[PATCH net-next 0/4] ionic Tx updates

[PATCH net-next 0/4] ionic Tx updates

[Shannon Nelson]

Just as the Rx path recently got a face lift, it is time for the Tx path to
get some attention.  The original TSO-to-descriptor mapping was ugly and
convoluted and needed some deep work.  This series pulls the dma mapping
out of the descriptor frag mapping loop and makes the dma mapping more
generic for use in the non-TSO case.

Shannon Nelson (4):
  ionic: simplify TSO descriptor mapping
  ionic: generic tx skb mapping
  ionic: simplify tx clean
  ionic: aggregate Tx byte counting calls

 .../net/ethernet/pensando/ionic/ionic_dev.h   |   6 +-
 .../net/ethernet/pensando/ionic/ionic_txrx.c  | 374 +++++++++---------
 2 files changed, 186 insertions(+), 194 deletions(-)

-- 
2.17.1

[PATCH net-next 1/4] ionic: simplify TSO descriptor mapping

[Shannon Nelson]

One issue with the original TSO code was that it was working too
hard to deal with skb layouts that were never going to show up,
such as an skb->data that was longer than a single descriptor's
length.  The other issue was trying to arrange the fragment dma
mapping at the same time as figuring out the descriptors needed.
There was just too much going on at the same time.

Now we do the dma mapping first, which sets up the buffers with
skb->data in buf[0] and the remaining frags in buf[1..n-1].
Next we spread the bufs across the descriptors needed, where
each descriptor gets up to mss number of bytes.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
---
 .../net/ethernet/pensando/ionic/ionic_dev.h   |   5 +-
 .../net/ethernet/pensando/ionic/ionic_txrx.c  | 237 +++++++++---------
 2 files changed, 117 insertions(+), 125 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.h b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
index 339824cfd618..d0c969a6d43e 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
@@ -179,8 +179,11 @@ struct ionic_buf_info {
 	struct page *page;
 	dma_addr_t dma_addr;
 	u32 page_offset;
+	u32 len;
 };
 
+#define IONIC_MAX_FRAGS			(1 + IONIC_TX_MAX_SG_ELEMS_V1)
+
 struct ionic_desc_info {
 	union {
 		void *desc;
@@ -194,7 +197,7 @@ struct ionic_desc_info {
 		struct ionic_rxq_sg_desc *rxq_sgl_desc;
 	};
 	unsigned int nbufs;
-	struct ionic_buf_info bufs[IONIC_RX_MAX_SG_ELEMS + 1];
+	struct ionic_buf_info bufs[IONIC_MAX_FRAGS];
 	ionic_desc_cb cb;
 	void *cb_arg;
 };
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index c63e6e7aa47b..639000a2e495 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -605,12 +605,51 @@ static dma_addr_t ionic_tx_map_frag(struct ionic_queue *q,
 	return dma_addr;
 }
 
+static int ionic_tx_map_tso(struct ionic_queue *q, struct sk_buff *skb,
+			    struct ionic_buf_info *buf_info)
+{
+	struct device *dev = q->dev;
+	dma_addr_t dma_addr;
+	skb_frag_t *frag;
+	int frag_idx;
+
+	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
+	if (dma_mapping_error(dev, dma_addr))
+		return -EIO;
+	buf_info->dma_addr = dma_addr;
+	buf_info->len = skb_headlen(skb);
+	buf_info++;
+
+	for (frag_idx = 0; frag_idx < skb_shinfo(skb)->nr_frags; frag_idx++, buf_info++) {
+		frag = &skb_shinfo(skb)->frags[frag_idx];
+		dma_addr = ionic_tx_map_frag(q, frag, 0, skb_frag_size(frag));
+		if (dma_mapping_error(dev, dma_addr))
+			goto dma_fail;
+		buf_info->dma_addr = dma_addr;
+		buf_info->len = skb_frag_size(frag);
+	}
+
+	return 0;
+
+dma_fail:
+	/* unwind the frag mappings and the head mapping */
+	while (frag_idx > 0) {
+		frag_idx--;
+		buf_info--;
+		dma_unmap_page(dev, buf_info->dma_addr,
+			       buf_info->len, DMA_TO_DEVICE);
+	}
+	dma_unmap_single(dev, buf_info->dma_addr, buf_info->len, DMA_TO_DEVICE);
+	return -EIO;
+}
+
 static void ionic_tx_clean(struct ionic_queue *q,
 			   struct ionic_desc_info *desc_info,
 			   struct ionic_cq_info *cq_info,
 			   void *cb_arg)
 {
 	struct ionic_txq_sg_desc *sg_desc = desc_info->sg_desc;
+	struct ionic_buf_info *buf_info = desc_info->bufs;
 	struct ionic_txq_sg_elem *elem = sg_desc->elems;
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
 	struct ionic_txq_desc *desc = desc_info->desc;
@@ -623,20 +662,22 @@ static void ionic_tx_clean(struct ionic_queue *q,
 	decode_txq_desc_cmd(le64_to_cpu(desc->cmd),
 			    &opcode, &flags, &nsge, &addr);
 
