From: Andrew Rybchenko <arybchenko@solarflare.com>
Date: Wed, 3 Oct 2018 09:03:53 +0000 (+0100)
Subject: net/sfc: avoid usage of prepared packets number in EF10 Rx
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=3be2268435762adf01547f5bddb917c5cd7c5066;p=dpdk.git

net/sfc: avoid usage of prepared packets number in EF10 Rx

Number of prepared packets is good when one Rx descriptor is one packet.
Introduce pending Rx descriptor pointer which points to the first not
processed Rx descriptors. Rx descriptors from completed to pending have
buffers ready to be passed to application.

Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Ivan Malov <ivan.malov@oktetlabs.ru>
---

diff --git a/drivers/net/sfc/sfc_ef10_rx.c b/drivers/net/sfc/sfc_ef10_rx.c
index d4af07d44e..9c921c0576 100644
--- a/drivers/net/sfc/sfc_ef10_rx.c
+++ b/drivers/net/sfc/sfc_ef10_rx.c
@@ -57,7 +57,7 @@ struct sfc_ef10_rxq {
 #define SFC_EF10_RXQ_EXCEPTION		0x4
 #define SFC_EF10_RXQ_RSS_HASH		0x8
 	unsigned int			ptr_mask;
-	unsigned int			prepared;
+	unsigned int			pending;
 	unsigned int			completed;
 	unsigned int			evq_read_ptr;
 	efx_qword_t			*evq_hw_ring;
@@ -187,15 +187,14 @@ sfc_ef10_rx_prefetch_next(struct sfc_ef10_rxq *rxq, unsigned int next_id)
 }
 
 static struct rte_mbuf **
-sfc_ef10_rx_prepared(struct sfc_ef10_rxq *rxq, struct rte_mbuf **rx_pkts,
-		     uint16_t nb_pkts)
+sfc_ef10_rx_pending(struct sfc_ef10_rxq *rxq, struct rte_mbuf **rx_pkts,
+		    uint16_t nb_pkts)
 {
-	uint16_t n_rx_pkts = RTE_MIN(nb_pkts, rxq->prepared);
+	uint16_t n_rx_pkts = RTE_MIN(nb_pkts, rxq->pending - rxq->completed);
 
 	if (n_rx_pkts != 0) {
 		unsigned int completed = rxq->completed;
 
-		rxq->prepared -= n_rx_pkts;
 		rxq->completed = completed + n_rx_pkts;
 
 		do {
@@ -225,42 +224,40 @@ sfc_ef10_rx_process_event(struct sfc_ef10_rxq *rxq, efx_qword_t rx_ev,
 			  struct rte_mbuf ** const rx_pkts_end)
 {
 	const unsigned int ptr_mask = rxq->ptr_mask;
-	unsigned int completed = rxq->completed;
+	unsigned int pending = rxq->pending;
 	unsigned int ready;
 	struct sfc_ef10_rx_sw_desc *rxd;
 	struct rte_mbuf *m;
 	struct rte_mbuf *m0;
-	uint16_t n_rx_pkts;
 	const uint8_t *pseudo_hdr;
 	uint16_t pkt_len;
 
-	ready = (EFX_QWORD_FIELD(rx_ev, ESF_DZ_RX_DSC_PTR_LBITS) - completed) &
+	ready = (EFX_QWORD_FIELD(rx_ev, ESF_DZ_RX_DSC_PTR_LBITS) - pending) &
 		EFX_MASK32(ESF_DZ_RX_DSC_PTR_LBITS);
 	SFC_ASSERT(ready > 0);
 
+	rxq->pending = pending + ready;
+
 	if (rx_ev.eq_u64[0] &
 	    rte_cpu_to_le_64((1ull << ESF_DZ_RX_ECC_ERR_LBN) |
 			     (1ull << ESF_DZ_RX_ECRC_ERR_LBN))) {
-		SFC_ASSERT(rxq->prepared == 0);
-		rxq->completed += ready;
-		while (ready-- > 0) {
-			rxd = &rxq->sw_ring[completed++ & ptr_mask];
+		SFC_ASSERT(rxq->completed == pending);
+		do {
+			rxd = &rxq->sw_ring[pending++ & ptr_mask];
 			rte_mbuf_raw_free(rxd->mbuf);
-		}
+		} while (pending != rxq->pending);
+		rxq->completed = pending;
 		return rx_pkts;
 	}
 
