From patchwork Tue Jan 5 18:58:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000121 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 377A5C43381 for ; Tue, 5 Jan 2021 19:02:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E705F22D57 for ; Tue, 5 Jan 2021 19:02:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730570AbhAETBu (ORCPT ); Tue, 5 Jan 2021 14:01:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729925AbhAETBt (ORCPT ); Tue, 5 Jan 2021 14:01:49 -0500 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60176C06179E; Tue, 5 Jan 2021 11:00:47 -0800 (PST) Received: by mail-ed1-x536.google.com with SMTP id y24so1833305edt.10; Tue, 05 Jan 2021 11:00:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=mNfzPBhLMMZWAzE97w1+ZZWCiryTh9dlLPyVpfooGOM=; b=htjenFF8D1wjRCV3Ivb7XsHIeCHimPGwGS2vuqUQM1szLxo7iNRaUPr0j5UQSyh838 M9lHVFoIKQisFHKPJEYMX0TPnYxmdiycPagXmEL5LnARRCIep2pYeuiVZCfz7sv9k+iy u8L6iEtVRj1jiyR22zkYxi24d5xHEgRbvGJM1p3ZqXPnXIaNZuO9Fk5UA+A69hClpIup RpS6hCqZhtFo3SvTeU1SSoqOHA+cy5BcR9d/deiGTtNdOXL1mfJemeHwtgYvcl66JlTI zSu3YJJ/PEMtTfAUPW0I0K2mw37nolU4LqM6g68W/BVIxz82ESI2k66h2BM6h5c0DvL6 uAnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=mNfzPBhLMMZWAzE97w1+ZZWCiryTh9dlLPyVpfooGOM=; b=ohL7RT28V2IpzJCZaGllNiPK1H7SZTOtPmV4Ko+5GAiBtEd1LShUU8Qh22MvBM0YM6 GKpyvVlZZ10hH8ftE1zRIh2+Ic/25oJvUqDJpC06+gwL+h1uNWW/W1b3TG8oba51ae4f DR0Dbf7LSYya/C4UJ4NRHJ+rJEKzuYc0S/OBN5MzPBcx6ilDJQjXBm/UiEo/TUytKlic 3ZWzsxOPmFBNBTGjNORCxQWs2ieWeFPMem5cscqS42uu8Y1YLFcm0Z2AxzxWoIoEY+p+ zDK/OUs1Gx0KHUIO3YF2qIqQEtWMhW5zJn8Km9ULxw1HZFF0BF7lZfl2/FjmU1WR/pg4 HZlQ== X-Gm-Message-State: AOAM530QfN09NfIE6zMrGWv1uX+OTARffmgPNTYgwPvUZTOpv9Q0Cx8A lOsl+MQr5OsANP3obyo8WZY= X-Google-Smtp-Source: ABdhPJx4rUUBv+jkf79k31dTgo8if/HFn3r0jcnyalTjeVo11EAzybHYg2Gskk4tCRAHxNA1SnVCyA== X-Received: by 2002:a50:ec18:: with SMTP id g24mr1236916edr.6.1609873246100; Tue, 05 Jan 2021 11:00:46 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:45 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 01/12] net: mark dev_base_lock for deprecation Date: Tue, 5 Jan 2021 20:58:51 +0200 Message-Id: <20210105185902.3922928-2-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean There is a movement to eliminate the usage of dev_base_lock, which exists since as far as I could track the kernel history down (the "7a2deb329241 Import changeset" commit from the bitkeeper branch). The dev_base_lock approach has multiple issues: - It is global and not per netns. - Its meaning has mutated over the years and the vast majority of current users is using it to protect against changes of network device state, as opposed to changes of the interface list. - It is overlapping with other protection mechanisms introduced in the meantime, which have higher performance for readers, like RCU introduced in 2009 by Eric Dumazet for kernel 2.6. The old comment that I just deleted made this distinction: writers protect only against readers by holding dev_base_lock, whereas they need to protect against other writers by holding the RTNL mutex. This is slightly confusing/incorrect, since a rwlock_t cannot have more than one concurrently running writer, so that explanation does not justify why the RTNL mutex would be necessary. Instead, Stephen Hemminger makes this clarification here: https://lore.kernel.org/netdev/20201129211230.4d704931@hermes.local/T/#u | There are really two different domains being covered by locks here. | | The first area is change of state of network devices. This has traditionally | been covered by RTNL because there are places that depend on coordinating | state between multiple devices. RTNL is too big and held too long but getting | rid of it is hard because there are corner cases (like state changes from userspace | for VPN devices). | | The other area is code that wants to do read access to look at list of devices. | These pure readers can/should be converted to RCU by now. Writers should hold RTNL. This patch edits the comment for dev_base_lock, minimizing its role in the protection of network interface lists, and clarifies that it is has other purposes as well. Signed-off-by: Vladimir Oltean --- net/core/dev.c | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index a46334906c94..2aa613d22318 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -169,23 +169,22 @@ static int call_netdevice_notifiers_extack(unsigned long val, static struct napi_struct *napi_by_id(unsigned int napi_id); /* - * The @dev_base_head list is protected by @dev_base_lock and the rtnl - * semaphore. - * - * Pure readers hold dev_base_lock for reading, or rcu_read_lock() - * - * Writers must hold the rtnl semaphore while they loop through the - * dev_base_head list, and hold dev_base_lock for writing when they do the - * actual updates. This allows pure readers to access the list even - * while a writer is preparing to update it. - * - * To put it another way, dev_base_lock is held for writing only to - * protect against pure readers; the rtnl semaphore provides the - * protection against other writers. - * - * See, for example usages, register_netdevice() and - * unregister_netdevice(), which must be called with the rtnl - * semaphore held. + * The network interface list of a netns (@net->dev_base_head) and the hash + * tables per ifindex (@net->dev_index_head) and per name (@net->dev_name_head) + * are protected using the following rules: + * + * Pure readers should hold rcu_read_lock() which should protect them against + * concurrent changes to the interface lists made by the writers. Pure writers + * must serialize by holding the RTNL mutex while they loop through the list + * and make changes to it. + * + * It is also possible to hold the global rwlock_t @dev_base_lock for + * protection (holding its read side as an alternative to rcu_read_lock, and + * its write side as an alternative to the RTNL mutex), however this should not + * be done in new code, since it is deprecated and pending removal. + * + * One other role of @dev_base_lock is to protect against changes in the + * operational state of a network interface. */ DEFINE_RWLOCK(dev_base_lock); EXPORT_SYMBOL(dev_base_lock); From patchwork Tue Jan 5 18:58:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000153 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A822C07D5B for ; Tue, 5 Jan 2021 19:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7178022D58 for ; Tue, 5 Jan 2021 19:02:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730876AbhAETCk (ORCPT ); Tue, 5 Jan 2021 14:02:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730718AbhAETCG (ORCPT ); Tue, 5 Jan 2021 14:02:06 -0500 Received: from mail-ed1-x533.google.com (mail-ed1-x533.google.com [IPv6:2a00:1450:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5853AC06179F; Tue, 5 Jan 2021 11:00:49 -0800 (PST) Received: by mail-ed1-x533.google.com with SMTP id y24so1833525edt.10; Tue, 05 Jan 2021 11:00:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=RJ8dUowMPq3ju2B2o3YV26hFEb1pomATUmoxAPlTqus=; b=GO7hev4U0YJdcgEsK88J9bkR8g3/S6oOiXXivS8BAO4XXMadjuyWthyEQaJfLTQU8H 1DtCrBIJpgmhfZHYYpCpCbObm1o8+Q3w0br77uRKGySHd+NErjtbo8nUJ9uTBaikj/xm ha+1zPYpGxf7Q24YsQkP6ajnLAhmnT33sqAZMipWWhHzaxoZ4NrGUpqHBX/6Mfda7CA9 v2zWxCC3JjJjZFOhV570Qiuul7gfegHhSSn1kYhfygu72yKpW9xu3WnYUJmU8oBXb8QL 5E43oPwO2ZORacZGW+gxBLzBPjyGXgjmmI9/8/JlN+Aw3OF8hOCq/UXbkw60orAEk1ry Sf8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=RJ8dUowMPq3ju2B2o3YV26hFEb1pomATUmoxAPlTqus=; b=YKE9GK9EjToIeEGDOTzt4I/pApo21DCBxB53EB1P72VU2pfrdwfjJXtMlNpQzs8dnZ GeR94gxfiNY23sZfIvRa4itgE92+hMkQD88+r8AdmUwNU00FHbG0V/ugEsa9f0OjSEjL ctQgr/7To3yd1T1cvPf3HigNg4+1OgqEz6rGUMyAAnQOuIkPn6WTJJMF32tTk0j2fpjk +p3fYOi+Ylc0vZDNmBeaXGUmJuOKYvjjzz7awyezxHCf+ZPKTPisOVHpcF3chyJstHHT SgEvhabvryCe3ffdGyKiPL7+tY1/8/H4i8wU6k/sgxJajxVqSFL70gHb0CtIUkrVaxqE tk+Q== X-Gm-Message-State: AOAM532qG3WXudTEjpmYXYIw7C9qYP9aSoubNp3Egar9z7Jfkwy/JLYT eOpRCSHeJwPqd2CA6OjEGVM= X-Google-Smtp-Source: ABdhPJzWjpEMpRNRloZq9Mto5vPvzjgXXIC9uZYEM/t0Vlmggp+gh9m7BU6tGVHsrf+F/rfiXtSgog== X-Received: by 2002:a05:6402:1692:: with SMTP id a18mr1145030edv.321.1609873248090; Tue, 05 Jan 2021 11:00:48 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:47 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 02/12] net: introduce a mutex for the netns interface lists Date: Tue, 5 Jan 2021 20:58:52 +0200 Message-Id: <20210105185902.3922928-3-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean Currently, any writer that wants to alter the lists of network interfaces (either the plain list net->dev_base_head, or the hash tables net->dev_index_head and net->dev_name_head) can keep other writers at bay using the RTNL mutex. However, the RTNL mutex has become a very contended resource over the years, so there is a movement to do finer grained locking. This patch adds one more way for writers to the network interface lists to serialize themselves. We assume that all writers to the network interface lists are easily identifiable because the write side of dev_base_lock also needs to be held (note that some instances of that were deliberately skipped, since they only dealt with protecting the operational state of the netdev). Holding the RTNL mutex is now optional for new code that alters the lists, since all relevant writers were made to also hold the new lock. Signed-off-by: Vladimir Oltean --- include/linux/netdevice.h | 10 +++++++++ include/net/net_namespace.h | 6 +++++ net/core/dev.c | 44 +++++++++++++++++++++++++------------ 3 files changed, 46 insertions(+), 14 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 7bf167993c05..199b3be2cce4 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4393,6 +4393,16 @@ static inline void netif_addr_unlock_bh(struct net_device *dev) spin_unlock_bh(&dev->addr_list_lock); } +static inline void netif_lists_lock(struct net *net) +{ + mutex_lock(&net->netif_lists_lock); +} + +static inline void netif_lists_unlock(struct net *net) +{ + mutex_unlock(&net->netif_lists_lock); +} + /* * dev_addrs walker. Should be used only for read access. Call with * rcu_read_lock held. diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 29567875f428..cac64c3c7ce0 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -183,6 +183,12 @@ struct net { struct sock *crypto_nlsk; #endif struct sock *diag_nlsk; + + /* Serializes writers to @dev_base_head, @dev_name_head and + * @dev_index_head. It does _not_ protect the netif adjacency lists + * (struct net_device::adj_list). + */ + struct mutex netif_lists_lock; } __randomize_layout; #include diff --git a/net/core/dev.c b/net/core/dev.c index 2aa613d22318..1bd41cc91f71 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -175,13 +175,16 @@ static struct napi_struct *napi_by_id(unsigned int napi_id); * * Pure readers should hold rcu_read_lock() which should protect them against * concurrent changes to the interface lists made by the writers. Pure