From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8896137DEAB for ; Thu, 17 Sep 2026 02:19:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789611544; cv=none; b=AgSfrR//koh1Z/9x8MhttjjIi9rDa+iYSs+hBBgUDGFDtp3tb/KV/qDNsNBxneHfwD9pnwAbOvhJ5qCz/XHpl7xoxR2HVUAesmXLV0fpR1XfnvQQjeXWNJZE+jya4JgW5Lzpy7wRx+ngrCc8+XUkhGqMwutr5LnYjVvWK57bN2E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789611544; c=relaxed/simple; bh=Gr+ZaYU5pw5plVhuT66H3bMCJ0TvNJ3vGg/jXhhSYJM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hlzTjjDSyRAr9lNfTZJus5OZYfaK+VOQ1Uaq61UPxpXx2XTOw658uLKHZaVFGBs+cra6+NOMPoDMyfxj39n0/Mb6DiDeiWll0nVY0RafDLKaeDjqfsdlihZ5Gnh1cp3K+qDFiBDrfSmTmOHiJ6iqQMuvK70A0XKxV8C+kypBTF8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HDDfUKuM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HDDfUKuM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2DF61F0089B; Thu, 17 Sep 2026 02:19:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789611543; bh=uSDp4J6mjwnqVpXhFoexGYoplVyIMho3mr2Lv33muNM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HDDfUKuMvAqI96E9Rxqtm0RsIiCm6JU7jThpBvMnqhnaw7VRpzYP32TlLHr8vsdtS 3FKDPG+HRI1yMZkEkmgq01r45HI55yV6IoX29GcQBivZNCVWD6Ejzj+O+RsoPNBD49 PjI/ovrZRq/eXo5X2z+FR6boY/W8GBP6zls25/aHVG6Y2p+tHn2UJAuKnoGBIv1JBR +ijeOXb3j/Ne0VQvHTZJRASboThW0WfXJ3sFxycy1IbmlNnJtNQimDD6HNNhu9xxZB UP9EBY3/0Cf1bl5ucrShzIsGpi3qcNn5o/fIlAUDKwlUheKNXycivzMBBl66z0mpEo vdghm3mKSxJUg== From: Sasha Levin To: stable@vger.kernel.org Cc: Eric Dumazet , Kuniyuki Iwashima , David Ahern , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y 3/7] ipv4: remove fib_info_devhash[] Date: Wed, 16 Sep 2026 22:18:55 -0400 Message-ID: <20260917021859.3810309-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260917021859.3810309-1-sashal@kernel.org> References: <2026091655-dejected-hammock-755e@gregkh> <20260917021859.3810309-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit a3f5f4c2f9b6bc2aa6f5a3e8e23b7519e4f2e3e3 ] Upcoming per-netns RTNL conversion needs to get rid of shared hash tables. fib_info_devhash[] is one of them. It is unclear why we used a hash table, because a single hlist_head per net device was cheaper and scalable. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Reviewed-by: David Ahern Link: https://patch.msgid.link/20241004134720.579244-5-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 8d6cd1885085 ("ipv6: flowlabel: cap duplicate leases per socket") Signed-off-by: Sasha Levin --- .../networking/net_cachelines/net_device.rst | 1 + include/linux/netdevice.h | 3 ++ net/ipv4/fib_semantics.c | 35 ++++++++----------- 3 files changed, 19 insertions(+), 20 deletions(-) diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst index 22b07c814f4a4..a8e2a7ce03833 100644 --- a/Documentation/networking/net_cachelines/net_device.rst +++ b/Documentation/networking/net_cachelines/net_device.rst @@ -83,6 +83,7 @@ unsigned_int allmulti bool uc_promisc unsigned_char nested_level struct_in_device* ip_ptr read_mostly read_mostly __in_dev_get +struct hlist_head fib_nh_head struct_inet6_dev* ip6_ptr read_mostly read_mostly __in6_dev_get struct_vlan_info* vlan_info struct_dsa_port* dsa_ptr diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 0aa536df9cb59..8e6ed0079f381 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2217,6 +2217,9 @@ struct net_device { /* Protocol-specific pointers */ struct in_device __rcu *ip_ptr; + /** @fib_nh_head: nexthops associated with this netdev */ + struct hlist_head fib_nh_head; + #if IS_ENABLED(CONFIG_VLAN_8021Q) struct vlan_info __rcu *vlan_info; #endif diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index 8c20209fbff35..b3861d2740c6d 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -57,10 +57,6 @@ static unsigned int fib_info_hash_size; static unsigned int fib_info_hash_bits; static unsigned int fib_info_cnt; -#define DEVINDEX_HASHBITS 8 -#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) -static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; - /* for_nexthops and change_nexthops only used when nexthop object * is not set in a fib_info. The logic within can reference fib_nh. */ @@ -322,12 +318,9 @@ static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) return 0; } -static struct hlist_head * -fib_info_devhash_bucket(const struct net_device *dev) +static struct hlist_head *fib_nh_head(struct net_device *dev) { - u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex; - - return &fib_info_devhash[hash_32(val, DEVINDEX_HASHBITS)]; + return &dev->fib_nh_head; } static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, @@ -439,11 +432,11 @@ int ip_fib_check_default(__be32 gw, struct net_device *dev) struct hlist_head *head; struct fib_nh *nh; - head = fib_info_devhash_bucket(dev); + head = fib_nh_head(dev); hlist_for_each_entry_rcu(nh, head, nh_hash) { - if (nh->fib_nh_dev == dev && - nh->fib_nh_gw4 == gw && + DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); + if (nh->fib_nh_gw4 == gw && !(nh->fib_nh_flags & RTNH_F_DEAD)) { return 0; } @@ -1632,7 +1625,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, if (!nexthop_nh->fib_nh_dev) continue; - head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); + head = fib_nh_head(nexthop_nh->fib_nh_dev); hlist_add_head_rcu(&nexthop_nh->nh_hash, head); } endfor_nexthops(fi) } @@ -1974,12 +1967,12 @@ void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) { - struct hlist_head *head = fib_info_devhash_bucket(dev); + struct hlist_head *head = fib_nh_head(dev); struct fib_nh *nh; hlist_for_each_entry(nh, head, nh_hash) { - if (nh->fib_nh_dev == dev) - fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); + DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); + fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); } } @@ -1993,7 +1986,7 @@ void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) */ int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) { - struct hlist_head *head = fib_info_devhash_bucket(dev); + struct hlist_head *head = fib_nh_head(dev); struct fib_info *prev_fi = NULL; int scope = RT_SCOPE_NOWHERE; struct fib_nh *nh; @@ -2007,7 +2000,8 @@ int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) int dead; BUG_ON(!fi->fib_nhs); - if (nh->fib_nh_dev != dev || fi == prev_fi) + DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); + if (fi == prev_fi) continue; prev_fi = fi; dead = 0; @@ -2157,7 +2151,7 @@ int fib_sync_up(struct net_device *dev, unsigned char nh_flags) } prev_fi = NULL; - head = fib_info_devhash_bucket(dev); + head = fib_nh_head(dev); ret = 0; hlist_for_each_entry(nh, head, nh_hash) { @@ -2165,7 +2159,8 @@ int fib_sync_up(struct net_device *dev, unsigned char nh_flags) int alive; BUG_ON(!fi->fib_nhs); - if (nh->fib_nh_dev != dev || fi == prev_fi) + DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); + if (fi == prev_fi) continue; prev_fi = fi; -- 2.53.0