drivers/net/ethernet/google/gve/gve_rx.c - linux/kernel/git/davem/net - Git at Google

 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
 /* Google virtual Ethernet (gve) driver
  *
  * Copyright (C) 2015-2019 Google, Inc.
  */

 #include "gve.h"
 #include "gve_adminq.h"
 #include <linux/etherdevice.h>

 static void gve_rx_remove_from_block(struct gve_priv *priv, int queue_idx)
 {
 	struct gve_notify_block *block =
 			&priv->ntfy_blocks[gve_rx_idx_to_ntfy(priv, queue_idx)];

 	block->rx = NULL;
 }

 static void gve_rx_free_ring(struct gve_priv *priv, int idx)
 {
 	struct gve_rx_ring *rx = &priv->rx[idx];
 	struct device *dev = &priv->pdev->dev;
 	size_t bytes;
 	u32 slots;

 	gve_rx_remove_from_block(priv, idx);

 	bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
 	dma_free_coherent(dev, bytes, rx->desc.desc_ring, rx->desc.bus);
 	rx->desc.desc_ring = NULL;

 	dma_free_coherent(dev, sizeof(*rx->q_resources),
 			  rx->q_resources, rx->q_resources_bus);
 	rx->q_resources = NULL;

 	gve_unassign_qpl(priv, rx->data.qpl->id);
 	rx->data.qpl = NULL;
 	kvfree(rx->data.page_info);

 	slots = rx->mask + 1;
 	bytes = sizeof(*rx->data.data_ring) * slots;
 	dma_free_coherent(dev, bytes, rx->data.data_ring,
 			  rx->data.data_bus);
 	rx->data.data_ring = NULL;
 	netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
 }

 static void gve_setup_rx_buffer(struct gve_rx_slot_page_info *page_info,
 				struct gve_rx_data_slot *slot,
 				dma_addr_t addr, struct page *page)
 {
 	page_info->page = page;
 	page_info->page_offset = 0;
 	page_info->page_address = page_address(page);
 	slot->qpl_offset = cpu_to_be64(addr);
 }

 static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
 {
 	struct gve_priv *priv = rx->gve;
 	u32 slots;
 	int i;

 	/* Allocate one page per Rx queue slot. Each page is split into two
 	 * packet buffers, when possible we "page flip" between the two.
 	 */
 	slots = rx->mask + 1;

 	rx->data.page_info = kvzalloc(slots *
 				      sizeof(*rx->data.page_info), GFP_KERNEL);
 	if (!rx->data.page_info)
 		return -ENOMEM;

 	rx->data.qpl = gve_assign_rx_qpl(priv);

 	for (i = 0; i < slots; i++) {
 		struct page *page = rx->data.qpl->pages[i];
 		dma_addr_t addr = i * PAGE_SIZE;

 		gve_setup_rx_buffer(&rx->data.page_info[i],
 				    &rx->data.data_ring[i], addr, page);
 	}

 	return slots;
 }

 static void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx)
 {
 	u32 ntfy_idx = gve_rx_idx_to_ntfy(priv, queue_idx);
 	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
 	struct gve_rx_ring *rx = &priv->rx[queue_idx];

 	block->rx = rx;
 	rx->ntfy_id = ntfy_idx;
 }

 static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
 {
 	struct gve_rx_ring *rx = &priv->rx[idx];
 	struct device *hdev = &priv->pdev->dev;
 	u32 slots, npages;
 	int filled_pages;
 	size_t bytes;
 	int err;

 	netif_dbg(priv, drv, priv->dev, "allocating rx ring\n");
 	/* Make sure everything is zeroed to start with */
 	memset(rx, 0, sizeof(*rx));

 	rx->gve = priv;
 	rx->q_num = idx;

 	slots = priv->rx_pages_per_qpl;
 	rx->mask = slots - 1;

 	/* alloc rx data ring */
 	bytes = sizeof(*rx->data.data_ring) * slots;
 	rx->data.data_ring = dma_alloc_coherent(hdev, bytes,
 						&rx->data.data_bus,
 						GFP_KERNEL);
 	if (!rx->data.data_ring)
 		return -ENOMEM;
 	filled_pages = gve_prefill_rx_pages(rx);
 	if (filled_pages < 0) {
 		err = -ENOMEM;
 		goto abort_with_slots;
 	}
 	rx->fill_cnt = filled_pages;
 	/* Ensure data ring slots (packet buffers) are visible. */
 	dma_wmb();

