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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Sabrina Dubroca , Jiri Pirko , Simon Horman , Ido Schimmel , Shuah Khan , Stanislav Fomichev , Stanislav Fomichev , Kuniyuki Iwashima , Ahmed Zaki , Alexander Lobakin , bridge@lists.linux.dev, linux-kselftest@vger.kernel.org, Hangbin Liu Subject: [PATCHv4 net-next 1/4] net: add a common function to compute features from lowers devices Date: Tue, 14 Oct 2025 08:02:14 +0000 Message-ID: <20251014080217.47988-2-liuhangbin@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20251014080217.47988-1-liuhangbin@gmail.com> References: <20251014080217.47988-1-liuhangbin@gmail.com> Precedence: bulk X-Mailing-List: bridge@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Some high level virtual drivers need to compute features from lower devices. But each has their own implementations and may lost some feature compute. Let's use one common function to compute features for kinds of these devices. The new helper uses the current bond implementation as the reference one, as the latter already handles all the relevant aspects: netdev features, TSO limits and dst retention. Suggested-by: Paolo Abeni Signed-off-by: Hangbin Liu --- include/linux/netdev_features.h | 18 +++++++ include/linux/netdevice.h | 1 + net/core/dev.c | 95 +++++++++++++++++++++++++++++++++ 3 files changed, 114 insertions(+) diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h index 7a01c518e573..f3fe2d59ea96 100644 --- a/include/linux/netdev_features.h +++ b/include/linux/netdev_features.h @@ -255,6 +255,24 @@ static inline int find_next_netdev_feature(u64 feature, unsigned long start) NETIF_F_GSO_UDP_TUNNEL | \ NETIF_F_GSO_UDP_TUNNEL_CSUM) +/* virtual device features */ +#define VIRTUAL_DEV_VLAN_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | \ + NETIF_F_FRAGLIST | NETIF_F_GSO_SOFTWARE | \ + NETIF_F_GSO_ENCAP_ALL | \ + NETIF_F_HIGHDMA | NETIF_F_LRO) + +#define VIRTUAL_DEV_ENC_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | \ + NETIF_F_RXCSUM | NETIF_F_GSO_SOFTWARE | \ + NETIF_F_GSO_PARTIAL) + +#define VIRTUAL_DEV_MPLS_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | \ + NETIF_F_GSO_SOFTWARE) + +#define VIRTUAL_DEV_XFRM_FEATURES (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM | \ + NETIF_F_GSO_ESP) + +#define VIRTUAL_DEV_GSO_PARTIAL_FEATURES (NETIF_F_GSO_ESP) + static inline netdev_features_t netdev_base_features(netdev_features_t features) { features &= ~NETIF_F_ONE_FOR_ALL; diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index d1a687444b27..8e28fee247f5 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -5304,6 +5304,7 @@ static inline netdev_features_t netdev_add_tso_features(netdev_features_t featur int __netdev_update_features(struct net_device *dev); void netdev_update_features(struct net_device *dev); void netdev_change_features(struct net_device *dev); +void netdev_compute_features_from_lowers(struct net_device *dev, bool update_header); void netif_stacked_transfer_operstate(const struct net_device *rootdev, struct net_device *dev); diff --git a/net/core/dev.c b/net/core/dev.c index a64cef2c537e..54f0e792fbd2 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -12616,6 +12616,101 @@ netdev_features_t netdev_increment_features(netdev_features_t all, } EXPORT_SYMBOL(netdev_increment_features); +/** + * netdev_compute_features_from_lowers - compute feature from lowers + * @dev: the upper device + * @update_header: whether to update upper device's header_len/headroom/tailroom + * + * Recompute the upper device's feature based on all lower devices. + */ +void netdev_compute_features_from_lowers(struct net_device *dev, bool update_header) +{ + unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM; + netdev_features_t gso_partial_features = VIRTUAL_DEV_GSO_PARTIAL_FEATURES; +#ifdef CONFIG_XFRM_OFFLOAD + netdev_features_t xfrm_features = VIRTUAL_DEV_XFRM_FEATURES; +#endif + netdev_features_t mpls_features = VIRTUAL_DEV_MPLS_FEATURES; + netdev_features_t vlan_features = VIRTUAL_DEV_VLAN_FEATURES; + netdev_features_t enc_features = VIRTUAL_DEV_ENC_FEATURES; + unsigned short max_header_len = ETH_HLEN; + unsigned int tso_max_size = TSO_MAX_SIZE; + u16 tso_max_segs = TSO_MAX_SEGS; + struct net_device *lower_dev; + unsigned short max_headroom; + unsigned short max_tailroom; + struct list_head *iter; + + mpls_features = netdev_base_features(mpls_features); + vlan_features = netdev_base_features(vlan_features); + enc_features = netdev_base_features(enc_features); + + netdev_for_each_lower_dev(dev, lower_dev, iter) { + gso_partial_features = netdev_increment_features(gso_partial_features, + lower_dev->gso_partial_features, + VIRTUAL_DEV_GSO_PARTIAL_FEATURES); + + vlan_features = netdev_increment_features(vlan_features, + lower_dev->vlan_features, + VIRTUAL_DEV_VLAN_FEATURES); + + enc_features = netdev_increment_features(enc_features, + lower_dev->hw_enc_features, + VIRTUAL_DEV_ENC_FEATURES); + +#ifdef CONFIG_XFRM_OFFLOAD + xfrm_features = netdev_increment_features(xfrm_features, + lower_dev->hw_enc_features, + VIRTUAL_DEV_XFRM_FEATURES); +#endif + + mpls_features = netdev_increment_features(mpls_features, + lower_dev->mpls_features, + VIRTUAL_DEV_MPLS_FEATURES); + + dst_release_flag &= lower_dev->priv_flags; + + if (update_header) { + max_header_len = max_t(unsigned short, max_header_len, + lower_dev->hard_header_len); + max_headroom = max_t(unsigned short, max_headroom, + lower_dev->needed_headroom); + max_tailroom = max_t(unsigned short, max_tailroom, + lower_dev->needed_tailroom); + } + + tso_max_size = min(tso_max_size, lower_dev->tso_max_size); + tso_max_segs = min(tso_max_segs, lower_dev->tso_max_segs); + } + + dev->gso_partial_features = gso_partial_features; + dev->vlan_features = vlan_features; + dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL | + NETIF_F_HW_VLAN_CTAG_TX | + NETIF_F_HW_VLAN_STAG_TX; +#ifdef CONFIG_XFRM_OFFLOAD + dev->hw_enc_features |= xfrm_features; +#endif + dev->mpls_features = mpls_features; + + dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + if ((dev->priv_flags & IFF_XMIT_DST_RELEASE_PERM) && + dst_release_flag == (IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM)) + dev->priv_flags |= IFF_XMIT_DST_RELEASE; + + if (update_header) { + dev->hard_header_len = max_header_len; + dev->needed_headroom = max_headroom; + dev->needed_tailroom = max_tailroom; + } + + netif_set_tso_max_segs(dev, tso_max_segs); + netif_set_tso_max_size(dev, tso_max_size); + + netdev_change_features(dev); +} +EXPORT_SYMBOL(netdev_compute_features_from_lowers); + static struct hlist_head * __net_init netdev_create_hash(void) { int i; -- 2.50.1