[PATCH can-next v2 5/6] can: remove private CAN skb headroom infrastructure
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: 2026-01-28 09:29:31
Also in:
linux-can, lkml
Subsystem:
can network drivers, can network layer, can-j1939 network layer, the rest · Maintainers:
Marc Kleine-Budde, Vincent Mailhol, Oliver Hartkopp, Robin van der Gracht, Oleksij Rempel, Linus Torvalds
From: Oliver Hartkopp <socketcan@hartkopp.net> This patch removes struct can_skb_priv which was stored at skb->head and the can_skb_reserve() helper which was used to shift skb->head. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> --- drivers/net/can/dev/skb.c | 31 +++++++++---------------------- include/linux/can/skb.h | 31 ------------------------------- net/can/bcm.c | 7 ++----- net/can/isotp.c | 12 ++++-------- net/can/j1939/socket.c | 4 +--- net/can/j1939/transport.c | 7 ++----- net/can/raw.c | 4 +--- 7 files changed, 19 insertions(+), 77 deletions(-)
diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
index 408ee49abce1..95fcdc1026f8 100644
--- a/drivers/net/can/dev/skb.c
+++ b/drivers/net/can/dev/skb.c@@ -206,16 +206,10 @@ void can_free_echo_skb(struct net_device *dev, unsigned int idx, EXPORT_SYMBOL_GPL(can_free_echo_skb); /* fill common values for CAN sk_buffs */ -static void init_can_skb_reserve(struct sk_buff *skb) +static void init_can_skb(struct sk_buff *skb) { skb->pkt_type = PACKET_BROADCAST; skb->ip_summed = CHECKSUM_UNNECESSARY; - - skb_reset_mac_header(skb); - skb_reset_network_header(skb); - skb_reset_transport_header(skb); - - can_skb_reserve(skb); } struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
@@ -223,8 +217,7 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf) struct sk_buff *skb; struct can_skb_ext *csx; - skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) + - sizeof(struct can_frame)); + skb = netdev_alloc_skb(dev, sizeof(struct can_frame)); if (unlikely(!skb)) goto out_error_cc;
@@ -235,7 +228,7 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf) } skb->protocol = htons(ETH_P_CAN); - init_can_skb_reserve(skb); + init_can_skb(skb); csx->can_iif = dev->ifindex; *cf = skb_put_zero(skb, sizeof(struct can_frame));
@@ -255,8 +248,7 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev, struct sk_buff *skb; struct can_skb_ext *csx; - skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) + - sizeof(struct canfd_frame)); + skb = netdev_alloc_skb(dev, sizeof(struct canfd_frame)); if (unlikely(!skb)) goto out_error_fd;
@@ -267,7 +259,7 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev, } skb->protocol = htons(ETH_P_CANFD); - init_can_skb_reserve(skb); + init_can_skb(skb); csx->can_iif = dev->ifindex; *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
@@ -294,8 +286,7 @@ struct sk_buff *alloc_canxl_skb(struct net_device *dev, if (data_len < CANXL_MIN_DLEN || data_len > CANXL_MAX_DLEN) goto out_error_xl; - skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) + - CANXL_HDR_SIZE + data_len); + skb = netdev_alloc_skb(dev, CANXL_HDR_SIZE + data_len); if (unlikely(!skb)) goto out_error_xl;
@@ -306,7 +297,7 @@ struct sk_buff *alloc_canxl_skb(struct net_device *dev, } skb->protocol = htons(ETH_P_CANXL); - init_can_skb_reserve(skb); + init_can_skb(skb); csx->can_iif = dev->ifindex; *cxl = skb_put_zero(skb, CANXL_HDR_SIZE + data_len);
@@ -340,14 +331,10 @@ struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf) EXPORT_SYMBOL_GPL(alloc_can_err_skb); /* Check for outgoing skbs that have not been created by the CAN subsystem */ -static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb) +static bool can_skb_init_valid(struct net_device *dev, struct sk_buff *skb) { struct can_skb_ext *csx = can_skb_ext_find(skb); - /* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */ - if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv))) - return false; - /* af_packet does not apply CAN skb specific settings */ if (skb->ip_summed == CHECKSUM_NONE || !csx) { /* init CAN skb content */
@@ -405,7 +392,7 @@ bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb) goto inval_skb; } - if (!can_skb_headroom_valid(dev, skb)) + if (!can_skb_init_valid(dev, skb)) goto inval_skb; return false;
diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index aeb08f47de48..cacbbb185bb9 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h@@ -38,37 +38,6 @@ struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf); bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb); -/* - * The struct can_skb_priv is used to transport additional information along - * with the stored struct can(fd)_frame that can not be contained in existing - * struct sk_buff elements. - * N.B. that this information must not be modified in cloned CAN sk_buffs. - * To modify the CAN frame content or the struct can_skb_priv content - * skb_copy() needs to be used instead of skb_clone(). - */ - -/** - * struct can_skb_priv - private additional data inside CAN sk_buffs - * @ifindex: ifindex of the first interface the CAN frame appeared on - * @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; - unsigned int frame_len; - struct can_frame cf[]; -}; - -static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb) -{ - return (struct can_skb_priv *)(skb->head); -} - -static inline void can_skb_reserve(struct sk_buff *skb) -{ - skb_reserve(skb, sizeof(struct can_skb_priv)); -} - static inline struct can_skb_ext *can_skb_ext_add(struct sk_buff *skb) { return skb_ext_add(skb, SKB_EXT_CAN);