 	/* Alloc gve_queue_resources */
 	rx->q_resources =
 		dma_alloc_coherent(hdev,
 				   sizeof(*rx->q_resources),
 				   &rx->q_resources_bus,
 				   GFP_KERNEL);
 	if (!rx->q_resources) {
 		err = -ENOMEM;
 		goto abort_filled;
 	}
 	netif_dbg(priv, drv, priv->dev, "rx[%d]->data.data_bus=%lx\n", idx,
 		  (unsigned long)rx->data.data_bus);

 	/* alloc rx desc ring */
 	bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
 	npages = bytes / PAGE_SIZE;
 	if (npages * PAGE_SIZE != bytes) {
 		err = -EIO;
 		goto abort_with_q_resources;
 	}

 	rx->desc.desc_ring = dma_alloc_coherent(hdev, bytes, &rx->desc.bus,
 						GFP_KERNEL);
 	if (!rx->desc.desc_ring) {
 		err = -ENOMEM;
 		goto abort_with_q_resources;
 	}
 	rx->mask = slots - 1;
 	rx->cnt = 0;
 	rx->desc.seqno = 1;
 	gve_rx_add_to_block(priv, idx);

 	return 0;

 abort_with_q_resources:
 	dma_free_coherent(hdev, sizeof(*rx->q_resources),
 			  rx->q_resources, rx->q_resources_bus);
 	rx->q_resources = NULL;
 abort_filled:
 	kvfree(rx->data.page_info);
 abort_with_slots:
 	bytes = sizeof(*rx->data.data_ring) * slots;
 	dma_free_coherent(hdev, bytes, rx->data.data_ring, rx->data.data_bus);
 	rx->data.data_ring = NULL;

 	return err;
 }

 int gve_rx_alloc_rings(struct gve_priv *priv)
 {
 	int err = 0;
 	int i;

 	for (i = 0; i < priv->rx_cfg.num_queues; i++) {
 		err = gve_rx_alloc_ring(priv, i);
 		if (err) {
 			netif_err(priv, drv, priv->dev,
 				  "Failed to alloc rx ring=%d: err=%d\n",
 				  i, err);
 			break;
 		}
 	}
 	/* Unallocate if there was an error */
 	if (err) {
 		int j;

 		for (j = 0; j < i; j++)
 			gve_rx_free_ring(priv, j);
 	}
 	return err;
 }

 void gve_rx_free_rings(struct gve_priv *priv)
 {
 	int i;

 	for (i = 0; i < priv->rx_cfg.num_queues; i++)
 		gve_rx_free_ring(priv, i);
 }

 void gve_rx_write_doorbell(struct gve_priv *priv, struct gve_rx_ring *rx)
 {
 	u32 db_idx = be32_to_cpu(rx->q_resources->db_index);

 	iowrite32be(rx->fill_cnt, &priv->db_bar2[db_idx]);
 }

 static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
 {
 	if (likely(pkt_flags & (GVE_RXF_TCP | GVE_RXF_UDP)))
 		return PKT_HASH_TYPE_L4;
 	if (pkt_flags & (GVE_RXF_IPV4 | GVE_RXF_IPV6))
 		return PKT_HASH_TYPE_L3;
 	return PKT_HASH_TYPE_L2;
 }

 static struct sk_buff *gve_rx_copy(struct net_device *dev,
 				   struct napi_struct *napi,
 				   struct gve_rx_slot_page_info *page_info,
 				   u16 len)
 {
 	struct sk_buff *skb = napi_alloc_skb(napi, len);
 	void *va = page_info->page_address + GVE_RX_PAD +
 		   page_info->page_offset;

 	if (unlikely(!skb))
 		return NULL;

