From d4fb6514ff8ed6912a71294e6b66a5d59ee88007 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Sun, 1 Feb 2026 15:33:16 +0100 Subject: [PATCH] can: use skb hash instead of private variable in headroom The can_skb_priv::skbcnt variable is used to identify CAN skbs in the RX path analogue to the skb->hash. As the skb hash is not filled in CAN skbs move the private skbcnt value to skb->hash and set skb->sw_hash accordingly. The skb->hash is a value used for RPS to identify skbs. Use it as intended. Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260201-can_skb_ext-v8-1-3635d790fe8b@hartkopp.net Signed-off-by: Paolo Abeni --- drivers/net/can/dev/skb.c | 2 -- include/linux/can/core.h | 1 + include/linux/can/skb.h | 2 -- net/can/af_can.c | 14 +++++++++++--- net/can/bcm.c | 2 -- net/can/isotp.c | 3 --- net/can/j1939/socket.c | 1 - net/can/j1939/transport.c | 2 -- net/can/raw.c | 7 +++---- 9 files changed, 15 insertions(+), 19 deletions(-) diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c index 3ebd4f779b9bd..0da615afa04de 100644 --- a/drivers/net/can/dev/skb.c +++ b/drivers/net/can/dev/skb.c @@ -202,7 +202,6 @@ static void init_can_skb_reserve(struct sk_buff *skb) skb_reset_transport_header(skb); can_skb_reserve(skb); - can_skb_prv(skb)->skbcnt = 0; } struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf) @@ -312,7 +311,6 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb) if (skb->ip_summed == CHECKSUM_NONE) { /* init headroom */ can_skb_prv(skb)->ifindex = dev->ifindex; - can_skb_prv(skb)->skbcnt = 0; skb->ip_summed = CHECKSUM_UNNECESSARY; diff --git a/include/linux/can/core.h b/include/linux/can/core.h index 5fb8d0e3f9c1d..3287232e3cad9 100644 --- a/include/linux/can/core.h +++ b/include/linux/can/core.h @@ -58,6 +58,7 @@ extern void can_rx_unregister(struct net *net, struct net_device *dev, void *data); extern int can_send(struct sk_buff *skb, int loop); +void can_set_skb_uid(struct sk_buff *skb); void can_sock_destruct(struct sock *sk); #endif /* !_CAN_CORE_H */ diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h index 1abc25a8d144e..869ea574a40a1 100644 --- a/include/linux/can/skb.h +++ b/include/linux/can/skb.h @@ -49,13 +49,11 @@ bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb); /** * struct can_skb_priv - private additional data inside CAN sk_buffs * @ifindex: ifindex of the first interface the CAN frame appeared on - * @skbcnt: atomic counter to have an unique id together with skb pointer * @frame_len: length of CAN frame in data link layer * @cf: align to the following CAN frame at skb->data */ struct can_skb_priv { int ifindex; - int skbcnt; unsigned int frame_len; struct can_frame cf[]; }; diff --git a/net/can/af_can.c b/net/can/af_can.c index 770173d8db428..70659987ef4d2 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -641,6 +641,16 @@ static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buf return matches; } +void can_set_skb_uid(struct sk_buff *skb) +{ + /* create non-zero unique skb identifier together with *skb */ + while (!(skb->hash)) + skb->hash = atomic_inc_return(&skbcounter); + + skb->sw_hash = 1; +} +EXPORT_SYMBOL(can_set_skb_uid); + static void can_receive(struct sk_buff *skb, struct net_device *dev) { struct can_dev_rcv_lists *dev_rcv_lists; @@ -652,9 +662,7 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev) atomic_long_inc(&pkg_stats->rx_frames); atomic_long_inc(&pkg_stats->rx_frames_delta); - /* create non-zero unique skb identifier together with *skb */ - while (!