Commit 37149e93 authored by David Awogbemila's avatar David Awogbemila Committed by David S. Miller
Browse files

gve: Implement packet continuation for RX. 



This enables the driver to receive RX packets spread across multiple
buffers:

For a given multi-fragment packet the "packet continuation" bit is set
on all descriptors except the last one. These descriptors' payloads are
combined into a single SKB before the SKB is handed to the
networking stack.

This change adds a "packet buffer size" notion for RX queues. The
CreateRxQueue AdminQueue command sent to the device now includes the
packet_buffer_size.

We opt for a packet_buffer_size of PAGE_SIZE / 2 to give the
driver the opportunity to flip pages where we can instead of copying.

Signed-off-by: default avatarDavid Awogbemila <awogbemila@google.com>
Signed-off-by: default avatarJeroen de Borst <jeroendb@google.com>
Reviewed-by: default avatarCatherine Sullivan <csully@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1344e751

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

+8 −0
Original line number Diff line number Diff line
@@ -149,6 +149,10 @@ struct gve_rx_ctx { 
	/* head and tail of skb chain for the current packet or NULL if none */

	struct sk_buff *skb_head;

	struct sk_buff *skb_tail;

	u16 total_expected_size;

	u8 expected_frag_cnt;

	u8 curr_frag_cnt;

	u8 reuse_frags;

};



/* Contains datapath state used to represent an RX queue. */
@@ -162,6 +166,7 @@ struct gve_rx_ring { 


			/* threshold for posting new buffs and descs */

			u32 db_threshold;

			u16 packet_buffer_size;

		};



		/* DQO fields. */
@@ -209,6 +214,9 @@ struct gve_rx_ring { 
	u64 rx_skb_alloc_fail; /* free-running count of skb alloc fails */

	u64 rx_buf_alloc_fail; /* free-running count of buffer alloc fails */

	u64 rx_desc_err_dropped_pkt; /* free-running count of packets dropped by descriptor error */

	u64 rx_cont_packet_cnt; /* free-running multi-fragment packets received */

	u64 rx_frag_flip_cnt; /* free-running count of rx segments where page_flip was used */

	u64 rx_frag_copy_cnt; /* free-running count of rx segments copied into skb linear portion */

	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_adminq.c

+1 −0
Original line number Diff line number Diff line
@@ -530,6 +530,7 @@ static int gve_adminq_create_rx_queue(struct gve_priv *priv, u32 queue_index) 
			cpu_to_be64(rx->data.data_bus),

		cmd.create_rx_queue.index = cpu_to_be32(queue_index);

		cmd.create_rx_queue.queue_page_list_id = cpu_to_be32(qpl_id);

		cmd.create_rx_queue.packet_buffer_size = cpu_to_be16(rx->packet_buffer_size);

	} else {

		cmd.create_rx_queue.rx_ring_size =

			cpu_to_be16(priv->rx_desc_cnt);

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

+7 −6
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ union gve_rx_data_slot { 
#define	GVE_RXF_TCP		GVE_RXFLG(6)	/* TCP Packet			*/

#define	GVE_RXF_UDP		GVE_RXFLG(7)	/* UDP Packet			*/

#define	GVE_RXF_ERR		GVE_RXFLG(8)	/* Packet Error Detected	*/

#define	GVE_RXF_PKT_CONT	GVE_RXFLG(10)	/* Multi Fragment RX packet	*/



/* GVE IRQ */

#define GVE_IRQ_ACK	BIT(31)

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

+4 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ static const char gve_gstrings_main_stats[][ETH_GSTRING_LEN] = { 


static const char gve_gstrings_rx_stats[][ETH_GSTRING_LEN] = {

	"rx_posted_desc[%u]", "rx_completed_desc[%u]", "rx_bytes[%u]",

	"rx_cont_packet_cnt[%u]", "rx_frag_flip_cnt[%u]", "rx_frag_copy_cnt[%u]",

	"rx_dropped_pkt[%u]", "rx_copybreak_pkt[%u]", "rx_copied_pkt[%u]",

	"rx_queue_drop_cnt[%u]", "rx_no_buffers_posted[%u]",

	"rx_drops_packet_over_mru[%u]", "rx_drops_invalid_checksum[%u]",
@@ -265,6 +266,9 @@ gve_get_ethtool_stats(struct net_device *netdev, 
			} while (u64_stats_fetch_retry(&priv->rx[ring].statss,

						       start));

			data[i++] = tmp_rx_bytes;

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

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

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

			/* rx dropped packets */

			data[i++] = tmp_rx_skb_alloc_fail +

				tmp_rx_buf_alloc_fail +

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

+0 −8
Original line number Diff line number Diff line
@@ -1371,14 +1371,6 @@ static int gve_init_priv(struct gve_priv *priv, bool skip_describe_device) 
			"Could not get device information: err=%d\n", err);

		goto err;

	}

	if (gve_is_gqi(priv) && priv->dev->max_mtu > PAGE_SIZE) {

		priv->dev->max_mtu = PAGE_SIZE;

		err = gve_adminq_set_mtu(priv, priv->dev->mtu);

		if (err) {

			dev_err(&priv->pdev->dev, "Could not set mtu");

			goto err;

		}

	}

	priv->dev->mtu = priv->dev->max_mtu;

	num_ntfy = pci_msix_vec_count(priv->pdev);

	if (num_ntfy <= 0) {