5.4-stable review patch. If anyone has any objections, please let me know.
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From: Hou Tao houtao1@huawei.com
[ Upstream commit eae6a075e9537dd69891cf77ca5a88fa8a28b4a1 ]
Add the currently missing handling for the BPF_EXIST and BPF_NOEXIST flags. These flags can be specified by users and are relevant since LPM trie supports exact matches during update.
Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation") Reviewed-by: Toke Høiland-Jørgensen toke@redhat.com Acked-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Hou Tao houtao1@huawei.com Link: https://lore.kernel.org/r/20241206110622.1161752-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 c372be6df264e..1f92d531b4466 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -364,6 +364,10 @@ static int 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; } @@ -372,18 +376,31 @@ static int 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); kfree_rcu(node, rcu);
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. */