From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB10C248F47 for ; Tue, 11 Nov 2025 10:47:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762858079; cv=none; b=ez1BlKM598HX8nvJglPGCP427jIgKH6CEtgTAfk7NSy/mYhNv6l74dD78/tbncR8Cy22JXT/xyQthiDDzWTIDxjkxo/+jq5WTL3uJRlpS5ggh7JcT77uBwhyacdMvwNYQwhNJZUKz9l4Jbn/yRCvNvG4P1dDn1Zge2WkkYO9rZc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762858079; c=relaxed/simple; bh=WfUCYKomq065xhjullLuTILgOb0RdHyS2EMF53wqVws=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XbkHDGMdMaF2q544J/2fg886aBs6g4buHGN5QpRScCE+zan+AphTUXctY70GgOUREOqT2CBz1oZ+P5/+CQygTQiDmw8FKRrhV9VYFwEs07pDJndm3J6CP/aB2e39Pg3lV/deBkL+Txsc8g8KhiivLJFKpCNDzZXEMDmYK2t2Jk4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=InNTWs9p; arc=none smtp.client-ip=209.85.210.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="InNTWs9p" Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-7afc154e411so2427874b3a.1 for ; Tue, 11 Nov 2025 02:47:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1762858077; x=1763462877; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=KGM7v17X5fBjnUVPBs36cQEsoFHwlXkRLxBvLVWWErg=; b=InNTWs9pHe/+aVO8dwNa+HcMialSUjjTYWzOPDgL3TCnagT87j2UVwGBGYpFzcFqP1 CD+7gHWpC0HRT3CYdW2gDRMj+dN8qEYxEsqLtm4oXzFUlKnVAGHdRIvsSnGLupuHqgQD bmQeo1dNsVmDG2DpF61pAEtqSCKSAgyn5LCn1GQvjiKaXNRVhbmANeENrwc0/cQC7/g3 fKFgJ0kakyW+Ewwz+G4B1QIACdraTBqwNYtJpm/KzfVvDb5fWBT3r0qIzIStm64Tn2xI WaYbQcU9xJxLlDog6ROOcLPhLZCb5iTJgTELGyzeZ/geWX9zYoQBX1UPnq0RiWhbsHei pGWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762858077; x=1763462877; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=KGM7v17X5fBjnUVPBs36cQEsoFHwlXkRLxBvLVWWErg=; b=VQCXjAYjaVPgTHrkvxsPPPnFywhBuSj/jL0zrPu5VcgYaa7FHLsnTgcpQr5+N3/4Wx 2KexoFw5+2ZWuPfsuook36BoDkaX1dYJTpfZLfABOFz0insPSrtZD/Q+uY1zIFCmNGue I0RDpA3oWVMt7zcvstkWRcIhF1Igri86f7HRkK8cgdzukhMEKGP9KBfNdC9dooO3rLPD 4Rwk/S4nzdL/HILCBRIjE16cALrMVIRMHm3y6zems2GSWQj/19nkCakpsHaY+Ywbxj+l UACiSj8el9nr3hmj5ZM6h/aQO15Q2gmQ0GdtIFGgzzNrPLbI4jmL6Jrbb0VCaP/Glovz lv0g== X-Gm-Message-State: AOJu0YydJc+5woGRQHnR2Bmn/fureIH4On7SiE3298bdSgoI7Yd2MmcK I4x6DgIwStq6tbnSayYzvFhkqUhEF2OlFpFDECEsxWmnEWKmnj4EZcAS X-Gm-Gg: ASbGncs9O9PUKo5uAIM+CHypZ6dZkCpNYxc7CEtCeub8uPlX7g7okoBET/bp8QNOcNG ANl4iHfyqPd/atHGe5TZcw5XQHWTayIXM02CsWzYNFjSq2QL6AOdbOBsSlMG+XlO8yPyEpel82Q uR+vWiHz7M+JA5yfK245X2JJye5PSUB/4TqZYfsz98tbqbDok4z7uP3JSrFjD/W9wuzkcdNz79d OVSIbSyH8pWPO1VBnZPEn0vrIZk2RTfqyJw+S6xhGCAd6HDaiDkK46nADySR0ap8jy0MayYMUK8 hmIGAXDjw9mO6dndJPElX2Zd/0WpNUZ8rl28XQNxuo8Ceihr/BhPWUmhNuj26kywPW6cDBBdPgf 1J4mtZHjxk2F6YWNgg9el5spIXZ0zAWOBKSf/IcEniWUcILXc3ROXRZ2cqocfSbiFa3CYb3PxzA == X-Google-Smtp-Source: AGHT+IEGEeJH5qOCRfzOE45L5zCqZ3JL5eKpNLRtF+FdalHg2ufAcdmgy4UMZm2EL294xytUUaIh9g== X-Received: by 2002:a05:6a00:ccc:b0:77f:4c3e:c19d with SMTP id d2e1a72fcca58-7b225c8d22bmr14790664b3a.12.1762858077096; Tue, 11 Nov 2025 02:47:57 -0800 (PST) Received: from gmail.com ([2a09:bac1:19c0:20::4:2ee]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7b0ccd4edc3sm14912911b3a.66.2025.11.11.02.47.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Nov 2025 02:47:56 -0800 (PST) From: Qingfang Deng To: Namjae Jeon , Steve French , Sergey Senozhatsky , Tom Talpey , Hyunchul Lee , Ronnie Sahlberg , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org, Stefan Metzmacher Subject: [PATCH v2] ksmbd: server: avoid busy polling in accept loop Date: Tue, 11 Nov 2025 18:47:49 +0800 Message-ID: <20251111104750.25739-1-dqfext@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The ksmbd listener thread was using busy waiting on a listening socket by