[PATCH 1/2] net: dsa: tag_ksz: linearize SKB before adding DSA tag

From: Lino Sanfilippo
Date: Wed Jul 14 2021 - 15:18:24 EST


In ksz9477_xmit() skb_put() is used to add the DSA tag to the passed SKB.
However skb_put() must only be called for linear SKBs which may not be the
case if the DSA slave device inherited NETIF_F_SG from the master device.
So make sure the SKB is always linearized.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
---
net/dsa/tag_ksz.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index 53565f48934c..364f509d7cd7 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -53,6 +53,9 @@ static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev)
u8 *tag;
u8 *addr;

+ if (skb_linearize(skb))
+ return NULL;
+
/* Tag encoding */
tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
addr = skb_mac_header(skb);
@@ -114,6 +117,9 @@ static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
u8 *addr;
u16 val;

+ if (skb_linearize(skb))
+ return NULL;
+
/* Tag encoding */
tag = skb_put(skb, KSZ9477_INGRESS_TAG_LEN);
addr = skb_mac_header(skb);
@@ -164,6 +170,9 @@ static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
u8 *addr;
u8 *tag;

+ if (skb_linearize(skb))
+ return NULL;
+
/* Tag encoding */
tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
addr = skb_mac_header(skb);
--
2.32.0