-	/* use unmap_single only if either this is not TSO,
-	 * or this is first descriptor of a TSO
-	 */
-	if (opcode != IONIC_TXQ_DESC_OPCODE_TSO ||
-	    flags & IONIC_TXQ_DESC_FLAG_TSO_SOT)
+	if (opcode != IONIC_TXQ_DESC_OPCODE_TSO) {
 		dma_unmap_single(dev, (dma_addr_t)addr,
 				 le16_to_cpu(desc->len), DMA_TO_DEVICE);
-	else
-		dma_unmap_page(dev, (dma_addr_t)addr,
-			       le16_to_cpu(desc->len), DMA_TO_DEVICE);
-
-	for (i = 0; i < nsge; i++, elem++)
-		dma_unmap_page(dev, (dma_addr_t)le64_to_cpu(elem->addr),
-			       le16_to_cpu(elem->len), DMA_TO_DEVICE);
+		for (i = 0; i < nsge; i++, elem++)
+			dma_unmap_page(dev, (dma_addr_t)le64_to_cpu(elem->addr),
+				       le16_to_cpu(elem->len), DMA_TO_DEVICE);
+	} else {
+		if (flags & IONIC_TXQ_DESC_FLAG_TSO_EOT) {
+			dma_unmap_single(dev, (dma_addr_t)buf_info->dma_addr,
+					 buf_info->len, DMA_TO_DEVICE);
+			buf_info++;
+			for (i = 1; i < desc_info->nbufs; i++, buf_info++)
+				dma_unmap_page(dev, (dma_addr_t)buf_info->dma_addr,
+					       buf_info->len, DMA_TO_DEVICE);
+		}
+	}
 
 	if (cb_arg) {
 		struct sk_buff *skb = cb_arg;
@@ -794,29 +835,23 @@ static struct ionic_txq_desc *ionic_tx_tso_next(struct ionic_queue *q,
 
 static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 {
+	struct ionic_buf_info buf_info[IONIC_MAX_FRAGS] = {{0}};
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
-	struct ionic_desc_info *rewind_desc_info;
 	struct ionic_txq_sg_elem *elem;
-	struct device *dev = q->dev;
 	struct ionic_txq_desc *desc;
-	unsigned int frag_left = 0;
-	unsigned int offset = 0;
-	u16 abort = q->head_idx;
-	unsigned int len_left;
+	unsigned int chunk_len;
+	unsigned int frag_rem;
+	unsigned int frag_idx;
+	unsigned int tso_rem;
+	unsigned int seg_rem;
 	dma_addr_t desc_addr;
+	dma_addr_t frag_addr;
 	unsigned int hdrlen;
 	unsigned int nfrags;
-	unsigned int seglen;
-	u64 total_bytes = 0;
-	u64 total_pkts = 0;
-	u16 rewind = abort;
-	unsigned int left;
 	unsigned int len;
 	unsigned int mss;
-	skb_frag_t *frag;
 	bool start, done;
 	bool outer_csum;
-	dma_addr_t addr;
 	bool has_vlan;
 	u16 desc_len;
 	u8 desc_nsge;
@@ -824,9 +859,12 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 	bool encap;
 	int err;
 
+	if (unlikely(ionic_tx_map_tso(q, skb, buf_info)))
+		return -EIO;
+
+	len = skb->len;
 	mss = skb_shinfo(skb)->gso_size;
 	nfrags = skb_shinfo(skb)->nr_frags;
-	len_left = skb->len - skb_headlen(skb);
 	outer_csum = (skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM) ||
 		     (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
 	has_vlan = !!skb_vlan_tag_present(skb);
@@ -851,117 +889,68 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 	else
 		hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
 