writers - * must serialize by holding the RTNL mutex while they loop through the list - * and make changes to it. + * must serialize by holding the @net->netif_lists_lock mutex while they loop + * through the list and make changes to it. + * + * It is possible to hold the RTNL mutex for serializing the writers too, but + * this should be avoided in new code due to lock contention. * * It is also possible to hold the global rwlock_t @dev_base_lock for * protection (holding its read side as an alternative to rcu_read_lock, and - * its write side as an alternative to the RTNL mutex), however this should not - * be done in new code, since it is deprecated and pending removal. + * its write side as an alternative to @net->netif_lists_lock), however this + * should not be done in new code, since it is deprecated and pending removal. * * One other role of @dev_base_lock is to protect against changes in the * operational state of a network interface. @@ -360,12 +363,14 @@ static void list_netdevice(struct net_device *dev) ASSERT_RTNL(); + netif_lists_lock(net); write_lock_bh(&dev_base_lock); list_add_tail_rcu(&dev->dev_list, &net->dev_base_head); netdev_name_node_add(net, dev->name_node); hlist_add_head_rcu(&dev->index_hlist, dev_index_hash(net, dev->ifindex)); write_unlock_bh(&dev_base_lock); + netif_lists_unlock(net); dev_base_seq_inc(net); } @@ -375,16 +380,20 @@ static void list_netdevice(struct net_device *dev) */ static void unlist_netdevice(struct net_device *dev) { + struct net *net = dev_net(dev); + ASSERT_RTNL(); /* Unlink dev from the device chain */ + netif_lists_lock(net); write_lock_bh(&dev_base_lock); list_del_rcu(&dev->dev_list); netdev_name_node_del(dev->name_node); hlist_del_rcu(&dev->index_hlist); write_unlock_bh(&dev_base_lock); + netif_lists_unlock(net); - dev_base_seq_inc(dev_net(dev)); + dev_base_seq_inc(net); } /* @@ -850,11 +859,11 @@ EXPORT_SYMBOL_GPL(dev_fill_metadata_dst); * @net: the applicable net namespace * @name: name to find * - * Find an interface by name. Must be called under RTNL semaphore - * or @dev_base_lock. If the name is found a pointer to the device - * is returned. If the name is not found then %NULL is returned. The - * reference counters are not incremented so the caller must be - * careful with locks. + * Find an interface by name. Must be called under RTNL semaphore, + * @net->netif_lists_lock or @dev_base_lock. If the name is found, + * a pointer to the device is returned. If the name is not found then + * %NULL is returned. The reference counters are not incremented so the + * caller must be careful with locks. */ struct net_device *__dev_get_by_name(struct net *net, const char *name) @@ -920,8 +929,8 @@ EXPORT_SYMBOL(dev_get_by_name); * Search for an interface by index. Returns %NULL if the device * is not found or a pointer to the device. The device has not * had its reference counter increased so the caller must be careful - * about locking. The caller must hold either the RTNL semaphore - * or @dev_base_lock. + * about locking. The caller must hold either the RTNL semaphore, + * @net->netif_lists_lock or @dev_base_lock. */ struct net_device *__dev_get_by_index(struct net *net, int ifindex) @@ -1330,15 +1339,19 @@ int dev_change_name(struct net_device *dev, const char *newname) netdev_adjacent_rename_links(dev, oldname); + netif_lists_lock(net); write_lock_bh(&dev_base_lock); netdev_name_node_del(dev->name_node); write_unlock_bh(&dev_base_lock); + netif_lists_unlock(net); synchronize_rcu(); + netif_lists_lock(net); write_lock_bh(&dev_base_lock); netdev_name_node_add(net, dev->name_node); write_unlock_bh(&dev_base_lock); + netif_lists_unlock(net); ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev); ret = notifier_to_errno(ret); @@ -9397,8 +9410,9 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, * @net: the applicable net namespace * * Returns a suitable unique value for a new device interface - * number. The caller must hold the rtnl semaphore or the - * dev_base_lock to be sure it remains unique. + * number. + * The caller must hold the rtnl semaphore, @net->netif_lists_lock or the + * @dev_base_lock to be sure it remains unique. */ static int dev_new_index(struct net *net) { @@ -10981,6 +10995,8 @@ static int __net_init netdev_init(struct net *net) if (net->dev_index_head == NULL) goto err_idx; + mutex_init(&net->netif_lists_lock); + RAW_INIT_NOTIFIER_HEAD(&net->netdev_chain); return 0; From patchwork Tue Jan 5 18:58:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000155 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7363BC433E9 for ; Tue, 5 Jan 2021 19:02:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3663122D5B for ; Tue, 5 Jan 2021 19:02:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730867AbhAETCj (ORCPT ); Tue, 5 Jan 2021 14:02:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43270 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730721AbhAETCG (ORCPT ); Tue, 5 Jan 2021 14:02:06 -0500 Received: from mail-ej1-x629.google.com (mail-ej1-x629.google.com [IPv6:2a00:1450:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41C6FC0617A0; Tue, 5 Jan 2021 11:00:51 -0800 (PST) Received: by mail-ej1-x629.google.com with SMTP id ce23so1808096ejb.8; Tue, 05 Jan 2021 11:00:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=gXxH7XycmXvUqlZcFwUkejt1OoMf3vVYxjArYoaytKU=; b=k7aJk7JSeBhjkdQYFq1o74fF9008dhO4twF9GnhDJvNLCvysN5ghZY0MukuT6Ldx5r hjfmUJdABmhBk5KkOrsRUGqy0EapxPCvw1mhmSEDxpRuKg2aFvSKl40pSwwrWuOV3Hk0 GSN6axVYXCoqvCJoZmhqklr+jXNapYiDSKpCfSYX0D2SPOo2HfWFN1L2/P7hd9Ctrvdr yqVyTWk2F8ND0tpE8NarPyhgoS7DeBdv5pU7bmV9kEcmM5lXdfcp1Q8dLMmFyQ4fH3kN F4q1o1beQ8QiB4w4k+5OJ7v09Lhd9FnBi26qe9nITMkNxJPdmGZg9xIeStMil/AoyFlW eVkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gXxH7XycmXvUqlZcFwUkejt1OoMf3vVYxjArYoaytKU=; b=l+v46VUrqZIb/uO1BYtiq9U2bJ895oDtGjMTH/1+Qd/jNNoysrViIanymfiTGDMgzJ YLo/CbqKkeXWhZ36VshyVzeWYhaFU0bW2Ry3vTXC+a2ZBBA6mS0isA7SbJu3G48ktt7m VL3/VzsljlXV1Skk3sUJV4i5PPCGqUVrLcKbD9Rc6abFhDTyz2MYqGAjHjiexdakR6/B sUmx+wjSRD1aKQPqKA1mtAbcHgq+RXll4mQOGaZ/Wnw+bK1aed2u3YZcsTZh+gqYjgyF lfLM6GQ1GXbAcuKI2ReACM02teefWSA87oDR5qm0FMEfHjqvtzAj6Ms4LmgNSurv/W9q 23Kw== X-Gm-Message-State: AOAM532eS4uy6EojWBE/JX8BjCxaexyKIfWnilVnBPUIaW0iPF9kj1EO B30LLkxYMKeQTN5NCOD557k= X-Google-Smtp-Source: ABdhPJwpcymrW8DoPhCny1stgOREGqkJGxUm2ZUJNyqT3MOT+DQW0wnVqqZPBdtZFvzWUrkJqlkOyw== X-Received: by 2002:a17:906:e94c:: with SMTP id jw12mr524669ejb.56.1609873249982; Tue, 05 Jan 2021 11:00:49 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:49 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 03/12] net: procfs: hold netif_lists_lock when retrieving device statistics Date: Tue, 5 Jan 2021 20:58:53 +0200 Message-Id: <20210105185902.3922928-4-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean In the effort of making .ndo_get_stats64 be able to sleep, we need to ensure the callers of dev_get_stats do not use atomic context. The /proc/net/dev file uses an RCU read-side critical section to ensure the integrity of the list of network interfaces, because it iterates through all net devices in the netns to show their statistics. To offer the equivalent protection against an interface registering or deregistering, while also remaining in sleepable context, we can use the netns mutex for the interface lists. Cc: Cong Wang Cc: Eric Dumazet Signed-off-by: Vladimir Oltean --- net/core/net-procfs.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c index c714e6a9dad4..4784703c1e39 100644 --- a/net/core/net-procfs.c +++ b/net/core/net-procfs.c @@ -21,7 +21,7 @@ static inline struct net_device *dev_from_same_bucket(struct seq_file *seq, loff unsigned int count = 0, offset = get_offset(*pos); h = &net->dev_index_head[get_bucket(*pos)]; - hlist_for_each_entry_rcu(dev, h, index_hlist) { + hlist_for_each_entry(dev, h, index_hlist) { if (++count == offset) return dev; } @@ -51,9 +51,11 @@ static inline struct net_device *dev_from_bucket(struct seq_file *seq, loff_t *p * in detail. */ static void *dev_seq_start(struct seq_file *seq, loff_t *pos) - __acquires(RCU) { - rcu_read_lock(); + struct net *net = seq_file_net(seq); + + netif_lists_lock(net); + if (!*pos) return SEQ_START_TOKEN; @@ -70,9 +72,10 @@ static void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos) } static void dev_seq_stop(struct seq_file *seq, void *v) - __releases(RCU) { - rcu_read_unlock(); + struct net *net = seq_file_net(seq); + + netif_lists_unlock(net); } static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev) From patchwork Tue Jan 5 18:58:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000151 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37AA4C433DB for ; Tue, 5 Jan 2021 19:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0895322D57 for ; Tue, 5 Jan 2021 19:02:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730837AbhAETC1 (ORCPT ); Tue, 5 Jan 2021 14:02:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725838AbhAETCH (ORCPT ); Tue, 5 Jan 2021 14:02:07 -0500 Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25E13C0617A2; Tue, 5 Jan 2021 11:00:53 -0800 (PST) Received: by mail-ej1-x636.google.com with SMTP id w1so1758613ejf.11; Tue, 05 Jan 2021 11:00:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VqKUbghIDfYrfb3O7qIi6ZxV/2bVKA7+VXpaNALoN60=; b=o72EV0y5XH6HchkYJqkf18+T0vm0Uz19QPiFec6UrE0bJV5bAouj5tUFThd+IbUeaH yUe448KhNG1blJQxDZTQOSx3bw/rjUuPJafSLUnhGcVcmX+vwhSeVoHv6FFJBmfUSV+u a+CFVILyASpZpXFmOVMNnfqc28/9V6Dagm/1/RVHEVBz9ZLAMbGJ2DgFzJCl+FaHemvK 1GjY//UjxbnawtELZ84EsOXDBNfazICZGH71XgnOA+CXCFm1CTMHQfQ9UV70yrAuXfPB oS/PFIl8l1oqOkgmzlk+HI19tTlFGLDsv257e3gWMIM1kgKEOxMeY7CZjnCo1NcYYmKo gsYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=VqKUbghIDfYrfb3O7qIi6ZxV/2bVKA7+VXpaNALoN60=; b=M1hutG4tPrb4hRVKgwJ0Eg1RUHkNyiR0cC4WrgZI4iiC7Swpc7K1yq8N5SifqP1ZLu hqiO1N+HWterCDoTORwQ3FCeHH2y5RvBz9KZxbhbD8bsV0urLW5RtKpGDszsYFsd7z5K kfw6zsx5MxJRqCIPzPnVZCI4GAyXxl7itZ79+snsCX2aiw2Du8ryKcVn7BDt7uEsQESg 9V2pIvLcrkMUyRed6IIc6pCQWeyv0TAC0rptoraJZJjYiyw2WQuoGbekEcH48AQQtGWa oD1vM9vuhziETvh7C6AmYmH7jpTgX/1yuVp+i5fbv8az0V5zMTjH/4YfCpvgOlHn2yuB roJg== X-Gm-Message-State: AOAM531RutI4t0UBg4w1Xo31Gt+X70Mhk2pFxwDCIyMnGftIZ5/6JPeB SCtV2mABQMJQtisH1TP5JQQ= X-Google-Smtp-Source: ABdhPJz1wURDbCR0bNBYRS2W9HuLCgl2tOQ8FkzBLbjCThN+VIxGm1iq/S2lOXku8roTHNgJI/WFnQ== X-Received: by 2002:a17:906:f0cc:: with SMTP id dk12mr488324ejb.480.1609873251916; Tue, 05 Jan 2021 11:00:51 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:51 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 04/12] net: sysfs: don't hold dev_base_lock while retrieving device statistics Date: Tue, 5 Jan 2021 20:58:54 +0200 Message-Id: <20210105185902.3922928-5-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean In the effort of making .ndo_get_stats64 be able to sleep, we need to ensure the callers of dev_get_stats do not use atomic context. I need to preface this by saying that I have no idea why netstat_show takes the dev_base_lock rwlock. Two things can be observed: (a) it does not appear to be due to dev_isalive requiring it for some reason, because broadcast_show() also calls dev_isalive() and has had no problem existing since the beginning of git. (b) the dev_get_stats function definitely does not need dev_base_lock protection either. In fact, holding the dev_base_lock is the entire problem here, because we want to make dev_get_stats sleepable, and holding a rwlock gives us atomic context. So since no protection seems to be necessary, just run unlocked while retrieving the /sys/class/net/eth0/statistics/* values. Cc: Christian Brauner Cc: Eric Dumazet Signed-off-by: Vladimir Oltean --- net/core/net-sysfs.