header: add skb_put_padto()

skb_put_padto() is used by the igb driver.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/backport/backport-include/linux/skbuff.h b/backport/backport-include/linux/skbuff.h
index 53c1aa4b..687297c3 100644
--- a/backport/backport-include/linux/skbuff.h
+++ b/backport/backport-include/linux/skbuff.h
@@ -269,6 +269,30 @@ static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
 {
 	return memcpy_fromiovec(data, msg->msg_iov, len);
 }
+
+/**
+ *	skb_put_padto - increase size and pad an skbuff up to a minimal size
+ *	@skb: buffer to pad
+ *	@len: minimal length
+ *
+ *	Pads up a buffer to ensure the trailing bytes exist and are
+ *	blanked. If the buffer already contains sufficient data it
+ *	is untouched. Otherwise it is extended. Returns zero on
+ *	success. The skb is freed on error.
+ */
+#define skb_put_padto LINUX_BACKPORT(skb_put_padto)
+static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
+{
+	unsigned int size = skb->len;
+
+	if (unlikely(size < len)) {
+		len -= size;
+		if (skb_pad(skb, len))
+			return -ENOMEM;
+		__skb_put(skb, len);
+	}
+	return 0;
+}
 #endif /* LINUX_VERSION_CODE < KERNEL_VERSION(3,19,0) */
 
 #endif /* __BACKPORT_SKBUFF_H */