(can_skb_prv(skb)->skbcnt)) - can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter); + can_set_skb_uid(skb); rcu_read_lock(); diff --git a/net/can/bcm.c b/net/can/bcm.c index 7eba8ae01a5b1..8ed60f18c2eaf 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -316,7 +316,6 @@ static void bcm_can_tx(struct bcm_op *op) can_skb_reserve(skb); can_skb_prv(skb)->ifindex = dev->ifindex; - can_skb_prv(skb)->skbcnt = 0; skb_put_data(skb, cf, op->cfsiz); @@ -1344,7 +1343,6 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk, } can_skb_prv(skb)->ifindex = dev->ifindex; - can_skb_prv(skb)->skbcnt = 0; skb->dev = dev; can_skb_set_owner(skb, sk); err = can_send(skb, 1); /* send with loopback */ diff --git a/net/can/isotp.c b/net/can/isotp.c index ce588b85665a0..4bb60b8f9b961 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -230,7 +230,6 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus) can_skb_reserve(nskb); can_skb_prv(nskb)->ifindex = dev->ifindex; - can_skb_prv(nskb)->skbcnt = 0; nskb->dev = dev; can_skb_set_owner(nskb, sk); @@ -780,7 +779,6 @@ static void isotp_send_cframe(struct isotp_sock *so) can_skb_reserve(skb); can_skb_prv(skb)->ifindex = dev->ifindex; - can_skb_prv(skb)->skbcnt = 0; cf = (struct canfd_frame *)skb->data; skb_put_zero(skb, so->ll.mtu); @@ -1009,7 +1007,6 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) can_skb_reserve(skb); can_skb_prv(skb)->ifindex = dev->ifindex; - can_skb_prv(skb)->skbcnt = 0; so->tx.len = size; so->tx.idx = 0; diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index ff9c4fd7b4337..1589e8ca634ec 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -897,7 +897,6 @@ static struct sk_buff *j1939_sk_alloc_skb(struct net_device *ndev, can_skb_reserve(skb); can_skb_prv(skb)->ifindex = ndev->ifindex; - can_skb_prv(skb)->skbcnt = 0; skb_reserve(skb, offsetof(struct can_frame, data)); ret = memcpy_from_msg(skb_put(skb, size), msg, size); diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index 8656ab388c83e..d5d3e5320f7ac 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -601,7 +601,6 @@ sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv, skb->dev = priv->ndev; can_skb_reserve(skb); can_skb_prv(skb)->ifindex = priv->ndev->ifindex; - can_skb_prv(skb)->skbcnt = 0; /* reserve CAN header */ skb_reserve(skb, offsetof(struct can_frame, data)); @@ -1536,7 +1535,6 @@ j1939_session *j1939_session_fresh_new(struct j1939_priv *priv, skb->dev = priv->ndev; can_skb_reserve(skb); can_skb_prv(skb)->ifindex = priv->ndev->ifindex; - can_skb_prv(skb)->skbcnt = 0; skcb = j1939_skb_to_cb(skb); memcpy(skcb, rel_skcb, sizeof(*skcb)); diff --git a/net/can/raw.c b/net/can/raw.c index 12293363413ce..fb4f9c854df04 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -76,7 +76,7 @@ MODULE_ALIAS("can-proto-1"); struct uniqframe { const struct sk_buff *skb; - int skbcnt; + u32 hash; unsigned int join_rx_count; }; @@ -164,7 +164,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data) /* eliminate multiple filter matches for the same skb */ if (this_cpu_ptr(ro->uniq)->skb == oskb && - this_cpu_ptr(ro->uniq)->skbcnt == can_skb_prv(oskb)->skbcnt) { + this_cpu_ptr(ro->uniq)->hash == oskb->hash) { if (!ro->join_filters) return; @@ -174,7 +174,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data) return; } else { this_cpu_ptr(ro->uniq)->skb = oskb; - this_cpu_ptr(ro->uniq)->skbcnt = can_skb_prv(oskb)->skbcnt; + this_cpu_ptr(ro->uniq)->hash = oskb->hash; this_cpu_ptr(ro->uniq)->join_rx_count = 1; /* drop first frame to check all enabled filters? */ if (ro->join_filters && ro->count > 1) @@ -958,7 +958,6 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) can_skb_reserve(skb); can_skb_prv(skb)->ifindex = dev->ifindex; - can_skb_prv(skb)->skbcnt = 0; /* fill the skb before testing for valid CAN frames */ err = memcpy_from_msg(skb_put(skb, size), msg, size); -- 2.47.3