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 999b70c59761..0782a476b424 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -585,14 +585,13 @@ static ssize_t netstat_show(const struct device *d, WARN_ON(offset > sizeof(struct rtnl_link_stats64) || offset % sizeof(u64) != 0); - read_lock(&dev_base_lock); if (dev_isalive(dev)) { struct rtnl_link_stats64 temp; const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp); ret = sprintf(buf, fmt_u64, *(u64 *)(((u8 *)stats) + offset)); } - read_unlock(&dev_base_lock); + return ret; } From patchwork Tue Jan 5 18:58:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000137 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F514C433DB for ; Tue, 5 Jan 2021 19:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC90522D58 for ; Tue, 5 Jan 2021 19:02:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730773AbhAETCI (ORCPT ); Tue, 5 Jan 2021 14:02:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730731AbhAETCH (ORCPT ); Tue, 5 Jan 2021 14:02:07 -0500 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BC9EC0617A3; Tue, 5 Jan 2021 11:00:55 -0800 (PST) Received: by mail-ed1-x52b.google.com with SMTP id u19so1925350edx.2; Tue, 05 Jan 2021 11:00:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=GLvxCKLmR2t5WVjRUZehiWKIjudvryuha5j5MLp+E+U=; b=qumLfxH/uosKGVeB1d+uK3MGmbPBDq3Tefsa6LeB4yOaqE4sDVmjq8n88J3Af9SWID zE/OzdCWUBmYqSDveMUrnjfExUwlKcXIKocVP4DRlKfB8X7dPGqH22aeXXE/q6RuD9Zb LQwfxmfEdGl3TbU+0kKPfiVdt/xC2UzgwNEoAb2tjMddMwrS4DBZLCzfkVXqKzIo0zW3 CP9CZwsQphbG9aViNf0hnIKUqOBDi3ElTHZlnmNm2VBSM393jCAQK5YMPuys8IGY0V7X +dfIzPdUu6R7MiLk9T5blM730FvW/A6il2bYDlUbIgzJ1vBpdu7ow9UXKeZzSiAcXlmL 98eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=GLvxCKLmR2t5WVjRUZehiWKIjudvryuha5j5MLp+E+U=; b=MWtGXN+NbRv2wHJEFBYPCFMQ/iOrrzCIDIwwFJBynsegB+rB1cVCx6g23V+vDBPX48 VD62MXH8CNrzBJgD6OuzXN1DM0dMACtmwgm83vouBqKWeYCin0VwPtfp7o/CT4xcD5I1 Cz1Y+Wyu+V5/n4UU6zo9K23VTbkBWjhZnI1xjt/qXiTTR+3ovmTGE875l0tewMQTbjR3 M4ib0aFzwPpVyOJ9Yf1uBsYkWOR7qnCpGwvGP9VZD7ybDvVU28lU1pJOt62HpNblPDr3 OIhCnR/UBA2hmvesJdxSm29O2Q3N9ea0bCO5V2zHkfPaYPYO6YwHLlY/4CcfbcNWw5NL jZVA== X-Gm-Message-State: AOAM530FSiRNQCUfVs8q+SpBGQcoXhY/dpSqcTBCtMJgB2G0KS3kM6sd XXXtNjHUwk7OHrozhADcA2k= X-Google-Smtp-Source: ABdhPJy8kPqxEk8FQReSydm1oqxA729aS1Dqn6n2NIipxNBNdXArGt1146Pufkl9aVpc3ocJnHwq7g== X-Received: by 2002:a05:6402:3546:: with SMTP id f6mr1184932edd.242.1609873253835; Tue, 05 Jan 2021 11:00:53 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:53 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 05/12] s390/appldata_net_sum: hold the netdev lists lock when retrieving device statistics Date: Tue, 5 Jan 2021 20:58:55 +0200 Message-Id: <20210105185902.3922928-6-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean In the effort of making .ndo_get_stats64 be able to sleep, we need to ensure the callers of dev_get_stats do not use atomic context. In the case of the appldata driver, an RCU read-side critical section is used to ensure the integrity of the list of network interfaces, because the driver iterates through all net devices in the netns to aggregate statistics. We still need some protection against an interface registering or deregistering, and the writer-side lock, the netns's mutex, is fine for that, because it offers sleepable context. The ops->callback function is called from under appldata_ops_mutex protection, so this is proof that the context is sleepable and holding a mutex is therefore fine. Cc: Heiko Carstens Cc: Vasily Gorbik Cc: linux-s390@vger.kernel.org Signed-off-by: Vladimir Oltean --- arch/s390/appldata/appldata_net_sum.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/s390/appldata/appldata_net_sum.c b/arch/s390/appldata/appldata_net_sum.c index 59c282ca002f..4db886980cba 100644 --- a/arch/s390/appldata/appldata_net_sum.c +++ b/arch/s390/appldata/appldata_net_sum.c @@ -78,8 +78,9 @@ static void appldata_get_net_sum_data(void *data) tx_dropped = 0; collisions = 0; - rcu_read_lock(); - for_each_netdev_rcu(&init_net, dev) { + netif_lists_lock(&init_net); + + for_each_netdev(&init_net, dev) { const struct rtnl_link_stats64 *stats; struct rtnl_link_stats64 temp; @@ -95,7 +96,8 @@ static void appldata_get_net_sum_data(void *data) collisions += stats->collisions; i++; } - rcu_read_unlock(); + + netif_lists_unlock(&init_net); net_data->nr_interfaces = i; net_data->rx_packets = rx_packets; From patchwork Tue Jan 5 18:58:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000145 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21BD1C43142 for ; Tue, 5 Jan 2021 19:02:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E719122EBD for ; Tue, 5 Jan 2021 19:02:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730843AbhAETC2 (ORCPT ); Tue, 5 Jan 2021 14:02:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730730AbhAETCH (ORCPT ); Tue, 5 Jan 2021 14:02:07 -0500 Received: from mail-ed1-x531.google.com (mail-ed1-x531.google.com [IPv6:2a00:1450:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E4CFC0617A4; Tue, 5 Jan 2021 11:00:57 -0800 (PST) Received: by mail-ed1-x531.google.com with SMTP id u19so1925574edx.2; Tue, 05 Jan 2021 11:00:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=eVeK9xT+cQg4LNXHEMfEbDRIq/x+/jlGFuxcqUdAXkk=; b=jcC1h1LA3LIffEisBnCLmI474BqldfIodx219oNGc+tt7jVCAeTtqKvTzzBz9wGywY xLXZnkXKRb4tJyGv2FSzJHQe3VCsEwbeyxT8AM+ZiOvrAmuwX60JfOgfKjjpTrCSdR17 31gEckmvlt5ym/S4IPYsGKaPpRfbE8UmicBunfKEp+VmZp+4a4khM6JGxjI3Hp6mfIJ8 SBgCA6Ud37X2fK6DaSkslK97YsA56gd1r+QXOt2owRbKPq8OTBsc1SvCxnroBUNP6LFZ KYUhIkh6CgrLu0+wPKq4g6GQqq79w3dVBQd9zkObnAhpZI5YaBcR4QNJ4qwqV8rd68uY AMGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=eVeK9xT+cQg4LNXHEMfEbDRIq/x+/jlGFuxcqUdAXkk=; b=H7y3w1G2Hv2h0mbmS8OdpZ0Ftp1U5mc65bZQ26l5x+G8WS791HiJKU9lDCopa3SP+D 7hzk4x/bqkAZIdwwr1BA05NDSNTiFBjKN93CPFA6vJ4u81N6JmAJxBFkOWRuGefsvUiY O/qbGr9l5FipHShAWvw2xTXs7G6l3k8S96SJAUoWaCs3QXQW0Boy54m0fMhA0pidZwfq ZH/Oe8SwGv38u+BqizTuyVVmH1wWSK7VvzjCuIGhGsmd25nuT0uDScw6gC0HcumKWWKS UWqiEAJrqShXqc6ljOo7U+FKzosCURBpkXYpg73g3fJCeFaqQFMMWerI5Dg7VdbH8rgu Lmrg== X-Gm-Message-State: AOAM530P2kp/jg9mRC+2sJZL5Qvbki3w44vR6wNNLdOiyI+QK9GB7fp9 W/Iuu/i7HfVGy6LwGviIONM= X-Google-Smtp-Source: ABdhPJywzGOkFcZAVkyk8PQ8M2oMIBob7kn/MLt8bOAZoMi0V7lOOqZiCgYYmkEvgxwjnb5ltoYSHw== X-Received: by 2002:aa7:dd17:: with SMTP id i23mr1249282edv.14.1609873255865; Tue, 05 Jan 2021 11:00:55 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:55 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 06/12] parisc/led: reindent the code that gathers device statistics Date: Tue, 5 Jan 2021 20:58:56 +0200 Message-Id: <20210105185902.3922928-7-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean The standard in the Linux kernel is to use one tab character per indentation level. Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: linux-parisc@vger.kernel.org Signed-off-by: Vladimir Oltean --- drivers/parisc/led.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c index 36c6613f7a36..3cada632a4be 100644 --- a/drivers/parisc/led.c +++ b/drivers/parisc/led.c @@ -359,16 +359,19 @@ static __inline__ int led_get_net_activity(void) /* we are running as a workqueue task, so we can use an RCU lookup */ rcu_read_lock(); for_each_netdev_rcu(&init_net, dev) { - const struct rtnl_link_stats64 *stats; - struct rtnl_link_stats64 temp; - struct in_device *in_dev = __in_dev_get_rcu(dev); - if (!in_dev || !in_dev->ifa_list) - continue; - if (ipv4_is_loopback(in_dev->ifa_list->ifa_local)) - continue; - stats = dev_get_stats(dev, &temp); - rx_total += stats->rx_packets; - tx_total += stats->tx_packets; + const struct rtnl_link_stats64 *stats; + struct rtnl_link_stats64 temp; + struct in_device *in_dev = __in_dev_get_rcu(dev); + + if (!in_dev || !in_dev->ifa_list) + continue; + + if (ipv4_is_loopback(in_dev->ifa_list->ifa_local)) + continue; + + stats = dev_get_stats(dev, &temp); + rx_total += stats->rx_packets; + tx_total += stats->tx_packets; } rcu_read_unlock(); From patchwork Tue Jan 5 18:58:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000143 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 119A2C43603 for ; Tue, 5 Jan 2021 19:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E97F622D6E for ; Tue, 5 Jan 2021 19:02:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730785AbhAETCJ (ORCPT ); Tue, 5 Jan 2021 14:02:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730733AbhAETCH (ORCPT ); Tue, 5 Jan 2021 14:02:07 -0500 Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22212C0617A5; Tue, 5 Jan 2021 11:00:59 -0800 (PST) Received: by mail-ej1-x62c.google.com with SMTP id q22so1906708eja.2; Tue, 05 Jan 2021 11:00:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=pumKytNb6HfM0fji93xr5G/BhQEYT7JsjEW2ZBlR5iU=; b=JEckJaQsFgR2VLSNLG5i7z0+KlnFs83ZYxvR0iQpvNPQVQcSticPBwdGCbSF9D1XDP faMVx76guT6YBo+oghMniuv45XGzCI9kOXx34jKAUzWzgH3l2lWQ8qRYGB6JP12yfGdf PXk1Uyi+mFeT3ptjmyVyAmzEG8s03OO8PMaQEcI5fSbhi+CZdoBgQozSyOlIBYee4ka/ TuQC8hW7oOtFk41zzRi7d5iy1v8jOvtmUcz3y0ARCtdpxBwKE5wnx5JZLZIicLXqTBHJ Aqa1KrvCJBQmuvF7CwMtnx1arxBqIA8R27l2ApWKEoYhQLef8w9qWcrMbb+cWzRe4dls E77Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=pumKytNb6HfM0fji93xr5G/BhQEYT7JsjEW2ZBlR5iU=; b=ihVIQGBykCeYFC4LDic7xfQ7ebN7NNGOI3pf6+NsCyNm1GWWxNYOi/qsf56ytEFjDE jScEIeZlmwktxfXx+iVfgH0VixxiDedd7bRgU49xkOTjJxuulBkdg5qS2KvZzKtUvMlU CBXnc1c7M8IWcmT2EueMaSa5jQ0hRq1Skm9KCTlPCPQP7A9HnW33nvlV6+8v/sXiH+NO 7VP1lMvd1GbBAYQxin8dRJE1NXIy080mLBTOBwaXGtW9fB5nvoje+nqRwd9fNpgJpUxu IEY41GxFgqRuRh7e5ypF+Vjc/AYxTbbda/1MFhqcfMPWl2nB5KTzvhKnaoWxnZnZ670m aXvg== X-Gm-Message-State: AOAM531J2qZQAynWxNTn42JmEvSijqi26/cEOfloB2N63UR7SagY5+dT YjWQlxUct51eoVhxicaiGw0= X-Google-Smtp-Source: ABdhPJz+1ICzC5RVM3oZs0oQoaJmiaftG0zPzA6tae5qdGfc+GpxdTiRp0F9FQexln0n4DdvvvIthg== X-Received: by 2002:a17:907:d10:: with SMTP id gn16mr478354ejc.496.1609873257847; Tue, 05 Jan 2021 11:00:57 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:57 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 07/12] parisc/led: hold the netdev lists lock when retrieving device statistics Date: Tue, 5 Jan 2021 20:58:57 +0200 Message-Id: <20210105185902.3922928-8-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean In the effort of making .ndo_get_stats64 be able to sleep, we need to ensure the callers of dev_get_stats do not use atomic context. The LED driver for HP-PARISC workstations uses a workqueue to periodically check for updates in network interface statistics, and flicker when those have changed (i.e. there has been activity on the line). Ignoring the fact that this driver is completely duplicating drivers/leds/trigger/ledtrig-netdev.c, there is an even bigger problem. Now, the dev_get_stats call can sleep, and iterating through the list of network interfaces still needs to ensure the integrity of list of network interfaces. So that leaves us only one locking option given the current design of the network stack, and that is the netns mutex. Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: linux-parisc@vger.kernel.org Signed-off-by: Vladimir Oltean --- drivers/parisc/led.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c index 3cada632a4be..c8c6b2301dc9 100644 --- a/drivers/parisc/led.c +++ b/drivers/parisc/led.c @@ -38,7 +38,6 @@ #include #include #include -#include #include #include #include @@ -355,25 +354,29 @@ static __inline__ int led_get_net_activity(void) int retval; rx_total = tx_total = 0; - - /* we are running as a workqueue task, so we can use an RCU lookup */ - rcu_read_lock(); - for_each_netdev_rcu(&init_net, dev) { + + /* we are running as a workqueue task, so we can sleep */ + netif_lists_lock(&init_net); + + for_each_netdev(&init_net, dev) { + struct in_device *in_dev = in_dev_get(dev); const struct rtnl_link_stats64 *stats; struct rtnl_link_stats64 temp; - struct in_device *in_dev = __in_dev_get_rcu(dev); - if (!in_dev || !in_dev->ifa_list) + if (!in_dev || !in_dev->ifa_list || + ipv4_is_loopback(in_dev->ifa_list->ifa_local)) { + in_dev_put(in_dev); continue; + } - if (ipv4_is_loopback(in_dev->ifa_list->ifa_local)) - continue; + in_dev_put(in_dev); stats = dev_get_stats(dev, &temp); rx_total += stats->rx_packets; tx_total += stats->tx_packets; } - rcu_read_unlock(); + + netif_lists_unlock(&init_net); retval = 0; From patchwork Tue Jan 5 18:58:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000141 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F018C43332 for ; Tue, 5 Jan 2021 19:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2191122D6E for ; Tue, 5 Jan 2021 19:02:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730741AbhAETCI (ORCPT ); Tue, 5 Jan 2021 14:02:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730736AbhAETCH (ORCPT ); Tue, 5 Jan 2021 14:02:07 -0500 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CB59C0617A6; Tue, 5 Jan 2021 11:01:01 -0800 (PST) Received: by mail-ej1-x62e.google.com with SMTP id d17so1796358ejy.9; Tue, 05 Jan 2021 11:01:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=uxks8afnGIy+XLwQBohZxs/FQk9BCJLCOLrg4jkUy8E=; b=i8DPvFOrG1nKe5X0EBwtR+0x752ZoanxoNdHHclzm55tWqRgkU8yDTHx/PhXGhLSue dmco61hSzYgpEIHvMhO+Dh2TG4k5REzx+czbSkPIPrKLfY+bBxNhMBplAEPCezeYBM4b HkL7CjxiOSLgmhlW40WWakOnhElVqDjRcit5fCWUURmtrwehQQmQCBugV/ZxXk/DtkYC ksUgcdmM668ZHBHA1r+7rlaDkxUVtsqUB7cUyQv43fQcGb7kz+fz9hX+3U7WNHo4u+Yj WnS86GfwTrOEEdvu2bEH0IQGTXcu/86/zrKdynkPLuDluRBHqan3GXDr+HH1MpPVzgMJ kZmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=uxks8afnGIy+XLwQBohZxs/FQk9BCJLCOLrg4jkUy8E=; b=WnIn61w3v7G+qQCF2yHlNFLdQDPDPeLBcXd2OXfZjNV6UzJkVsqzqWs35nZ+hNEXhs F13Tv+jjb5b4kGfnysQnvkcsxLqAnIcGjzNtzsj0HHcwAUjZ6xKrKfJNMaCqppuNvdHD iJxZLNbW2pSXqc/YqFARUV3fAOk+CWMGL4CeyC/cD7DCZDIDNyHiBYIaDSwL9l7pRCjo o52raWj6DLlHt3dcCqZCaVH9XV7Xt5Q7gJ9gMjNg37RtBhzuUE4Bt3FZnRbc5pK67liX zvzzE6iv/rVHnBbNE266In8B46WLoZPesDsn1MBxP7JvTGvzOSgNRMyn0gjB70Ym0Vc8 0L5A== X-Gm-Message-State: AOAM532a6Ru723hO8ft7uKU0qfOywyyK3s/5nwmrvtxvWG7AlrdjuYqN Gt5Za6CrR01FS+cFOXk6FZQ= X-Google-Smtp-Source: ABdhPJwFtz5XVcYzVYblKBjNLhtUnRq4jTLh2Jlzf3emwvQQyyUgppL8GEBHy31ByrrRGhiTJijE7w== X-Received: by 2002:a17:906:3685:: with SMTP id a5mr472447ejc.544.1609873259843; Tue, 05 Jan 2021 11:00:59 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:00:59 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 08/12] net: make dev_get_stats return void Date: Tue, 5 Jan 2021 20:58:58 +0200 Message-Id: <20210105185902.3922928-9-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean After commit 28172739f0a2 ("net: fix 64 bit counters on 32 bit arches"), dev_get_stats got an additional argument for storage of statistics. At this point, dev_get_stats could return either the passed "storage" argument, or the output of .ndo_get_stats64. Then commit caf586e5f23c ("net: add a core netdev->rx_dropped counter") came, and the output of .ndo_get_stats64 (still returning a pointer to struct rtnl_link_stats64) started being ignored. Then came commit bc1f44709cf2 ("net: make ndo_get_stats64 a void function") which made .ndo_get_stats64 stop returning anything. So now, dev_get_stats always reports the "storage" pointer received as argument. This is useless. Some drivers are dealing with unnecessary complexity due to this, so refactor them to ignore the return value completely. Signed-off-by: Vladimir Oltean --- arch/s390/appldata/appldata_net_sum.c | 25 +++++---- drivers/leds/trigger/ledtrig-netdev.c | 9 ++-- drivers/net/bonding/bond_main.c | 7 ++- .../net/ethernet/hisilicon/hns/hns_ethtool.c | 51 +++++++++---------- .../net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 7 ++- drivers/net/ethernet/intel/ixgbevf/ethtool.c | 7 ++- drivers/net/net_failover.c | 13 +++-- drivers/parisc/led.c | 9 ++-- drivers/scsi/fcoe/fcoe_transport.c | 6 +-- drivers/usb/gadget/function/rndis.c | 45 ++++++---------- include/linux/netdevice.h | 3 +- net/8021q/vlanproc.c | 15 +++--- net/core/dev.c | 6 +-- net/core/net-procfs.c | 35 ++++++------- net/core/net-sysfs.c | 7 +-- net/openvswitch/vport.c | 25 +++++---- 16 files changed, 123 insertions(+), 147 deletions(-) diff --git a/arch/s390/appldata/appldata_net_sum.c b/arch/s390/appldata/appldata_net_sum.c index 4db886980cba..6146606ac9a3 100644 --- a/arch/s390/appldata/appldata_net_sum.c +++ b/arch/s390/appldata/appldata_net_sum.c @@ -81,19 +81,18 @@ static void appldata_get_net_sum_data(void *data) netif_lists_lock(&init_net); for_each_netdev(&init_net, dev) { - const struct rtnl_link_stats64 *stats; - struct rtnl_link_stats64 temp; - - stats = dev_get_stats(dev, &temp); - rx_packets += stats->rx_packets; - tx_packets += stats->tx_packets; - rx_bytes += stats->rx_bytes; - tx_bytes += stats->tx_bytes; - rx_errors += stats->rx_errors; - tx_errors += stats->tx_errors; - rx_dropped += stats->rx_dropped; - tx_dropped += stats->tx_dropped; - collisions += stats->collisions; + struct rtnl_link_stats64 stats; + + dev_get_stats(dev, &stats); + rx_packets += stats.rx_packets; + tx_packets += stats.tx_packets; + rx_bytes += stats.rx_bytes; + tx_bytes += stats.tx_bytes; + rx_errors += stats.rx_errors; + tx_errors += stats.tx_errors; + rx_dropped += stats.rx_dropped; + tx_dropped += stats.tx_dropped; + collisions += stats.collisions; i++; } diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c index d5e774d83021..4382ee278309 100644 --- a/drivers/leds/trigger/ledtrig-netdev.c +++ b/drivers/leds/trigger/ledtrig-netdev.c @@ -347,9 +347,8 @@ static void netdev_trig_work(struct work_struct *work) { struct led_netdev_data *trigger_data = container_of(work, struct led_netdev_data, work.work); - struct rtnl_link_stats64 *dev_stats; + struct rtnl_link_stats64 dev_stats; unsigned int new_activity; - struct rtnl_link_stats64 temp; unsigned long interval; int invert; @@ -364,12 +363,12 @@ static void netdev_trig_work(struct work_struct *work) !test_bit(NETDEV_LED_RX, &trigger_data->mode)) return; - dev_stats = dev_get_stats(trigger_data->net_dev, &temp); + dev_get_stats(trigger_data->net_dev, &dev_stats); new_activity = (test_bit(NETDEV_LED_TX, &trigger_data->mode) ? - dev_stats->tx_packets : 0) + + dev_stats.tx_packets : 0) + (test_bit(NETDEV_LED_RX, &trigger_data->mode) ? - dev_stats->rx_packets : 0); + dev_stats.rx_packets : 0); if (trigger_data->last_activity != new_activity) { led_stop_software_blink(trigger_data->led_cdev); diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 5fe5232cc3f3..714aa0e5d041 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -3753,13 +3753,12 @@ static void bond_get_stats(struct net_device *bond_dev, memcpy(stats, &bond->bond_stats, sizeof(*stats)); bond_for_each_slave_rcu(bond, slave, iter) { - const struct rtnl_link_stats64 *new = - dev_get_stats(slave->dev, &temp); + dev_get_stats(slave->dev, &temp); - bond_fold_stats(stats, new, &slave->slave_stats); + bond_fold_stats(stats, &temp, &slave->slave_stats); /* save off the slave stats for the next run */ - memcpy(&slave->slave_stats, new, sizeof(*new)); + memcpy(&slave->slave_stats, &temp, sizeof(temp)); } memcpy(&bond->bond_stats, stats, sizeof(*stats)); diff --git a/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c b/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c index 7165da0ee9aa..57625e4d10da 100644 --- a/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c +++ b/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c @@ -835,8 +835,7 @@ static void hns_get_ethtool_stats(struct net_device *netdev, u64 *p = data; struct hns_nic_priv *priv = netdev_priv(netdev); struct hnae_handle *h = priv->ae_handle; - const struct rtnl_link_stats64 *net_stats; - struct rtnl_link_stats64 temp; + struct rtnl_link_stats64 net_stats; if (!h->dev->ops->get_stats || !h->dev->ops->update_stats) { netdev_err(netdev, "get_stats or update_stats is null!