From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB

---
 kernel/drivers/net/wan/hdlc_fr.c |   87 +++++++++++++++++++++----------------------
 1 files changed, 43 insertions(+), 44 deletions(-)

diff --git a/kernel/drivers/net/wan/hdlc_fr.c b/kernel/drivers/net/wan/hdlc_fr.c
index 96b4ce1..409e5a7 100644
--- a/kernel/drivers/net/wan/hdlc_fr.c
+++ b/kernel/drivers/net/wan/hdlc_fr.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic HDLC support routines for Linux
  * Frame Relay support
  *
  * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of version 2 of the GNU General Public License
- * as published by the Free Software Foundation.
  *
 
             Theory of PVC state
@@ -274,10 +271,8 @@
 }
 
 
-static int fr_hard_header(struct sk_buff **skb_p, u16 dlci)
+static int fr_hard_header(struct sk_buff *skb, u16 dlci)
 {
-	struct sk_buff *skb = *skb_p;
-
 	if (!skb->dev) { /* Control packets */
 		switch (dlci) {
 		case LMI_CCITT_ANSI_DLCI:
@@ -319,13 +314,6 @@
 		}
 
 	} else if (skb->dev->type == ARPHRD_ETHER) {
-		if (skb_headroom(skb) < 10) {
-			struct sk_buff *skb2 = skb_realloc_headroom(skb, 10);
-			if (!skb2)
-				return -ENOBUFS;
-			dev_kfree_skb(skb);
-			skb = *skb_p = skb2;
-		}
 		skb_push(skb, 10);
 		skb->data[3] = FR_PAD;
 		skb->data[4] = NLPID_SNAP;
@@ -419,38 +407,49 @@
 {
 	struct pvc_device *pvc = dev->ml_priv;
 
-	if (pvc->state.active) {
-		if (dev->type == ARPHRD_ETHER) {
-			int pad = ETH_ZLEN - skb->len;
-			if (pad > 0) { /* Pad the frame with zeros */
-				int len = skb->len;
-				if (skb_tailroom(skb) < pad)
-					if (pskb_expand_head(skb, 0, pad,
-							     GFP_ATOMIC)) {
-						dev->stats.tx_dropped++;
-						dev_kfree_skb(skb);
-						return NETDEV_TX_OK;
-					}
-				skb_put(skb, pad);
-				memset(skb->data + len, 0, pad);
-			}
-		}
-		skb->dev = dev;
-		if (!fr_hard_header(&skb, pvc->dlci)) {
-			dev->stats.tx_bytes += skb->len;
-			dev->stats.tx_packets++;
-			if (pvc->state.fecn) /* TX Congestion counter */
-				dev->stats.tx_compressed++;
-			skb->dev = pvc->frad;
-			skb->protocol = htons(ETH_P_HDLC);
-			skb_reset_network_header(skb);
-			dev_queue_xmit(skb);
-			return NETDEV_TX_OK;
+	if (!pvc->state.active)
+		goto drop;
+
+	if (dev->type == ARPHRD_ETHER) {
+		int pad = ETH_ZLEN - skb->len;
+
+		if (pad > 0) { /* Pad the frame with zeros */
+			if (__skb_pad(skb, pad, false))
+				goto drop;
+			skb_put(skb, pad);
 		}
 	}
 
+	/* We already requested the header space with dev->needed_headroom.
+	 * So this is just a protection in case the upper layer didn't take
+	 * dev->needed_headroom into consideration.
+	 */
+	if (skb_headroom(skb) < 10) {
+		struct sk_buff *skb2 = skb_realloc_headroom(skb, 10);
+
+		if (!skb2)
+			goto drop;
+		dev_kfree_skb(skb);
+		skb = skb2;
+	}
+
+	skb->dev = dev;
+	if (fr_hard_header(skb, pvc->dlci))
+		goto drop;
+
+	dev->stats.tx_bytes += skb->len;
+	dev->stats.tx_packets++;
+	if (pvc->state.fecn) /* TX Congestion counter */
+		dev->stats.tx_compressed++;
+	skb->dev = pvc->frad;
+	skb->protocol = htons(ETH_P_HDLC);
+	skb_reset_network_header(skb);
+	dev_queue_xmit(skb);
+	return NETDEV_TX_OK;
+
+drop:
 	dev->stats.tx_dropped++;
-	dev_kfree_skb(skb);
+	kfree_skb(skb);
 	return NETDEV_TX_OK;
 }
 
@@ -503,9 +502,9 @@
 	memset(skb->data, 0, len);
 	skb_reserve(skb, 4);
 	if (lmi == LMI_CISCO) {
-		fr_hard_header(&skb, LMI_CISCO_DLCI);
+		fr_hard_header(skb, LMI_CISCO_DLCI);
 	} else {
-		fr_hard_header(&skb, LMI_CCITT_ANSI_DLCI);
+		fr_hard_header(skb, LMI_CCITT_ANSI_DLCI);
 	}
 	data = skb_tail_pointer(skb);
 	data[i++] = LMI_CALLREF;

--
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