 	__skb_put(skb, len);

 	skb_copy_to_linear_data(skb, va, len);

 	skb->protocol = eth_type_trans(skb, dev);
 	return skb;
 }

 static struct sk_buff *gve_rx_add_frags(struct net_device *dev,
 					struct napi_struct *napi,
 					struct gve_rx_slot_page_info *page_info,
 					u16 len)
 {
 	struct sk_buff *skb = napi_get_frags(napi);

 	if (unlikely(!skb))
 		return NULL;

 	skb_add_rx_frag(skb, 0, page_info->page,
 			page_info->page_offset +
 			GVE_RX_PAD, len, PAGE_SIZE / 2);

 	return skb;
 }

 static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info,
 			     struct gve_rx_data_slot *data_ring)
 {
 	u64 addr = be64_to_cpu(data_ring->qpl_offset);

 	page_info->page_offset ^= PAGE_SIZE / 2;
 	addr ^= PAGE_SIZE / 2;
 	data_ring->qpl_offset = cpu_to_be64(addr);
 }

 static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
 		   netdev_features_t feat, u32 idx)
 {
 	struct gve_rx_slot_page_info *page_info;
 	struct gve_priv *priv = rx->gve;
 	struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
 	struct net_device *dev = priv->dev;
 	struct sk_buff *skb;
 	int pagecount;
 	u16 len;

 	/* drop this packet */
 	if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR))
 		return true;

 	len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;
 	page_info = &rx->data.page_info[idx];

 	/* gvnic can only receive into registered segments. If the buffer
 	 * can't be recycled, our only choice is to copy the data out of
 	 * it so that we can return it to the device.
 	 */

 	if (PAGE_SIZE == 4096) {
 		if (len <= priv->rx_copybreak) {
 			/* Just copy small packets */
 			skb = gve_rx_copy(dev, napi, page_info, len);
 			goto have_skb;
 		}
 		if (unlikely(!gve_can_recycle_pages(dev))) {
 			skb = gve_rx_copy(dev, napi, page_info, len);
 			goto have_skb;
 		}
 		pagecount = page_count(page_info->page);
 		if (pagecount == 1) {
 			/* No part of this page is used by any SKBs; we attach
 			 * the page fragment to a new SKB and pass it up the
 			 * stack.
 			 */
 			skb = gve_rx_add_frags(dev, napi, page_info, len);
 			if (!skb)
 				return true;
 			/* Make sure the kernel stack can't release the page */
 			get_page(page_info->page);
 			/* "flip" to other packet buffer on this page */
 			gve_rx_flip_buff(page_info, &rx->data.data_ring[idx]);
 		} else if (pagecount >= 2) {
 			/* We have previously passed the other half of this
 			 * page up the stack, but it has not yet been freed.
 			 */
 			skb = gve_rx_copy(dev, napi, page_info, len);
 		} else {
 			WARN(pagecount < 1, "Pagecount should never be < 1");
 			return false;
 		}
 	} else {
 		skb = gve_rx_copy(dev, napi, page_info, len);
 	}

 have_skb:
 	/* We didn't manage to allocate an skb but we haven't had any
 	 * reset worthy failures.
 	 */
 	if (!skb)
 		return true;

 	if (likely(feat & NETIF_F_RXCSUM)) {
 		/* NIC passes up the partial sum */
 		if (rx_desc->csum)
 			skb->ip_summed = CHECKSUM_COMPLETE;
 		else
 			skb->ip_summed = CHECKSUM_NONE;
 		skb->csum = csum_unfold(rx_desc->csum);
 	}

 	/* parse flags & pass relevant info up */
 	if (likely(feat & NETIF_F_RXHASH) &&
 	    gve_needs_rss(rx_desc->flags_seq))
 		skb_set_hash(skb, be32_to_cpu(rx_desc->rss_hash),
 			     gve_rss_type(rx_desc->flags_seq));

 	if (skb_is_nonlinear(skb))
 		napi_gro_frags(napi);
 	else
 		napi_gro_receive(napi, skb);
 	return true;
 }

 static bool gve_rx_work_pending(struct gve_rx_ring *rx)
 {
 	struct gve_rx_desc *desc;
 	__be16 flags_seq;
 	u32 next_idx;

 	next_idx = rx->cnt & rx->mask;
 	desc = rx->desc.desc_ring + next_idx;

 	flags_seq = desc->flags_seq;
 	/* Make sure we have synchronized the seq no with the device */
 	smp_rmb();