\n"); @@ -845,32 +844,32 @@ static void hns_get_ethtool_stats(struct net_device *netdev, h->dev->ops->update_stats(h, &netdev->stats); - net_stats = dev_get_stats(netdev, &temp); + dev_get_stats(netdev, &net_stats); /* get netdev statistics */ - p[0] = net_stats->rx_packets; - p[1] = net_stats->tx_packets; - p[2] = net_stats->rx_bytes; - p[3] = net_stats->tx_bytes; - p[4] = net_stats->rx_errors; - p[5] = net_stats->tx_errors; - p[6] = net_stats->rx_dropped; - p[7] = net_stats->tx_dropped; - p[8] = net_stats->multicast; - p[9] = net_stats->collisions; - p[10] = net_stats->rx_over_errors; - p[11] = net_stats->rx_crc_errors; - p[12] = net_stats->rx_frame_errors; - p[13] = net_stats->rx_fifo_errors; - p[14] = net_stats->rx_missed_errors; - p[15] = net_stats->tx_aborted_errors; - p[16] = net_stats->tx_carrier_errors; - p[17] = net_stats->tx_fifo_errors; - p[18] = net_stats->tx_heartbeat_errors; - p[19] = net_stats->rx_length_errors; - p[20] = net_stats->tx_window_errors; - p[21] = net_stats->rx_compressed; - p[22] = net_stats->tx_compressed; + p[0] = net_stats.rx_packets; + p[1] = net_stats.tx_packets; + p[2] = net_stats.rx_bytes; + p[3] = net_stats.tx_bytes; + p[4] = net_stats.rx_errors; + p[5] = net_stats.tx_errors; + p[6] = net_stats.rx_dropped; + p[7] = net_stats.tx_dropped; + p[8] = net_stats.multicast; + p[9] = net_stats.collisions; + p[10] = net_stats.rx_over_errors; + p[11] = net_stats.rx_crc_errors; + p[12] = net_stats.rx_frame_errors; + p[13] = net_stats.rx_fifo_errors; + p[14] = net_stats.rx_missed_errors; + p[15] = net_stats.tx_aborted_errors; + p[16] = net_stats.tx_carrier_errors; + p[17] = net_stats.tx_fifo_errors; + p[18] = net_stats.tx_heartbeat_errors; + p[19] = net_stats.rx_length_errors; + p[20] = net_stats.tx_window_errors; + p[21] = net_stats.rx_compressed; + p[22] = net_stats.tx_compressed; p[23] = netdev->rx_dropped.counter; p[24] = netdev->tx_dropped.counter; diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c index a280aa34ca1d..2b8084664403 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c @@ -1295,19 +1295,18 @@ static void ixgbe_get_ethtool_stats(struct net_device *netdev, struct ethtool_stats *stats, u64 *data) { struct ixgbe_adapter *adapter = netdev_priv(netdev); - struct rtnl_link_stats64 temp; - const struct rtnl_link_stats64 *net_stats; + struct rtnl_link_stats64 net_stats; unsigned int start; struct ixgbe_ring *ring; int i, j; char *p = NULL; ixgbe_update_stats(adapter); - net_stats = dev_get_stats(netdev, &temp); + dev_get_stats(netdev, &net_stats); for (i = 0; i < IXGBE_GLOBAL_STATS_LEN; i++) { switch (ixgbe_gstrings_stats[i].type) { case NETDEV_STATS: - p = (char *) net_stats + + p = (char *) &net_stats + ixgbe_gstrings_stats[i].stat_offset; break; case IXGBE_STATS: diff --git a/drivers/net/ethernet/intel/ixgbevf/ethtool.c b/drivers/net/ethernet/intel/ixgbevf/ethtool.c index e49fb1cd9a99..3b9b7e5c2998 100644 --- a/drivers/net/ethernet/intel/ixgbevf/ethtool.c +++ b/drivers/net/ethernet/intel/ixgbevf/ethtool.c @@ -420,19 +420,18 @@ static void ixgbevf_get_ethtool_stats(struct net_device *netdev, struct ethtool_stats *stats, u64 *data) { struct ixgbevf_adapter *adapter = netdev_priv(netdev); - struct rtnl_link_stats64 temp; - const struct rtnl_link_stats64 *net_stats; + struct rtnl_link_stats64 net_stats; unsigned int start; struct ixgbevf_ring *ring; int i, j; char *p; ixgbevf_update_stats(adapter); - net_stats = dev_get_stats(netdev, &temp); + dev_get_stats(netdev, &net_stats); for (i = 0; i < IXGBEVF_GLOBAL_STATS_LEN; i++) { switch (ixgbevf_gstrings_stats[i].type) { case NETDEV_STATS: - p = (char *)net_stats + + p = (char *)&net_stats + ixgbevf_gstrings_stats[i].stat_offset; break; case IXGBEVF_STATS: diff --git a/drivers/net/net_failover.c b/drivers/net/net_failover.c index 2a4892402ed8..4f83165412bd 100644 --- a/drivers/net/net_failover.c +++ b/drivers/net/net_failover.c @@ -183,7 +183,6 @@ static void net_failover_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats) { struct net_failover_info *nfo_info = netdev_priv(dev); - const struct rtnl_link_stats64 *new; struct rtnl_link_stats64 temp; struct net_device *slave_dev; @@ -194,16 +193,16 @@ static void net_failover_get_stats(struct net_device *dev, slave_dev = rcu_dereference(nfo_info->primary_dev); if (slave_dev) { - new = dev_get_stats(slave_dev, &temp); - net_failover_fold_stats(stats, new, &nfo_info->primary_stats); - memcpy(&nfo_info->primary_stats, new, sizeof(*new)); + dev_get_stats(slave_dev, &temp); + net_failover_fold_stats(stats, &temp, &nfo_info->primary_stats); + memcpy(&nfo_info->primary_stats, &temp, sizeof(temp)); } slave_dev = rcu_dereference(nfo_info->standby_dev); if (slave_dev) { - new = dev_get_stats(slave_dev, &temp); - net_failover_fold_stats(stats, new, &nfo_info->standby_stats); - memcpy(&nfo_info->standby_stats, new, sizeof(*new)); + dev_get_stats(slave_dev, &temp); + net_failover_fold_stats(stats, &temp, &nfo_info->standby_stats); + memcpy(&nfo_info->standby_stats, &temp, sizeof(temp)); } rcu_read_unlock(); diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c index c8c6b2301dc9..cc6108785323 100644 --- a/drivers/parisc/led.c +++ b/drivers/parisc/led.c @@ -360,8 +360,7 @@ static __inline__ int led_get_net_activity(void) for_each_netdev(&init_net, dev) { struct in_device *in_dev = in_dev_get(dev); - const struct rtnl_link_stats64 *stats; - struct rtnl_link_stats64 temp; + struct rtnl_link_stats64 stats; if (!in_dev || !in_dev->ifa_list || ipv4_is_loopback(in_dev->ifa_list->ifa_local)) { @@ -371,9 +370,9 @@ static __inline__ int led_get_net_activity(void) in_dev_put(in_dev); - stats = dev_get_stats(dev, &temp); - rx_total += stats->rx_packets; - tx_total += stats->tx_packets; + dev_get_stats(dev, &stats); + rx_total += stats.rx_packets; + tx_total += stats.tx_packets; } netif_lists_unlock(&init_net); diff --git a/drivers/scsi/fcoe/fcoe_transport.c b/drivers/scsi/fcoe/fcoe_transport.c index b927b3d84523..f8ba6495e745 100644 --- a/drivers/scsi/fcoe/fcoe_transport.c +++ b/drivers/scsi/fcoe/fcoe_transport.c @@ -170,11 +170,11 @@ void __fcoe_get_lesb(struct fc_lport *lport, struct fc_els_lesb *fc_lesb, struct net_device *netdev) { + struct rtnl_link_stats64 stats; unsigned int cpu; u32 lfc, vlfc, mdac; struct fc_stats *stats; struct fcoe_fc_els_lesb *lesb; - struct rtnl_link_stats64 temp; lfc = 0; vlfc = 0; @@ -190,8 +190,8 @@ void __fcoe_get_lesb(struct fc_lport *lport, lesb->lesb_link_fail = htonl(lfc); lesb->lesb_vlink_fail = htonl(vlfc); lesb->lesb_miss_fka = htonl(mdac); - lesb->lesb_fcs_error = - htonl(dev_get_stats(netdev, &temp)->rx_crc_errors); + dev_get_stats(netdev, &stats); + lesb->lesb_fcs_error = htonl(stats.rx_crc_errors); } EXPORT_SYMBOL_GPL(__fcoe_get_lesb); diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c index 64de9f1b874c..7ec29e007ae9 100644 --- a/drivers/usb/gadget/function/rndis.c +++ b/drivers/usb/gadget/function/rndis.c @@ -169,14 +169,13 @@ static const u32 oid_supported_list[] = { static int gen_ndis_query_resp(struct rndis_params *params, u32 OID, u8 *buf, unsigned buf_len, rndis_resp_t *r) { + struct rtnl_link_stats64 stats; int retval = -ENOTSUPP; u32 length = 4; /* usually */ __le32 *outbuf; int i, count; rndis_query_cmplt_type *resp; struct net_device *net; - struct rtnl_link_stats64 temp; - const struct rtnl_link_stats64 *stats; if (!r) return -ENOMEM; resp = (rndis_query_cmplt_type *)r->buf; @@ -199,7 +198,7 @@ static int gen_ndis_query_resp(struct rndis_params *params, u32 OID, u8 *buf, resp->InformationBufferOffset = cpu_to_le32(16); net = params->dev; - stats = dev_get_stats(net, &temp); + dev_get_stats(net, &stats); switch (OID) { @@ -353,51 +352,41 @@ static int gen_ndis_query_resp(struct rndis_params *params, u32 OID, u8 *buf, case RNDIS_OID_GEN_XMIT_OK: if (rndis_debug > 1) pr_debug("%s: RNDIS_OID_GEN_XMIT_OK\n", __func__); - if (stats) { - *outbuf = cpu_to_le32(stats->tx_packets - - stats->tx_errors - stats->tx_dropped); - retval = 0; - } + *outbuf = cpu_to_le32(stats.tx_packets - stats.tx_errors - + stats.tx_dropped); + retval = 0; break; /* mandatory */ case RNDIS_OID_GEN_RCV_OK: if (rndis_debug > 1) pr_debug("%s: RNDIS_OID_GEN_RCV_OK\n", __func__); - if (stats) { - *outbuf = cpu_to_le32(stats->rx_packets - - stats->rx_errors - stats->rx_dropped); - retval = 0; - } + *outbuf = cpu_to_le32(stats.rx_packets - stats.rx_errors - + stats.rx_dropped); + retval = 0; break; /* mandatory */ case RNDIS_OID_GEN_XMIT_ERROR: if (rndis_debug > 1) pr_debug("%s: RNDIS_OID_GEN_XMIT_ERROR\n", __func__); - if (stats) { - *outbuf = cpu_to_le32(stats->tx_errors); - retval = 0; - } + *outbuf = cpu_to_le32(stats.tx_errors); + retval = 0; break; /* mandatory */ case RNDIS_OID_GEN_RCV_ERROR: if (rndis_debug > 1) pr_debug("%s: RNDIS_OID_GEN_RCV_ERROR\n", __func__); - if (stats) { - *outbuf = cpu_to_le32(stats->rx_errors); - retval = 0; - } + *outbuf = cpu_to_le32(stats.rx_errors); + retval = 0; break; /* mandatory */ case RNDIS_OID_GEN_RCV_NO_BUFFER: pr_debug("%s: RNDIS_OID_GEN_RCV_NO_BUFFER\n", __func__); - if (stats) { - *outbuf = cpu_to_le32(stats->rx_dropped); - retval = 0; - } + *outbuf = cpu_to_le32(stats.rx_dropped); + retval = 0; break; /* ieee802.3 OIDs (table 4-3) */ @@ -449,10 +438,8 @@ static int gen_ndis_query_resp(struct rndis_params *params, u32 OID, u8 *buf, /* mandatory */ case RNDIS_OID_802_3_RCV_ERROR_ALIGNMENT: pr_debug("%s: RNDIS_OID_802_3_RCV_ERROR_ALIGNMENT\n", __func__); - if (stats) { - *outbuf = cpu_to_le32(stats->rx_frame_errors); - retval = 0; - } + *outbuf = cpu_to_le32(stats.rx_frame_errors); + retval = 0; break; /* mandatory */ diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 199b3be2cce4..9bd23455d952 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4561,8 +4561,7 @@ void netdev_notify_peers(struct net_device *dev); void netdev_features_change(struct net_device *dev); /* Load a device via the kmod */ void dev_load(struct net *net, const char *name); -struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev, - struct rtnl_link_stats64 *storage); +void dev_get_stats(struct net_device *dev, struct rtnl_link_stats64 *storage); void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64, const struct net_device_stats *netdev_stats); void dev_fetch_sw_netstats(struct rtnl_link_stats64 *s, diff --git a/net/8021q/vlanproc.c b/net/8021q/vlanproc.c index ec87dea23719..3a6682d79630 100644 --- a/net/8021q/vlanproc.c +++ b/net/8021q/vlanproc.c @@ -242,26 +242,25 @@ static int vlandev_seq_show(struct seq_file *seq, void *offset) { struct net_device *vlandev = (struct net_device *) seq->private; const struct vlan_dev_priv *vlan = vlan_dev_priv(vlandev); - struct rtnl_link_stats64 temp; - const struct rtnl_link_stats64 *stats; static const char fmt64[] = "%30s %12llu\n"; + struct rtnl_link_stats64 stats; int i; if (!is_vlan_dev(vlandev)) return 0; - stats = dev_get_stats(vlandev, &temp); + dev_get_stats(vlandev, &stats); seq_printf(seq, "%s VID: %d REORDER_HDR: %i dev->priv_flags: %hx\n", vlandev->name, vlan->vlan_id, (int)(vlan->flags & 1), vlandev->priv_flags); - seq_printf(seq, fmt64, "total frames received", stats->rx_packets); - seq_printf(seq, fmt64, "total bytes received", stats->rx_bytes); - seq_printf(seq, fmt64, "Broadcast/Multicast Rcvd", stats->multicast); + seq_printf(seq, fmt64, "total frames received", stats.rx_packets); + seq_printf(seq, fmt64, "total bytes received", stats.rx_bytes); + seq_printf(seq, fmt64, "Broadcast/Multicast Rcvd", stats.multicast); seq_puts(seq, "\n"); - seq_printf(seq, fmt64, "total frames transmitted", stats->tx_packets); - seq_printf(seq, fmt64, "total bytes transmitted", stats->tx_bytes); + seq_printf(seq, fmt64, "total frames transmitted", stats.tx_packets); + seq_printf(seq, fmt64, "total bytes transmitted", stats.tx_bytes); seq_printf(seq, "Device: %s", vlan->real_dev->name); /* now show all PRIORITY mappings relating to this VLAN */ seq_printf(seq, "\nINGRESS priority mappings: " diff --git a/net/core/dev.c b/net/core/dev.c index 1bd41cc91f71..d48b75479b3e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10380,13 +10380,12 @@ EXPORT_SYMBOL(netdev_stats_to_stats64); * @dev: device to get statistics from * @storage: place to store stats * - * Get network statistics from device. Return @storage. + * Get network statistics from device. * The device driver may provide its own method by setting * dev->netdev_ops->get_stats64 or dev->netdev_ops->get_stats; * otherwise the internal statistics structure is used. */ -struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev, - struct rtnl_link_stats64 *storage) +void dev_get_stats(struct net_device *dev, struct rtnl_link_stats64 *storage) { const struct net_device_ops *ops = dev->netdev_ops; @@ -10401,7 +10400,6 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev, storage->rx_dropped += (unsigned long)atomic_long_read(&dev->rx_dropped); storage->tx_dropped += (unsigned long)atomic_long_read(&dev->tx_dropped); storage->rx_nohandler += (unsigned long)atomic_long_read(&dev->rx_nohandler); - return storage; } EXPORT_SYMBOL(dev_get_stats); diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c index 4784703c1e39..64666ba7ccab 100644 --- a/net/core/net-procfs.c +++ b/net/core/net-procfs.c @@ -80,26 +80,27 @@ static void dev_seq_stop(struct seq_file *seq, void *v) static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev) { - struct rtnl_link_stats64 temp; - const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp); + struct rtnl_link_stats64 stats; + + dev_get_stats(dev, &stats); seq_printf(seq, "%6s: %7llu %7llu %4llu %4llu %4llu %5llu %10llu %9llu " "%8llu %7llu %4llu %4llu %4llu %5llu %7llu %10llu\n", - dev->name, stats->rx_bytes, stats->rx_packets, - stats->rx_errors, - stats->rx_dropped + stats->rx_missed_errors, - stats->rx_fifo_errors, - stats->rx_length_errors + stats->rx_over_errors + - stats->rx_crc_errors + stats->rx_frame_errors, - stats->rx_compressed, stats->multicast, - stats->tx_bytes, stats->tx_packets, - stats->tx_errors, stats->tx_dropped, - stats->tx_fifo_errors, stats->collisions, - stats->tx_carrier_errors + - stats->tx_aborted_errors + - stats->tx_window_errors + - stats->tx_heartbeat_errors, - stats->tx_compressed); + dev->name, stats.rx_bytes, stats.rx_packets, + stats.rx_errors, + stats.rx_dropped + stats.rx_missed_errors, + stats.rx_fifo_errors, + stats.rx_length_errors + stats.rx_over_errors + + stats.rx_crc_errors + stats.rx_frame_errors, + stats.rx_compressed, stats.multicast, + stats.tx_bytes, stats.tx_packets, + stats.tx_errors, stats.tx_dropped, + stats.tx_fifo_errors, stats.collisions, + stats.tx_carrier_errors + + stats.tx_aborted_errors + + stats.tx_window_errors + + stats.tx_heartbeat_errors, + stats.tx_compressed); } /* diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 0782a476b424..d22f010e8e5a 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -586,10 +586,11 @@ static ssize_t netstat_show(const struct device *d, offset % sizeof(u64) != 0); if (dev_isalive(dev)) { - struct rtnl_link_stats64 temp; - const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp); + struct rtnl_link_stats64 stats; - ret = sprintf(buf, fmt_u64, *(u64 *)(((u8 *)stats) + offset)); + dev_get_stats(dev, &stats); + + ret = sprintf(buf, fmt_u64, *(u64 *)(((u8 *)&stats) + offset)); } return ret; diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c index 4ed7e52c7012..215a818bf9ce 100644 --- a/net/openvswitch/vport.c +++ b/net/openvswitch/vport.c @@ -269,19 +269,18 @@ void ovs_vport_del(struct vport *vport) */ void ovs_vport_get_stats(struct vport *vport, struct ovs_vport_stats *stats) { - const struct rtnl_link_stats64 *dev_stats; - struct rtnl_link_stats64 temp; - - dev_stats = dev_get_stats(vport->dev, &temp); - stats->rx_errors = dev_stats->rx_errors; - stats->tx_errors = dev_stats->tx_errors; - stats->tx_dropped = dev_stats->tx_dropped; - stats->rx_dropped = dev_stats->rx_dropped; - - stats->rx_bytes = dev_stats->rx_bytes; - stats->rx_packets = dev_stats->rx_packets; - stats->tx_bytes = dev_stats->tx_bytes; - stats->tx_packets = dev_stats->tx_packets; + struct rtnl_link_stats64 dev_stats; + + dev_get_stats(vport->dev, &dev_stats); + stats->rx_errors = dev_stats.rx_errors; + stats->tx_errors = dev_stats.tx_errors; + stats->tx_dropped = dev_stats.tx_dropped; + stats->rx_dropped = dev_stats.rx_dropped; + + stats->rx_bytes = dev_stats.rx_bytes; + stats->rx_packets = dev_stats.rx_packets; + stats->tx_bytes = dev_stats.tx_bytes; + stats->tx_packets = dev_stats.tx_packets; } /** From patchwork Tue Jan 5 18:58:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000139 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E463DC4332D for ; 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[5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.00.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:01:01 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 09/12] net: net_failover: ensure .ndo_get_stats64 can sleep Date: Tue, 5 Jan 2021 20:58:59 +0200 Message-Id: <20210105185902.3922928-10-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean The failover framework sets up a virtio_net interface [ when it has the VIRTIO_NET_F_STANDBY feature ] and a VF interface, having the same MAC address, in a standby/active relationship. When the active VF is unplugged, the standby virtio_net temporarily kicks in. The failover framework registers a common upper for the active and the standby interface, which is what the application layer uses. This is similar to bonding/team. The statistics of the upper interface are the sum of the statistics of the active and of the standby interface. There is an effort to convert .ndo_get_stats64 to sleepable context, and for that to work, we need to prevent callers of dev_get_stats from using atomic locking. The failover driver needs protection via an RCU read-side critical section to access the standby and the active interface. This has two features: - It is atomic: this needs to change. - It is reentrant: this is ok, because generally speaking, dev_get_stats is recursive, and taking global locks is a bad thing from a recursive context. A better locking architecture would be to do what the team driver does. Instead of using something as broad as the rtnl_mutex to ensure serialization of updates, it should use something more specific, like a private mutex. This patch adds that and names it slaves_lock. The slaves_lock now protects the only updater, the rcu_assign_pointer sections from net_failover_slave_register. In the team driver, a separate lockdep class is created for each team lock, to account for possible nesting (team over team over ...). For the net_failover driver, we can do something simpler, which is to just not hold any lock while we call dev_get_stats recursively. We can "cheat" and use dev_hold to take a reference on the active and backup interfaces, and netdev_wait_allrefs() will just have to wait until we finish. Signed-off-by: Vladimir Oltean --- drivers/net/net_failover.c | 62 +++++++++++++++++++++++++++----------- include/net/net_failover.h | 9 ++++-- 2 files changed, 52 insertions(+), 19 deletions(-) diff --git a/drivers/net/net_failover.c b/drivers/net/net_failover.c index 4f83165412bd..c83066b0ef70 100644 --- a/drivers/net/net_failover.c +++ b/drivers/net/net_failover.c @@ -27,6 +27,9 @@ #include #include +#define nfo_dereference(nfo_info, p) \ + rcu_dereference_protected(p, lockdep_is_held(&nfo_info->slaves_lock)) + static bool net_failover_xmit_ready(struct net_device *dev) { return netif_running(dev) && netif_carrier_ok(dev); @@ -183,32 +186,48 @@ static void net_failover_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats) { struct net_failover_info *nfo_info = netdev_priv(dev); - struct rtnl_link_stats64 temp; - struct net_device *slave_dev; + struct rtnl_link_stats64 primary_stats; + struct rtnl_link_stats64 standby_stats; + struct net_device *primary_dev; + struct net_device *standby_dev; - spin_lock(&nfo_info->stats_lock); - memcpy(stats, &nfo_info->failover_stats, sizeof(*stats)); + mutex_lock(&nfo_info->slaves_lock); - rcu_read_lock(); + primary_dev = nfo_dereference(nfo_info, nfo_info->primary_dev); + if (primary_dev) + dev_hold(primary_dev); - slave_dev = rcu_dereference(nfo_info->primary_dev); - if (slave_dev) { - dev_get_stats(slave_dev, &temp); - net_failover_fold_stats(stats, &temp, &nfo_info->primary_stats); - memcpy(&nfo_info->primary_stats, &temp, sizeof(temp)); + standby_dev = nfo_dereference(nfo_info, nfo_info->standby_dev); + if (standby_dev) + dev_hold(standby_dev); + + mutex_unlock(&nfo_info->slaves_lock); + + /* Don't hold slaves_lock while calling dev_get_stats, just a + * reference to ensure they won't get unregistered. + */ + if (primary_dev) { + dev_get_stats(primary_dev, &primary_stats); + dev_put(primary_dev); } - slave_dev = rcu_dereference(nfo_info->standby_dev); - if (slave_dev) { - dev_get_stats(slave_dev, &temp); - net_failover_fold_stats(stats, &temp, &nfo_info->standby_stats); - memcpy(&nfo_info->standby_stats, &temp, sizeof(temp)); + if (standby_dev) { + dev_get_stats(standby_dev, &standby_stats); + dev_put(standby_dev); } - rcu_read_unlock(); + mutex_lock(&nfo_info->stats_lock); + + memcpy(stats, &nfo_info->failover_stats, sizeof(*stats)); + + net_failover_fold_stats(stats, &primary_stats, &nfo_info->primary_stats); + memcpy(&nfo_info->primary_stats, &primary_stats, sizeof(primary_stats)); + net_failover_fold_stats(stats, &standby_stats, &nfo_info->standby_stats); + memcpy(&nfo_info->standby_stats, &standby_stats, sizeof(standby_stats)); memcpy(&nfo_info->failover_stats, stats, sizeof(*stats)); - spin_unlock(&nfo_info->stats_lock); + + mutex_unlock(&nfo_info->stats_lock); } static int net_failover_change_mtu(struct net_device *dev, int new_mtu) @@ -540,6 +559,8 @@ static int net_failover_slave_register(struct net_device *slave_dev, primary_dev = rtnl_dereference(nfo_info->primary_dev); slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent; + mutex_lock(&nfo_info->slaves_lock); + if (slave_is_standby) { rcu_assign_pointer(nfo_info->standby_dev, slave_dev); standby_dev = slave_dev; @@ -552,6 +573,8 @@ static int net_failover_slave_register(struct net_device *slave_dev, failover_dev->max_mtu = slave_dev->max_mtu; } + mutex_unlock(&nfo_info->slaves_lock); + net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev); net_failover_compute_features(failover_dev); @@ -709,6 +732,7 @@ static struct failover_ops net_failover_ops = { struct failover *net_failover_create(struct net_device *standby_dev) { struct device *dev = standby_dev->dev.parent; + struct net_failover_info *nfo_info; struct net_device *failover_dev; struct failover *failover; int err; @@ -753,6 +777,10 @@ struct failover *net_failover_create(struct net_device *standby_dev) failover_dev->min_mtu = standby_dev->min_mtu; failover_dev->max_mtu = standby_dev->max_mtu; + nfo_info = netdev_priv(failover_dev); + mutex_init(&nfo_info->slaves_lock); + mutex_init(&nfo_info->stats_lock); + err = register_netdev(failover_dev); if (err) { dev_err(dev, "Unable to register failover_dev!