[net-next v4 06/12] net: bnxt: Add TX inline buffer infrastructure
From: Joe Damato <hidden>
Date: 2026-03-20 14:42:01
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Subsystem:
broadcom bnxt_en 50 gigabit ethernet driver, networking drivers, the rest · Maintainers:
Michael Chan, Pavan Chebbi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Add per-ring pre-allocated inline buffer fields (tx_inline_buf, tx_inline_dma, tx_inline_size) to bnxt_tx_ring_info and helpers to allocate and free them. A producer and consumer (tx_inline_prod, tx_inline_cons) are added to track which slot(s) of the inline buffer are in-use. The inline buffer will be used by the SW USO path for pre-allocated, pre-DMA-mapped per-segment header copies. In the future, this could be extended to support TX copybreak. Allocation helper is marked __maybe_unused in this commit because it will be wired in later. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Joe Damato <redacted> --- rfcv2: - Added a producer and consumer to correctly track the in use header slots. drivers/net/ethernet/broadcom/bnxt/bnxt.c | 35 +++++++++++++++++++++++ drivers/net/ethernet/broadcom/bnxt/bnxt.h | 6 ++++ 2 files changed, 41 insertions(+)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index ea8081aeb5ae..8929264a54b1 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c@@ -3983,6 +3983,39 @@ static int bnxt_alloc_rx_rings(struct bnxt *bp) return rc; } +static void bnxt_free_tx_inline_buf(struct bnxt_tx_ring_info *txr, + struct pci_dev *pdev) +{ + if (!txr->tx_inline_buf) + return; + + dma_unmap_single(&pdev->dev, txr->tx_inline_dma, + txr->tx_inline_size, DMA_TO_DEVICE); + kfree(txr->tx_inline_buf); + txr->tx_inline_buf = NULL; + txr->tx_inline_size = 0; +} + +static int __maybe_unused bnxt_alloc_tx_inline_buf(struct bnxt_tx_ring_info *txr, + struct pci_dev *pdev, + unsigned int size) +{ + txr->tx_inline_buf = kmalloc(size, GFP_KERNEL); + if (!txr->tx_inline_buf) + return -ENOMEM; + + txr->tx_inline_dma = dma_map_single(&pdev->dev, txr->tx_inline_buf, + size, DMA_TO_DEVICE); + if (dma_mapping_error(&pdev->dev, txr->tx_inline_dma)) { + kfree(txr->tx_inline_buf); + txr->tx_inline_buf = NULL; + return -ENOMEM; + } + txr->tx_inline_size = size; + + return 0; +} + static void bnxt_free_tx_rings(struct bnxt *bp) { int i;
@@ -4001,6 +4034,8 @@ static void bnxt_free_tx_rings(struct bnxt *bp) txr->tx_push = NULL; } + bnxt_free_tx_inline_buf(txr, pdev); + ring = &txr->tx_ring_struct; bnxt_free_ring(bp, &ring->ring_mem);
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index a822bbb71146..d9543d6048d8 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h@@ -994,6 +994,12 @@ struct bnxt_tx_ring_info { dma_addr_t tx_push_mapping; __le64 data_mapping; + void *tx_inline_buf; + dma_addr_t tx_inline_dma; + unsigned int tx_inline_size; + u16 tx_inline_prod; + u16 tx_inline_cons; + #define BNXT_DEV_STATE_CLOSING 0x1 u32 dev_state;
--
2.52.0