 	return (GVE_SEQNO(flags_seq) == rx->desc.seqno);
 }

 bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
 		       netdev_features_t feat)
 {
 	struct gve_priv *priv = rx->gve;
 	struct gve_rx_desc *desc;
 	u32 cnt = rx->cnt;
 	u32 idx = cnt & rx->mask;
 	u32 work_done = 0;
 	u64 bytes = 0;

 	desc = rx->desc.desc_ring + idx;
 	while ((GVE_SEQNO(desc->flags_seq) == rx->desc.seqno) &&
 	       work_done < budget) {
 		netif_info(priv, rx_status, priv->dev,
 			   "[%d] idx=%d desc=%p desc->flags_seq=0x%x\n",
 			   rx->q_num, idx, desc, desc->flags_seq);
 		netif_info(priv, rx_status, priv->dev,
 			   "[%d] seqno=%d rx->desc.seqno=%d\n",
 			   rx->q_num, GVE_SEQNO(desc->flags_seq),
 			   rx->desc.seqno);
 		bytes += be16_to_cpu(desc->len) - GVE_RX_PAD;
 		if (!gve_rx(rx, desc, feat, idx))
 			gve_schedule_reset(priv);
 		cnt++;
 		idx = cnt & rx->mask;
 		desc = rx->desc.desc_ring + idx;
 		rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
 		work_done++;
 	}

 	if (!work_done)
 		return false;

 	u64_stats_update_begin(&rx->statss);
 	rx->rpackets += work_done;
 	rx->rbytes += bytes;
 	u64_stats_update_end(&rx->statss);
 	rx->cnt = cnt;
 	rx->fill_cnt += work_done;

 	/* restock desc ring slots */
 	dma_wmb();	/* Ensure descs are visible before ringing doorbell */
 	gve_rx_write_doorbell(priv, rx);
 	return gve_rx_work_pending(rx);
 }

 bool gve_rx_poll(struct gve_notify_block *block, int budget)
 {
 	struct gve_rx_ring *rx = block->rx;
 	netdev_features_t feat;
 	bool repoll = false;

 	feat = block->napi.dev->features;

 	/* If budget is 0, do all the work */
 	if (budget == 0)
 		budget = INT_MAX;

 	if (budget > 0)
 		repoll |= gve_clean_rx_done(rx, budget, feat);
 	else
 		repoll |= gve_rx_work_pending(rx);
 	return repoll;
 }
	// SPDX-License-Identifier: (GPL-2.0 OR MIT)
	/* Google virtual Ethernet (gve) driver
	*
	* Copyright (C) 2015-2019 Google, Inc.
	*/

	#include "gve.h"
	#include "gve_adminq.h"
	#include <linux/etherdevice.h>

	static void gve_rx_remove_from_block(struct gve_priv *priv, int queue_idx)
	{
	struct gve_notify_block *block =
	&priv->ntfy_blocks[gve_rx_idx_to_ntfy(priv, queue_idx)];

	block->rx = NULL;
	}

	static void gve_rx_free_ring(struct gve_priv *priv, int idx)
	{
	struct gve_rx_ring *rx = &priv->rx[idx];
	struct device *dev = &priv->pdev->dev;
	size_t bytes;
	u32 slots;

	gve_rx_remove_from_block(priv, idx);

	bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
	dma_free_coherent(dev, bytes, rx->desc.desc_ring, rx->desc.bus);
	rx->desc.desc_ring = NULL;

	dma_free_coherent(dev, sizeof(*rx->q_resources),
	rx->q_resources, rx->q_resources_bus);
	rx->q_resources = NULL;

	gve_unassign_qpl(priv, rx->data.qpl->id);
	rx->data.qpl = NULL;
	kvfree(rx->data.page_info);

	slots = rx->mask + 1;
	bytes = sizeof(rx->data.data_ring) slots;
	dma_free_coherent(dev, bytes, rx->data.data_ring,
	rx->data.data_bus);
	rx->data.data_ring = NULL;
	netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
	}

	static void gve_setup_rx_buffer(struct gve_rx_slot_page_info *page_info,
	struct gve_rx_data_slot *slot,
	dma_addr_t addr, struct page *page)
	{
	page_info->page = page;
	page_info->page_offset = 0;
	page_info->page_address = page_address(page);
	slot->qpl_offset = cpu_to_be64(addr);
	}

	static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
	{
	struct gve_priv *priv = rx->gve;
	u32 slots;
	int i;

