Upon encountering a DMA_MAPPING_ERROR during skb allocation and mapping, the driver would leave DMA_MAPPING_ERROR in the buffer_info->dma field. This would lead several buffer_info->dma == 0 conditions down unwanted paths:
* In e1000_alloc_jumbo_rx_buffers(), it would not re-attempt the failed mapping and instead write DMA_MAPPING_ERROR to the h/w descriptor on the next allocation call. On cleaning or teardown it would attempt to dma_unmap_page() DMA_MAPPING_ERROR. This case would only be reachable at MTU > 1518 and page size > 16K. * In e1000_clean_rx_ring(), it would attempt to dma_unmap_page/single() DMA_MAPPING_ERROR (unless cleaned by the jumbo path first). This case would be reachable at any combination of MTU and page size. Use buffer_info->dma = 0 as the sentinel for "DMA is not mapped." Set it immediately upon detecting the failure. The map error value was 0 on some platforms (including most common x86) until error values were unified to DMA_MAPPING_ERROR in v4.20/v5.0. Since then the error handling in this driver has been incorrect on all platforms. Signed-off-by: Matt Vollrath <[email protected]> Suggested-by: Jakub Kicinski <[email protected]> Fixes: bc7f75fa9788 ("[E1000E]: New pci-express e1000 driver (currently for ICH9 devices only)") Cc: [email protected] --- v2: * Add history blurb to description. --- drivers/net/ethernet/intel/e1000e/netdev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 844f31ab37ad..26f45ee8c7e7 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -691,6 +691,7 @@ static void e1000_alloc_rx_buffers(struct e1000_ring *rx_ring, adapter->rx_buffer_len, DMA_FROM_DEVICE); if (dma_mapping_error(&pdev->dev, buffer_info->dma)) { + buffer_info->dma = 0; dev_err(&pdev->dev, "Rx DMA map failed\n"); adapter->rx_dma_failed++; break; @@ -791,6 +792,7 @@ static void e1000_alloc_rx_buffers_ps(struct e1000_ring *rx_ring, adapter->rx_ps_bsize0, DMA_FROM_DEVICE); if (dma_mapping_error(&pdev->dev, buffer_info->dma)) { + buffer_info->dma = 0; dev_err(&pdev->dev, "Rx DMA map failed\n"); adapter->rx_dma_failed++; /* cleanup skb */ @@ -877,6 +879,7 @@ static void e1000_alloc_jumbo_rx_buffers(struct e1000_ring *rx_ring, PAGE_SIZE, DMA_FROM_DEVICE); if (dma_mapping_error(&pdev->dev, buffer_info->dma)) { + buffer_info->dma = 0; adapter->alloc_rx_buff_failed++; break; } base-commit: 78445023439506ebd83b86d40b1e428a3b309d4a -- 2.43.0
