From nobody Mon Feb 9 07:57:30 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2594111713; Sun, 4 Feb 2024 08:24:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707035071; cv=none; b=MF0UyPpC5Mrcdas3SynwJw7Imtzvlwzb8F974e4lnEkFg0ylbeEUO/rQVDgGImDguxfvL7tG9lJVyaikv06Zg3YooKDlbQpEnmDx/QGB+hrX9kDywmDXyDtU6gWlnXZZvyHJqWIELRdQ5emclnq6OTami/rtRvGSeieoywHLo4c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707035071; c=relaxed/simple; bh=5J+cliO+JfXljBtGpCxBP37ieE0cdrIyo1s8/G5n0vM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=XjGoY+cJhuJyaJLI+uWmX2Om7MQDFgj+nd/ZPGd5eryitk3tdkMoJWntyIJ2xD5s+2ip5Qhp1qogP6A67qb7f5K6UdQtPqgc0lOK1qSgE+2D2Ah6fBn1aElOSyBzR3k3Cc4RDScEFceWra+i3P/ldLbQKOseVRV/GayKg5Ivivc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=E9cnJY86; arc=none smtp.client-ip=220.197.31.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="E9cnJY86" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=6hr8j nxuo0qxber3AjHkZ7sw07jBpaZDRkw/V8bFWuU=; b=E9cnJY86fbOiNGulMVQbc Cr45HoPhTbyTNDDetFyxr6RWX84azZ7B7y+XcV6HovA47UjkSxcZnqRMVVsVRQVL 5kkzScCqqQNm8/ra1vT1gEyoD4RrmA3FJXqFmUoIqDnkrBBlcGE2p/lCpwdtBHWY fHRWJ4d/C64lo4mPtDoBuA= Received: from localhost.localdomain (unknown [111.202.47.2]) by gzga-smtp-mta-g1-1 (Coremail) with SMTP id _____wCHD26ASb9lFOq2Ag--.34886S2; Sun, 04 Feb 2024 16:23:29 +0800 (CST) From: Keqi Wang To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Keqi Wang , kernel test robot Subject: [PATCH] connector/cn_proc: cn_netlink_has_listeners replaces proc_event_num_listeners Date: Sun, 4 Feb 2024 16:22:51 +0800 Message-Id: <20240204082251.5118-1-wangkeqi_chris@163.com> X-Mailer: git-send-email 2.27.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wCHD26ASb9lFOq2Ag--.34886S2 X-Coremail-Antispam: 1Uf129KBjvJXoW3Xry5uF1kur1xur4DJrW3Awb_yoW3Jr1UpF Z09r9xtrWDKr17Wwn8A3Wq9rnxZa4kXayUCFWxKwn3Ar1fKr1kJFW8JanxAF1fJ34kKr17 Za17KFWa9F4DAaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pRqsUNUUUUU= X-CM-SenderInfo: 5zdqwy5htlsupkul2qqrwthudrp/xtbBzwZ63GV4HslgngAAsb Content-Type: text/plain; charset="utf-8" It is not accurate to reset proc_event_num_listeners according to cn_netlink_send_mult() return value -ESRCH. In the case of stress-ng netlink-proc, -ESRCH will always be returned, because netlink_broadcast_filtered will return -ESRCH, which may cause stress-ng netlink-proc performance degradation. proc_event_num_listeners cannot accurately reflect whether the listener exists, so add cn_netlink_has_listeners() functon and use that instead of proc_event_num_listeners. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202401112259.b23a1567-oliver.sang@in= tel.com Fixes: c46bfba1337d ("connector: Fix proc_event_num_listeners count not cle= ared") Signed-off-by: Keqi Wang --- drivers/connector/cn_proc.c | 46 +++++++++++++++++------------------ drivers/connector/connector.c | 9 +++++++ include/linux/connector.h | 2 ++ 3 files changed, 34 insertions(+), 23 deletions(-) diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index 3d5e6d705..5d0339ee7 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -36,7 +36,6 @@ static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffe= r) return (struct cn_msg *)(buffer + 4); } =20 -static atomic_t proc_event_num_listeners =3D ATOMIC_INIT(0); static struct cb_id cn_proc_event_id =3D { CN_IDX_PROC, CN_VAL_PROC }; =20 /* local_event.count is used as the sequence number of the netlink message= */ @@ -85,6 +84,16 @@ static int cn_filter(struct sock *dsk, struct sk_buff *s= kb, void *data) return 1; } =20 +static int cn_netlink_has_listeners(void) +{ + struct sock *sk =3D cn_cdev_nls_get(); + + if (sk) + return netlink_has_listeners(sk, CN_IDX_PROC); + else + return 0; +} + static inline void send_msg(struct cn_msg *msg) { __u32 filter_data[2]; @@ -108,9 +117,8 @@ static inline void send_msg(struct cn_msg *msg) filter_data[1] =3D 0; } =20 - if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT, - cn_filter, (void *)filter_data) =3D=3D -ESRCH) - atomic_set(&proc_event_num_listeners, 0); + cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT, + cn_filter, (void *)filter_data); =20 local_unlock(&local_event.lock); } @@ -122,7 +130,7 @@ void proc_fork_connector(struct task_struct *task) __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); struct task_struct *parent; =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -151,7 +159,7 @@ void proc_exec_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -176,7 +184,7 @@ void proc_id_connector(struct task_struct *task, int wh= ich_id) __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); const struct cred *cred; =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -213,7 +221,7 @@ void proc_sid_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -237,7 +245,7 @@ void proc_ptrace_connector(struct task_struct *task, in= t ptrace_id) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -269,7 +277,7 @@ void proc_comm_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -295,7 +303,7 @@ void proc_coredump_connector(struct task_struct *task) struct task_struct *parent; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -328,7 +336,7 @@ void proc_exit_connector(struct task_struct *task) struct task_struct *parent; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -370,7 +378,7 @@ static void cn_proc_ack(int err, int rcvd_seq, int rcvd= _ack) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -396,10 +404,10 @@ static void cn_proc_ack(int err, int rcvd_seq, int rc= vd_ack) static void cn_proc_mcast_ctl(struct cn_msg *msg, struct netlink_skb_parms *nsp) { - enum proc_cn_mcast_op mc_op =3D 0, prev_mc_op =3D 0; + enum proc_cn_mcast_op mc_op =3D 0; struct proc_input *pinput =3D NULL; enum proc_cn_event ev_type =3D 0; - int err =3D 0, initial =3D 0; + int err =3D 0; struct sock *sk =3D NULL; =20 /*=20 @@ -436,10 +444,6 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, err =3D ENOMEM; goto out; } - initial =3D 1; - } else { - prev_mc_op =3D - ((struct proc_input *)(sk->sk_user_data))->mcast_op; } ((struct proc_input *)(sk->sk_user_data))->event_type =3D ev_type; @@ -448,12 +452,8 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, =20 switch (mc_op) { case PROC_CN_MCAST_LISTEN: - if (initial || (prev_mc_op !=3D PROC_CN_MCAST_LISTEN)) - atomic_inc(&proc_event_num_listeners); break; case PROC_CN_MCAST_IGNORE: - if (!initial && (prev_mc_op !=3D PROC_CN_MCAST_IGNORE)) - atomic_dec(&proc_event_num_listeners); ((struct proc_input *)(sk->sk_user_data))->event_type =3D PROC_EVENT_NONE; break; diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c index 7f7b94f61..540249d6d 100644 --- a/drivers/connector/connector.c +++ b/drivers/connector/connector.c @@ -129,6 +129,15 @@ int cn_netlink_send(struct cn_msg *msg, u32 portid, u3= 2 __group, } EXPORT_SYMBOL_GPL(cn_netlink_send); =20 +struct sock *cn_cdev_nls_get(void) +{ + if (cn_already_initialized =3D=3D 1) + return cdev.nls; + else + return NULL; +} +EXPORT_SYMBOL_GPL(cn_cdev_nls_get); + /* * Callback helper - queues work and setup destructor for given data. */ diff --git a/include/linux/connector.h b/include/linux/connector.h index cec2d99ae..ca4d0cca7 100644 --- a/include/linux/connector.h +++ b/include/linux/connector.h @@ -127,6 +127,8 @@ int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u= 32 portid, */ int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_m= ask); =20 +struct sock *cn_cdev_nls_get(void); + int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name, const struct cb_id *id, void (*callback)(struct cn_msg *, struct netlink_skb_parms *)); --=20 2.27.0