Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754352Ab0LAHq5 (ORCPT ); Wed, 1 Dec 2010 02:46:57 -0500 Received: from mga02.intel.com ([134.134.136.20]:46558 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754206Ab0LAHqx (ORCPT ); Wed, 1 Dec 2010 02:46:53 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,282,1288594800"; d="scan'208";a="682672469" From: xiaohui.xin@intel.com To: netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, mingo@elte.hu, davem@davemloft.net, herbert@gondor.hengli.com.au, jdike@linux.intel.com Cc: Xin Xiaohui Subject: [PATCH v16 16/17]An example how to modifiy NIC driver to use napi_gro_frags() interface Date: Wed, 1 Dec 2010 16:08:27 +0800 Message-Id: <4caf4ea3c444ad5ef346e7c9fb36192c72db8c3a.1291187695.git.xiaohui.xin@intel.com> X-Mailer: git-send-email 1.7.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10496 Lines: 310 From: Xin Xiaohui This example is made on ixgbe driver. It provides API is_rx_buffer_mapped_as_page() to indicate if the driver use napi_gro_frags() interface or not. The example allocates 2 pages for DMA for one ring descriptor using netdev_alloc_page(). When packets is coming, using napi_gro_frags() to allocate skb and to receive the packets. Signed-off-by: Xin Xiaohui --- drivers/net/ixgbe/ixgbe.h | 3 + drivers/net/ixgbe/ixgbe_main.c | 169 +++++++++++++++++++++++++++++++-------- 2 files changed, 137 insertions(+), 35 deletions(-) diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h index 9e15eb9..89367ca 100644 --- a/drivers/net/ixgbe/ixgbe.h +++ b/drivers/net/ixgbe/ixgbe.h @@ -131,6 +131,9 @@ struct ixgbe_rx_buffer { struct page *page; dma_addr_t page_dma; unsigned int page_offset; + u16 mapped_as_page; + struct page *page_skb; + unsigned int page_skb_offset; }; struct ixgbe_queue_stats { diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c index e32af43..cd69080 100644 --- a/drivers/net/ixgbe/ixgbe_main.c +++ b/drivers/net/ixgbe/ixgbe_main.c @@ -1029,6 +1029,12 @@ static inline void ixgbe_release_rx_desc(struct ixgbe_hw *hw, IXGBE_WRITE_REG(hw, IXGBE_RDT(rx_ring->reg_idx), val); } +static bool is_rx_buffer_mapped_as_page(struct ixgbe_rx_buffer *bi, + struct net_device *dev) +{ + return true; +} + /** * ixgbe_alloc_rx_buffers - Replace used receive buffers; packet split * @adapter: address of board private structure @@ -1045,13 +1051,17 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter, i = rx_ring->next_to_use; bi = &rx_ring->rx_buffer_info[i]; + while (cleaned_count--) { rx_desc = IXGBE_RX_DESC_ADV(*rx_ring, i); + bi->mapped_as_page = + is_rx_buffer_mapped_as_page(bi, adapter->netdev); + if (!bi->page_dma && (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED)) { if (!bi->page) { - bi->page = alloc_page(GFP_ATOMIC); + bi->page = netdev_alloc_page(adapter->netdev); if (!bi->page) { adapter->alloc_rx_page_failed++; goto no_buffers; @@ -1068,7 +1078,7 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter, DMA_FROM_DEVICE); } - if (!bi->skb) { + if (!bi->mapped_as_page && !bi->skb) { struct sk_buff *skb; /* netdev_alloc_skb reserves 32 bytes up front!! */ uint bufsz = rx_ring->rx_buf_len + SMP_CACHE_BYTES; @@ -1088,6 +1098,19 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter, rx_ring->rx_buf_len, DMA_FROM_DEVICE); } + + if (bi->mapped_as_page && !bi->page_skb) { + bi->page_skb = netdev_alloc_page(adapter->netdev); + if (!bi->page_skb) { + adapter->alloc_rx_page_failed++; + goto no_buffers; + } + bi->page_skb_offset = 0; + bi->dma = dma_map_page(&pdev->dev, bi->page_skb, + bi->page_skb_offset, + (PAGE_SIZE / 2), + PCI_DMA_FROMDEVICE); + } /* Refresh the desc even if buffer_addrs didn't change because * each write-back erases this info. */ if (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED) { @@ -1165,6 +1188,13 @@ struct ixgbe_rsc_cb { bool delay_unmap; }; +static bool is_no_buffer(struct ixgbe_rx_buffer *rx_buffer_info) +{ + return (!rx_buffer_info->skb || + !rx_buffer_info->page_skb) && + !rx_buffer_info->page; +} + #define IXGBE_RSC_CB(skb) ((struct ixgbe_rsc_cb *)(skb)->cb) static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, @@ -1174,6 +1204,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, struct ixgbe_adapter *adapter = q_vector->adapter; struct net_device *netdev = adapter->netdev; struct pci_dev *pdev = adapter->pdev; + struct napi_struct *napi = &q_vector->napi; union ixgbe_adv_rx_desc *rx_desc, *next_rxd; struct ixgbe_rx_buffer *rx_buffer_info, *next_buffer; struct sk_buff *skb; @@ -1211,32 +1242,74 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, len = le16_to_cpu(rx_desc->wb.upper.length); } + if (is_no_buffer(rx_buffer_info)) + break; cleaned = true; - skb = rx_buffer_info->skb; - prefetch(skb->data); - rx_buffer_info->skb = NULL; - if (rx_buffer_info->dma) { - if ((adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) && - (!(staterr & IXGBE_RXD_STAT_EOP)) && - (!(skb->prev))) { - /* - * When HWRSC is enabled, delay unmapping - * of the first packet. It carries the - * header information, HW may still - * access the header after the writeback. - * Only unmap it when EOP is reached - */ - IXGBE_RSC_CB(skb)->delay_unmap = true; - IXGBE_RSC_CB(skb)->dma = rx_buffer_info->dma; - } else { - dma_unmap_single(&pdev->dev, - rx_buffer_info->dma, - rx_ring->rx_buf_len, - DMA_FROM_DEVICE); + if (!rx_buffer_info->mapped_as_page) { + skb = rx_buffer_info->skb; + prefetch(skb->data); + rx_buffer_info->skb = NULL; + + if (rx_buffer_info->dma) { + if ((adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) && + (!(staterr & IXGBE_RXD_STAT_EOP)) && + (!(skb->prev))) { + /* + * When HWRSC is enabled, delay unmapping + * of the first packet. It carries the + * header information, HW may still + * access the header after the writeback. + * Only unmap it when EOP is reached + */ + IXGBE_RSC_CB(skb)->delay_unmap = true; + IXGBE_RSC_CB(skb)->dma = rx_buffer_info->dma; + } else + dma_unmap_single(&pdev->dev, + rx_buffer_info->dma, + rx_ring->rx_buf_len, + DMA_FROM_DEVICE); + rx_buffer_info->dma = 0; + skb_put(skb, len); + } + } else { + if (!rx_buffer_info->skb && rx_buffer_info->page_skb) { + napi->skb = NULL; + skb = napi_get_frags(napi); + } else { + skb = rx_buffer_info->skb; + napi->skb = skb; + } + prefetch(rx_buffer_info->page_skb_offset); + rx_buffer_info->skb = NULL; + if (rx_buffer_info->dma) { + if ((adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) && + (!(staterr & IXGBE_RXD_STAT_EOP)) && + (!