From beb5a9bea8239cdf4adf6b62672e30db3e9fa5ce Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Thu, 29 Aug 2024 14:33:36 +0200 Subject: netdevice: convert private flags > BIT(31) to bitfields Make dev->priv_flags `u32` back and define bits higher than 31 as bitfield booleans as per Jakub's suggestion. This simplifies code which accesses these bits with no optimization loss (testb both before/after), allows to not extend &netdev_priv_flags each time, but also scales better as bits > 63 in the future would only add a new u64 to the structure with no complications, comparing to that extending ::priv_flags would require converting it to a bitmap. Note that I picked `unsigned long :1` to not lose any potential optimizations comparing to `bool :1` etc. Suggested-by: Jakub Kicinski Signed-off-by: Alexander Lobakin Signed-off-by: Paolo Abeni --- include/linux/netdevice.h | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) (limited to 'include/linux') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index fce70990b209..d6f35c9d8580 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1613,7 +1613,8 @@ struct net_device_ops { * userspace; this means that the order of these flags can change * during any kernel release. * - * You should have a pretty good reason to be extending these flags. + * You should add bitfield booleans after either net_device::priv_flags + * (hotpath) or ::threaded (slowpath) instead of extending these flags. * * @IFF_802_1Q_VLAN: 802.1Q VLAN device * @IFF_EBRIDGE: Ethernet bridging device @@ -1652,10 +1653,6 @@ struct net_device_ops { * @IFF_NO_ADDRCONF: prevent ipv6 addrconf * @IFF_TX_SKB_NO_LINEAR: device/driver is capable of xmitting frames with * skb_headlen(skb) == 0 (data starts from frag0) - * @IFF_CHANGE_PROTO_DOWN: device supports setting carrier via IFLA_PROTO_DOWN - * @IFF_SEE_ALL_HWTSTAMP_REQUESTS: device wants to see calls to - * ndo_hwtstamp_set() for all timestamp requests regardless of source, - * even if those aren't HWTSTAMP_SOURCE_NETDEV. */ enum netdev_priv_flags { IFF_802_1Q_VLAN = 1<<0, @@ -1690,8 +1687,6 @@ enum netdev_priv_flags { IFF_L3MDEV_RX_HANDLER = 1<<29, IFF_NO_ADDRCONF = BIT_ULL(30), IFF_TX_SKB_NO_LINEAR = BIT_ULL(31), - IFF_CHANGE_PROTO_DOWN = BIT_ULL(32), - IFF_SEE_ALL_HWTSTAMP_REQUESTS = BIT_ULL(33), }; /* Specifies the type of the struct net_device::ml_priv pointer */ @@ -1723,6 +1718,9 @@ enum netdev_reg_state { * data with strictly "high-level" data, and it has to know about * almost every data structure used in the INET module. * + * @priv_flags: flags invisible to userspace defined as bits, see + * enum netdev_priv_flags for the definitions + * * @name: This is the first field of the "visible" part of this structure * (i.e. as seen by users in the "Space.c" file). It is the name * of the interface. @@ -1789,8 +1787,6 @@ enum netdev_reg_state { * * @flags: Interface flags (a la BSD) * @xdp_features: XDP capability supported by the device - * @priv_flags: Like 'flags' but invisible to userspace, - * see if.h for the definitions * @gflags: Global flags ( kept as legacy ) * @priv_len: Size of the ->priv flexible array * @priv: Flexible array containing private data @@ -1964,6 +1960,12 @@ enum netdev_reg_state { * * @threaded: napi threaded mode is enabled * + * @see_all_hwtstamp_requests: device wants to see calls to + * ndo_hwtstamp_set() for all timestamp requests + * regardless of source, even if those aren't + * HWTSTAMP_SOURCE_NETDEV + * @change_proto_down: device supports setting carrier via IFLA_PROTO_DOWN + * * @net_notifier_list: List of per-net netdev notifier block * that follow this device when it is moved * to another network namespace. @@ -2014,7 +2016,9 @@ struct net_device { /* TX read-mostly hotpath */ __cacheline_group_begin(net_device_read_tx); - unsigned long long priv_flags; + struct_group(priv_flags_fast, + unsigned long priv_flags:32; + ); const struct net_device_ops *netdev_ops; const struct header_ops *header_ops; struct netdev_queue *_tx; @@ -2350,6 +2354,10 @@ struct net_device { bool proto_down; bool threaded; + /* priv_flags_slow, ungrouped to save space */ + unsigned long see_all_hwtstamp_requests:1; + unsigned long change_proto_down:1; + struct list_head net_notifier_list; #if IS_ENABLED(CONFIG_MACSEC) -- cgit v1.2.3