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.
> 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
>
