5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hou Tao <houtao1@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241206110622.1161752-4-houtao@xxxxxxxxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@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 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.
*/
--
2.43.0
