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>

1 files changed, 9 insertions, 22 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;