diff mbox series

[bpf-next,01/10] bpf: Remove unnecessary check when updating LPM trie

Message ID 20241118010808.2243555-2-houtao@huaweicloud.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series Fixes for LPM trie | expand

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Commit Message

Hou Tao Nov. 18, 2024, 1:07 a.m. UTC 
From: Hou Tao <houtao1@huawei.com>

When "node->prefixlen == matchlen" is true, it means that the node is
fully matched. If "node->prefixlen == key->prefixlen" is false, it means
the prefix length of key is greater than the prefix length of node,
otherwise, matchlen will not be equal with node->prefixlen. However, it
also implies that the prefix length of node must be less than
max_prefixlen.

Therefore, "node->prefixlen == trie->max_prefixlen" will always be false
when the check of "node->prefixlen == key->prefixlen" returns false.
Remove this unnecessary comparison.

Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 kernel/bpf/lpm_trie.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Toke Høiland-Jørgensen Nov. 21, 2024, 10:22 a.m. UTC | #1 
Hou Tao <houtao@huaweicloud.com> writes:

> From: Hou Tao <houtao1@huawei.com>
>
> When "node->prefixlen == matchlen" is true, it means that the node is
> fully matched. If "node->prefixlen == key->prefixlen" is false, it means
> the prefix length of key is greater than the prefix length of node,
> otherwise, matchlen will not be equal with node->prefixlen. However, it
> also implies that the prefix length of node must be less than
> max_prefixlen.
>
> Therefore, "node->prefixlen == trie->max_prefixlen" will always be false
> when the check of "node->prefixlen == key->prefixlen" returns false.
> Remove this unnecessary comparison.
>
> Signed-off-by: Hou Tao <houtao1@huawei.com>


Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
diff mbox series

Patch

diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 9b60eda0f727..73fd593d3745 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -364,8 +364,7 @@  static long trie_update_elem(struct bpf_map *map,
 		matchlen = longest_prefix_match(trie, node, key);
 
 		if (node->prefixlen != matchlen ||
-		    node->prefixlen == key->prefixlen ||
-		    node->prefixlen == trie->max_prefixlen)
+		    node->prefixlen == key->prefixlen)
 			break;
 
 		next_bit = extract_bit(key->data, node->prefixlen);