> On Jan 12, 2024, at 11:05 AM, Martin KaFai Lau <martin.lau@xxxxxxxxx> wrote:
>
> From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
>
> The current logic is to use a default size 16 to batch the whole bucket.
> If it is too small, it will retry with a larger batch size.
>
> The current code accidentally does a state->bucket-- before retrying.
> This goes back to retry with the previous bucket which has already
> been done. This patch fixed it.
>
> It is hard to create a selftest. I added a WARN_ON(state->bucket < 0),
> forced a particular port to be hashed to the first bucket,
> created >16 sockets, and observed the for-loop went back
> to the "-1" bucket.
>
> Cc: Aditi Ghag <aditi.ghag@xxxxxxxxxxxxx>
> Fixes: c96dac8d369f ("bpf: udp: Implement batching for sockets iterator")
> Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx>
> Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Reviewed-by: Aditi Ghag <aditi.ghag@xxxxxxxxxxxxx>
LGTM!
> ---
> net/ipv4/udp.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index 89e5a806b82e..978b83d3c094 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -3213,7 +3213,6 @@ static struct sock *bpf_iter_udp_batch(struct seq_file *seq)
> /* After allocating a larger batch, retry one more time to grab
> * the whole bucket.
> */
> - state->bucket--;
> goto again;
> }
> done:
> --
> 2.34.1
>