	/* Allocate one page per Rx queue slot. Each page is split into two
	* packet buffers, when possible we "page flip" between the two.
	*/
	slots = rx->mask + 1;

	rx->data.page_info = kvzalloc(slots *
	sizeof(*rx->data.page_info), GFP_KERNEL);
	if (!rx->data.page_info)
	return -ENOMEM;

	rx->data.qpl = gve_assign_rx_qpl(priv);

	for (i = 0; i < slots; i++) {
	struct page *page = rx->data.qpl->pages[i];
	dma_addr_t addr = i * PAGE_SIZE;

	gve_setup_rx_buffer(&rx->data.page_info[i],
	&rx->data.data_ring[i], addr, page);
	}

	return slots;
	}

	static void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx)
	{
	u32 ntfy_idx = gve_rx_idx_to_ntfy(priv, queue_idx);
	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
	struct gve_rx_ring *rx = &priv->rx[queue_idx];

	block->rx = rx;
	rx->ntfy_id = ntfy_idx;
	}

	static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
	{
	struct gve_rx_ring *rx = &priv->rx[idx];
	struct device *hdev = &priv->pdev->dev;
	u32 slots, npages;
	int filled_pages;
	size_t bytes;
	int err;

	netif_dbg(priv, drv, priv->dev, "allocating rx ring\n");
	/* Make sure everything is zeroed to start with */
	memset(rx, 0, sizeof(*rx));

	rx->gve = priv;
	rx->q_num = idx;

	slots = priv->rx_pages_per_qpl;
	rx->mask = slots - 1;

	/* alloc rx data ring */
	bytes = sizeof(rx->data.data_ring) slots;
	rx->data.data_ring = dma_alloc_coherent(hdev, bytes,
	&rx->data.data_bus,
	GFP_KERNEL);
	if (!rx->data.data_ring)
	return -ENOMEM;
	filled_pages = gve_prefill_rx_pages(rx);
	if (filled_pages < 0) {
	err = -ENOMEM;
	goto abort_with_slots;
	}
	rx->fill_cnt = filled_pages;
	/* Ensure data ring slots (packet buffers) are visible. */
	dma_wmb();

	/* Alloc gve_queue_resources */
	rx->q_resources =
	dma_alloc_coherent(hdev,
	sizeof(*rx->q_resources),
	&rx->q_resources_bus,
	GFP_KERNEL);
	if (!rx->q_resources) {
	err = -ENOMEM;
	goto abort_filled;
	}
	netif_dbg(priv, drv, priv->dev, "rx[%d]->data.data_bus=%lx\n", idx,
	(unsigned long)rx->data.data_bus);

	/* alloc rx desc ring */
	bytes = sizeof(struct gve_rx_desc) * priv->rx_desc_cnt;
	npages = bytes / PAGE_SIZE;
	if (npages * PAGE_SIZE != bytes) {
	err = -EIO;
	goto abort_with_q_resources;
	}

	rx->desc.desc_ring = dma_alloc_coherent(hdev, bytes, &rx->desc.bus,
	GFP_KERNEL);
	if (!rx->desc.desc_ring) {
	err = -ENOMEM;
	goto abort_with_q_resources;
	}
	rx->mask = slots - 1;
	rx->cnt = 0;
	rx->desc.seqno = 1;
	gve_rx_add_to_block(priv, idx);

	return 0;

	abort_with_q_resources:
	dma_free_coherent(hdev, sizeof(*rx->q_resources),
	rx->q_resources, rx->q_resources_bus);
	rx->q_resources = NULL;
	abort_filled:
	kvfree(rx->data.page_info);
	abort_with_slots:
	bytes = sizeof(rx->data.data_ring) slots;
	dma_free_coherent(hdev, bytes, rx->data.data_ring, rx->data.data_bus);
	rx->data.data_ring = NULL;

	return err;
	}

	int gve_rx_alloc_rings(struct gve_priv *priv)
	{
	int err = 0;
	int i;

