Hi Thomas,
On 11/18/2024 9:39 PM, Thomas Weißschuh wrote:
> On Mon, Nov 18, 2024 at 09:08:01AM +0800, Hou Tao wrote:
>> From: Hou Tao <houtao1@xxxxxxxxxx>
>>
>> There is exact match during the update of LPM trie, therefore, add the
>> missed handling for BPF_EXIST and BPF_NOEXIST flags.
> "There is" can be interpreted as "this can be true" and "this will
> always be true".
>
> Maybe:
>
> Add the currently missing handling for the BPF_EXIST and BPF_NOEXIST
> flags, as these can be specified by users.
Will fix it in v2. Thanks.
>
>> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
>> ---
>> kernel/bpf/lpm_trie.c | 23 ++++++++++++++++++++---
>> 1 file changed, 20 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
>> index c6f036e3044b..4300bd51ec6e 100644
>> --- a/kernel/bpf/lpm_trie.c
>> +++ b/kernel/bpf/lpm_trie.c
>> @@ -375,6 +375,10 @@ static long trie_update_elem(struct bpf_map *map,
>> * simply assign the @new_node to that slot and be done.
>> */
>> if (!node) {
>> + if (flags == BPF_EXIST) {
>> + ret = -ENOENT;
>> + goto out;
>> + }
>> rcu_assign_pointer(*slot, new_node);
>> goto out;
>> }
>> @@ -383,18 +387,31 @@ static long trie_update_elem(struct bpf_map *map,
>> * which already has the correct data array set.
>> */
>> if (node->prefixlen == matchlen) {
>> + if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) {
>> + if (flags == BPF_NOEXIST) {
>> + ret = -EEXIST;
>> + goto out;
>> + }
>> + trie->n_entries--;
>> + } else if (flags == BPF_EXIST) {
>> + ret = -ENOENT;
>> + goto out;
>> + }
>> +
>> new_node->child[0] = node->child[0];
>> new_node->child[1] = node->child[1];
>>
>> - if (!(node->flags & LPM_TREE_NODE_FLAG_IM))
>> - trie->n_entries--;
>> -
>> rcu_assign_pointer(*slot, new_node);
>> free_node = node;
>>
>> goto out;
>> }
>>
>> + if (flags == BPF_EXIST) {
>> + ret = -ENOENT;
>> + goto out;
>> + }
>> +
>> /* If the new node matches the prefix completely, it must be inserted
>> * as an ancestor. Simply insert it between @node and *@slot.
>> */
>> --
>> 2.29.2
>>
