Subject: Re: [PATCH net-next v3 2/2] gve: Handle alternate miss completions

From: Saeed Mahameed <[email-masked]>
Date: Tue, 15 Nov 2022 21:17:06 -0800

On 14 Nov 15:35, Jeroen de Borst wrote:
>The virtual NIC has 2 ways of indicating a miss-path
>completion. This handles the alternate.
>
>Signed-off-by: Jeroen de Borst <[email-masked]>
>Reviewed-by: Jesse Brandeburg <[email-masked]>
>---
> drivers/net/ethernet/google/gve/gve_adminq.h   |  4 +++-
> drivers/net/ethernet/google/gve/gve_desc_dqo.h |  5 +++++
> drivers/net/ethernet/google/gve/gve_tx_dqo.c   | 18 ++++++++++++------
> 3 files changed, 20 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/net/ethernet/google/gve/gve_adminq.h b/drivers/net/ethernet/google/gve/gve_adminq.h
>index b9ee8be73f96..cf29662e6ad1 100644
>--- a/drivers/net/ethernet/google/gve/gve_adminq.h
>+++ b/drivers/net/ethernet/google/gve/gve_adminq.h
>@@ -154,6 +154,7 @@ enum gve_driver_capbility {
> 	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)
>@@ -164,7 +165,8 @@ enum gve_driver_capbility {
> #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
>diff --git a/drivers/net/ethernet/google/gve/gve_desc_dqo.h b/drivers/net/ethernet/google/gve/gve_desc_dqo.h
>index e8fe9adef7f2..f79cd0591110 100644
>--- a/drivers/net/ethernet/google/gve/gve_desc_dqo.h
>+++ b/drivers/net/ethernet/google/gve/gve_desc_dqo.h
>@@ -176,6 +176,11 @@ static_assert(sizeof(struct gve_tx_compl_desc) == 8);
> #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 */
>diff --git a/drivers/net/ethernet/google/gve/gve_tx_dqo.c b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
>index 588d64819ed5..762915c6063b 100644
>--- a/drivers/net/ethernet/google/gve/gve_tx_dqo.c
>+++ b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
>@@ -953,12 +953,18 @@ int gve_clean_tx_done_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
> 			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;

nit: __test_and_clear_bit() and reduce to oneline. also you can drop the
braces in the if else statements once you squashed the two lines.

>+				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,
>+							     /*is_reinjection=*/false);
>+			}
> 		} else if (type == GVE_COMPL_TYPE_DQO_MISS) {
> 			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
>
>-- 
>2.38.1.431.g37b22c650d-goog
>