From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 61B58315D58 for ; Wed, 13 May 2026 15:04:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778684651; cv=none; b=HnEk6z8fhmombvh+cTMvltJrOiHgrX1KNoVQT7K+vDDaDMDW7qvCCDfH5jJND2zaBT8W/8/GQgUKr+GBYNRsDIHrU31tlqZR7RLVHFpkquxESmBmtC19o8mtRCssCvXqEwdnXR3059mWcNJO39SN2zTDMt+wdpnNLXTo12+V77I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778684651; c=relaxed/simple; bh=iliNH01E0zCiR4ewRpQV15XeBpC7YO/HdMRcKK4W6Pc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=facL3UbGRiND/Gkcgk2rpZMLCa+KNCEAV9IRcaGFnzLrf4tv1c8VdOtVbfB+4v6LdEb9XhlOkt3RYjbkGJNfoaPZK4I7fhPGpNe6GIhi6fgYQfVOzc0Wliag2mmQ67vwUVFunOCmhftmwHAqZfBZdid2uOCbxJHQYcDtPhuZG0g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bjBDGjnb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bjBDGjnb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEDDBC19425; Wed, 13 May 2026 15:04:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778684651; bh=iliNH01E0zCiR4ewRpQV15XeBpC7YO/HdMRcKK4W6Pc=; h=From:Date:Subject:To:Cc:From; b=bjBDGjnbHvLYaOEiG9nuqJk7YEMQb2VQpKoPHXjdQXblqZcdm561Qe/3MuOtCDaZd FKzh1KCl0FBkts3VT4Ks6sJnnoKYOe3ByrO5mKx83nfoN9tTZOgSqXS9CE9B/n3luX Qb4lv/pVLkbf8crrPPNsUQnFnvwJlhUodzxSqAj7l6L+VM+s0O2wjqn2E2Bx7XtZut uikhh8u5QNKm9F00CxrprCmzOSoon4Wu8vkvafONK2ukxs3StgVssSdLXYasSisvpl K9Fj1rBSe2VxTBm36tKU+Dqei+6/lRU5bEbPFlQNPZOqyrFPSKKQYCY+RtTd70IbM7 70tS4jddPVnLQ== From: Lorenzo Bianconi Date: Wed, 13 May 2026 17:03:59 +0200 Subject: [PATCH net-next] net: airoha: Reserve RX headroom to avoid skb reallocation Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260513-airoha-rx-headroom-v1-1-bd87798e422d@kernel.org> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/x3MQQqEMAxA0atI1hNonSp1rjLMIthos7AdUpGCe HeLy7f4/4TCKlzg052gfEiRnBrsq4M5UloZJTRDb/rRDPaNJJojoVaMTEFz3tAFO83knSfroIV /5UXqM/1C4h0T1x1+13UDkkWbjm4AAAA= X-Change-ID: 20260513-airoha-rx-headroom-4d19ca848a14 To: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Lorenzo Bianconi Cc: linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, netdev@vger.kernel.org, Xuegang Lu X-Mailer: b4 0.14.3 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 Signed-off-by: Lorenzo Bianconi --- drivers/net/ethernet/airoha/airoha_eth.c | 14 ++++++++------ drivers/net/ethernet/airoha/airoha_eth.h | 2 ++ 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c index f71fb18197ec..5a027cc7ffcb 100644 --- a/drivers/net/ethernet/airoha/airoha_eth.c +++ b/drivers/net/ethernet/airoha/airoha_eth.c @@ -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; diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h index 58530d096de7..d3781103abb5 100644 --- a/drivers/net/ethernet/airoha/airoha_eth.h +++ b/drivers/net/ethernet/airoha/airoha_eth.h @@ -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 --- base-commit: 8ebd24a7822cbae25beeafba49b2159d6a68a5f2 change-id: 20260513-airoha-rx-headroom-4d19ca848a14 Best regards, -- Lorenzo Bianconi