calling kernel_accept() with SOCK_NONBLOCK and retrying every 100ms on -EAGAIN. Since this thread is dedicated to accepting new connections, there is no need for non-blocking mode. Switch to a blocking accept() call instead, allowing the thread to sleep until a new connection arrives. This avoids unnecessary wakeups and CPU usage. During teardown, call shutdown() on the listening socket so that accept() returns -EINVAL and the thread exits cleanly. The socket release mutex is redundant because kthread_stop() blocks until the listener thread returns, guaranteeing safe teardown ordering. Also remove sk_rcvtimeo and sk_sndtimeo assignments, which only caused accept() to return -EAGAIN prematurely. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Signed-off-by: Qingfang Deng --- v1 -> v2: https://lore.kernel.org/linux-cifs/20251030064736.24061-1-dqfext@gmail.com Do not remove TCP_NODELAY, as accepted sockets inherits from it. Fix accept() blocking forever on older kernel versions. Remove a redundant mutex fs/smb/server/transport_tcp.c | 28 ++++++---------------------- 1 file changed, 6 insertions(+), 22 deletions(-) diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 6e03e93321b8..79319815b2fc 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -22,7 +22,6 @@ struct interface { struct socket *ksmbd_socket; struct list_head entry; char *name; - struct mutex sock_release_lock; int state; }; @@ -236,20 +235,14 @@ static int ksmbd_kthread_fn(void *p) unsigned int max_ip_conns; while (!kthread_should_stop()) { - mutex_lock(&iface->sock_release_lock); if (!iface->ksmbd_socket) { - mutex_unlock(&iface->sock_release_lock); break; } - ret = kernel_accept(iface->ksmbd_socket, &client_sk, - SOCK_NONBLOCK); - mutex_unlock(&iface->sock_release_lock); - if (ret) { - if (ret == -EAGAIN) - /* check for new connections every 100 msecs */ - schedule_timeout_interruptible(HZ / 10); + ret = kernel_accept(iface->ksmbd_socket, &client_sk, 0); + if (ret == -EINVAL) + break; + if (ret) continue; - } if (!server_conf.max_ip_connections) goto skip_max_ip_conns_limit; @@ -458,10 +451,6 @@ static void tcp_destroy_socket(struct socket *ksmbd_socket) if (!ksmbd_socket) return; - /* set zero to timeout */ - ksmbd_tcp_rcv_timeout(ksmbd_socket, 0); - ksmbd_tcp_snd_timeout(ksmbd_socket, 0); - ret = kernel_sock_shutdown(ksmbd_socket, SHUT_RDWR); if (ret) pr_err("Failed to shutdown socket: %d\n", ret); @@ -532,9 +521,6 @@ static int create_socket(struct interface *iface) goto out_error; } - ksmbd_socket->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT; - ksmbd_socket->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT; - ret = kernel_listen(ksmbd_socket, KSMBD_SOCKET_BACKLOG); if (ret) { pr_err("Port listen() error: %d\n", ret); @@ -604,12 +590,11 @@ static int ksmbd_netdev_event(struct notifier_block *nb, unsigned long event, if (iface && iface->state == IFACE_STATE_CONFIGURED) { ksmbd_debug(CONN, "netdev-down event: netdev(%s) is going down\n", iface->name); + kernel_sock_shutdown(iface->ksmbd_socket, SHUT_RDWR); tcp_stop_kthread(iface->ksmbd_kthread); iface->ksmbd_kthread = NULL; - mutex_lock(&iface->sock_release_lock); - tcp_destroy_socket(iface->ksmbd_socket); + sock_release(iface->ksmbd_socket); iface->ksmbd_socket = NULL; - mutex_unlock(&iface->sock_release_lock); iface->state = IFACE_STATE_DOWN; break; @@ -672,7 +657,6 @@ static struct interface *alloc_iface(char *ifname) iface->name = ifname; iface->state = IFACE_STATE_DOWN; list_add(&iface->entry, &iface_list); - mutex_init(&iface->sock_release_lock); return iface; } -- 2.43.0