\n"); diff --git a/include/net/net_failover.h b/include/net/net_failover.h index b12a1c469d1c..988cdfaf14ca 100644 --- a/include/net/net_failover.h +++ b/include/net/net_failover.h @@ -23,8 +23,13 @@ struct net_failover_info { /* aggregated stats */ struct rtnl_link_stats64 failover_stats; - /* spinlock while updating stats */ - spinlock_t stats_lock; + /* lock for updating stats */ + struct mutex stats_lock; + + /* lock for protecting lower interfaces. + * TODO: convert all rtnl_dereference instances to nfo_dereference + */ + struct mutex slaves_lock; }; struct failover *net_failover_create(struct net_device *standby_dev); From patchwork Tue Jan 5 18:59:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000157 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7201C433E6 for ; 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[5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.01.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:01:04 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 10/12] net: bonding: ensure .ndo_get_stats64 can sleep Date: Tue, 5 Jan 2021 20:59:00 +0200 Message-Id: <20210105185902.3922928-11-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean There is an effort to convert .ndo_get_stats64 to sleepable context, and for that to work, we need to prevent callers of dev_get_stats from using atomic locking. The bonding driver retrieves its statistics recursively from its lower interfaces, with additional care to only count packets sent/received while those lowers were actually enslaved to the bond - see commit 5f0c5f73e5ef ("bonding: make global bonding stats more reliable"). Since commit 87163ef9cda7 ("bonding: remove last users of bond->lock and bond->lock itself"), the bonding driver uses the following protection for its array of slaves: RCU for readers and rtnl_mutex for updaters. This is not great because there is another movement [ somehow simultaneous with the one to make .ndo_get_stats64 sleepable ] to reduce driver usage of rtnl_mutex. This makes sense, because the rtnl_mutex has become a very contended resource. The aforementioned commit removed an interesting comment: /* [...] we can't hold bond->lock [...] because we'll * deadlock. The only solution is to rely on the fact * that we're under rtnl_lock here, and the slaves * list won't change. This doesn't solve the problem * of setting the slave's MTU while it is * transmitting, but the assumption is that the base * driver can handle that. * * TODO: figure out a way to safely iterate the slaves * list, but without holding a lock around the actual * call to the base driver. */ The above summarizes pretty well the challenges we have with nested bonding interfaces (bond over bond over bond over...), which need to be addressed by a better locking scheme that also not relies on the bloated rtnl_mutex. Instead of using something as broad as the rtnl_mutex to ensure serialization of updates to the slave array, we can reintroduce a private mutex in the bonding driver, called slaves_lock. This mutex circles the only updater, bond_update_slave_arr, and ensures that whatever other readers want to see a consistent slave array, they don't need to hold the rtnl_mutex for that. Now _of_course_ I did not convert the entire driver to use bond_for_each_slave protected by the bond->slaves_lock, and rtnl_dereference to bond_dereference. I just started that process by converting the one reader I needed: ndo_get_stats64. Not only is it nice to not hold rtnl_mutex in .ndo_get_stats64, but it is also in fact forbidden to do so (since top-level callers may hold netif_lists_lock, which is a sub-lock of the rtnl_mutex, and therefore this would cause a lock inversion and a deadlock). To solve the nesting problem, the simple way is to not hold any locks when recursing into the slave netdev operation, which is exactly the approach that we take. We can "cheat" and use dev_hold to take a reference on the slave net_device, which is enough to ensure that netdev_wait_allrefs() waits until we finish, and the kernel won't fault. However, the slave structure might no longer be valid, just its associated net_device. That isn't a biggie. We just need to do some more work to ensure that the slave exists after we took the statistics, and if it still does, reapply the logic from Andy's commit 5f0c5f73e5ef. Signed-off-by: Vladimir Oltean --- drivers/net/bonding/bond_main.c | 120 +++++++++++++++----------------- include/net/bonding.h | 52 +++++++++++++- 2 files changed, 109 insertions(+), 63 deletions(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 714aa0e5d041..fbae3b9746fc 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -3693,77 +3693,65 @@ static void bond_fold_stats(struct rtnl_link_stats64 *_res, } } -#ifdef CONFIG_LOCKDEP -static int bond_get_lowest_level_rcu(struct net_device *dev) -{ - struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1]; - struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1]; - int cur = 0, max = 0; - - now = dev; - iter = &dev->adj_list.lower; - - while (1) { - next = NULL; - while (1) { - ldev = netdev_next_lower_dev_rcu(now, &iter); - if (!ldev) - break; - - next = ldev; - niter = &ldev->adj_list.lower; - dev_stack[cur] = now; - iter_stack[cur++] = iter; - if (max <= cur) - max = cur; - break; - } - - if (!next) { - if (!cur) - return max; - next = dev_stack[--cur]; - niter = iter_stack[cur]; - } - - now = next; - iter = niter; - } - - return max; -} -#endif - static void bond_get_stats(struct net_device *bond_dev, struct rtnl_link_stats64 *stats) { struct bonding *bond = netdev_priv(bond_dev); - struct rtnl_link_stats64 temp; - struct list_head *iter; - struct slave *slave; - int nest_level = 0; + struct rtnl_link_stats64 *dev_stats; + struct net_device **slaves; + int i, res, num_slaves; + res = bond_get_slave_arr(bond, &slaves, &num_slaves); + if (res) { + netdev_err(bond->dev, + "failed to allocate memory for slave array\n"); + return; + } - rcu_read_lock(); -#ifdef CONFIG_LOCKDEP - nest_level = bond_get_lowest_level_rcu(bond_dev); -#endif + dev_stats = kcalloc(num_slaves, sizeof(*dev_stats), GFP_KERNEL); + if (!dev_stats) { + netdev_err(bond->dev, + "failed to allocate memory for slave stats\n"); + bond_put_slave_arr(slaves, num_slaves); + return; + } + + /* Recurse with no locks taken */ + for (i = 0; i < num_slaves; i++) + dev_get_stats(slaves[i], &dev_stats[i]); + + /* When taking the slaves lock again, the new slave array might be + * different from the original one. + */ + mutex_lock(&bond->slaves_lock); + mutex_lock(&bond->stats_lock); - spin_lock_nested(&bond->stats_lock, nest_level); memcpy(stats, &bond->bond_stats, sizeof(*stats)); - bond_for_each_slave_rcu(bond, slave, iter) { - dev_get_stats(slave->dev, &temp); + for (i = 0; i < num_slaves; i++) { + struct list_head *iter; + struct slave *slave; - bond_fold_stats(stats, &temp, &slave->slave_stats); + bond_for_each_slave(bond, slave, iter) { + if (slave->dev != slaves[i]) + continue; - /* save off the slave stats for the next run */ - memcpy(&slave->slave_stats, &temp, sizeof(temp)); + bond_fold_stats(stats, &dev_stats[i], + &slave->slave_stats); + + /* save off the slave stats for the next run */ + memcpy(&slave->slave_stats, &dev_stats[i], + sizeof(dev_stats[i])); + break; + } } memcpy(&bond->bond_stats, stats, sizeof(*stats)); - spin_unlock(&bond->stats_lock); - rcu_read_unlock(); + + mutex_unlock(&bond->stats_lock); + mutex_unlock(&bond->slaves_lock); + + bond_put_slave_arr(slaves, num_slaves); } static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd) @@ -4287,11 +4275,11 @@ static void bond_set_slave_arr(struct bonding *bond, { struct bond_up_slave *usable, *all; - usable = rtnl_dereference(bond->usable_slaves); + usable = bond_dereference(bond, bond->usable_slaves); rcu_assign_pointer(bond->usable_slaves, usable_slaves); kfree_rcu(usable, rcu); - all = rtnl_dereference(bond->all_slaves); + all = bond_dereference(bond, bond->all_slaves); rcu_assign_pointer(bond->all_slaves, all_slaves); kfree_rcu(all, rcu); } @@ -4333,6 +4321,8 @@ int bond_update_slave_arr(struct bonding *bond, struct slave *skipslave) WARN_ON(lockdep_is_held(&bond->mode_lock)); #endif + mutex_lock(&bond->slaves_lock); + usable_slaves = kzalloc(struct_size(usable_slaves, arr, bond->slave_cnt), GFP_KERNEL); all_slaves = kzalloc(struct_size(all_slaves, arr, @@ -4376,17 +4366,22 @@ int bond_update_slave_arr(struct bonding *bond, struct slave *skipslave) } bond_set_slave_arr(bond, usable_slaves, all_slaves); + + mutex_unlock(&bond->slaves_lock); + return ret; out: if (ret != 0 && skipslave) { - bond_skip_slave(rtnl_dereference(bond->all_slaves), + bond_skip_slave(bond_dereference(bond, bond->all_slaves), skipslave); - bond_skip_slave(rtnl_dereference(bond->usable_slaves), + bond_skip_slave(bond_dereference(bond, bond->usable_slaves), skipslave); } kfree_rcu(all_slaves, rcu); kfree_rcu(usable_slaves, rcu); + mutex_unlock(&bond->slaves_lock); + return ret; } @@ -4699,6 +4694,8 @@ void bond_setup(struct net_device *bond_dev) { struct bonding *bond = netdev_priv(bond_dev); + mutex_init(&bond->slaves_lock); + mutex_init(&bond->stats_lock); spin_lock_init(&bond->mode_lock); bond->params = bonding_defaults; @@ -5189,7 +5186,6 @@ static int bond_init(struct net_device *bond_dev) if (!bond->wq) return -ENOMEM; - spin_lock_init(&bond->stats_lock); netdev_lockdep_set_classes(bond_dev); list_add_tail(&bond->bond_list, &bn->dev_list); diff --git a/include/net/bonding.h b/include/net/bonding.h index adc3da776970..3fd2443e7800 100644 --- a/include/net/bonding.h +++ b/include/net/bonding.h @@ -222,7 +222,6 @@ struct bonding { * ALB mode (6) - to sync the use and modifications of its hash table */ spinlock_t mode_lock; - spinlock_t stats_lock; u8 send_peer_notif; u8 igmp_retrans; #ifdef CONFIG_PROC_FS @@ -249,6 +248,14 @@ struct bonding { #ifdef CONFIG_XFRM_OFFLOAD struct xfrm_state *xs; #endif /* CONFIG_XFRM_OFFLOAD */ + + /* Protects the slave array. TODO: convert all instances of + * rtnl_dereference to bond_dereference + */ + struct mutex slaves_lock; + + /* Serializes access to bond_stats */ + struct mutex stats_lock; }; #define bond_slave_get_rcu(dev) \ @@ -257,6 +264,9 @@ struct bonding { #define bond_slave_get_rtnl(dev) \ ((struct slave *) rtnl_dereference(dev->rx_handler_data)) +#define bond_dereference(bond, p) \ + rcu_dereference_protected(p, lockdep_is_held(&(bond)->slaves_lock)) + void bond_queue_slave_event(struct slave *slave); void bond_lower_state_changed(struct slave *slave); @@ -449,6 +459,46 @@ static inline void bond_hw_addr_copy(u8 *dst, const u8 *src, unsigned int len) memcpy(dst, src, len); } +static inline int bond_get_slave_arr(struct bonding *bond, + struct net_device ***slaves, + int *num_slaves) +{ + struct net *net = dev_net(bond->dev); + struct list_head *iter; + struct slave *slave; + int i = 0; + + mutex_lock(&bond->slaves_lock); + + *slaves = kcalloc(bond->slave_cnt, sizeof(*slaves), GFP_KERNEL); + if (!