can: remove private CAN skb headroom infrastructure

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: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20260201-can_skb_ext-v8-5-3635d790fe8b@hartkopp.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

5 files changed, 11 insertions, 24 deletions

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 164c4fbf3e23..da3b72e7afcc 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;
@@ -1030,7 +1027,6 @@ 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 cc698a6dc363..0502b030d238 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;
@@ -904,7 +903,6 @@ 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 3456ef481799..2cbe94fc487a 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));
@@ -1548,7 +1546,7 @@ 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;
 
@@ -1559,7 +1557,6 @@ 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 022154b0f6cc..eee244ffc31e 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -953,8 +953,8 @@ 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;
 
@@ -965,7 +965,6 @@ 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 */