From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F1A44A0F07 for ; Sat, 3 Oct 2026 21:23:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791062602; cv=none; b=a5stu3YaA8IE+JFmhHSbGhhlUkxZz3RqTtQdbR2Cg/JgLUzu4NAdaVgYXfj3OQscrlF24sSb6S8MGdUyoWlYBPjqwmYYLUp4oIf4xrur1/T+drLIMvTceCAwg2QBxQ00aGV+A8jFheTlOu9ivndUhDRyEgkGvXiJQZgFdw8p3xU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791062602; c=relaxed/simple; bh=1EeFj1ZlhitmmWxDfH08SGgeO3KfRnyxMcOAjujKwdo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=QKRc4vi+03lRUbVXq1cS//PIsz2/NMVa7RK5Q+xV0nwsAwxS+yYlisHKvCMH0NZc/MW7O7gu9J72cGdkXrgGEMnmID/g+xsxSg9EiYfQMmQPczi8NEIG01C78JKQ3cxNn1uPqxBGqHuhky/iu00OHp61oKL8Z9ExZghnSWZSWdM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--lrizzo.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=i8JPqA3J; arc=none smtp.client-ip=209.85.208.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--lrizzo.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="i8JPqA3J" Received: by mail-ed1-f70.google.com with SMTP id 4fb4d7f45d1cf-6afaf6c1e82so514266a12.3 for ; Sat, 03 Oct 2026 14:23:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1791062595; x=1791667395; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=tZXqnIYzt9QIr5pps91sOm75Wt59xbsH7uSVOSxPBhc=; b=i8JPqA3JCuKKvnXy512tTyDSx8MyaT8eBnYmS4R7buRZO/tyNJWWa5U+6uhSSrbl5Y CHEKeUR2qBuTQ5+pvZaMMLLOqgQmhqoPatNDnLFoqAZa0avrLqRXpI/UZA4HyQA0br4f +bvqk5AdDJTbzYqChPZNX02kNbNvkrT3fEfABckAQyuhasdA1cwYx/Ny21l9Wf9FntKw 2bMdsCOF+i+8GEFt42rtLFKVTon0IYdqoOt/XELXKdzecKDMpdsyizJDXO9g3IjX5Obh g8+hPXdQc9wYuvKxkeUdU8ya/QxPxkWaPnNimdNVAeDWvd2Ajzmk3id+eBdVwpSEGKYV eKBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791062595; x=1791667395; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=tZXqnIYzt9QIr5pps91sOm75Wt59xbsH7uSVOSxPBhc=; b=b/HwsfjlNXkD8udxxoEzdYCs2pmMt/tRYr83cjLot9zbPvlvpI6cLtyt5hp9vCXhfC 1+/XdjZ1U57UWdFdvUliMnI0aqZPiJxeOpv+z5UNsN5TixVOE7rGcqYQOxWPI4kZo7Nd gfKX7PDCDkhwDnHnknTNEkmnzaW0QamX84wjSmO1dLQyTrInRvoTVsn6q2+WSbPi/rN+ yJpkPDCkZxZtMlmYuIDERJFTdk46u0wcfa6VhI3xQddESx+nnczIF2g7JjdlENKfdxHJ 7ZEM9G2i6c43yahnJeNxl640LIz7GnJncI6HKunOKPusFGaMq/1/BFFpb9VKMArheMxl VIgQ== X-Forwarded-Encrypted: i=1; AKwUvBzYBZfUW9bYLpgRD87PtNuNN2t4AWlnpcWuZUB1R+B5jD/7hVVRjKEN5KP0WdHRGbFDT37Fkk3MIBY=@vger.kernel.org X-Gm-Message-State: AFq9FYLuYvco7g6xfl/Ua9xwEZAuMQx8zjuVzCyTe/0xQxjmVIA3AJY0 izPtH4sYwARsHRV6wkrueRmvZoxKr7KoxS9RH9+KFOuuVTS+lvbPJD3qxtkNAmb5IUGB6BeGvGH TeXUS8A== X-Received: from edev16-n1.prod.google.com ([2002:a05:6402:a2d0:10b0:6aa:e8d7:1a1]) (user=lrizzo job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:4605:b0:6ac:7868:b68a with SMTP id 4fb4d7f45d1cf-6afad8ce0efmr2325349a12.9.1791062594530; Sat, 03 Oct 2026 14:23:14 -0700 (PDT) Date: Sat, 3 Oct 2026 21:22:40 +0000 In-Reply-To: <20261003212241.3432303-1-lrizzo@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20261003212241.3432303-1-lrizzo@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20261003212241.3432303-22-lrizzo@google.com> Subject: [RFC: DMA_PMD 21/22] net/bnxt: Use DMA_PMD memory for tx header bounce buffers From: Luigi Rizzo To: Luigi Rizzo , Joerg Roedel , Will Deacon , Robin Murphy , Christoph Hellwig , Marek Szyprowski , Andrew Morton , Vlastimil Babka , David Hildenbrand , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , Jonathan Corbet , Jesper Dangaard Brouer , Ilias Apalodimas , Willem de Bruijn , Kuniyuki Iwashima , Joshua Washington , Harshitha Ramamurthy , Saeed Mahameed , Tariq Toukan , Tony Nguyen , Przemek