From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs@vger.kernel.org, smfrench@gmail.com, tom@talpey.com,
atteh.mailbox@gmail.com
Subject: Re: [PATCH] ksmbd: add max connections parameter
Date: Thu, 29 Dec 2022 11:29:06 +0900 [thread overview]
Message-ID: <Y6z7cjj+OkkVYFYR@google.com> (raw)
In-Reply-To: <20221227145954.9663-1-linkinjeon@kernel.org>
On (22/12/27 23:59), Namjae Jeon wrote:
[..]
> csin = KSMBD_TCP_PEER_SOCKADDR(KSMBD_TRANS(t)->conn);
> if (kernel_getpeername(client_sk, csin) < 0) {
> @@ -239,6 +243,17 @@ static int ksmbd_kthread_fn(void *p)
> continue;
> }
>
> + if (server_conf.max_connections) {
> + if (atomic_read(&active_num_conn) >= server_conf.max_connections) {
> + pr_info("Limit the maximum number of connections(%u)\n",
> + atomic_read(&active_num_conn));
> + sock_release(client_sk);
> + continue;
> + }
> +
> + atomic_inc(&active_num_conn);
> + }
This has to be one atomic op:
if (atomic_inc_return() >= max_connections) {
atomic_dec
sock_release
continue
}
Otherwise it's racy and it's possible to have more active
connections than the limit.
I'd also note that pr_info() is risky there, it would be safer
to use rate-limited printk().
next prev parent reply other threads:[~2022-12-29 2:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-27 14:59 [PATCH] ksmbd: add max connections parameter Namjae Jeon
2022-12-29 2:29 ` Sergey Senozhatsky [this message]
2022-12-29 9:40 ` Namjae Jeon
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