From nobody Mon Feb 9 14:38:19 2026 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (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 81080345CA6 for ; Wed, 28 Jan 2026 09:29:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769592572; cv=none; b=St1CqN+Ev6cDO+XYTXYa3fJFt5wtWAaXQfTS/mV7Q7LwHUwczRKP6bD9r6yRSnyKA8waM4tocKa0fk1793uEpHiR9Ea8Yyt+4ajb49vyzdAUpUeStR0Argjrf8ilipIVXGgB7pT9SG9gf4VPjwQ/OUOv/XWSGaCl/kHit5SXPOQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769592572; c=relaxed/simple; bh=7CoeWa8oYypCob5zi+rtGEUygWFQEPsRRN1+F2cTtu8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lb14P58rNtKL5fbvuEK65d7JzwpZ8syZclHGNTI0AHJNgzl/HSVzmHol4Ma3JlCnHTwwSdMik4bTF9Ne2pBoWfb28pmEHsw7CJ4NSVh7Sy7JN2hTdFjF9GGhkruldfelellstyZEvf0HbzkqVwB+jXHkcxoUhf+zy4BsgKvHxEY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1vl1rN-0007xU-Mu; Wed, 28 Jan 2026 10:29:13 +0100 Received: from moin.white.stw.pengutronix.de ([2a0a:edc0:0:b01:1d::7b] helo=bjornoya.blackshift.org) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vl1rN-002tQC-0e; Wed, 28 Jan 2026 10:29:12 +0100 Received: from hardanger.blackshift.org (p54b15bf8.dip0.t-ipconnect.de [84.177.91.248]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: mkl-all@blackshift.org) by smtp.blackshift.org (Postfix) with ESMTPSA id 3C8584DA02C; Wed, 28 Jan 2026 09:29:12 +0000 (UTC) From: Marc Kleine-Budde Date: Wed, 28 Jan 2026 10:28:53 +0100 Subject: [PATCH can-next v2 1/6] can: use skb hash instead of private variable in headroom Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260128-can-skb-ext-v2-1-fe64aa152c8a@pengutronix.de> References: <20260128-can-skb-ext-v2-0-fe64aa152c8a@pengutronix.de> In-Reply-To: <20260128-can-skb-ext-v2-0-fe64aa152c8a@pengutronix.de> To: Marc Kleine-Budde , Vincent Mailhol , Oliver Hartkopp , Robin van der Gracht , Oleksij Rempel , kernel@pengutronix.de, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman Cc: linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org X-Mailer: b4 0.15-dev-47773 X-Developer-Signature: v=1; a=openpgp-sha256; l=7924; i=mkl@pengutronix.de; h=from:subject:message-id; bh=BvDTg1HN+JG/lCMuii/eyDlcJ3crtPEK1Ee+44YKxy0=; b=owEBbQGS/pANAwAKAQx0Zd/5kJGcAcsmYgBpedbcRy5O7g0NtCQ3QgOZeDedZ71yu3SYI4alQ hC3LCMK98SJATMEAAEKAB0WIQSf+wzYr2eoX/wVbPMMdGXf+ZCRnAUCaXnW3AAKCRAMdGXf+ZCR nCxqCACvlSE7H3zO2/+JoYSi70iSI06XPzzUYf6gaboD9k5KMIw2L0UHale0IU6nHEvHQGfi0w8 zPSgjUAtjP9T6imCFEabGq6z88oSPGj89Q64TXN8jb72otMT782uLr+4u/2X+5iFUWLu646ZElk 2J8TEdbMwFMwEHveltd4sRzTvDP8BsdnihfL7+nm9LvkTls21UL/EQyZVf6+xL2olvpxXLf6N/I i5NVxCZRMU+q7z/RFZhLSUjka3nbKfhLzXhyxgOuyprDexWYzEVoqAzKUhYn0jl9xWqKia9KcWX Rh+DFtJwIXkQ+GQoc/yYMIrxcavox3R2vESLqUJAVJ908kbV X-Developer-Key: i=mkl@pengutronix.de; a=openpgp; fpr=C1400BA0B3989E6FBC7D5B5C2B5EE211C58AEA54 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org From: Oliver Hartkopp 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: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- 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 3ebd4f779b9b..0da615afa04d 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); =20 can_skb_reserve(skb); - can_skb_prv(skb)->skbcnt =3D 0; } =20 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **c= f) @@ -312,7 +311,6 @@ static bool can_skb_headroom_valid(struct net_device *d= ev, struct sk_buff *skb) if (skb->ip_summed =3D=3D CHECKSUM_NONE) { /* init headroom */ can_skb_prv(skb)->ifindex =3D dev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; =20 skb->ip_summed =3D CHECKSUM_UNNECESSARY; =20 diff --git a/include/linux/can/core.h b/include/linux/can/core.h index 5fb8d0e3f9c1..5c382ed61755 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); =20 extern int can_send(struct sk_buff *skb, int loop); +extern void can_set_skb_uid(struct sk_buff *skb); void can_sock_destruct(struct sock *sk); =20 #endif /* !_CAN_CORE_H */ diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h index 1abc25a8d144..869ea574a40a 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, st= ruct 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 770173d8db42..70659987ef4d 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 *de= v_rcv_lists, struct sk_buf return matches; } =20 +void can_set_skb_uid(struct sk_buff *skb) +{ + /* create non-zero unique skb identifier together with *skb */ + while (!