[PATCH net-next] tcp_metrics: fix tcp_metrics_nl_dump() return value

[PATCH net-next] tcp_metrics: fix tcp_metrics_nl_dump() return value

[Eric Dumazet]

Change tcp_metrics_nl_dump() to return 0 at the end
of a dump so that NLMSG_DONE can be appended
to the current skb, saving one recvmsg() system call.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp_metrics.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index c2a925538542b5d787596b7d76705dda86cf48d8..301881eb23f376339d59a62bebf150b4b1cae3fb 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -766,6 +766,7 @@ static int tcp_metrics_nl_dump(struct sk_buff *skb,
 	unsigned int max_rows = 1U << tcp_metrics_hash_log;
 	unsigned int row, s_row = cb->args[0];
 	int s_col = cb->args[1], col = s_col;
+	int res = 0;
 
 	for (row = s_row; row < max_rows; row++, s_col = 0) {
 		struct tcp_metrics_block *tm;
@@ -778,7 +779,8 @@ static int tcp_metrics_nl_dump(struct sk_buff *skb,
 				continue;
 			if (col < s_col)
 				continue;
-			if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
+			res = tcp_metrics_dump_info(skb, cb, tm);
+			if (res < 0) {
 				rcu_read_unlock();
 				goto done;
 			}
@@ -789,7 +791,7 @@ static int tcp_metrics_nl_dump(struct sk_buff *skb,
 done:
 	cb->args[0] = row;
 	cb->args[1] = col;
-	return skb->len;
+	return res;
 }
 
 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
-- 
2.44.0.683.g7961c838ac-goog

Re: [PATCH net-next] tcp_metrics: fix tcp_metrics_nl_dump() return value

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 16 Apr 2024 16:11:12 +0000 you wrote:
> Change tcp_metrics_nl_dump() to return 0 at the end
> of a dump so that NLMSG_DONE can be appended
> to the current skb, saving one recvmsg() system call.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
>  net/ipv4/tcp_metrics.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Here is the summary with links:
  - [net-next] tcp_metrics: fix tcp_metrics_nl_dump() return value
    https://git.kernel.org/netdev/net-next/c/ade1c9cc404a

You are awesome, thank you!
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