Merge branch 'skb_cow_head'

Eric Dumazet says: ==================== net: use skb_cow_head() to deal with cloned skbs James Hughes found an issue with smsc95xx driver. Same problematic code is found in other drivers. ==================== Signed-off-by: David S. Miller <[email protected]>
raspberrypi · Apr 21, 2017 · 918b702 · 918b702
2 parents 95b9b88 + 39fba78
commit 918b702
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Showing 6 changed files with 16 additions and 44 deletions.
diff --git a/drivers/net/usb/ch9200.c b/drivers/net/usb/ch9200.c
@@ -254,14 +254,9 @@ static struct sk_buff *ch9200_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 	tx_overhead = 0x40;
 
 	len = skb->len;
-	if (skb_headroom(skb) < tx_overhead) {
-		struct sk_buff *skb2;
-
-		skb2 = skb_copy_expand(skb, tx_overhead, 0, flags);
+	if (skb_cow_head(skb, tx_overhead)) {
 		dev_kfree_skb_any(skb);
-		skb = skb2;
-		if (!skb)
-			return NULL;
+		return NULL;
 	}
 
 	__skb_push(skb, tx_overhead);

diff --git a/drivers/net/usb/cx82310_eth.c b/drivers/net/usb/cx82310_eth.c
@@ -293,12 +293,9 @@ static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 {
 	int len = skb->len;
 
-	if (skb_headroom(skb) < 2) {
-		struct sk_buff *skb2 = skb_copy_expand(skb, 2, 0, flags);
+	if (skb_cow_head(skb, 2)) {
 		dev_kfree_skb_any(skb);
-		skb = skb2;
-		if (!skb)
-			return NULL;
+		return NULL;
 	}
 	skb_push(skb, 2);
 

diff --git a/drivers/net/usb/kaweth.c b/drivers/net/usb/kaweth.c
@@ -803,18 +803,12 @@ static netdev_tx_t kaweth_start_xmit(struct sk_buff *skb,
 	}
 
 	/* We now decide whether we can put our special header into the sk_buff */
-	if (skb_cloned(skb) || skb_headroom(skb) < 2) {
-		/* no such luck - we make our own */
-		struct sk_buff *copied_skb;
-		copied_skb = skb_copy_expand(skb, 2, 0, GFP_ATOMIC);
-		dev_kfree_skb_irq(skb);
-		skb = copied_skb;
-		if (!copied_skb) {
-			kaweth->stats.tx_errors++;
-			netif_start_queue(net);
-			spin_unlock_irq(&kaweth->device_lock);
-			return NETDEV_TX_OK;
-		}
+	if (skb_cow_head(skb, 2)) {
+		kaweth->stats.tx_errors++;
+		netif_start_queue(net);
+		spin_unlock_irq(&kaweth->device_lock);
+		dev_kfree_skb_any(skb);
+		return NETDEV_TX_OK;
 	}
 
 	private_header = (__le16 *)__skb_push(skb, 2);

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
@@ -2607,14 +2607,9 @@ static struct sk_buff *lan78xx_tx_prep(struct lan78xx_net *dev,
 {
 	u32 tx_cmd_a, tx_cmd_b;
 
-	if (skb_headroom(skb) < TX_OVERHEAD) {
-		struct sk_buff *skb2;
-
-		skb2 = skb_copy_expand(skb, TX_OVERHEAD, 0, flags);
+	if (skb_cow_head(skb, TX_OVERHEAD)) {
 		dev_kfree_skb_any(skb);
-		skb = skb2;
-		if (!skb)
-			return NULL;
+		return NULL;
 	}
 
 	if (lan78xx_linearize(skb) < 0)

diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
@@ -2203,13 +2203,9 @@ static struct sk_buff *smsc75xx_tx_fixup(struct usbnet *dev,
 {
 	u32 tx_cmd_a, tx_cmd_b;
 
-	if (skb_headroom(skb) < SMSC75XX_TX_OVERHEAD) {
-		struct sk_buff *skb2 =
-			skb_copy_expand(skb, SMSC75XX_TX_OVERHEAD, 0, flags);
+	if (skb_cow_head(skb, SMSC75XX_TX_OVERHEAD)) {
 		dev_kfree_skb_any(skb);
-		skb = skb2;
-		if (!skb)
-			return NULL;
+		return NULL;
 	}
 
 	tx_cmd_a = (u32)(skb->len & TX_CMD_A_LEN) | TX_CMD_A_FCS;

diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
@@ -456,14 +456,9 @@ static struct sk_buff *sr9700_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 
 	len = skb->len;
 
-	if (skb_headroom(skb) < SR_TX_OVERHEAD) {
-		struct sk_buff *skb2;
-
-		skb2 = skb_copy_expand(skb, SR_TX_OVERHEAD, 0, flags);
+	if (skb_cow_head(skb, SR_TX_OVERHEAD)) {
 		dev_kfree_skb_any(skb);
-		skb = skb2;
-		if (!skb)
-			return NULL;
+		return NULL;
 	}
 
 	__skb_push(skb, SR_TX_OVERHEAD);