ixgbe: Use bool flag to see if the packet unmapping is delayed in HWRSC

We can't use zero magic "bad" value to check if IXGBE_RSC_CB(skb)->dma
is valid. It is only valid in x86/arm/m68k/alpha architectures and in
spark, powerPC and other architectures it should be ~0. As per
Benjamin Herrenschmidt feedback use a bool flag to decide if
the packet unmapping is delayed in hardware RSC till EOP is reached

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 15032c79e003..3fb9f23c7502 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -1160,6 +1160,7 @@ static inline struct sk_buff *ixgbe_transform_rsc_queue(struct sk_buff *skb,
 
 struct ixgbe_rsc_cb {
         dma_addr_t dma;
+        bool delay_unmap;
 };
 
 #define IXGBE_RSC_CB(skb) ((struct ixgbe_rsc_cb *)(skb)->cb)
@@ -1215,7 +1216,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                 if (rx_buffer_info->dma) {
                         if ((adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) &&
                             (!(staterr & IXGBE_RXD_STAT_EOP)) &&
-                                 (!(skb->prev)))
+                                 (!(skb->prev))) {
                                 /*
                                  * When HWRSC is enabled, delay unmapping
                                  * of the first packet. It carries the
@@ -1223,12 +1224,14 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                                  * 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
+                        } else {
                                 dma_unmap_single(&pdev->dev,
-                                                 rx_buffer_info->dma,
+                                                 rx_buffer_info->dma,
                                                  rx_ring->rx_buf_len,
-                                                 DMA_FROM_DEVICE);
+                                                 DMA_FROM_DEVICE);
+                        }
                         rx_buffer_info->dma = 0;
                         skb_put(skb, len);
                 }
@@ -1276,12 +1279,13 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                         if (skb->prev)
                                 skb = ixgbe_transform_rsc_queue(skb, &(rx_ring->rsc_count));
                         if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) {
-                                if (IXGBE_RSC_CB(skb)->dma) {
+                                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);
                                         IXGBE_RSC_CB(skb)->dma = 0;
+                                        IXGBE_RSC_CB(skb)->delay_unmap = false;
                                 }
                                 if (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED)
                                         rx_ring->rsc_count += skb_shinfo(skb)->nr_frags;
@@ -3505,12 +3509,13 @@ static void ixgbe_clean_rx_ring(struct ixgbe_adapter *adapter,
                         rx_buffer_info->skb = NULL;
                         do {
                                 struct sk_buff *this = skb;
-                                if (IXGBE_RSC_CB(this)->dma) {
+                                if (IXGBE_RSC_CB(this)->delay_unmap) {
                                         dma_unmap_single(&pdev->dev,
                                                          IXGBE_RSC_CB(this)->dma,
                                                          rx_ring->rx_buf_len,
                                                          DMA_FROM_DEVICE);
                                         IXGBE_RSC_CB(this)->dma = 0;
+                                        IXGBE_RSC_CB(skb)->delay_unmap = false;
                                 }
                                 skb = skb->prev;
                                 dev_kfree_skb(this);