-	seglen = hdrlen + mss;
-	left = skb_headlen(skb);
+	tso_rem = len;
+	seg_rem = min(tso_rem, hdrlen + mss);
 
-	desc = ionic_tx_tso_next(q, &elem);
-	start = true;
+	frag_idx = 0;
+	frag_addr = 0;
+	frag_rem = 0;
 
-	/* Chop skb->data up into desc segments */
+	start = true;
 
-	while (left > 0) {
-		len = min(seglen, left);
-		frag_left = seglen - len;
-		desc_addr = ionic_tx_map_single(q, skb->data + offset, len);
-		if (dma_mapping_error(dev, desc_addr))
-			goto err_out_abort;
-		desc_len = len;
+	while (tso_rem > 0) {
+		desc = NULL;
+		elem = NULL;
+		desc_addr = 0;
+		desc_len = 0;
 		desc_nsge = 0;
-		left -= len;
-		offset += len;
-		if (nfrags > 0 && frag_left > 0)
-			continue;
-		done = (nfrags == 0 && left == 0);
-		ionic_tx_tso_post(q, desc, skb,
-				  desc_addr, desc_nsge, desc_len,
-				  hdrlen, mss,
-				  outer_csum,
-				  vlan_tci, has_vlan,
-				  start, done);
-		total_pkts++;
-		total_bytes += start ? len : len + hdrlen;
-		desc = ionic_tx_tso_next(q, &elem);
-		start = false;
-		seglen = mss;
-	}
-
-	/* Chop skb frags into desc segments */
-
-	for (frag = skb_shinfo(skb)->frags; len_left; frag++) {
-		offset = 0;
-		left = skb_frag_size(frag);
-		len_left -= left;
-		nfrags--;
-		stats->frags++;
-
-		while (left > 0) {
-			if (frag_left > 0) {
-				len = min(frag_left, left);
-				frag_left -= len;
-				addr = ionic_tx_map_frag(q, frag, offset, len);
-				if (dma_mapping_error(dev, addr))
-					goto err_out_abort;
-				elem->addr = cpu_to_le64(addr);
-				elem->len = cpu_to_le16(len);
-				elem++;
-				desc_nsge++;
-				left -= len;
-				offset += len;
-				if (nfrags > 0 && frag_left > 0)
-					continue;
-				done = (nfrags == 0 && left == 0);
-				ionic_tx_tso_post(q, desc, skb, desc_addr,
-						  desc_nsge, desc_len,
-						  hdrlen, mss, outer_csum,
-						  vlan_tci, has_vlan,
-						  start, done);
-				total_pkts++;
-				total_bytes += start ? len : len + hdrlen;
+		/* loop until a full tcp segment can be created */
+		while (seg_rem > 0) {
+			/* if the fragment is exhausted get the next one */
+			if (frag_rem == 0) {
+				/* grab the next fragment */
+				frag_addr = buf_info[frag_idx].dma_addr;
+				frag_rem = buf_info[frag_idx].len;
+				frag_idx++;
+			}
+			chunk_len = min(frag_rem, seg_rem);
+			if (!desc) {
+				/* fill main descriptor */
 				desc = ionic_tx_tso_next(q, &elem);
-				start = false;
+				desc_addr = frag_addr;
+				desc_len = chunk_len;
 			} else {
-				len = min(mss, left);
-				frag_left = mss - len;
-				desc_addr = ionic_tx_map_frag(q, frag,
-							      offset, len);
-				if (dma_mapping_error(dev, desc_addr))
-					goto err_out_abort;
-				desc_len = len;
-				desc_nsge = 0;
-				left -= len;
-				offset += len;
-				if (nfrags > 0 && frag_left > 0)
-					continue;
-				done = (nfrags == 0 && left == 0);
-				ionic_tx_tso_post(q, desc, skb, desc_addr,
-						  desc_nsge, desc_len,
-						  hdrlen, mss, outer_csum,
-						  vlan_tci, has_vlan,
-						  start, done);
-				total_pkts++;
-				total_bytes += start ? len : len + hdrlen;
-				desc = ionic_tx_tso_next(q, &elem);
-				start = false;
+				/* fill sg descriptor */
+				elem->addr = cpu_to_le64(frag_addr);
+				elem->len = cpu_to_le16(chunk_len);
+				elem++;
+				desc_nsge++;
 			}
+			frag_addr += chunk_len;
+			frag_rem -= chunk_len;
+			tso_rem -= chunk_len;
+			seg_rem -= chunk_len;
+		}
+		seg_rem = min(tso_rem, mss);
+		done = (tso_rem == 0);
+		if (done) {
+			memcpy(&q->info[q->head_idx].bufs, buf_info, sizeof(buf_info));
+			q->info[q->head_idx].nbufs = nfrags + 1;
 		}
+		/* post descriptor */
+		ionic_tx_tso_post(q, desc, skb,
+				  desc_addr, desc_nsge, desc_len,
+				  hdrlen, mss, outer_csum, vlan_tci, has_vlan,
+				  start, done);
+		start = false;
 	}
 
