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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: Catherine Sullivan <csully@google.com>
Reviewed-by: Sagi Shahar <sagis@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Catherine Sullivan 2019-08-01 16:07:31 -07:00 committed by David S. Miller
parent cff6a327d7
commit 438b43bdb9
3 changed files with 20 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/net/ethernet/google/gve/gve.h
View File

@ -31,9 +31,6 @@
struct gve_rx_desc_queue { struct gve_rx_desc_queue {
struct gve_rx_desc *desc_ring; /* the descriptor ring */ struct gve_rx_desc *desc_ring; /* the descriptor ring */
dma_addr_t bus; /* the bus for the desc_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*/ 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 */ 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_rx_slot_page_info *page_info; /* page info of the buffers */
struct gve_queue_page_list *qpl; /* qpl assigned to this queue */ 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; struct gve_priv;
@ -73,6 +68,9 @@ struct gve_rx_ring {
struct gve_rx_data_queue data; struct gve_rx_data_queue data;
u64 rbytes; /* free-running bytes received */ u64 rbytes; /* free-running bytes received */
u64 rpackets; /* free-running packets 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 q_num; /* queue index */
u32 ntfy_id; /* notification block index */ u32 ntfy_id; /* notification block index */
struct gve_queue_resources *q_resources; /* head and tail pointer idx */ struct gve_queue_resources *q_resources; /* head and tail pointer idx */

4
drivers/net/ethernet/google/gve/gve_ethtool.c
View File

@ -138,8 +138,8 @@ gve_get_ethtool_stats(struct net_device *netdev,
for (ring = 0; ring < priv->rx_cfg.num_queues; ring++) { for (ring = 0; ring < priv->rx_cfg.num_queues; ring++) {
struct gve_rx_ring *rx = &priv->rx[ring]; struct gve_rx_ring *rx = &priv->rx[ring];
data[i++] = rx->desc.cnt; data[i++] = rx->cnt;
data[i++] = rx->desc.fill_cnt; data[i++] = rx->fill_cnt;
} }
} else { } else {
i += priv->rx_cfg.num_queues * NUM_GVE_RX_CNTS; i += priv->rx_cfg.num_queues * NUM_GVE_RX_CNTS;

34
drivers/net/ethernet/google/gve/gve_rx.c
View File

@ -37,7 +37,7 @@ static void gve_rx_free_ring(struct gve_priv *priv, int idx)
rx->data.qpl = NULL; rx->data.qpl = NULL;
kvfree(rx->data.page_info); kvfree(rx->data.page_info);
slots = rx->data.mask + 1; slots = rx->mask + 1;
bytes = sizeof(*rx->data.data_ring) * slots; bytes = sizeof(*rx->data.data_ring) * slots;
dma_free_coherent(dev, bytes, rx->data.data_ring, dma_free_coherent(dev, bytes, rx->data.data_ring,
rx->data.data_bus); 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 /* Allocate one page per Rx queue slot. Each page is split into two
* packet buffers, when possible we "page flip" between the 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 * rx->data.page_info = kvzalloc(slots *
sizeof(*rx->data.page_info), GFP_KERNEL); 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; rx->q_num = idx;
slots = priv->rx_pages_per_qpl; slots = priv->rx_pages_per_qpl;
rx->data.mask = slots - 1; rx->mask = slots - 1;
/* alloc rx data ring */ /* alloc rx data ring */
bytes = sizeof(*rx->data.data_ring) * slots; 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; err = -ENOMEM;
goto abort_with_slots; goto abort_with_slots;
} }
rx->desc.fill_cnt = filled_pages; rx->fill_cnt = filled_pages;
/* Ensure data ring slots (packet buffers) are visible. */ /* Ensure data ring slots (packet buffers) are visible. */
dma_wmb(); dma_wmb();
@ -156,8 +156,8 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
err = -ENOMEM; err = -ENOMEM;
goto abort_with_q_resources; goto abort_with_q_resources;
} }
rx->desc.mask = slots - 1; rx->mask = slots - 1;
rx->desc.cnt = 0; rx->cnt = 0;
rx->desc.seqno = 1; rx->desc.seqno = 1;
gve_rx_add_to_block(priv, idx); 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); 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) 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, 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_rx_slot_page_info *page_info;
struct gve_priv *priv = rx->gve; 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; struct sk_buff *skb;
int pagecount; int pagecount;
u16 len; u16 len;
u32 idx;
/* drop this packet */ /* drop this packet */
if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR)) if (unlikely(rx_desc->flags_seq & GVE_RXF_ERR))
return true; return true;
len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD; len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;
idx = rx->data.cnt & rx->data.mask;
page_info = &rx->data.page_info[idx]; page_info = &rx->data.page_info[idx];
/* gvnic can only receive into registered segments. If the buffer /* gvnic can only receive into registered segments. If the buffer
@ -340,8 +338,6 @@ have_skb:
if (!skb) if (!skb)
return true; return true;
rx->data.cnt++;
if (likely(feat & NETIF_F_RXCSUM)) { if (likely(feat & NETIF_F_RXCSUM)) {
/* NIC passes up the partial sum */ /* NIC passes up the partial sum */
if (rx_desc->csum) if (rx_desc->csum)
@ -370,7 +366,7 @@ static bool gve_rx_work_pending(struct gve_rx_ring *rx)
__be16 flags_seq; __be16 flags_seq;
u32 next_idx; u32 next_idx;
next_idx = rx->desc.cnt & rx->desc.mask; next_idx = rx->cnt & rx->mask;
desc = rx->desc.desc_ring + next_idx; desc = rx->desc.desc_ring + next_idx;
flags_seq = desc->flags_seq; 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_priv *priv = rx->gve;
struct gve_rx_desc *desc; struct gve_rx_desc *desc;
u32 cnt = rx->desc.cnt; u32 cnt = rx->cnt;
u32 idx = cnt & rx->desc.mask; u32 idx = cnt & rx->mask;
u32 work_done = 0; u32 work_done = 0;
u64 bytes = 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->q_num, GVE_SEQNO(desc->flags_seq),
rx->desc.seqno); rx->desc.seqno);
bytes += be16_to_cpu(desc->len) - GVE_RX_PAD; 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); gve_schedule_reset(priv);
cnt++; cnt++;
idx = cnt & rx->desc.mask; idx = cnt & rx->mask;
desc = rx->desc.desc_ring + idx; desc = rx->desc.desc_ring + idx;
rx->desc.seqno = gve_next_seqno(rx->desc.seqno); rx->desc.seqno = gve_next_seqno(rx->desc.seqno);
work_done++; work_done++;
@ -417,8 +413,8 @@ bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
rx->rpackets += work_done; rx->rpackets += work_done;
rx->rbytes += bytes; rx->rbytes += bytes;
u64_stats_update_end(&rx->statss); u64_stats_update_end(&rx->statss);
rx->desc.cnt = cnt; rx->cnt = cnt;
rx->desc.fill_cnt += work_done; rx->fill_cnt += work_done;
/* restock desc ring slots */ /* restock desc ring slots */
dma_wmb(); /* Ensure descs are visible before ringing doorbell */ dma_wmb(); /* Ensure descs are visible before ringing doorbell */