sfc: commonise TSO fallback code

ef100 will need this if it gets GSO skbs it can't handle (e.g. too long
 header length).

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/tx_common.c b/drivers/net/ethernet/sfc/tx_common.c
index 70876df1da69..9a005e7c2c68 100644
--- a/drivers/net/ethernet/sfc/tx_common.c
+++ b/drivers/net/ethernet/sfc/tx_common.c
@@ -405,3 +405,30 @@ unsigned int efx_tx_max_skb_descs(struct efx_nic *efx)
 
 	return max_descs;
 }
+
+/*
+ * Fallback to software TSO.
+ *
+ * This is used if we are unable to send a GSO packet through hardware TSO.
+ * This should only ever happen due to per-queue restrictions - unsupported
+ * packets should first be filtered by the feature flags.
+ *
+ * Returns 0 on success, error code otherwise.
+ */
+int efx_tx_tso_fallback(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
+{
+	struct sk_buff *segments, *next;
+
+	segments = skb_gso_segment(skb, 0);
+	if (IS_ERR(segments))
+		return PTR_ERR(segments);
+
+	dev_consume_skb_any(skb);
+
+	skb_list_walk_safe(segments, skb, next) {
+		skb_mark_not_on_list(skb);
+		efx_enqueue_skb(tx_queue, skb);
+	}
+
+	return 0;
+}