-	stats->pkts += total_pkts;
-	stats->bytes += total_bytes;
+	stats->pkts += DIV_ROUND_UP(len - hdrlen, mss);
+	stats->bytes += len;
 	stats->tso++;
-	stats->tso_bytes += total_bytes;
+	stats->tso_bytes = len;
 
 	return 0;
-
-err_out_abort:
-	while (rewind != q->head_idx) {
-		rewind_desc_info = &q->info[rewind];
-		ionic_tx_clean(q, rewind_desc_info, NULL, NULL);
-		rewind = (rewind + 1) & (q->num_descs - 1);
-	}
-	q->head_idx = abort;
-
-	return -ENOMEM;
 }
 
 static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
-- 
2.17.1

[PATCH net-next 2/4] ionic: generic tx skb mapping

[Shannon Nelson]

Make the new ionic_tx_map_tso() usable by the non-TSO paths,
and pull the call up a level into ionic_tx() before calling
the csum or no-csum routines.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
---
 .../net/ethernet/pensando/ionic/ionic_txrx.c  | 142 +++++++++---------
 1 file changed, 68 insertions(+), 74 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 639000a2e495..1d27d6cad504 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -605,11 +605,13 @@ static dma_addr_t ionic_tx_map_frag(struct ionic_queue *q,
 	return dma_addr;
 }
 
-static int ionic_tx_map_tso(struct ionic_queue *q, struct sk_buff *skb,
-			    struct ionic_buf_info *buf_info)
+static int ionic_tx_map_skb(struct ionic_queue *q, struct sk_buff *skb,
+			    struct ionic_desc_info *desc_info)
 {
+	struct ionic_buf_info *buf_info = desc_info->bufs;
 	struct device *dev = q->dev;
 	dma_addr_t dma_addr;
+	unsigned int nfrags;
 	skb_frag_t *frag;
 	int frag_idx;
 
@@ -620,15 +622,19 @@ static int ionic_tx_map_tso(struct ionic_queue *q, struct sk_buff *skb,
 	buf_info->len = skb_headlen(skb);
 	buf_info++;
 
-	for (frag_idx = 0; frag_idx < skb_shinfo(skb)->nr_frags; frag_idx++, buf_info++) {
-		frag = &skb_shinfo(skb)->frags[frag_idx];
+	frag = skb_shinfo(skb)->frags;
+	nfrags = skb_shinfo(skb)->nr_frags;
+	for (frag_idx = 0; frag_idx < nfrags; frag_idx++, frag++) {
 		dma_addr = ionic_tx_map_frag(q, frag, 0, skb_frag_size(frag));
 		if (dma_mapping_error(dev, dma_addr))
 			goto dma_fail;
 		buf_info->dma_addr = dma_addr;
 		buf_info->len = skb_frag_size(frag);
+		buf_info++;
 	}
 
+	desc_info->nbufs = 1 + nfrags;
+
 	return 0;
 
 dma_fail:
@@ -814,40 +820,29 @@ static void ionic_tx_tso_post(struct ionic_queue *q, struct ionic_txq_desc *desc
 	desc->hdr_len = cpu_to_le16(hdrlen);
 	desc->mss = cpu_to_le16(mss);
 
-	if (done) {
+	if (start) {
 		skb_tx_timestamp(skb);
 		netdev_tx_sent_queue(q_to_ndq(q), skb->len);
-		ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
+		ionic_txq_post(q, false, ionic_tx_clean, skb);
 	} else {
-		ionic_txq_post(q, false, ionic_tx_clean, NULL);
+		ionic_txq_post(q, done, NULL, NULL);
 	}
 }
 
