[PATCH] connector: Fix proc_event_num_listeners count not cleared

[PATCH] connector: Fix proc_event_num_listeners count not cleared

[wangkeqi]

From: wangkeqi <wangkeqiwang@didiglobal.com>

When we register a cn_proc listening event, the proc_event_num_listener
variable will be incremented by one, but if PROC_CN_MCAST_IGNORE is
not called, the count will not decrease.
This will cause the proc_*_connector function to take the wrong path.
It will reappear when the forkstat tool exits via ctrl + c.
We solve this problem by determining whether
there are still listeners to clear proc_event_num_listener.

Signed-off-by: wangkeqi <wangkeqiwang@didiglobal.com>
---
 drivers/connector/cn_proc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 44b19e696..3d5e6d705 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -108,8 +108,9 @@ static inline void send_msg(struct cn_msg *msg)
 		filter_data[1] = 0;
 	}
 
-	cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
-			     cn_filter, (void *)filter_data);
+	if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
+			     cn_filter, (void *)filter_data) == -ESRCH)
+		atomic_set(&proc_event_num_listeners, 0);
 
 	local_unlock(&local_event.lock);
 }
-- 
2.27.0

Re: [PATCH] connector: Fix proc_event_num_listeners count not cleared

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Sat, 23 Dec 2023 14:50:32 +0800 you wrote:
> From: wangkeqi <wangkeqiwang@didiglobal.com>
> 
> When we register a cn_proc listening event, the proc_event_num_listener
> variable will be incremented by one, but if PROC_CN_MCAST_IGNORE is
> not called, the count will not decrease.
> This will cause the proc_*_connector function to take the wrong path.
> It will reappear when the forkstat tool exits via ctrl + c.
> We solve this problem by determining whether
> there are still listeners to clear proc_event_num_listener.
> 
> [...]

Here is the summary with links:
  - connector: Fix proc_event_num_listeners count not cleared
    https://git.kernel.org/netdev/net/c/c46bfba1337d

You are awesome, thank you!
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