netdev - [PATCH net-next 01/12] sfc: remove tx and MCDI handling from NAPI budget consideration

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Message-ID: <8b03f234-fa82-a85c-20cd-9c2d4ce1c170@solarflare.com>
Date:   Thu, 25 Jan 2018 17:24:20 +0000
From:   Edward Cree <ecree@...arflare.com>
To:     <linux-net-drivers@...arflare.com>, <davem@...emloft.net>
CC:     <netdev@...r.kernel.org>, <levans@...arflare.com>
Subject: [PATCH net-next 01/12] sfc: remove tx and MCDI handling from NAPI
 budget consideration

From: Bert Kenward <bkenward@...arflare.com>

The NAPI budget is only for RX processing work, not other work such as
 TX or MCDI completion handling.

Signed-off-by: Bert Kenward <bkenward@...arflare.com>
Signed-off-by: Edward Cree <ecree@...arflare.com>
---
 drivers/net/ethernet/sfc/ef10.c  | 20 ++++----------------
 drivers/net/ethernet/sfc/farch.c | 17 +++--------------
 2 files changed, 7 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 8ae467db9162..03ec2cc1eab4 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -3572,31 +3572,26 @@ static int efx_ef10_handle_rx_event(struct efx_channel *channel,
 	return n_packets;
 }
 
-static int
+static void
 efx_ef10_handle_tx_event(struct efx_channel *channel, efx_qword_t *event)
 {
 	struct efx_nic *efx = channel->efx;
 	struct efx_tx_queue *tx_queue;
 	unsigned int tx_ev_desc_ptr;
 	unsigned int tx_ev_q_label;
-	int tx_descs = 0;
 
 	if (unlikely(READ_ONCE(efx->reset_pending)))
-		return 0;
+		return;
 
 	if (unlikely(EFX_QWORD_FIELD(*event, ESF_DZ_TX_DROP_EVENT)))
-		return 0;
+		return;
 
 	/* Transmit completion */
 	tx_ev_desc_ptr = EFX_QWORD_FIELD(*event, ESF_DZ_TX_DESCR_INDX);
 	tx_ev_q_label = EFX_QWORD_FIELD(*event, ESF_DZ_TX_QLABEL);
 	tx_queue = efx_channel_get_tx_queue(channel,
 					    tx_ev_q_label % EFX_TXQ_TYPES);
-	tx_descs = ((tx_ev_desc_ptr + 1 - tx_queue->read_count) &
-		    tx_queue->ptr_mask);
 	efx_xmit_done(tx_queue, tx_ev_desc_ptr & tx_queue->ptr_mask);
-
-	return tx_descs;
 }
 
 static void
@@ -3658,7 +3653,6 @@ static int efx_ef10_ev_process(struct efx_channel *channel, int quota)
 	efx_qword_t event, *p_event;
 	unsigned int read_ptr;
 	int ev_code;
-	int tx_descs = 0;
 	int spent = 0;
 
 	if (quota <= 0)
@@ -3698,13 +3692,7 @@ static int efx_ef10_ev_process(struct efx_channel *channel, int quota)
 			}
 			break;
 		case ESE_DZ_EV_CODE_TX_EV:
-			tx_descs += efx_ef10_handle_tx_event(channel, &event);
-			if (tx_descs > efx->txq_entries) {
-				spent = quota;
-				goto out;
-			} else if (++spent == quota) {
-				goto out;
-			}
+			efx_ef10_handle_tx_event(channel, &event);
 			break;
 		case ESE_DZ_EV_CODE_DRIVER_EV:
 			efx_ef10_handle_driver_event(channel, &event);
diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index 5334dc83d926..ca79ac6d0ac3 100644
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -818,17 +818,16 @@ static void efx_farch_magic_event(struct efx_channel *channel, u32 magic)
  * The NIC batches TX completion events; the message we receive is of
  * the form "complete all TX events up to this index".
  */
-static int
+static void
 efx_farch_handle_tx_event(struct efx_channel *channel, efx_qword_t *event)
 {
 	unsigned int tx_ev_desc_ptr;
 	unsigned int tx_ev_q_label;
 	struct efx_tx_queue *tx_queue;
 	struct efx_nic *efx = channel->efx;
-	int tx_packets = 0;
 
 	if (unlikely(READ_ONCE(efx->reset_pending)))
-		return 0;
+		return;
 
 	if (likely(EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_COMP))) {
 		/* Transmit completion */
@@ -836,8 +835,6 @@ efx_farch_handle_tx_event(struct efx_channel *channel, efx_qword_t *event)
 		tx_ev_q_label = EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_Q_LABEL);
 		tx_queue = efx_channel_get_tx_queue(
 			channel, tx_ev_q_label % EFX_TXQ_TYPES);
-		tx_packets = ((tx_ev_desc_ptr - tx_queue->read_count) &
-			      tx_queue->ptr_mask);
 		efx_xmit_done(tx_queue, tx_ev_desc_ptr);
 	} else if (EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_WQ_FF_FULL)) {
 		/* Rewrite the FIFO write pointer */
@@ -856,8 +853,6 @@ efx_farch_handle_tx_event(struct efx_channel *channel, efx_qword_t *event)
 			  EFX_QWORD_FMT"\n", channel->channel,
 			  EFX_QWORD_VAL(*event));
 	}
-
-	return tx_packets;
 }
 
 /* Detect errors included in the rx_evt_pkt_ok bit. */
@@ -1270,7 +1265,6 @@ int efx_farch_ev_process(struct efx_channel *channel, int budget)
 	unsigned int read_ptr;
 	efx_qword_t event, *p_event;
 	int ev_code;
-	int tx_packets = 0;
 	int spent = 0;
 
 	if (budget <= 0)
@@ -1304,12 +1298,7 @@ int efx_farch_ev_process(struct efx_channel *channel, int budget)
 				goto out;
 			break;
 		case FSE_AZ_EV_CODE_TX_EV:
-			tx_packets += efx_farch_handle_tx_event(channel,
-								&event);
-			if (tx_packets > efx->txq_entries) {
-				spent = budget;
-				goto out;
-			}
+			efx_farch_handle_tx_event(channel, &event);
 			break;
 		case FSE_AZ_EV_CODE_DRV_GEN_EV:
 			efx_farch_handle_generated_event(channel, &event);