[PATCH v11 16/17]An example how to alloc user buffer based on napi_gro_frags() interface.

[xiaohui . xin]

From: Xin Xiaohui <xiaohui....@intel.com>

This example is made on ixgbe driver which using napi_gro_frags().
It can get buffers from guest side directly using netdev_alloc_page()
and release guest buffers using netdev_free_page().

---
 drivers/net/ixgbe/ixgbe_main.c |   25 +++++++++++++++++++++----
 1 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 905d6d2..0977f2f 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -691,7 +691,14 @@ static inline void ixgbe_release_rx_desc(struct ixgbe_hw 
*hw,
 static bool is_rx_buffer_mapped_as_page(struct ixgbe_rx_buffer *bi,
                                        struct net_device *dev)
 {
-       return true;
+       return dev_is_mpassthru(dev);
+}
+
+static u32 get_page_skb_offset(struct net_device *dev)
+{
+       if (!dev_is_mpassthru(dev))
+               return 0;
+       return dev->mp_port->vnet_hlen;
 }
 
 /**
@@ -764,7 +771,8 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter 
*adapter,
                                adapter->alloc_rx_page_failed++;
                                goto no_buffers;
                        }
-                       bi->page_skb_offset = 0;
+                       bi->page_skb_offset =
+                               get_page_skb_offset(adapter->netdev);
                        bi->dma = pci_map_page(pdev, bi->page_skb,
                                        bi->page_skb_offset,
                                        (PAGE_SIZE / 2),
@@ -899,8 +907,10 @@ 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))
+               if (is_no_buffer(rx_buffer_info)) {
+                       printk("no buffers\n");
                        break;
+               }
 
                cleaned = true;
 
@@ -959,6 +969,12 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector 
*q_vector,
                                                rx_buffer_info->page_skb,
                                                rx_buffer_info->page_skb_offset,
                                                len);
+                               if (dev_is_mpassthru(netdev) &&
+                                               netdev->mp_port->hash)
+                                       skb_shinfo(skb)->destructor_arg =
+                                       netdev->mp_port->hash(netdev,
+                                       rx_buffer_info->page_skb);
+
                                rx_buffer_info->page_skb = NULL;
                                skb->len += len;
                                skb->data_len += len;
@@ -976,7 +992,8 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector 
*q_vector,
                                           upper_len);
 
                        if ((rx_ring->rx_buf_len > (PAGE_SIZE / 2)) ||
-                           (page_count(rx_buffer_info->page) != 1))
+                           (page_count(rx_buffer_info->page) != 1) ||
+                               dev_is_mpassthru(netdev))
                                rx_buffer_info->page = NULL;
                        else
                                get_page(rx_buffer_info->page);
-- 
1.7.3

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