-static struct ionic_txq_desc *ionic_tx_tso_next(struct ionic_queue *q,
-						struct ionic_txq_sg_elem **elem)
-{
-	struct ionic_txq_sg_desc *sg_desc = q->info[q->head_idx].txq_sg_desc;
-	struct ionic_txq_desc *desc = q->info[q->head_idx].txq_desc;
-
-	*elem = sg_desc->elems;
-	return desc;
-}
-
 static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 {
-	struct ionic_buf_info buf_info[IONIC_MAX_FRAGS] = {{0}};
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct ionic_desc_info *desc_info;
+	struct ionic_buf_info *buf_info;
 	struct ionic_txq_sg_elem *elem;
 	struct ionic_txq_desc *desc;
 	unsigned int chunk_len;
 	unsigned int frag_rem;
-	unsigned int frag_idx;
 	unsigned int tso_rem;
 	unsigned int seg_rem;
 	dma_addr_t desc_addr;
 	dma_addr_t frag_addr;
 	unsigned int hdrlen;
-	unsigned int nfrags;
 	unsigned int len;
 	unsigned int mss;
 	bool start, done;
@@ -859,12 +854,14 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 	bool encap;
 	int err;
 
-	if (unlikely(ionic_tx_map_tso(q, skb, buf_info)))
+	desc_info = &q->info[q->head_idx];
+	buf_info = desc_info->bufs;
+
+	if (unlikely(ionic_tx_map_skb(q, skb, desc_info)))
 		return -EIO;
 
 	len = skb->len;
 	mss = skb_shinfo(skb)->gso_size;
-	nfrags = skb_shinfo(skb)->nr_frags;
 	outer_csum = (skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM) ||
 		     (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
 	has_vlan = !!skb_vlan_tag_present(skb);
@@ -892,7 +889,6 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 	tso_rem = len;
 	seg_rem = min(tso_rem, hdrlen + mss);
 
-	frag_idx = 0;
 	frag_addr = 0;
 	frag_rem = 0;
 
@@ -904,19 +900,20 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 		desc_addr = 0;
 		desc_len = 0;
 		desc_nsge = 0;
-		/* loop until a full tcp segment can be created */
+		/* use fragments until we have enough to post a single descriptor */
 		while (seg_rem > 0) {
-			/* if the fragment is exhausted get the next one */
+			/* if the fragment is exhausted then move to the next one */
 			if (frag_rem == 0) {
 				/* grab the next fragment */
-				frag_addr = buf_info[frag_idx].dma_addr;
-				frag_rem = buf_info[frag_idx].len;
-				frag_idx++;
+				frag_addr = buf_info->dma_addr;
+				frag_rem = buf_info->len;
+				buf_info++;
 			}
 			chunk_len = min(frag_rem, seg_rem);
 			if (!desc) {
 				/* fill main descriptor */
-				desc = ionic_tx_tso_next(q, &elem);
+				desc = desc_info->txq_desc;
+				elem = desc_info->txq_sg_desc->elems;
 				desc_addr = frag_addr;
 				desc_len = chunk_len;
 			} else {
@@ -933,16 +930,15 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 		}
 		seg_rem = min(tso_rem, mss);
 		done = (tso_rem == 0);
-		if (done) {
-			memcpy(&q->info[q->head_idx].bufs, buf_info, sizeof(buf_info));
-			q->info[q->head_idx].nbufs = nfrags + 1;
-		}
 		/* post descriptor */
 		ionic_tx_tso_post(q, desc, skb,
 				  desc_addr, desc_nsge, desc_len,
 				  hdrlen, mss, outer_csum, vlan_tci, has_vlan,
 				  start, done);
 		start = false;
+		/* Buffer information is stored with the first tso descriptor */
+		desc_info = &q->info[q->head_idx];
+		desc_info->nbufs = 0;
 	}
 
 	stats->pkts += DIV_ROUND_UP(len - hdrlen, mss);
@@ -953,12 +949,12 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 	return 0;
 }
 
