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

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Date:   Wed, 16 Nov 2022 08:23:23 -0800
From:   Jeroen de Borst <jeroendb@...gle.com>
To:     Saeed Mahameed <saeed@...nel.org>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org,
        jesse.brandeburg@...el.com
Subject: Re: [PATCH net-next v3 2/2] gve: Handle alternate miss completions

Saeed,

Thanks for your review. I like the suggestion, but
__test_and_clear_bit is for unsigned longs, comptag is a short.

Jeroen


On Tue, Nov 15, 2022 at 9:17 PM Saeed Mahameed <saeed@...nel.org> wrote:
>
> 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 <jeroendb@...gle.com>
> >Reviewed-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
> >---
> > 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
> >