	for (i = 0; i < priv->rx_cfg.num_queues; i++) {
	err = gve_rx_alloc_ring(priv, i);
	if (err) {
	netif_err(priv, drv, priv->dev,
	"Failed to alloc rx ring=%d: err=%d\n",
	i, err);
	break;
	}
	}
	/* Unallocate if there was an error */
	if (err) {
	int j;

	for (j = 0; j < i; j++)
	gve_rx_free_ring(priv, j);
	}
	return err;
	}

	void gve_rx_free_rings(struct gve_priv *priv)
	{
	int i;

	for (i = 0; i < priv->rx_cfg.num_queues; i++)
	gve_rx_free_ring(priv, i);
	}

	void gve_rx_write_doorbell(struct gve_priv priv, struct gve_rx_ring rx)
	{
	u32 db_idx = be32_to_cpu(rx->q_resources->db_index);

	iowrite32be(rx->fill_cnt, &priv->db_bar2[db_idx]);
	}

	static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
	{
	if (likely(pkt_flags & (GVE_RXF_TCP \| GVE_RXF_UDP)))
	return PKT_HASH_TYPE_L4;
	if (pkt_flags & (GVE_RXF_IPV4 \| GVE_RXF_IPV6))
	return PKT_HASH_TYPE_L3;
	return PKT_HASH_TYPE_L2;
	}

	static struct sk_buff gve_rx_copy(struct net_device dev,
	struct napi_struct *napi,
	struct gve_rx_slot_page_info *page_info,
	u16 len)
	{
	struct sk_buff *skb = napi_alloc_skb(napi, len);
	void *va = page_info->page_address + GVE_RX_PAD +
	page_info->page_offset;

	if (unlikely(!skb))
	return NULL;

	__skb_put(skb, len);

	skb_copy_to_linear_data(skb, va, len);

	skb->protocol = eth_type_trans(skb, dev);
	return skb;
	}

	static struct sk_buff gve_rx_add_frags(struct net_device dev,
	struct napi_struct *napi,
	struct gve_rx_slot_page_info *page_info,
	u16 len)
	{
	struct sk_buff *skb = napi_get_frags(napi);

	if (unlikely(!skb))
	return NULL;

	skb_add_rx_frag(skb, 0, page_info->page,
	page_info->page_offset +
	GVE_RX_PAD, len, PAGE_SIZE / 2);

	return skb;
	}

	static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info,
	struct gve_rx_data_slot *data_ring)
	{
	u64 addr = be64_to_cpu(data_ring->qpl_offset);

	page_info->page_offset ^= PAGE_SIZE / 2;
	addr ^= PAGE_SIZE / 2;
	data_ring->qpl_offset = cpu_to_be64(addr);
	}

	static bool gve_rx(struct gve_rx_ring rx, struct gve_rx_desc rx_desc,
	netdev_features_t feat, u32 idx)
	{
	struct gve_rx_slot_page_info *page_info;
	struct gve_priv *priv = rx->gve;
	struct napi_struct *napi = &priv->ntfy_blocks[rx->ntfy_id].napi;
	struct net_device *dev = priv->dev;
	struct sk_buff *skb;
	int pagecount;
	u16 len;

	/* drop this packet */
	if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR))
	return true;

	len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;
	page_info = &rx->data.page_info[idx];

	/* gvnic can only receive into registered segments. If the buffer
	* can't be recycled, our only choice is to copy the data out of
	* it so that we can return it to the device.
	*/

	if (PAGE_SIZE == 4096) {
	if (len <= priv->rx_copybreak) {
	/* Just copy small packets */
	skb = gve_rx_copy(dev, napi, page_info, len);
	goto have_skb;
	}
	if (unlikely(!gve_can_recycle_pages(dev))) {
	skb = gve_rx_copy(dev, napi, page_info, len);
	goto have_skb;
	}
	pagecount = page_count(page_info->page);
	if (pagecount == 1) {
	/* No part of this page is used by any SKBs; we attach
	* the page fragment to a new SKB and pass it up the
	* stack.
	*/
	skb = gve_rx_add_frags(dev, napi, page_info, len);
	if (!skb)
	return true;
	/* Make sure the kernel stack can't release the page */
	get_page(page_info->page);
	/* "flip" to other packet buffer on this page */
	gve_rx_flip_buff(page_info, &rx->data.data_ring[idx]);
	} else if (pagecount >= 2) {
	/* We have previously passed the other half of this
	* page up the stack, but it has not yet been freed.
	*/
	skb = gve_rx_copy(dev, napi, page_info, len);
	} else {
	WARN(pagecount < 1, "Pagecount should never be < 1");
	return false;
	}
	} else {
	skb = gve_rx_copy(dev, napi, page_info, len);
	}