-static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
+static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb,
+			      struct ionic_desc_info *desc_info)
 {
-	struct ionic_txq_desc *desc = q->info[q->head_idx].txq_desc;
+	struct ionic_txq_desc *desc = desc_info->txq_desc;
+	struct ionic_buf_info *buf_info = desc_info->bufs;
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
-	struct device *dev = q->dev;
-	dma_addr_t dma_addr;
 	bool has_vlan;
 	u8 flags = 0;
 	bool encap;
@@ -967,23 +963,22 @@ static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
 	has_vlan = !!skb_vlan_tag_present(skb);
 	encap = skb->encapsulation;
 
-	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
-	if (dma_mapping_error(dev, dma_addr))
-		return -ENOMEM;
-
 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
 	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
 
 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_PARTIAL,
-				  flags, skb_shinfo(skb)->nr_frags, dma_addr);
+				  flags, skb_shinfo(skb)->nr_frags,
+				  buf_info->dma_addr);
 	desc->cmd = cpu_to_le64(cmd);
-	desc->len = cpu_to_le16(skb_headlen(skb));
-	desc->csum_start = cpu_to_le16(skb_checksum_start_offset(skb));
-	desc->csum_offset = cpu_to_le16(skb->csum_offset);
+	desc->len = cpu_to_le16(buf_info->len);
 	if (has_vlan) {
 		desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
 		stats->vlan_inserted++;
+	} else {
+		desc->vlan_tci = 0;
 	}
+	desc->csum_start = cpu_to_le16(skb_checksum_start_offset(skb));
+	desc->csum_offset = cpu_to_le16(skb->csum_offset);
 
 	if (skb_csum_is_sctp(skb))
 		stats->crc32_csum++;
@@ -993,12 +988,12 @@ static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
 	return 0;
 }
 
-static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb)
+static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb,
+				 struct ionic_desc_info *desc_info)
 {
-	struct ionic_txq_desc *desc = q->info[q->head_idx].txq_desc;
+	struct ionic_txq_desc *desc = desc_info->txq_desc;
+	struct ionic_buf_info *buf_info = desc_info->bufs;
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
-	struct device *dev = q->dev;
-	dma_addr_t dma_addr;
 	bool has_vlan;
 	u8 flags = 0;
 	bool encap;
@@ -1007,67 +1002,66 @@ static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb)
 	has_vlan = !!skb_vlan_tag_present(skb);
 	encap = skb->encapsulation;
 
-	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
-	if (dma_mapping_error(dev, dma_addr))
-		return -ENOMEM;
-
 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
 	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
 
 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_NONE,
-				  flags, skb_shinfo(skb)->nr_frags, dma_addr);
+				  flags, skb_shinfo(skb)->nr_frags,
+				  buf_info->dma_addr);
 	desc->cmd = cpu_to_le64(cmd);
-	desc->len = cpu_to_le16(skb_headlen(skb));
+	desc->len = cpu_to_le16(buf_info->len);
 	if (has_vlan) {
 		desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
 		stats->vlan_inserted++;
+	} else {
+		desc->vlan_tci = 0;
 	}
+	desc->csum_start = 0;
+	desc->csum_offset = 0;
 
 	stats->csum_none++;
 
 	return 0;
 }
 
-static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb)
+static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb,
+			      struct ionic_desc_info *desc_info)
 {
-	struct ionic_txq_sg_desc *sg_desc = q->info[q->head_idx].txq_sg_desc;
-	unsigned int len_left = skb->len - skb_headlen(skb);
+	struct ionic_txq_sg_desc *sg_desc = desc_info->txq_sg_desc;
+	struct ionic_buf_info *buf_info = &desc_info->bufs[1];
 	struct ionic_txq_sg_elem *elem = sg_desc->elems;
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
-	struct device *dev = q->dev;
-	dma_addr_t dma_addr;
-	skb_frag_t *frag;
-	u16 len;
+	unsigned int i;
 
-	for (frag = skb_shinfo(skb)->frags; len_left; frag++, elem++) {
-		len = skb_frag_size(frag);
-		elem->len = cpu_to_le16(len);
-		dma_addr = ionic_tx_map_frag(q, frag, 0, len);
-		if (dma_mapping_error(dev, dma_addr))
-			return -ENOMEM;
-		elem->addr = cpu_to_le64(dma_addr);
-		len_left -= len;
-		stats->frags++;
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, buf_info++, elem++) {
+		elem->addr = cpu_to_le64(buf_info->dma_addr);
+		elem->len = cpu_to_le16(buf_info->len);
 	}
 