(skb->prev))) { + /* + * When HWRSC is enabled, delay unmapping + * of the first packet. It carries the + * header information, HW may still + * access the header after the writeback. + * Only unmap it when EOP is reached + */ + IXGBE_RSC_CB(skb)->delay_unmap = true; + IXGBE_RSC_CB(skb)->dma = rx_buffer_info->dma; + } else + dma_unmap_page(&pdev->dev, rx_buffer_info->dma, + PAGE_SIZE / 2, + PCI_DMA_FROMDEVICE); + rx_buffer_info->dma = 0; + skb_fill_page_desc(skb, + skb_shinfo(skb)->nr_frags, + rx_buffer_info->page_skb, + rx_buffer_info->page_skb_offset, + len); + rx_buffer_info->page_skb = NULL; + skb->len += len; + skb->data_len += len; + skb->truesize += len; } - rx_buffer_info->dma = 0; - skb_put(skb, len); } if (upper_len) { @@ -1283,10 +1356,16 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, skb = ixgbe_transform_rsc_queue(skb, &(rx_ring->rsc_count)); if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) { if (IXGBE_RSC_CB(skb)->delay_unmap) { - dma_unmap_single(&pdev->dev, - IXGBE_RSC_CB(skb)->dma, - rx_ring->rx_buf_len, - DMA_FROM_DEVICE); + if (!rx_buffer_info->mapped_as_page) + dma_unmap_single(&pdev->dev, + IXGBE_RSC_CB(skb)->dma, + rx_ring->rx_buf_len, + DMA_FROM_DEVICE); + else + dma_unmap_page(&pdev->dev, + IXGBE_RSC_CB(skb)->dma, + PAGE_SIZE / 2, + DMA_FROM_DEVICE); IXGBE_RSC_CB(skb)->dma = 0; IXGBE_RSC_CB(skb)->delay_unmap = false; } @@ -1304,6 +1383,11 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, rx_buffer_info->dma = next_buffer->dma; next_buffer->skb = skb; next_buffer->dma = 0; + if (rx_buffer_info->mapped_as_page) { + rx_buffer_info->page_skb = + next_buffer->page_skb; + next_buffer->page_skb = NULL; + } } else { skb->next = next_buffer->skb; skb->next->prev = skb; @@ -1323,7 +1407,8 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, total_rx_bytes += skb->len; total_rx_packets++; - skb->protocol = eth_type_trans(skb, adapter->netdev); + if (!rx_buffer_info->mapped_as_page) + skb->protocol = eth_type_trans(skb, adapter->netdev); #ifdef IXGBE_FCOE /* if ddp, not passing to ULD unless for FCP_RSP or error */ if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) { @@ -1332,7 +1417,14 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, goto next_desc; } #endif /* IXGBE_FCOE */ - ixgbe_receive_skb(q_vector, skb, staterr, rx_ring, rx_desc); + + if (!rx_buffer_info->mapped_as_page) + ixgbe_receive_skb(q_vector, skb, staterr, + rx_ring, rx_desc); + else { + skb_record_rx_queue(skb, rx_ring->queue_index); + napi_gro_frags(napi); + } next_desc: rx_desc->wb.upper.status_error = 0; @@ -3622,9 +3714,16 @@ static void ixgbe_clean_rx_ring(struct ixgbe_adapter *adapter, rx_buffer_info = &rx_ring->rx_buffer_info[i]; if (rx_buffer_info->dma) { - dma_unmap_single(&pdev->dev, rx_buffer_info->dma, - rx_ring->rx_buf_len, - DMA_FROM_DEVICE); + if (!rx_buffer_info->mapped_as_page) + dma_unmap_single(&pdev->dev, rx_buffer_info->dma, + rx_ring->rx_buf_len, + PCI_DMA_FROMDEVICE); + else { + dma_unmap_page(&pdev->dev, rx_buffer_info->dma, + PAGE_SIZE / 2, + PCI_DMA_FROMDEVICE); + rx_buffer_info->page_skb = NULL; + } rx_buffer_info->dma = 0; } if (rx_buffer_info->skb) { @@ -3651,7 +3750,7 @@ static void ixgbe_clean_rx_ring(struct ixgbe_adapter *adapter, PAGE_SIZE / 2, DMA_FROM_DEVICE); rx_buffer_info->page_dma = 0; } - put_page(rx_buffer_info->page); + netdev_free_page(adapter->netdev, rx_buffer_info->page); rx_buffer_info->page = NULL; rx_buffer_info->page_offset = 0; } -- 1.7.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/