[PATCH net-next 4/5] net: hns3: Add skb chain when num of RX buf exceeds MAX_SKB_FRAGS

From: Salil Mehta
Date: Tue Nov 13 2018 - 05:14:43 EST


From: Peng Li <lipeng321@xxxxxxxxxx>

MAX_SKB_FRAGS in protocol stack is defined as:

MAX_SKB_FRAGS is 17 when PAGE_SIZE is 4K. If HW enable GRO, it may
merge small packets and the rx buffer may be more than
MAX_SKB_FRAGS. So driver will add skb chain when RX buffer num.
more than MAX_SKB_FRAGS.

Signed-off-by: Peng Li <lipeng321@xxxxxxxxxx>
Signed-off-by: Salil Mehta <salil.mehta@xxxxxxxxxx>
---
.../net/ethernet/hisilicon/hns3/hns3_enet.c | 37 ++++++++++++++++++-
.../net/ethernet/hisilicon/hns3/hns3_enet.h | 2 +
2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 860067898471..7776089b6bc2 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -2361,6 +2361,9 @@ static void hns3_rx_checksum(struct hns3_enet_ring *ring, struct sk_buff *skb,

static void hns3_rx_skb(struct hns3_enet_ring *ring, struct sk_buff *skb)
{
+ if (skb_has_frag_list(skb))
+ napi_gro_flush(&ring->tqp_vector->napi, false);
+
napi_gro_receive(&ring->tqp_vector->napi, skb);
}

@@ -2417,6 +2420,8 @@ static int hns3_alloc_skb(struct hns3_enet_ring *ring, int length,
prefetchw(skb->data);

ring->pending_buf = 1;
+ ring->frag_num = 0;
+ ring->tail_skb = NULL;
if (length <= HNS3_RX_HEAD_SIZE) {
memcpy(__skb_put(skb, length), va, ALIGN(length, sizeof(long)));

@@ -2435,7 +2440,7 @@ static int hns3_alloc_skb(struct hns3_enet_ring *ring, int length,

ring->pull_len = eth_get_headlen(va, HNS3_RX_HEAD_SIZE);
__skb_put(skb, ring->pull_len);
- hns3_nic_reuse_page(skb, 0, ring, ring->pull_len,
+ hns3_nic_reuse_page(skb, ring->frag_num++, ring, ring->pull_len,
desc_cb);
ring_ptr_move_fw(ring, next_to_clean);

@@ -2446,6 +2451,8 @@ static int hns3_add_frag(struct hns3_enet_ring *ring, struct hns3_desc *desc,
struct sk_buff **out_skb, bool pending)
{
struct sk_buff *skb = *out_skb;
+ struct sk_buff *head_skb = *out_skb;
+ struct sk_buff *new_skb;
struct hns3_desc_cb *desc_cb;
struct hns3_desc *pre_desc;
u32 bd_base_info;
@@ -2470,7 +2477,33 @@ static int hns3_add_frag(struct hns3_enet_ring *ring, struct hns3_desc *desc,
if (!hnae3_get_bit(bd_base_info, HNS3_RXD_VLD_B))
return -ENXIO;

- hns3_nic_reuse_page(skb, ring->pending_buf, ring, 0, desc_cb);
+ if (unlikely(ring->frag_num >= MAX_SKB_FRAGS)) {
+ new_skb = napi_alloc_skb(&ring->tqp_vector->napi,
+ HNS3_RX_HEAD_SIZE);
+ if (unlikely(!new_skb)) {
+ netdev_err(ring->tqp->handle->kinfo.netdev,
+ "alloc rx skb frag fail\n");
+ return -ENXIO;
+ }
+ ring->frag_num = 0;
+
+ if (ring->tail_skb) {
+ ring->tail_skb->next = new_skb;
+ ring->tail_skb = new_skb;
+ } else {
+ skb_shinfo(skb)->frag_list = new_skb;
+ ring->tail_skb = new_skb;
+ }
+ }
+
+ if (ring->tail_skb) {
+ head_skb->truesize += hnae3_buf_size(ring);
+ head_skb->data_len += le16_to_cpu(desc->rx.size);
+ head_skb->len += le16_to_cpu(desc->rx.size);
+ skb = ring->tail_skb;
+ }
+
+ hns3_nic_reuse_page(skb, ring->frag_num++, ring, 0, desc_cb);
ring_ptr_move_fw(ring, next_to_clean);
ring->pending_buf++;
}
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
index d8c0998127be..8e56b7e44978 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
@@ -402,6 +402,7 @@ struct hns3_enet_ring {
int next_to_clean;

int pull_len; /* head length for current packet */
+ u32 frag_num;
unsigned char *va; /* first buffer address for current packet */

u32 flag; /* ring attribute */
@@ -412,6 +413,7 @@ struct hns3_enet_ring {

int pending_buf;
struct sk_buff *skb;
+ struct sk_buff *tail_skb;
};

struct hns_queue;
--
2.17.1