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net: bnxt: Use dma_unmap_len for TX completion unmapping

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Store the DMA mapping length in each TX buffer descriptor via
dma_unmap_len_set at submit time, and use dma_unmap_len at completion
time.

This is a no-op for normal packets but prepares for software USO,
where header BDs set dma_unmap_len to 0 because the header buffer
is unmapped collectively rather than per-segment.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260408230607.2019402-5-joe@dama.to
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Joe Damato
2026-04-08 16:05:53 -07:00
committed by Jakub Kicinski
parent 637237d3d9
commit 3cb430e62c
1 changed files with 41 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

63
drivers/net/ethernet/broadcom/bnxt/bnxt.c
View File

@@ -656,6 +656,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
goto tx_free;
dma_unmap_addr_set(tx_buf, mapping, mapping);
dma_unmap_len_set(tx_buf, len, len);
flags = (len << TX_BD_LEN_SHIFT) | TX_BD_TYPE_LONG_TX_BD |
TX_BD_CNT(last_frag + 2);
@@ -720,6 +721,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
tx_buf = &txr->tx_buf_ring[RING_TX(bp, prod)];
netmem_dma_unmap_addr_set(skb_frag_netmem(frag), tx_buf,
mapping, mapping);
dma_unmap_len_set(tx_buf, len, len);
txbd->tx_bd_haddr = cpu_to_le64(mapping);
@@ -809,7 +811,8 @@ static bool __bnxt_tx_int(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
u16 hw_cons = txr->tx_hw_cons;
unsigned int tx_bytes = 0;
u16 cons = txr->tx_cons;
skb_frag_t *frag;
unsigned int dma_len;
dma_addr_t dma_addr;
int tx_pkts = 0;
bool rc = false;
@@ -844,19 +847,27 @@ static bool __bnxt_tx_int(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
goto next_tx_int;
}
dma_unmap_single(&pdev->dev, dma_unmap_addr(tx_buf, mapping),
skb_headlen(skb), DMA_TO_DEVICE);
if (dma_unmap_len(tx_buf, len)) {
dma_addr = dma_unmap_addr(tx_buf, mapping);
dma_len = dma_unmap_len(tx_buf, len);
dma_unmap_single(&pdev->dev, dma_addr, dma_len,
DMA_TO_DEVICE);
}
last = tx_buf->nr_frags;
for (j = 0; j < last; j++) {
frag = &skb_shinfo(skb)->frags[j];
cons = NEXT_TX(cons);
tx_buf = &txr->tx_buf_ring[RING_TX(bp, cons)];
netmem_dma_unmap_page_attrs(&pdev->dev,
dma_unmap_addr(tx_buf,
mapping),
skb_frag_size(frag),
DMA_TO_DEVICE, 0);
if (dma_unmap_len(tx_buf, len)) {
dma_addr = dma_unmap_addr(tx_buf, mapping);
dma_len = dma_unmap_len(tx_buf, len);
netmem_dma_unmap_page_attrs(&pdev->dev,
dma_addr, dma_len,
DMA_TO_DEVICE, 0);
}
}
if (unlikely(is_ts_pkt)) {
if (BNXT_CHIP_P5(bp)) {
@@ -3394,6 +3405,8 @@ static void bnxt_free_one_tx_ring_skbs(struct bnxt *bp,
{
int i, max_idx;
struct pci_dev *pdev = bp->pdev;
unsigned int dma_len;
dma_addr_t dma_addr;
max_idx = bp->tx_nr_pages * TX_DESC_CNT;
@@ -3404,9 +3417,10 @@ static void bnxt_free_one_tx_ring_skbs(struct bnxt *bp,
if (idx < bp->tx_nr_rings_xdp &&
tx_buf->action == XDP_REDIRECT) {
dma_unmap_single(&pdev->dev,
dma_unmap_addr(tx_buf, mapping),
dma_unmap_len(tx_buf, len),
dma_addr = dma_unmap_addr(tx_buf, mapping);
dma_len = dma_unmap_len(tx_buf, len);
dma_unmap_single(&pdev->dev, dma_addr, dma_len,
DMA_TO_DEVICE);
xdp_return_frame(tx_buf->xdpf);
tx_buf->action = 0;
@@ -3429,23 +3443,28 @@ static void bnxt_free_one_tx_ring_skbs(struct bnxt *bp,
continue;
}
dma_unmap_single(&pdev->dev,
dma_unmap_addr(tx_buf, mapping),
skb_headlen(skb),
DMA_TO_DEVICE);
if (dma_unmap_len(tx_buf, len)) {
dma_addr = dma_unmap_addr(tx_buf, mapping);
dma_len = dma_unmap_len(tx_buf, len);
dma_unmap_single(&pdev->dev, dma_addr, dma_len,
DMA_TO_DEVICE);
}
last = tx_buf->nr_frags;
i += 2;
for (j = 0; j < last; j++, i++) {
int ring_idx = i & bp->tx_ring_mask;
skb_frag_t *frag = &skb_shinfo(skb)->frags[j];
tx_buf = &txr->tx_buf_ring[ring_idx];
netmem_dma_unmap_page_attrs(&pdev->dev,
dma_unmap_addr(tx_buf,
mapping),
skb_frag_size(frag),
DMA_TO_DEVICE, 0);
if (dma_unmap_len(tx_buf, len)) {
dma_addr = dma_unmap_addr(tx_buf, mapping);
dma_len = dma_unmap_len(tx_buf, len);
netmem_dma_unmap_page_attrs(&pdev->dev,
dma_addr, dma_len,
DMA_TO_DEVICE, 0);
}
}
dev_kfree_skb(skb);
}