(skb->hash)) + skb->hash =3D atomic_inc_return(&skbcounter); + + skb->sw_hash =3D 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); =20 - /* create non-zero unique skb identifier together with *skb */ - while (!(can_skb_prv(skb)->skbcnt)) - can_skb_prv(skb)->skbcnt =3D atomic_inc_return(&skbcounter); + can_set_skb_uid(skb); =20 rcu_read_lock(); =20 diff --git a/net/can/bcm.c b/net/can/bcm.c index 7eba8ae01a5b..8ed60f18c2ea 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -316,7 +316,6 @@ static void bcm_can_tx(struct bcm_op *op) =20 can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D dev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; =20 skb_put_data(skb, cf, op->cfsiz); =20 @@ -1344,7 +1343,6 @@ static int bcm_tx_send(struct msghdr *msg, int ifinde= x, struct sock *sk, } =20 can_skb_prv(skb)->ifindex =3D dev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; skb->dev =3D dev; can_skb_set_owner(skb, sk); err =3D can_send(skb, 1); /* send with loopback */ diff --git a/net/can/isotp.c b/net/can/isotp.c index ce588b85665a..4bb60b8f9b96 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 fl= owstatus) =20 can_skb_reserve(nskb); can_skb_prv(nskb)->ifindex =3D dev->ifindex; - can_skb_prv(nskb)->skbcnt =3D 0; =20 nskb->dev =3D dev; can_skb_set_owner(nskb, sk); @@ -780,7 +779,6 @@ static void isotp_send_cframe(struct isotp_sock *so) =20 can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D dev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; =20 cf =3D (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) =20 can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D dev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; =20 so->tx.len =3D size; so->tx.idx =3D 0; diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index ff9c4fd7b433..1589e8ca634e 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_de= vice *ndev, =20 can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D ndev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; skb_reserve(skb, offsetof(struct can_frame, data)); =20 ret =3D memcpy_from_msg(skb_put(skb, size), msg, size); diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index 8656ab388c83..d5d3e5320f7a 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 =3D priv->ndev; can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D priv->ndev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; /* reserve CAN header */ skb_reserve(skb, offsetof(struct can_frame, data)); =20 @@ -1536,7 +1535,6 @@ j1939_session *j1939_session_fresh_new(struct j1939_p= riv *priv, skb->dev =3D priv->ndev; can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D priv->ndev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; skcb =3D j1939_skb_to_cb(skb); memcpy(skcb, rel_skcb, sizeof(*skcb)); =20 diff --git a/net/can/raw.c b/net/can/raw.c index 12293363413c..fb4f9c854df0 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -76,7 +76,7 @@ MODULE_ALIAS("can-proto-1"); =20 struct uniqframe { const struct sk_buff *skb; - int skbcnt; + u32 hash; unsigned int join_rx_count; }; =20 @@ -164,7 +164,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data) =20 /* eliminate multiple filter matches for the same skb */ if (this_cpu_ptr(ro->uniq)->skb =3D=3D oskb && - this_cpu_ptr(ro->uniq)->skbcnt =3D=3D can_skb_prv(oskb)->skbcnt) { + this_cpu_ptr(ro->uniq)->hash =3D=3D oskb->hash) { if (!ro->join_filters) return; =20 @@ -174,7 +174,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data) return; } else { this_cpu_ptr(ro->uniq)->skb =3D oskb; - this_cpu_ptr(ro->uniq)->skbcnt =3D can_skb_prv(oskb)->skbcnt; + this_cpu_ptr(ro->uniq)->hash =3D oskb->hash; this_cpu_ptr(ro->uniq)->join_rx_count =3D 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 msgh= dr *msg, size_t size) =20 can_skb_reserve(skb); can_skb_prv(skb)->ifindex =3D dev->ifindex; - can_skb_prv(skb)->skbcnt =3D 0; =20 /* fill the skb before testing for valid CAN frames */ err =3D memcpy_from_msg(skb_put(skb, size), msg, size); --=20 2.51.0