	have_skb:
	/* We didn't manage to allocate an skb but we haven't had any
	* reset worthy failures.
	*/
	if (!skb)
	return true;

	if (likely(feat & NETIF_F_RXCSUM)) {
	/* NIC passes up the partial sum */
	if (rx_desc->csum)
	skb->ip_summed = CHECKSUM_COMPLETE;
	else
	skb->ip_summed = CHECKSUM_NONE;
	skb->csum = csum_unfold(rx_desc->csum);
	}

	/* parse flags & pass relevant info up */
	if (likely(feat & NETIF_F_RXHASH) &&
	gve_needs_rss(rx_desc->flags_seq))
	skb_set_hash(skb, be32_to_cpu(rx_desc->rss_hash),
	gve_rss_type(rx_desc->flags_seq));

	if (skb_is_nonlinear(skb))
	napi_gro_frags(napi);
	else
	napi_gro_receive(napi, skb);
	return true;
	}

	static bool gve_rx_work_pending(struct gve_rx_ring *rx)
	{
	struct gve_rx_desc *desc;
	__be16 flags_seq;
	u32 next_idx;

	next_idx = rx->cnt & rx->mask;
	desc = rx->desc.desc_ring + next_idx;

	flags_seq = desc->flags_seq;
	/* Make sure we have synchronized the seq no with the device */
	smp_rmb();

	return (GVE_SEQNO(flags_seq) == rx->desc.seqno);
	}

	bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
	netdev_features_t feat)
	{
	struct gve_priv *priv = rx->gve;
	struct gve_rx_desc *desc;
	u32 cnt = rx->cnt;
	u32 idx = cnt & rx->mask;
	u32 work_done = 0;
	u64 bytes = 0;

	desc = rx->desc.desc_ring + idx;
	while ((GVE_SEQNO(desc->flags_seq) == rx->desc.seqno) &&
	work_done < budget) {
	netif_info(priv, rx_status, priv->dev,
	"[%d] idx=%d desc=%p desc->flags_seq=0x%x\n",
	rx->q_num, idx, desc, desc->flags_seq);
	netif_info(priv, rx_status, priv->dev,
	"[%d] seqno=%d rx->desc.seqno=%d\n",
	rx->q_num, GVE_SEQNO(desc->flags_seq),
	rx->desc.seqno);
	bytes += be16_to_cpu(desc->len) - GVE_RX_PAD;
	if (!gve_rx(rx, desc, feat, idx))
	gve_schedule_reset(priv);
	cnt++;
	idx = cnt & rx->mask;
	desc = rx->desc.desc_ring + idx;
	rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
	work_done++;
	}

	if (!work_done)
	return false;

	u64_stats_update_begin(&rx->statss);
	rx->rpackets += work_done;
	rx->rbytes += bytes;
	u64_stats_update_end(&rx->statss);
	rx->cnt = cnt;
	rx->fill_cnt += work_done;

	/* restock desc ring slots */
	dma_wmb(); /* Ensure descs are visible before ringing doorbell */
	gve_rx_write_doorbell(priv, rx);
	return gve_rx_work_pending(rx);
	}

	bool gve_rx_poll(struct gve_notify_block *block, int budget)
	{
	struct gve_rx_ring *rx = block->rx;
	netdev_features_t feat;
	bool repoll = false;

	feat = block->napi.dev->features;

	/* If budget is 0, do all the work */
	if (budget == 0)
	budget = INT_MAX;

	if (budget > 0)
	repoll \|= gve_clean_rx_done(rx, budget, feat);
	else
	repoll \|= gve_rx_work_pending(rx);
	return repoll;
	}