ixgbe: Fix Tx map failure path

This patch is a partial revert of "ixgbe: Don't bother clearing buffer
memory for descriptor rings". Specifically I messed up the exception
handling path a bit and this resulted in us incorrectly adding the count
back in when we didn't need to.

In order to make this simpler I am reverting most of the exception handling
path change and instead just replacing the bit that was handled by the
unmap_and_free call.

Fixes: ffed21bcee7a ("ixgbe: Don't bother clearing buffer memory for descriptor rings")
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 6 insertions, 12 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 4d76afd13868..6d5f31e94358 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -8020,29 +8020,23 @@ static int ixgbe_tx_map(struct ixgbe_ring *tx_ring,
         return 0;
 dma_error:
         dev_err(tx_ring->dev, "TX DMA map failed\n");
-        tx_buffer = &tx_ring->tx_buffer_info[i];
 
         /* clear dma mappings for failed tx_buffer_info map */
-        while (tx_buffer != first) {
+        for (;;) {
+                tx_buffer = &tx_ring->tx_buffer_info[i];
                 if (dma_unmap_len(tx_buffer, len))
                         dma_unmap_page(tx_ring->dev,
                                        dma_unmap_addr(tx_buffer, dma),
                                        dma_unmap_len(tx_buffer, len),
                                        DMA_TO_DEVICE);
                 dma_unmap_len_set(tx_buffer, len, 0);
-
-                if (i--)
+                if (tx_buffer == first)
+                        break;
+                if (i == 0)
                         i += tx_ring->count;
-                tx_buffer = &tx_ring->tx_buffer_info[i];
+                i--;
         }
 
-        if (dma_unmap_len(tx_buffer, len))
-                dma_unmap_single(tx_ring->dev,
-                                 dma_unmap_addr(tx_buffer, dma),
-                                 dma_unmap_len(tx_buffer, len),
-                                 DMA_TO_DEVICE);
-        dma_unmap_len_set(tx_buffer, len, 0);
-
         dev_kfree_skb_any(first->skb);
         first->skb = NULL;