntbl = bucket_table_alloc(tbl->size / 2);

	if (ntbl == NULL)

		return -ENOMEM;
@@ -341,7 +339,6 @@ EXPORT_SYMBOL_GPL(rhashtable_shrink); 
 * rhashtable_insert - insert object into hash hash table

 * @ht:		hash table

 * @obj:	pointer to hash head inside object

 * @flags:	allocation flags (table expansion)

 *

 * Will automatically grow the table via rhashtable_expand() if the the

 * grow_decision function specified at rhashtable_init() returns true.
@@ -349,8 +346,7 @@ EXPORT_SYMBOL_GPL(rhashtable_shrink); 
 * The caller must ensure that no concurrent table mutations occur. It is

 * however valid to have concurrent lookups if they are RCU protected.

 */

void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,

		       gfp_t flags)

void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj)

{

	struct bucket_table *tbl = rht_dereference(ht->tbl, ht);

	u32 hash;
@@ -363,7 +359,7 @@ void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj, 
	ht->nelems++;



	if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))

		rhashtable_expand(ht, flags);

		rhashtable_expand(ht);

}

EXPORT_SYMBOL_GPL(rhashtable_insert);
@@ -372,14 +368,13 @@ EXPORT_SYMBOL_GPL(rhashtable_insert); 
 * @ht:		hash table

 * @obj:	pointer to hash head inside object

 * @pprev:	pointer to previous element

 * @flags:	allocation flags (table expansion)

 *

 * Identical to rhashtable_remove() but caller is alreayd aware of the element

 * in front of the element to be deleted. This is in particular useful for

 * deletion when combined with walking or lookup.

 */

void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj,

			     struct rhash_head __rcu **pprev, gfp_t flags)

			     struct rhash_head __rcu **pprev)

{

	struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
@@ -390,7 +385,7 @@ void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj, 


	if (ht->p.shrink_decision &&

	    ht->p.shrink_decision(ht, tbl->size))

		rhashtable_shrink(ht, flags);

		rhashtable_shrink(ht);

}

EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
@@ -398,7 +393,6 @@ EXPORT_SYMBOL_GPL(rhashtable_remove_pprev); 
 * rhashtable_remove - remove object from hash table

 * @ht:		hash table

 * @obj:	pointer to hash head inside object

 * @flags:	allocation flags (table expansion)

 *

 * Since the hash chain is single linked, the removal operation needs to

 * walk the bucket chain upon removal. The removal operation is thus
@@ -410,8 +404,7 @@ EXPORT_SYMBOL_GPL(rhashtable_remove_pprev); 
 * 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,

		       gfp_t flags)

bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj)

{

	struct bucket_table *tbl = rht_dereference(ht->tbl, ht);

	struct rhash_head __rcu **pprev;
@@ -429,7 +422,7 @@ bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj, 
			continue;

		}



		rhashtable_remove_pprev(ht, he, pprev, flags);

		rhashtable_remove_pprev(ht, he, pprev);

		return true;

	}
@@ -576,7 +569,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) 
	if (params->nelem_hint)

		size = rounded_hashtable_size(params);



	tbl = bucket_table_alloc(size, GFP_KERNEL);

	tbl = bucket_table_alloc(size);

	if (tbl == NULL)

		return -ENOMEM;
@@ -713,7 +706,7 @@ static int __init test_rhashtable(struct rhashtable *ht) 
		obj->ptr = TEST_PTR;

		obj->value = i * 2;



		rhashtable_insert(ht, &obj->node, GFP_KERNEL);

		rhashtable_insert(ht, &obj->node);

	}



	rcu_read_lock();
@@ -724,7 +717,7 @@ static int __init test_rhashtable(struct rhashtable *ht) 


	for (i = 0; i < TEST_NEXPANDS; i++) {

		pr_info("  Table expansion iteration %u...\n", i);

		rhashtable_expand(ht, GFP_KERNEL);

		rhashtable_expand(ht);



		rcu_read_lock();

		pr_info("  Verifying lookups...\n");
@@ -734,7 +727,7 @@ static int __init test_rhashtable(struct rhashtable *ht) 


	for (i = 0; i < TEST_NEXPANDS; i++) {

		pr_info("  Table shrinkage iteration %u...\n", i);

		rhashtable_shrink(ht, GFP_KERNEL);

		rhashtable_shrink(ht);



		rcu_read_lock();

		pr_info("  Verifying lookups...\n");
@@ -749,7 +742,7 @@ static int __init test_rhashtable(struct rhashtable *ht) 
		obj = rhashtable_lookup(ht, &key);

		BUG_ON(!obj);



		rhashtable_remove(ht, &obj->node, GFP_KERNEL);

		rhashtable_remove(ht, &obj->node);

		kfree(obj);

	}

net/netfilter/nft_hash.c

+2 −2
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ static int nft_hash_insert(const struct nft_set *set, 
	if (set->flags & NFT_SET_MAP)

		nft_data_copy(he->data, &elem->data);



	rhashtable_insert(priv, &he->node, GFP_KERNEL);

	rhashtable_insert(priv, &he->node);



	return 0;

}
@@ -88,7 +88,7 @@ static void nft_hash_remove(const struct nft_set *set, 
	pprev = elem->cookie;

	he = rht_dereference((*pprev), priv);



	rhashtable_remove_pprev(priv, he, pprev, GFP_KERNEL);

	rhashtable_remove_pprev(priv, he, pprev);



	synchronize_rcu();

	kfree(he);

net/netlink/af_netlink.c

+2 −2
Original line number Diff line number Diff line
@@ -1092,7 +1092,7 @@ static int netlink_insert(struct sock *sk, struct net *net, u32 portid) 


	nlk_sk(sk)->portid = portid;

	sock_hold(sk);

	rhashtable_insert(&table->hash, &nlk_sk(sk)->node, GFP_KERNEL);

	rhashtable_insert(&table->hash, &nlk_sk(sk)->node);

	err = 0;

err:

	mutex_unlock(&nl_sk_hash_lock);
@@ -1105,7 +1105,7 @@ static void netlink_remove(struct sock *sk) 


	mutex_lock(&nl_sk_hash_lock);

	table = &nl_table[sk->sk_protocol];

	if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node, GFP_KERNEL)) {

	if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node)) {

		WARN_ON(atomic_read(&sk->sk_refcnt) == 1);

		__sock_put(sk);

	}

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