sfc: Fix DMA mapping cleanup in case of an error in TSO

commit a7ebd27a13757248863cd61e541af7fa9e7727ee upstream.

We need buffer->len to remain valid to work out the correct address to
be unmapped.  We therefore need to clear buffer->len after the unmap
operation.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c
index 14a14788566c6a4962413eb105f8da6739ea8e77..d36a2894f005fa317579473aff39f50f3ce33163 100644 (file)
--- a/drivers/net/sfc/tx.c
+++ b/drivers/net/sfc/tx.c
@@ -823,8 +823,6 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
                                           tx_queue->efx->type->txd_ring_mask];
                efx_tsoh_free(tx_queue, buffer);
                EFX_BUG_ON_PARANOID(buffer->skb);
-               buffer->len = 0;
-               buffer->continuation = true;
                if (buffer->unmap_len) {
                        unmap_addr = (buffer->dma_addr + buffer->len -
                                      buffer->unmap_len);
@@ -838,6 +836,8 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
                                               PCI_DMA_TODEVICE);
                        buffer->unmap_len = 0;
                }
+               buffer->len = 0;
+               buffer->continuation = true;
        }
 }