-	n_rx_pkts = RTE_MIN(ready, rx_pkts_end - rx_pkts);
-	rxq->prepared = ready - n_rx_pkts;
-	rxq->completed += n_rx_pkts;
+	rxd = &rxq->sw_ring[pending++ & ptr_mask];
 
-	rxd = &rxq->sw_ring[completed++ & ptr_mask];
-
-	sfc_ef10_rx_prefetch_next(rxq, completed & ptr_mask);
+	sfc_ef10_rx_prefetch_next(rxq, pending & ptr_mask);
 
 	m = rxd->mbuf;
 
 	*rx_pkts++ = m;
+	rxq->completed = pending;
 
 	RTE_BUILD_BUG_ON(sizeof(m->rearm_data[0]) != sizeof(rxq->rearm_data));
 	m->rearm_data[0] = rxq->rearm_data;
@@ -294,15 +291,17 @@ sfc_ef10_rx_process_event(struct sfc_ef10_rxq *rxq, efx_qword_t rx_ev,
 
 	/* Remember mbuf to copy offload flags and packet type from */
 	m0 = m;
-	for (--ready; ready > 0; --ready) {
-		rxd = &rxq->sw_ring[completed++ & ptr_mask];
+	while (pending != rxq->pending) {
+		rxd = &rxq->sw_ring[pending++ & ptr_mask];
 
-		sfc_ef10_rx_prefetch_next(rxq, completed & ptr_mask);
+		sfc_ef10_rx_prefetch_next(rxq, pending & ptr_mask);
 
 		m = rxd->mbuf;
 
-		if (ready > rxq->prepared)
+		if (rx_pkts != rx_pkts_end) {
 			*rx_pkts++ = m;
+			rxq->completed = pending;
+		}
 
 		RTE_BUILD_BUG_ON(sizeof(m->rearm_data[0]) !=
 				 sizeof(rxq->rearm_data));
@@ -366,7 +365,7 @@ sfc_ef10_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 	unsigned int evq_old_read_ptr;
 	efx_qword_t rx_ev;
 
-	rx_pkts = sfc_ef10_rx_prepared(rxq, rx_pkts, nb_pkts);
+	rx_pkts = sfc_ef10_rx_pending(rxq, rx_pkts, nb_pkts);
 
 	if (unlikely(rxq->flags &
 		     (SFC_EF10_RXQ_NOT_RUNNING | SFC_EF10_RXQ_EXCEPTION)))
@@ -601,8 +600,8 @@ sfc_ef10_rx_qstart(struct sfc_dp_rxq *dp_rxq, unsigned int evq_read_ptr)
 {
 	struct sfc_ef10_rxq *rxq = sfc_ef10_rxq_by_dp_rxq(dp_rxq);
 
-	SFC_ASSERT(rxq->prepared == 0);
 	SFC_ASSERT(rxq->completed == 0);
+	SFC_ASSERT(rxq->pending == 0);
 	SFC_ASSERT(rxq->added == 0);
 
 	sfc_ef10_rx_qrefill(rxq);
@@ -650,15 +649,13 @@ sfc_ef10_rx_qpurge(struct sfc_dp_rxq *dp_rxq)
 	unsigned int i;
 	struct sfc_ef10_rx_sw_desc *rxd;
 
-	rxq->prepared = 0;
-
 	for (i = rxq->completed; i != rxq->added; ++i) {
 		rxd = &rxq->sw_ring[i & rxq->ptr_mask];
 		rte_mbuf_raw_free(rxd->mbuf);
 		rxd->mbuf = NULL;
 	}
 
-	rxq->completed = rxq->added = 0;
+	rxq->completed = rxq->pending = rxq->added = 0;
 
 	rxq->flags &= ~SFC_EF10_RXQ_STARTED;
 }