diff --git a/net/can/bcm.c b/net/can/bcm.c
index f102d17e8619..b7324e9c955b 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c@@ -312,7 +312,7 @@ static void bcm_can_tx(struct bcm_op *op) return; } - skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any()); + skb = alloc_skb(op->cfsiz, gfp_any()); if (!skb) goto out;
@@ -322,7 +322,6 @@ static void bcm_can_tx(struct bcm_op *op) goto out; } - can_skb_reserve(skb); csx->can_iif = dev->ifindex; skb_put_data(skb, cf, op->cfsiz);
@@ -1333,7 +1332,7 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk, if (!ifindex) return -ENODEV; - skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL); + skb = alloc_skb(cfsiz, GFP_KERNEL); if (!skb) return -ENOMEM;
@@ -1343,8 +1342,6 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk, return -ENOMEM; } - can_skb_reserve(skb); - err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz); if (err < 0) { kfree_skb(skb);
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 01ceb3febbb7..434986cc8fe5 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c@@ -220,7 +220,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus) struct isotp_sock *so = isotp_sk(sk); int can_send_ret; - nskb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), gfp_any()); + nskb = alloc_skb(so->ll.mtu, gfp_any()); if (!nskb) return 1;
@@ -236,9 +236,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus) return 1; } - can_skb_reserve(nskb); csx->can_iif = dev->ifindex; - nskb->dev = dev; can_skb_set_owner(nskb, sk); ncf = (struct canfd_frame *)nskb->data;
@@ -780,7 +778,7 @@ static void isotp_send_cframe(struct isotp_sock *so) if (!dev) return; - skb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), GFP_ATOMIC); + skb = alloc_skb(so->ll.mtu, GFP_ATOMIC); if (!skb) { dev_put(dev); return;
@@ -793,7 +791,6 @@ static void isotp_send_cframe(struct isotp_sock *so) return; } - can_skb_reserve(skb); csx->can_iif = dev->ifindex; cf = (struct canfd_frame *)skb->data;
@@ -1015,8 +1012,8 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) goto err_out_drop; } - skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv), - msg->msg_flags & MSG_DONTWAIT, &err); + skb = sock_alloc_send_skb(sk, so->ll.mtu, msg->msg_flags & MSG_DONTWAIT, + &err); if (!skb) { dev_put(dev); goto err_out_drop;
@@ -1029,7 +1026,6 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) goto err_out_drop; } - can_skb_reserve(skb); csx->can_iif = dev->ifindex; so->tx.len = size;
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index f03bae79354e..10014d95c319 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c@@ -891,8 +891,7 @@ static struct sk_buff *j1939_sk_alloc_skb(struct net_device *ndev, skb = sock_alloc_send_skb(sk, size + sizeof(struct can_frame) - - sizeof(((struct can_frame *)NULL)->data) + - sizeof(struct can_skb_priv), + sizeof(((struct can_frame *)NULL)->data), msg->msg_flags & MSG_DONTWAIT, &ret); if (!skb) goto failure;
@@ -903,7 +902,6 @@ static struct sk_buff *j1939_sk_alloc_skb(struct net_device *ndev, goto failure; } - can_skb_reserve(skb); csx->can_iif = ndev->ifindex; skb_reserve(skb, offsetof(struct can_frame, data));
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index 96e02ad4a726..e63cf79af1c4 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c@@ -595,8 +595,7 @@ sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv, struct can_skb_ext *csx; struct j1939_sk_buff_cb *skcb; - skb = alloc_skb(sizeof(struct can_frame) + sizeof(struct can_skb_priv), - GFP_ATOMIC); + skb = alloc_skb(sizeof(struct can_frame), GFP_ATOMIC); if (unlikely(!skb)) return ERR_PTR(-ENOMEM);
@@ -607,7 +606,6 @@ sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv, } skb->dev = priv->ndev; - can_skb_reserve(skb); csx->can_iif = priv->ndev->ifindex; /* reserve CAN header */ skb_reserve(skb, offsetof(struct can_frame, data));
@@ -1537,7 +1535,7 @@ j1939_session *j1939_session_fresh_new(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb; struct j1939_session *session; - skb = alloc_skb(size + sizeof(struct can_skb_priv), GFP_ATOMIC); + skb = alloc_skb(size, GFP_ATOMIC); if (unlikely(!skb)) return NULL;
@@ -1548,7 +1546,6 @@ j1939_session *j1939_session_fresh_new(struct j1939_priv *priv, } skb->dev = priv->ndev; - can_skb_reserve(skb); csx->can_iif = priv->ndev->ifindex; 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 7c89962ec913..d200b6f66fb9 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c@@ -953,8 +953,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) goto put_dev; } - skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv), - msg->msg_flags & MSG_DONTWAIT, &err); + skb = sock_alloc_send_skb(sk, size, msg->msg_flags & MSG_DONTWAIT, &err); if (!skb) goto put_dev;
@@ -964,7 +963,6 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) goto put_dev; } - can_skb_reserve(skb); csx->can_iif = dev->ifindex; /* fill the skb before testing for valid CAN frames */
--
2.51.0