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Commit 438b43bd authored by Catherine Sullivan's avatar Catherine Sullivan Committed by David S. Miller
Browse files

gve: Fix case where desc_cnt and data_cnt can get out of sync 



desc_cnt and data_cnt should always be equal. In the case of a dropped
packet desc_cnt was still getting updated (correctly), data_cnt
was not. To eliminate this bug and prevent it from recurring this
patch combines them into one ring level cnt.

Signed-off-by: default avatarCatherine Sullivan <csully@google.com>
Reviewed-by: default avatarSagi Shahar <sagis@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cff6a327

drivers/net/ethernet/google/gve/gve.h

+3 −5
Original line number Diff line number Diff line
@@ -31,9 +31,6 @@ 
struct gve_rx_desc_queue {

	struct gve_rx_desc *desc_ring; /* the descriptor ring */

	dma_addr_t bus; /* the bus for the desc_ring */

	u32 cnt; /* free-running total number of completed packets */

	u32 fill_cnt; /* free-running total number of descriptors posted */

	u32 mask; /* masks the cnt to the size of the ring */

	u8 seqno; /* the next expected seqno for this desc*/

};
@@ -60,8 +57,6 @@ struct gve_rx_data_queue { 
	dma_addr_t data_bus; /* dma mapping of the slots */

	struct gve_rx_slot_page_info *page_info; /* page info of the buffers */

	struct gve_queue_page_list *qpl; /* qpl assigned to this queue */

	u32 mask; /* masks the cnt to the size of the ring */

	u32 cnt; /* free-running total number of completed packets */

};



struct gve_priv;
@@ -73,6 +68,9 @@ struct gve_rx_ring { 
	struct gve_rx_data_queue data;

	u64 rbytes; /* free-running bytes received */

	u64 rpackets; /* free-running packets received */

	u32 cnt; /* free-running total number of completed packets */

	u32 fill_cnt; /* free-running total number of descs and buffs posted */

	u32 mask; /* masks the cnt and fill_cnt to the size of the ring */

	u32 q_num; /* queue index */

	u32 ntfy_id; /* notification block index */

	struct gve_queue_resources *q_resources; /* head and tail pointer idx */

drivers/net/ethernet/google/gve/gve_ethtool.c

+2 −2
Original line number Diff line number Diff line
@@ -138,8 +138,8 @@ gve_get_ethtool_stats(struct net_device *netdev, 
		for (ring = 0; ring < priv->rx_cfg.num_queues; ring++) {

			struct gve_rx_ring *rx = &priv->rx[ring];



			data[i++] = rx->desc.cnt;

			data[i++] = rx->desc.fill_cnt;

			data[i++] = rx->cnt;

			data[i++] = rx->fill_cnt;

		}

	} else {

		i += priv->rx_cfg.num_queues * NUM_GVE_RX_CNTS;

drivers/net/ethernet/google/gve/gve_rx.c

+15 −19
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ static void gve_rx_free_ring(struct gve_priv *priv, int idx) 
	rx->data.qpl = NULL;

	kvfree(rx->data.page_info);



	slots = rx->data.mask + 1;

	slots = rx->mask + 1;

	bytes = sizeof(*rx->data.data_ring) * slots;

	dma_free_coherent(dev, bytes, rx->data.data_ring,

			  rx->data.data_bus);
@@ -64,7 +64,7 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx) 
	/* 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->data.mask + 1;

	slots = rx->mask + 1;



	rx->data.page_info = kvzalloc(slots *

				      sizeof(*rx->data.page_info), GFP_KERNEL);
@@ -111,7 +111,7 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx) 
	rx->q_num = idx;



	slots = priv->rx_pages_per_qpl;

	rx->data.mask = slots - 1;

	rx->mask = slots - 1;



	/* alloc rx data ring */

	bytes = sizeof(*rx->data.data_ring) * slots;
@@ -125,7 +125,7 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx) 
		err = -ENOMEM;

		goto abort_with_slots;

	}

	rx->desc.fill_cnt = filled_pages;

	rx->fill_cnt = filled_pages;

	/* Ensure data ring slots (packet buffers) are visible. */

	dma_wmb();
@@ -156,8 +156,8 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx) 
		err = -ENOMEM;

		goto abort_with_q_resources;

	}

	rx->desc.mask = slots - 1;

	rx->desc.cnt = 0;

	rx->mask = slots - 1;

	rx->cnt = 0;

	rx->desc.seqno = 1;

	gve_rx_add_to_block(priv, idx);
@@ -213,7 +213,7 @@ 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->desc.fill_cnt, &priv->db_bar2[db_idx]);

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

}



static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
@@ -273,7 +273,7 @@ static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info, 
}



static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,

		   netdev_features_t feat)

		   netdev_features_t feat, u32 idx)

{

	struct gve_rx_slot_page_info *page_info;

	struct gve_priv *priv = rx->gve;
@@ -282,14 +282,12 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc, 
	struct sk_buff *skb;

	int pagecount;

	u16 len;

	u32 idx;



	/* drop this packet */

	if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR))

		return true;



	len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;

	idx = rx->data.cnt & rx->data.mask;

	page_info = &rx->data.page_info[idx];



	/* gvnic can only receive into registered segments. If the buffer
@@ -340,8 +338,6 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc, 
	if (!skb)

		return true;



	rx->data.cnt++;



	if (likely(feat & NETIF_F_RXCSUM)) {

		/* NIC passes up the partial sum */

		if (rx_desc->csum)
@@ -370,7 +366,7 @@ static bool gve_rx_work_pending(struct gve_rx_ring *rx) 
	__be16 flags_seq;

	u32 next_idx;



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

	next_idx = rx->cnt & rx->mask;

	desc = rx->desc.desc_ring + next_idx;



	flags_seq = desc->flags_seq;
@@ -385,8 +381,8 @@ bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget, 
{

	struct gve_priv *priv = rx->gve;

	struct gve_rx_desc *desc;

	u32 cnt = rx->desc.cnt;

	u32 idx = cnt & rx->desc.mask;

	u32 cnt = rx->cnt;

	u32 idx = cnt & rx->mask;

	u32 work_done = 0;

	u64 bytes = 0;
@@ -401,10 +397,10 @@ bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget, 
			   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))

		if (!gve_rx(rx, desc, feat, idx))

			gve_schedule_reset(priv);

		cnt++;

		idx = cnt & rx->desc.mask;

		idx = cnt & rx->mask;

		desc = rx->desc.desc_ring + idx;

		rx->desc.seqno = gve_next_seqno(rx->desc.seqno);

		work_done++;
@@ -417,8 +413,8 @@ bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget, 
	rx->rpackets += work_done;

	rx->rbytes += bytes;

	u64_stats_update_end(&rx->statss);

	rx->desc.cnt = cnt;

	rx->desc.fill_cnt += work_done;

	rx->cnt = cnt;

	rx->fill_cnt += work_done;



	/* restock desc ring slots */

	dma_wmb();	/* Ensure descs are visible before ringing doorbell */