gve: Handle alternate miss completions

The virtual NIC has 2 ways of indicating a miss-path
completion. This handles the alternate.

Signed-off-by: Jeroen de Borst <[e-mail]>
Reviewed-by: Jesse Brandeburg <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/google/gve/gve_adminq.h

···
 	gve_driver_capability_gqi_rda = 1,
 	gve_driver_capability_dqo_qpl = 2, /* reserved for future use */
 	gve_driver_capability_dqo_rda = 3,
+	gve_driver_capability_alt_miss_compl = 4,
 };
 
 #define GVE_CAP1(a) BIT((int)a)
···
 #define GVE_DRIVER_CAPABILITY_FLAGS1 \
 	(GVE_CAP1(gve_driver_capability_gqi_qpl) | \
 	 GVE_CAP1(gve_driver_capability_gqi_rda) | \
-	 GVE_CAP1(gve_driver_capability_dqo_rda))
+	 GVE_CAP1(gve_driver_capability_dqo_rda) | \
+	 GVE_CAP1(gve_driver_capability_alt_miss_compl))
 
 #define GVE_DRIVER_CAPABILITY_FLAGS2 0x0
 #define GVE_DRIVER_CAPABILITY_FLAGS3 0x0

drivers/net/ethernet/google/gve/gve_desc_dqo.h

···
 #define GVE_COMPL_TYPE_DQO_MISS 0x1 /* Miss path completion */
 #define GVE_COMPL_TYPE_DQO_REINJECTION 0x3 /* Re-injection completion */
 
+/* The most significant bit in the completion tag can change the completion
+ * type from packet completion to miss path completion.
+ */
+#define GVE_ALT_MISS_COMPL_BIT BIT(15)
+
 /* Descriptor to post buffers to HW on buffer queue. */
 struct gve_rx_desc_dqo {
 	__le16 buf_id; /* ID returned in Rx completion descriptor */

drivers/net/ethernet/google/gve/gve_tx_dqo.c

···
 			atomic_set_release(&tx->dqo_compl.hw_tx_head, tx_head);
 		} else if (type == GVE_COMPL_TYPE_DQO_PKT) {
 			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
-
-			gve_handle_packet_completion(priv, tx, !!napi,
-						     compl_tag,
-						     &pkt_compl_bytes,
-						     &pkt_compl_pkts,
-						     /*is_reinjection=*/false);
+			if (compl_tag & GVE_ALT_MISS_COMPL_BIT) {
+				compl_tag &= ~GVE_ALT_MISS_COMPL_BIT;
+				gve_handle_miss_completion(priv, tx, compl_tag,
+							   &miss_compl_bytes,
+							   &miss_compl_pkts);
+			} else {
+				gve_handle_packet_completion(priv, tx, !!napi,
+							     compl_tag,
+							     &pkt_compl_bytes,
+							     &pkt_compl_pkts,
+							     false);
+			}
 		} else if (type == GVE_COMPL_TYPE_DQO_MISS) {
 			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
 
···
 						     compl_tag,
 						     &reinject_compl_bytes,
 						     &reinject_compl_pkts,
-						     /*is_reinjection=*/true);
+						     true);
 		}
 
 		tx->dqo_compl.head =