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net: airoha: Reserve RX headroom to avoid skb reallocation

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Reserve NET_SKB_PAD + NET_IP_ALIGN bytes of headroom for received packets
to avoid skb head reallocation when pushing protocol headers into the skb.

Tested-by: Xuegang Lu <xuegang.lu@airoha.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20260513-airoha-rx-headroom-v1-1-bd87798e422d@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Lorenzo Bianconi
2026-05-13 17:03:59 +02:00
committed by Jakub Kicinski
parent 55834f0d74
commit bbfb198394
2 changed files with 10 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/net/ethernet/airoha/airoha_eth.c
View File

@@ -543,9 +543,10 @@ static int airoha_qdma_fill_rx_queue(struct airoha_queue *q)
q->queued++;
nframes++;
offset += AIROHA_RX_HEADROOM;
e->buf = page_address(page) + offset;
e->dma_addr = page_pool_get_dma_addr(page) + offset;
e->dma_len = SKB_WITH_OVERHEAD(q->buf_size);
e->dma_len = SKB_WITH_OVERHEAD(AIROHA_RX_LEN(q->buf_size));
val = FIELD_PREP(QDMA_DESC_LEN_MASK, e->dma_len);
WRITE_ONCE(desc->ctrl, cpu_to_le32(val));
@@ -611,13 +612,12 @@ static int airoha_qdma_rx_process(struct airoha_queue *q, int budget)
q->tail = (q->tail + 1) % q->ndesc;
q->queued--;
dma_sync_single_for_cpu(eth->dev, e->dma_addr,
SKB_WITH_OVERHEAD(q->buf_size), dir);
dma_sync_single_for_cpu(eth->dev, e->dma_addr, e->dma_len,
dir);
page = virt_to_head_page(e->buf);
len = FIELD_GET(QDMA_DESC_LEN_MASK, desc_ctrl);
data_len = q->skb ? q->buf_size
: SKB_WITH_OVERHEAD(q->buf_size);
data_len = q->skb ? AIROHA_RX_LEN(q->buf_size) : e->dma_len;
if (!len || data_len < len)
goto free_frag;
@@ -627,10 +627,12 @@ static int airoha_qdma_rx_process(struct airoha_queue *q, int budget)
port = eth->ports[p];
if (!q->skb) { /* first buffer */
q->skb = napi_build_skb(e->buf, q->buf_size);
q->skb = napi_build_skb(e->buf - AIROHA_RX_HEADROOM,
q->buf_size);
if (!q->skb)
goto free_frag;
skb_reserve(q->skb, AIROHA_RX_HEADROOM);
__skb_put(q->skb, len);
skb_mark_for_recycle(q->skb);
q->skb->dev = port->dev;

2
drivers/net/ethernet/airoha/airoha_eth.h
View File

@@ -32,6 +32,8 @@
#define AIROHA_FE_MC_MAX_VLAN_TABLE 64
#define AIROHA_FE_MC_MAX_VLAN_PORT 16
#define AIROHA_NUM_TX_IRQ 2
#define AIROHA_RX_HEADROOM (NET_SKB_PAD + NET_IP_ALIGN)
#define AIROHA_RX_LEN(_n) ((_n) - AIROHA_RX_HEADROOM)
#define HW_DSCP_NUM 2048
#define IRQ_QUEUE_LEN(_n) ((_n) ? 1024 : 2048)
#define TX_DSCP_NUM 1024