+	stats->frags += skb_shinfo(skb)->nr_frags;
+
 	return 0;
 }
 
 static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb)
 {
+	struct ionic_desc_info *desc_info = &q->info[q->head_idx];
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
 	int err;
 
+	if (unlikely(ionic_tx_map_skb(q, skb, desc_info)))
+		return -EIO;
+
 	/* set up the initial descriptor */
 	if (skb->ip_summed == CHECKSUM_PARTIAL)
-		err = ionic_tx_calc_csum(q, skb);
+		err = ionic_tx_calc_csum(q, skb, desc_info);
 	else
-		err = ionic_tx_calc_no_csum(q, skb);
+		err = ionic_tx_calc_no_csum(q, skb, desc_info);
 	if (err)
 		return err;
 
 	/* add frags */
-	err = ionic_tx_skb_frags(q, skb);
+	err = ionic_tx_skb_frags(q, skb, desc_info);
 	if (err)
 		return err;
 
-- 
2.17.1

[PATCH net-next 3/4] ionic: simplify tx clean

[Shannon Nelson]

The descriptor mappings are set up the same way whether
or not it is a TSO, so we don't need separate logic for
the two cases.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
---
 .../net/ethernet/pensando/ionic/ionic_txrx.c  | 30 +++++--------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 1d27d6cad504..f841ccb5adfd 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -654,35 +654,19 @@ static void ionic_tx_clean(struct ionic_queue *q,
 			   struct ionic_cq_info *cq_info,
 			   void *cb_arg)
 {
-	struct ionic_txq_sg_desc *sg_desc = desc_info->sg_desc;
 	struct ionic_buf_info *buf_info = desc_info->bufs;
-	struct ionic_txq_sg_elem *elem = sg_desc->elems;
 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
-	struct ionic_txq_desc *desc = desc_info->desc;
 	struct device *dev = q->dev;
-	u8 opcode, flags, nsge;
 	u16 queue_index;
 	unsigned int i;
-	u64 addr;
-
-	decode_txq_desc_cmd(le64_to_cpu(desc->cmd),
-			    &opcode, &flags, &nsge, &addr);
 
-	if (opcode != IONIC_TXQ_DESC_OPCODE_TSO) {
-		dma_unmap_single(dev, (dma_addr_t)addr,
-				 le16_to_cpu(desc->len), DMA_TO_DEVICE);
-		for (i = 0; i < nsge; i++, elem++)
-			dma_unmap_page(dev, (dma_addr_t)le64_to_cpu(elem->addr),
-				       le16_to_cpu(elem->len), DMA_TO_DEVICE);
-	} else {
-		if (flags & IONIC_TXQ_DESC_FLAG_TSO_EOT) {
-			dma_unmap_single(dev, (dma_addr_t)buf_info->dma_addr,
-					 buf_info->len, DMA_TO_DEVICE);
-			buf_info++;
-			for (i = 1; i < desc_info->nbufs; i++, buf_info++)
-				dma_unmap_page(dev, (dma_addr_t)buf_info->dma_addr,
-					       buf_info->len, DMA_TO_DEVICE);
-		}
+	if (desc_info->nbufs) {
+		dma_unmap_single(dev, (dma_addr_t)buf_info->dma_addr,
+				 buf_info->len, DMA_TO_DEVICE);
+		buf_info++;
+		for (i = 1; i < desc_info->nbufs; i++, buf_info++)
+			dma_unmap_page(dev, (dma_addr_t)buf_info->dma_addr,
+				       buf_info->len, DMA_TO_DEVICE);
 	}
 
 	if (cb_arg) {
-- 
2.17.1

[PATCH net-next 4/4] ionic: aggregate Tx byte counting calls

[Shannon Nelson]

Gather the Tx packet and byte counts and call
netdev_tx_completed_queue() only once per clean cycle.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
---
 .../net/ethernet/pensando/ionic/ionic_dev.h   |  1 +
 .../net/ethernet/pensando/ionic/ionic_txrx.c  | 27 ++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.h b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
index d0c969a6d43e..ca7e55455165 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
@@ -196,6 +196,7 @@ struct ionic_desc_info {
 		struct ionic_txq_sg_desc *txq_sg_desc;
 		struct ionic_rxq_sg_desc *rxq_sgl_desc;
 	};
+	unsigned int bytes;
 	unsigned int nbufs;
 	struct ionic_buf_info bufs[IONIC_MAX_FRAGS];
 	ionic_desc_cb cb;
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index f841ccb5adfd..03e00a6c413a 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -671,7 +671,6 @@ static void ionic_tx_clean(struct ionic_queue *q,
 
