From patchwork Wed Feb 2 12:28:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 12732862 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3FF92C433F5 for ; Wed, 2 Feb 2022 12:28:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344067AbiBBM24 (ORCPT ); Wed, 2 Feb 2022 07:28:56 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:46532 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229955AbiBBM24 (ORCPT ); Wed, 2 Feb 2022 07:28:56 -0500 From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1643804934; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uxK2Br+YSRgI8layahcCJx/qLAO0UkG+gJh96tUahN0=; b=kaTIMGt1u8YwJHjfZz40FPcEepCRDvWM2zASqyzskNmcFdvhgLpgXEXQj+xSYbfCMAaC/n meBxkx7tkzWLx7WYmHOkUVc3iN0qpFsXk1TIh/EcJv+HHYZjZUKyfN76xc9UN/UCz+pI39 ZAuPGMHWbtpEs3sNpzDSD+6Xqub8PMUhAKyzXARrFT2TOw4iv/nWcRAL24Q212rR4q47SN g5Vsm8HOVIf3WdDAeIUkN/0Hp4JzDhypOlIa69Mw16e0J1XrONTERAZzTbplMv9FMzJhjo AVubCJSnfDKKF7Xp31Tz8EOCT51piP6V51WhThsoHEoI6jP4D1XzfFPMXtJGzQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1643804934; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uxK2Br+YSRgI8layahcCJx/qLAO0UkG+gJh96tUahN0=; b=dcOMhmhZoxT1bMa0qCKsJ14XIaEdRnOin1N4DHVjjYpOpJFnE7TP59FA08b7F5CRmZuvMU Und4qPBKeZqRQqDg== To: bpf@vger.kernel.org, netdev@vger.kernel.org Cc: "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Eric Dumazet , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , Thomas Gleixner , Sebastian Andrzej Siewior Subject: [PATCH net-next 3/4] net: dev: Makes sure netif_rx() can be invoked in any context. Date: Wed, 2 Feb 2022 13:28:47 +0100 Message-Id: <20220202122848.647635-4-bigeasy@linutronix.de> In-Reply-To: <20220202122848.647635-1-bigeasy@linutronix.de> References: <20220202122848.647635-1-bigeasy@linutronix.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Dave suggested a while ago (eleven years by now) "Let's make netif_rx() work in all contexts and get rid of netif_rx_ni()". Eric agreed and pointed out that modern devices should use netif_receive_skb() to avoid the overhead. In the meantime someone added another variant, netif_rx_any_context(), which behaves as suggested. netif_rx() must be invoked with disabled bottom halves to ensure that pending softirqs, which were raised within the function, are handled. netif_rx_ni() can be invoked only from process context (bottom halves must be enabled) because the function handles pending softirqs without checking if bottom halves were disabled or not. netif_rx_any_context() invokes on the former functions by checking in_interrupts(). netif_rx() could be taught to handle both cases (disabled and enabled bottom halves) by simply disabling bottom halves while invoking netif_rx_internal(). The local_bh_enable() invocation will then invoke pending softirqs only if the BH-disable counter drops to zero. Add a local_bh_disable() section in netif_rx() to ensure softirqs are handled if needed. Make netif_rx_ni() and netif_rx_any_context() invoke netif_rx() so they can be removed once they are no more users left. Link: https://lkml.kernel.org/r/20100415.020246.218622820.davem@davemloft.net Signed-off-by: Sebastian Andrzej Siewior --- include/linux/netdevice.h | 13 +++++++++++-- include/trace/events/net.h | 14 -------------- net/core/dev.c | 34 ++-------------------------------- 3 files changed, 13 insertions(+), 48 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index e490b84732d16..4086f312f814e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3669,8 +3669,17 @@ u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp, void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog); int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb); int netif_rx(struct sk_buff *skb); -int netif_rx_ni(struct sk_buff *skb); -int netif_rx_any_context(struct sk_buff *skb); + +static inline int netif_rx_ni(struct sk_buff *skb) +{ + return netif_rx(skb); +} + +static inline int netif_rx_any_context(struct sk_buff *skb) +{ + return netif_rx(skb); +} + int netif_receive_skb(struct sk_buff *skb); int netif_receive_skb_core(struct sk_buff *skb); void netif_receive_skb_list_internal(struct list_head *head); diff --git a/include/trace/events/net.h b/include/trace/events/net.h index 78c448c6ab4c5..032b431b987b6 100644 --- a/include/trace/events/net.h +++ b/include/trace/events/net.h @@ -260,13 +260,6 @@ DEFINE_EVENT(net_dev_rx_verbose_template, netif_rx_entry, TP_ARGS(skb) ); -DEFINE_EVENT(net_dev_rx_verbose_template, netif_rx_ni_entry, - - TP_PROTO(const struct sk_buff *skb), - - TP_ARGS(skb) -); - DECLARE_EVENT_CLASS(net_dev_rx_exit_template, TP_PROTO(int ret), @@ -312,13 +305,6 @@ DEFINE_EVENT(net_dev_rx_exit_template, netif_rx_exit, TP_ARGS(ret) ); -DEFINE_EVENT(net_dev_rx_exit_template, netif_rx_ni_exit, - - TP_PROTO(int ret), - - TP_ARGS(ret) -); - DEFINE_EVENT(net_dev_rx_exit_template, netif_receive_skb_list_exit, TP_PROTO(int ret), diff --git a/net/core/dev.c b/net/core/dev.c index 0d13340ed4054..f43d0580fa11d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4834,47 +4834,17 @@ int netif_rx(struct sk_buff *skb) { int ret; + local_bh_disable(); trace_netif_rx_entry(skb); ret = netif_rx_internal(skb); trace_netif_rx_exit(ret); + local_bh_enable(); return ret; } EXPORT_SYMBOL(netif_rx); -int netif_rx_ni(struct sk_buff *skb) -{ - int err; - - trace_netif_rx_ni_entry(skb); - - preempt_disable(); - err = netif_rx_internal(skb); - if (local_softirq_pending()) - do_softirq(); - preempt_enable(); - trace_netif_rx_ni_exit(err); - - return err; -} -EXPORT_SYMBOL(netif_rx_ni); - -int netif_rx_any_context(struct sk_buff *skb) -{ - /* - * If invoked from contexts which do not invoke bottom half - * processing either at return from interrupt or when softrqs are - * reenabled, use netif_rx_ni() which invokes bottomhalf processing - * directly. - */ - if (in_interrupt()) - return netif_rx(skb); - else - return netif_rx_ni(skb); -} -EXPORT_SYMBOL(netif_rx_any_context); - static __latent_entropy void net_tx_action(struct softirq_action *h) { struct softnet_data *sd = this_cpu_ptr(&softnet_data);