On Fri, Apr 3, 2015 at 8:51 AM, Tom Zanussi <tom.zanu...@linux.intel.com> wrote:
> +static struct hist_trigger_entry *
> +tracing_map_insert(struct tracing_map *map, void *key)
> +{
> + u32 idx, key_hash, test_key;
> +
> + key_hash = jhash(key, map->key_size, 0);
> + idx = key_hash >> (32 - (map->map_bits + 1));
> +
> + while (1) {
> + idx &= (map->map_size - 1);
> + test_key = map->map[idx].key;
> +
> + if (test_key && test_key == key_hash &&
> + keys_match(key, map->map[idx].val->key, map->key_size))
> + return map->map[idx].val;
> +
> + if (!test_key && !cmpxchg(&map->map[idx].key, 0, key_hash)) {
> + struct hist_trigger_entry *entry;
> +
> + entry = hist_trigger_entry_create(map);
> + if (!entry)
> + break;
> + memcpy(entry->key, key, map->key_size);
> + map->map[idx].val = entry;
> +
> + return map->map[idx].val;
> + }
There is obvious race here, since algorithm is not implemented correctly.
Partially inserted key/value is not handled.
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