ixgbe: split Tx/Rx ring clearing for ethtool loopback test

Commit: fed21bcee7a5
("ixgbe: Don't bother clearing buffer memory for descriptor rings)

exposed some issues with the logic in the current implementation of
ixgbe_clean_test_rings() that are being addressed in this patch:

- Split the clearing of the Tx and Rx rings in separate loops. Previously
both Tx and Rx rings were cleared in a rx_desc->wb.upper.length based
loop which could lead to issues if for w/e reason packets were received
outside of the frames transmitted for the loopback test.

- Add check for IXGBE_TXD_STAT_DD to avoid clearing the rings if the
transmits have not comlpeted by the time we enter ixgbe_clean_test_rings()

- Exit early on ixgbe_check_lbtest_frame() failure.

This change fixes a crash during ethtool diagnostic (ethtool -t).

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index 72c5657..6d89f28 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -1916,8 +1916,6 @@ static u16 ixgbe_clean_test_rings(struct ixgbe_ring *rx_ring,
                                  unsigned int size)
 {
        union ixgbe_adv_rx_desc *rx_desc;
-       struct ixgbe_rx_buffer *rx_buffer;
-       struct ixgbe_tx_buffer *tx_buffer;
        u16 rx_ntc, tx_ntc, count = 0;
 
        /* initialize next to clean and descriptor values */
@@ -1925,7 +1923,38 @@ static u16 ixgbe_clean_test_rings(struct ixgbe_ring *rx_ring,
        tx_ntc = tx_ring->next_to_clean;
        rx_desc = IXGBE_RX_DESC(rx_ring, rx_ntc);
 
+       while (tx_ntc != tx_ring->next_to_use) {
+               union ixgbe_adv_tx_desc *tx_desc;
+               struct ixgbe_tx_buffer *tx_buffer;
+
+               tx_desc = IXGBE_TX_DESC(tx_ring, tx_ntc);
+
+               /* if DD is not set transmit has not completed */
+               if (!(tx_desc->wb.status & cpu_to_le32(IXGBE_TXD_STAT_DD)))
+                       return count;
+
+               /* unmap buffer on Tx side */
+               tx_buffer = &tx_ring->tx_buffer_info[tx_ntc];
+
+               /* Free all the Tx ring sk_buffs */
+               dev_kfree_skb_any(tx_buffer->skb);
+
+               /* unmap skb header data */
+               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);
+
+               /* increment Tx next to clean counter */
+               tx_ntc++;
+               if (tx_ntc == tx_ring->count)
+                       tx_ntc = 0;
+       }
+
        while (rx_desc->wb.upper.length) {
+               struct ixgbe_rx_buffer *rx_buffer;
+
                /* check Rx buffer */
                rx_buffer = &rx_ring->rx_buffer_info[rx_ntc];
 
@@ -1938,6 +1967,8 @@ static u16 ixgbe_clean_test_rings(struct ixgbe_ring *rx_ring,
                /* verify contents of skb */
                if (ixgbe_check_lbtest_frame(rx_buffer, size))
                        count++;
+               else
+                       break;
 
                /* sync Rx buffer for device write */
                dma_sync_single_for_device(rx_ring->dev,
@@ -1945,26 +1976,10 @@ static u16 ixgbe_clean_test_rings(struct ixgbe_ring *rx_ring,
                                           ixgbe_rx_bufsz(rx_ring),
                                           DMA_FROM_DEVICE);
 
-               /* unmap buffer on Tx side */
-               tx_buffer = &tx_ring->tx_buffer_info[tx_ntc];
-
-               /* Free all the Tx ring sk_buffs */
-               dev_kfree_skb_any(tx_buffer->skb);
-
-               /* unmap skb header data */
-               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);
-
-               /* increment Rx/Tx next to clean counters */
+               /* increment Rx next to clean counter */
                rx_ntc++;
                if (rx_ntc == rx_ring->count)
                        rx_ntc = 0;
-               tx_ntc++;
-               if (tx_ntc == tx_ring->count)
-                       tx_ntc = 0;
 
                /* fetch next descriptor */
                rx_desc = IXGBE_RX_DESC(rx_ring, rx_ntc);