(*slaves)) { + netif_lists_unlock(net); + return -ENOMEM; + } + + bond_for_each_slave(bond, slave, iter) { + dev_hold(slave->dev); + *slaves[i++] = slave->dev; + } + + *num_slaves = bond->slave_cnt; + + mutex_unlock(&bond->slaves_lock); + + return 0; +} + +static inline void bond_put_slave_arr(struct net_device **slaves, + int num_slaves) +{ + int i; + + for (i = 0; i < num_slaves; i++) + dev_put(slaves[i]); + + kfree(slaves); +} + #define BOND_PRI_RESELECT_ALWAYS 0 #define BOND_PRI_RESELECT_BETTER 1 #define BOND_PRI_RESELECT_FAILURE 2 From patchwork Tue Jan 5 18:59:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000149 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83CB7C07EA3 for ; Tue, 5 Jan 2021 19:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58E6222D57 for ; Tue, 5 Jan 2021 19:02:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729684AbhAETCG (ORCPT ); Tue, 5 Jan 2021 14:02:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725838AbhAETCF (ORCPT ); Tue, 5 Jan 2021 14:02:05 -0500 Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 865D6C0617AA; Tue, 5 Jan 2021 11:01:08 -0800 (PST) Received: by mail-ed1-x52a.google.com with SMTP id c7so1881250edv.6; Tue, 05 Jan 2021 11:01:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=o9S5VetFLcZ6A9nQu4WMhm39cSlo6GMb/Zh6iH2PAWo=; b=YWokJ4VPJ94sBnkT+J4C7IXLt2kDzNBiTghXcM82L4KlMYRDSQqifLNZOGQ5Ut9y9y ZYiZ82rB9AIHdypa4FsXAC26qJoxHElT0kBMRGUjrsc29JcTFDlY94P4nE2dlq8lkW5p RObbbo/amQfqkKgkEHtgtEG6GmOiOS8vXyggValuLbpZUJLcOgUnstTIgSnT4Cl+PF0r M7LICV5lt5TZgUn1E3t7REd9NPVkyHWhDTfuYNvSIgwZAWGeCko00gqk4ZhFi44rujaV 0754bHfrxdO5Y9swDHvq9Ejhryrsc5R+dyJJGPIwMT7udP2PqylpCYgrjVtcl5BRYJ9I 0TPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=o9S5VetFLcZ6A9nQu4WMhm39cSlo6GMb/Zh6iH2PAWo=; b=liobCGwy7ffWz3HfrUCansUyENiSZvAfkoNT4AxB/b/f55cKdgXp7/yPA6YzIYGckP MAVcYLAOWkCv+of2sWHvowTDDI7IWIe0srsb9klMnMumdsDdvNJVoTdXPgEN8fZMJ7jh KRizWR5YVr8nkop7Upo/OXv+dKaFuqc3O1TdiSHpuvOHN8f4eNORqBNwvzlLpRDmjegT 3bqNid7XNmxv4YMmsHw7P8loHurRP/MGo7q9kxY1kYwdaLB+/X1OrRYAsNCo/CWbZK32 fe4S1H6QSgt1s1mxvzNrd/90zbQyIcV20H9XvqFGyvZTdSjxOIULI/cmn8EGirwTpN/Y CEFw== X-Gm-Message-State: AOAM532LEp7KHnf4/R3iU8ZE8dGC5wM5EvLFZmkIsG+HseV1lM9pFyeh PVvHLfPtNaAbAT4Wo1DFHQw= X-Google-Smtp-Source: ABdhPJxjE2k61m92yxHS+AwU9WB9vDDtGHYZ1kuHbwT7yr8ORT7g6VgNhr8Kz8oPy6UDV4hKTq121A== X-Received: by 2002:a05:6402:310f:: with SMTP id dc15mr1186577edb.225.1609873267285; Tue, 05 Jan 2021 11:01:07 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.01.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:01:06 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 11/12] net: mark ndo_get_stats64 as being able to sleep Date: Tue, 5 Jan 2021 20:59:01 +0200 Message-Id: <20210105185902.3922928-12-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean Now that all callers have been converted to not use atomic context when calling dev_get_stats, it is time to update the documentation and put a notice in the function that it expects process context. Signed-off-by: Vladimir Oltean --- Documentation/networking/netdevices.rst | 8 ++++++-- Documentation/networking/statistics.rst | 9 ++++----- net/core/dev.c | 2 ++ 3 files changed, 12 insertions(+), 7 deletions(-) diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst index 5a85fcc80c76..944599722c76 100644 --- a/Documentation/networking/netdevices.rst +++ b/Documentation/networking/netdevices.rst @@ -64,8 +64,12 @@ ndo_do_ioctl: Context: process ndo_get_stats: - Synchronization: dev_base_lock rwlock. - Context: nominally process, but don't sleep inside an rwlock + Synchronization: + none. netif_lists_lock(net) might be held, but not guaranteed. + It is illegal to hold rtnl_lock() in this method, since it will + cause a lock inversion with netif_lists_lock and a deadlock. + Context: + process ndo_start_xmit: Synchronization: __netif_tx_lock spinlock. diff --git a/Documentation/networking/statistics.rst b/Documentation/networking/statistics.rst index 234abedc29b2..ad3e353df0dd 100644 --- a/Documentation/networking/statistics.rst +++ b/Documentation/networking/statistics.rst @@ -155,11 +155,10 @@ Drivers must ensure best possible compliance with Please note for example that detailed error statistics must be added into the general `rx_error` / `tx_error` counters. -The `.ndo_get_stats64` callback can not sleep because of accesses -via `/proc/net/dev`. If driver may sleep when retrieving the statistics -from the device it should do so periodically asynchronously and only return -a recent copy from `.ndo_get_stats64`. Ethtool interrupt coalescing interface -allows setting the frequency of refreshing statistics, if needed. +Drivers may sleep when retrieving the statistics from the device, or they might +read the counters periodically and only return in `.ndo_get_stats64` a recent +copy collected asynchronously. In the latter case, the ethtool interrupt +coalescing interface allows setting the frequency of refreshing statistics. Retrieving ethtool statistics is a multi-syscall process, drivers are advised to keep the number of statistics constant to avoid race conditions with diff --git a/net/core/dev.c b/net/core/dev.c index d48b75479b3e..6b7cdf8ab875 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10389,6 +10389,8 @@ void dev_get_stats(struct net_device *dev, struct rtnl_link_stats64 *storage) { const struct net_device_ops *ops = dev->netdev_ops; + might_sleep(); + if (ops->ndo_get_stats64) { memset(storage, 0, sizeof(*storage)); ops->ndo_get_stats64(dev, storage); From patchwork Tue Jan 5 18:59:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12000147 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70030C072B1 for ; Tue, 5 Jan 2021 19:02:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4418322D5B for ; Tue, 5 Jan 2021 19:02:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730854AbhAETCb (ORCPT ); Tue, 5 Jan 2021 14:02:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730730AbhAETCa (ORCPT ); Tue, 5 Jan 2021 14:02:30 -0500 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 914C4C061574; Tue, 5 Jan 2021 11:01:10 -0800 (PST) Received: by mail-ej1-x62e.google.com with SMTP id jx16so1776266ejb.10; Tue, 05 Jan 2021 11:01:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=2Xkt1oCIrxKaf3It3JKv+vsp1Hey/NBy/qFeY9d8DZc=; b=Gt5QFu6I7aHo+8GOPj5R6UBnaDhbCplrfdTcdydwynZSIxhp9WE4gV3mh7aGBMhvd/ 2rSp5iOOh6nP27UsPfrjVeanyWIu7s1MfI/Sj7qYZizz3AsC8CTZ46nLPYgajUFzTdnL vcl31dKkTWMrIK3J8VFuZl0La4iCfKMMOcjSNTKaMokKfC3PC+/Wk5fnlzmJyUmCW2Ak Wz71qxVmVISS6e5HCu1t8G9zRraBu0jxxVzCbv6fdiGMern9MRd2d3L/y/bgN0w9R1ft SlO9N3Av0p/8zNw//Ah3Vmsfx35/2SKI8FB7cYchKY9eQBtOP21dvYqJq7ic4+BeuxJj +FWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=2Xkt1oCIrxKaf3It3JKv+vsp1Hey/NBy/qFeY9d8DZc=; b=bYeYVirHrNjC5BH/xSWNjRsE5cC7tzdSH7rZYNcR9WckLla9mv/v3CytoQyWF6DrA0 Xq50FqnQez2rvtk5CYrn7eepFOva4imwaAESln1KxbDiQ/WvGihEqrgzHGIwfGVF1HJr /s5M/2jqbKzfW6qOra0rFBskEXofKUfuOiuAEPrBTj0D+YWtcPm+1tn8qeMAonWPk6Go 7THInYcCnAhNKfx4HudcwZ6qz7pgiM76DxI0u0tpeFP2DBpucHdfU57+Fq4V4Y/QnBAS 5XBkeEKFdZ6NqQ5+lBUUZtZVVZQSehpvlzISQqhjx/CqUQVfxWEIHvNSZL4KubjKJBgv vHjg== X-Gm-Message-State: AOAM533TbjBF4j4OeRhiTR5iLFjI/xS64/PqnnMWCFgIq8VVQwIvjisq 4rqgY21pcapXzXh71BzIV44= X-Google-Smtp-Source: ABdhPJwJ20qomfS5nkztFWDy2mx/AXJKC58XuuP1SWp95xUhRb4sibo0a7Ho4ddPX1swb2PGZfDcEQ== X-Received: by 2002:a17:906:81d6:: with SMTP id e22mr490266ejx.476.1609873269304; Tue, 05 Jan 2021 11:01:09 -0800 (PST) Received: from localhost.localdomain (5-12-227-87.residential.rdsnet.ro. [5.12.227.87]) by smtp.gmail.com with ESMTPSA id z13sm205084edq.48.2021.01.05.11.01.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jan 2021 11:01:08 -0800 (PST) From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Paul Gortmaker , Pablo Neira Ayuso , Jiri Benc , Cong Wang , Jamal Hadi Salim , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Taehee Yoo , Jiri Pirko , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paolo Abeni , Christian Brauner , Florian Westphal , linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-parisc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, dev@openvswitch.org Subject: [RFC PATCH v2 net-next 12/12] net: remove obsolete comments about ndo_get_stats64 context from eth drivers Date: Tue, 5 Jan 2021 20:59:02 +0200 Message-Id: <20210105185902.3922928-13-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210105185902.3922928-1-olteanv@gmail.com> References: <20210105185902.3922928-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Vladimir Oltean Now that we have a good summary in Documentation/networking/netdevices.rst, these comments serve no purpose and are actually distracting/confusing. Signed-off-by: Vladimir Oltean --- drivers/net/ethernet/cisco/enic/enic_main.c | 1 - drivers/net/ethernet/nvidia/forcedeth.c | 2 -- drivers/net/ethernet/sfc/efx_common.c | 1 - drivers/net/ethernet/sfc/falcon/efx.c | 1 - 4 files changed, 5 deletions(-) diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c index fb269d587b74..7425f94f9091 100644 --- a/drivers/net/ethernet/cisco/enic/enic_main.c +++ b/drivers/net/ethernet/cisco/enic/enic_main.c @@ -870,7 +870,6 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb, return NETDEV_TX_OK; } -/* dev_base_lock rwlock held, nominally process context */ static void enic_get_stats(struct net_device *netdev, struct rtnl_link_stats64 *net_stats) { diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c index 8724d6a9ed02..8fa254dc64e9 100644 --- a/drivers/net/ethernet/nvidia/forcedeth.c +++ b/drivers/net/ethernet/nvidia/forcedeth.c @@ -1761,8 +1761,6 @@ static void nv_get_stats(int cpu, struct fe_priv *np, /* * nv_get_stats64: dev->ndo_get_stats64 function * Get latest stats value from the nic. - * Called with read_lock(&dev_base_lock) held for read - - * only synchronized against unregister_netdevice. */ static void nv_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *storage) diff --git a/drivers/net/ethernet/sfc/efx_common.c b/drivers/net/ethernet/sfc/efx_common.c index de797e1ac5a9..4d8047b35fb2 100644 --- a/drivers/net/ethernet/sfc/efx_common.c +++ b/drivers/net/ethernet/sfc/efx_common.c @@ -596,7 +596,6 @@ void efx_stop_all(struct efx_nic *efx) efx_stop_datapath(efx); } -/* Context: process, dev_base_lock or RTNL held, non-blocking. */ void efx_net_stats(struct net_device *net_dev, struct rtnl_link_stats64 *stats) { struct efx_nic *efx = netdev_priv(net_dev); diff --git a/drivers/net/ethernet/sfc/falcon/efx.c b/drivers/net/ethernet/sfc/falcon/efx.c index f8979991970e..6db2b6583dec 100644 --- a/drivers/net/ethernet/sfc/falcon/efx.c +++ b/drivers/net/ethernet/sfc/falcon/efx.c @@ -2096,7 +2096,6 @@ int ef4_net_stop(struct net_device *net_dev) return 0; } -/* Context: process, dev_base_lock or RTNL held, non-blocking. */ static void ef4_net_stats(struct net_device *net_dev, struct rtnl_link_stats64 *stats) {