Kitszel , Alexander Lobakin , Michael Chan , Pavan Chebbi , iommu@lists.linux.dev, netdev@vger.kernel.org, linux-mm@kvack.org, driver-core@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Luigi Rizzo Content-Type: text/plain; charset="UTF-8" When dev->dma_pmd_tx_hdrs is enabled, allocate a MAX_TCP_HEADER bounce buffer per TX ring slot out of the DMA_PMD arena. When the linear portion of a transmitted packet is at most MAX_TCP_HEADER bytes, copy it into the pre-mapped bounce buffer instead of calling dma_map_single()/dma_unmap_single() on every packet. Signed-off-by: Luigi Rizzo --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 45 ++++++++++++++++++----- drivers/net/ethernet/broadcom/bnxt/bnxt.h | 2 + 2 files changed, 37 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index d7728d0c5b6e6..b9c91eb3aaddd 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -680,13 +680,22 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) length = BNXT_MIN_PKT_SIZE; } - mapping = dma_map_single(&pdev->dev, skb->data, len, DMA_TO_DEVICE); - - if (unlikely(dma_mapping_error(&pdev->dev, mapping))) - goto tx_free; - - dma_unmap_addr_set(tx_buf, mapping, mapping); - dma_unmap_len_set(tx_buf, len, len); + if (txr->tx_hdr_bufs && len + pad <= MAX_TCP_HEADER) { + u32 off = RING_TX(bp, prod) * MAX_TCP_HEADER; + + memcpy(txr->tx_hdr_bufs + off, skb->data, len); + if (pad && !last_frag) + memset(txr->tx_hdr_bufs + off + len, 0, pad); + mapping = txr->tx_hdr_bufs_dma + off; + dma_unmap_len_set(tx_buf, len, 0); + } else { + mapping = dma_map_single(&pdev->dev, skb->data, len, + DMA_TO_DEVICE); + if (unlikely(dma_mapping_error(&pdev->dev, mapping))) + 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); @@ -800,8 +809,9 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) /* start back at beginning and unmap skb */ prod = txr->tx_prod; tx_buf = &txr->tx_buf_ring[RING_TX(bp, prod)]; - 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_unmap_single(&pdev->dev, dma_unmap_addr(tx_buf, mapping), + skb_headlen(skb), DMA_TO_DEVICE); prod = NEXT_TX(prod); /* unmap remaining mapped pages */ @@ -885,7 +895,6 @@ static bool __bnxt_tx_int(struct bnxt *bp, struct bnxt_tx_ring_info *txr, dma_unmap_single(&pdev->dev, dma_addr, dma_len, DMA_TO_DEVICE); } - last = tx_buf->nr_frags; for (j = 0; j < last; j++) { @@ -4111,6 +4120,15 @@ static void bnxt_free_tx_rings(struct bnxt *bp) ring = &txr->tx_ring_struct; + if (txr->tx_hdr_bufs) { + dma_free_coherent(&pdev->dev, + ring->ring_mem.nr_pages * + TX_DESC_CNT * MAX_TCP_HEADER, + txr->tx_hdr_bufs, + txr->tx_hdr_bufs_dma); + txr->tx_hdr_bufs = NULL; + } + bnxt_free_ring(bp, &ring->ring_mem); } } @@ -4181,6 +4199,13 @@ static int bnxt_alloc_tx_rings(struct bnxt *bp) if (rc) return rc; } + if (pdev->dev.dma_pmd_tx_hdrs && i >= bp->tx_nr_rings_xdp) + txr->tx_hdr_bufs = + dma_alloc_coherent(&pdev->dev, + ring->ring_mem.nr_pages * + TX_DESC_CNT * MAX_TCP_HEADER, + &txr->tx_hdr_bufs_dma, + GFP_KERNEL | __GFP_NOWARN); qidx = bp->tc_to_qidx[j]; ring->queue_id = bp->q_info[qidx].queue_id; spin_lock_init(&txr->xdp_tx_lock); diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h index c673b2ce4a0d2..b42bbabc0eb98 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h @@ -1003,6 +1003,8 @@ struct bnxt_tx_ring_info { struct tx_push_buffer *tx_push; dma_addr_t tx_push_mapping; __le64 data_mapping; + void *tx_hdr_bufs; + dma_addr_t tx_hdr_bufs_dma; void *tx_inline_buf; dma_addr_t tx_inline_dma; -- 2.56.0.rc1.315.gc6ed9934b7-goog