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Merge branch 'aram/isc_hasmap-iterators-use-atomics' into 'main'

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Use atomics for the the iterators number of isc_hashmap_t

See merge request isc-projects/bind9!8474
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Arаm Sаrgsyаn
2023-11-14 08:58:04 +00:00
parent 9ac0f2df9e b6ae7ec82b
commit 4b419cec95
2 changed files with 9 additions and 6 deletions
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3
CHANGES
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@@ -1,3 +1,6 @@
6283. [bug] Fix a data race in isc_hashmap by using atomics for the
iterators number. [GL !8474]
6282. [func] Deprecate AES-based DNS cookies. [GL #4421]
6281. [bug] Fix a data race in dns_tsigkeyring_dump(). [GL #4328]

12
lib/isc/hashmap.c
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@@ -31,6 +31,7 @@
#include <string.h>
#include <isc/ascii.h>
#include <isc/atomic.h>
#include <isc/entropy.h>
#include <isc/hash.h>
#include <isc/hashmap.h>
@@ -87,7 +88,7 @@ struct isc_hashmap {
isc_mem_t *mctx;
size_t count;
hashmap_table_t tables[HASHMAP_NUM_TABLES];
uint_fast32_t iterators;
atomic_uint_fast32_t iterators;
};
struct isc_hashmap_iter {
@@ -352,7 +353,7 @@ hashmap_rehash_one(isc_hashmap_t *hashmap) {
hashmap_node_t node;
/* Don't rehash when iterating */
INSIST(hashmap->iterators == 0);
INSIST(atomic_load_acquire(&hashmap->iterators) == 0);
/* Find first non-empty node */
while (hashmap->hiter < oldsize && oldtable[hashmap->hiter].key == NULL)
@@ -506,7 +507,7 @@ hashmap_add(isc_hashmap_t *hashmap, const uint32_t hashval,
hashmap_node_t *current = NULL;
uint32_t pos;
INSIST(hashmap->iterators == 0);
INSIST(atomic_load_acquire(&hashmap->iterators) == 0);
hash = isc_hash_bits32(hashval, hashmap->tables[idx].hashbits);
@@ -605,7 +606,7 @@ isc_hashmap_iter_create(isc_hashmap_t *hashmap, isc_hashmap_iter_t **iterp) {
.hindex = hashmap->hindex,
};
hashmap->iterators++;
(void)atomic_fetch_add_release(&hashmap->iterators, 1);
*iterp = iter;
}
@@ -622,8 +623,7 @@ isc_hashmap_iter_destroy(isc_hashmap_iter_t **iterp) {
hashmap = iter->hashmap;
isc_mem_put(hashmap->mctx, iter, sizeof(*iter));
INSIST(hashmap->iterators > 0);
hashmap->iterators--;
INSIST(atomic_fetch_sub_release(&hashmap->iterators, 1) > 0);
}
static isc_result_t