Commit 5af68ef7 authored by NeilBrown's avatar NeilBrown Committed by David S. Miller
Browse files

rhashtable: simplify nested_table_alloc() and rht_bucket_nested_insert() 



Now that we don't use the hash value or shift in nested_table_alloc()
there is room for simplification.
We only need to pass a "is this a leaf" flag to nested_table_alloc(),
and don't need to track as much information in
rht_bucket_nested_insert().

Note there is another minor cleanup in nested_table_alloc() here.
The number of elements in a page of "union nested_tables" is most naturally

  PAGE_SIZE / sizeof(ntbl[0])

The previous code had

  PAGE_SIZE / sizeof(ntbl[0].bucket)

which happens to be the correct value only because the bucket uses all
the space in the union.

Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9b4f64a2

lib/rhashtable.c

+6 −12
Original line number Diff line number Diff line
@@ -116,7 +116,7 @@ static void bucket_table_free_rcu(struct rcu_head *head) 


static union nested_table *nested_table_alloc(struct rhashtable *ht,

					      union nested_table __rcu **prev,

					      unsigned int shifted)

					      bool leaf)

{

	union nested_table *ntbl;

	int i;
@@ -127,8 +127,8 @@ static union nested_table *nested_table_alloc(struct rhashtable *ht, 


	ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC);



	if (ntbl && shifted) {

		for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0].bucket); i++)

	if (ntbl && leaf) {

		for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0]); i++)

			INIT_RHT_NULLS_HEAD(ntbl[i].bucket);

	}
@@ -155,7 +155,7 @@ static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, 
		return NULL;



	if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets,

				0)) {

				false)) {

		kfree(tbl);

		return NULL;

	}
@@ -1207,24 +1207,18 @@ struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, 
	unsigned int index = hash & ((1 << tbl->nest) - 1);

	unsigned int size = tbl->size >> tbl->nest;

	union nested_table *ntbl;

	unsigned int shifted;

	unsigned int nhash;



	ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);

	hash >>= tbl->nest;

	nhash = index;

	shifted = tbl->nest;

	ntbl = nested_table_alloc(ht, &ntbl[index].table,

				  size <= (1 << shift) ? shifted : 0);

				  size <= (1 << shift));



	while (ntbl && size > (1 << shift)) {

		index = hash & ((1 << shift) - 1);

		size >>= shift;

		hash >>= shift;

		nhash |= index << shifted;

		shifted += shift;

		ntbl = nested_table_alloc(ht, &ntbl[index].table,

					  size <= (1 << shift) ? shifted : 0);

					  size <= (1 << shift));

	}



	if (!ntbl)

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