 	if (cb_arg) {
 		struct sk_buff *skb = cb_arg;
-		u32 len = skb->len;
 
 		queue_index = skb_get_queue_mapping(skb);
 		if (unlikely(__netif_subqueue_stopped(q->lif->netdev,
@@ -679,9 +678,11 @@ static void ionic_tx_clean(struct ionic_queue *q,
 			netif_wake_subqueue(q->lif->netdev, queue_index);
 			q->wake++;
 		}
-		dev_kfree_skb_any(skb);
+
+		desc_info->bytes = skb->len;
 		stats->clean++;
-		netdev_tx_completed_queue(q_to_ndq(q), 1, len);
+
+		dev_consume_skb_any(skb);
 	}
 }
 
@@ -690,6 +691,8 @@ static bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
 	struct ionic_txq_comp *comp = cq_info->txcq;
 	struct ionic_queue *q = cq->bound_q;
 	struct ionic_desc_info *desc_info;
+	int bytes = 0;
+	int pkts = 0;
 	u16 index;
 
 	if (!color_match(comp->color, cq->done_color))
@@ -700,13 +703,21 @@ static bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
 	 */
 	do {
 		desc_info = &q->info[q->tail_idx];
+		desc_info->bytes = 0;
 		index = q->tail_idx;
 		q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
 		ionic_tx_clean(q, desc_info, cq_info, desc_info->cb_arg);
+		if (desc_info->cb_arg) {
+			pkts++;
+			bytes += desc_info->bytes;
+		}
 		desc_info->cb = NULL;
 		desc_info->cb_arg = NULL;
 	} while (index != le16_to_cpu(comp->comp_index));
 
+	if (pkts && bytes)
+		netdev_tx_completed_queue(q_to_ndq(q), pkts, bytes);
+
 	return true;
 }
 
@@ -725,15 +736,25 @@ void ionic_tx_flush(struct ionic_cq *cq)
 void ionic_tx_empty(struct ionic_queue *q)
 {
 	struct ionic_desc_info *desc_info;
+	int bytes = 0;
+	int pkts = 0;
 
 	/* walk the not completed tx entries, if any */
 	while (q->head_idx != q->tail_idx) {
 		desc_info = &q->info[q->tail_idx];
+		desc_info->bytes = 0;
 		q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
 		ionic_tx_clean(q, desc_info, NULL, desc_info->cb_arg);
+		if (desc_info->cb_arg) {
+			pkts++;
+			bytes += desc_info->bytes;
+		}
 		desc_info->cb = NULL;
 		desc_info->cb_arg = NULL;
 	}
+
+	if (pkts && bytes)
+		netdev_tx_completed_queue(q_to_ndq(q), pkts, bytes);
 }
 
 static int ionic_tx_tcp_inner_pseudo_csum(struct sk_buff *skb)
-- 
2.17.1

Re: [PATCH net-next 0/4] ionic Tx updates

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (refs/heads/master):

On Mon, 15 Mar 2021 19:31:32 -0700 you wrote:
> Just as the Rx path recently got a face lift, it is time for the Tx path to
> get some attention.  The original TSO-to-descriptor mapping was ugly and
> convoluted and needed some deep work.  This series pulls the dma mapping
> out of the descriptor frag mapping loop and makes the dma mapping more
> generic for use in the non-TSO case.
> 
> Shannon Nelson (4):
>   ionic: simplify TSO descriptor mapping
>   ionic: generic tx skb mapping
>   ionic: simplify tx clean
>   ionic: aggregate Tx byte counting calls
> 
> [...]

Here is the summary with links:
  - [net-next,1/4] ionic: simplify TSO descriptor mapping
    https://git.kernel.org/netdev/net-next/c/5b039241fe3a
  - [net-next,2/4] ionic: generic tx skb mapping
    https://git.kernel.org/netdev/net-next/c/2da479ca0814
  - [net-next,3/4] ionic: simplify tx clean
    https://git.kernel.org/netdev/net-next/c/19fef72cb4ba
  - [net-next,4/4] ionic: aggregate Tx byte counting calls
    https://git.kernel.org/netdev/net-next/c/633eddf120ac

You are awesome, thank you!
--
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