target/linux/generic/pending-5.15/704-01-v6.4-net-mvneta-fix-transmit-path-dma-unmapping-on-error.patch

   1 From d6d80269cf5c79f9dfe7d69f8b41a72015c89748 Mon Sep 17 00:00:00 2001
   2 From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
   3 Date: Mon, 3 Apr 2023 19:30:20 +0100
   4 Subject: [PATCH 1/5] net: mvneta: fix transmit path dma-unmapping on error
   5
   6 The transmit code assumes that the transmit descriptors that are used
   7 begin with the first descriptor in the ring, but this may not be the
   8 case. Fix this by providing a new function that dma-unmaps a range of
   9 numbered descriptor entries, and use that to do the unmapping.
  10
  11 Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
  12 ---
  13  drivers/net/ethernet/marvell/mvneta.c | 53 +++++++++++++++++----------
  14  1 file changed, 33 insertions(+), 20 deletions(-)
  15
  16 --- a/drivers/net/ethernet/marvell/mvneta.c
  17 +++ b/drivers/net/ethernet/marvell/mvneta.c
  18 @@ -2647,14 +2647,40 @@ mvneta_tso_put_data(struct net_device *d
  19         return 0;
  20  }
  21
  22 +static void mvneta_release_descs(struct mvneta_port *pp,
  23 +                                struct mvneta_tx_queue *txq,
  24 +                                int first, int num)
  25 +{
  26 +       int desc_idx, i;
  27 +
  28 +       desc_idx = first + num;
  29 +       if (desc_idx >= txq->size)
  30 +               desc_idx -= txq->size;
  31 +
  32 +       for (i = num; i >= 0; i--) {
  33 +               struct mvneta_tx_desc *tx_desc = txq->descs + desc_idx;
  34 +
  35 +               if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr))
  36 +                       dma_unmap_single(pp->dev->dev.parent,
  37 +                                        tx_desc->buf_phys_addr,
  38 +                                        tx_desc->data_size,
  39 +                                        DMA_TO_DEVICE);
  40 +
  41 +               mvneta_txq_desc_put(txq);
  42 +
  43 +               if (desc_idx == 0)
  44 +                       desc_idx = txq->size;
  45 +               desc_idx -= 1;
  46 +       }
  47 +}
  48 +
  49  static int mvneta_tx_tso(struct sk_buff *skb, struct net_device *dev,
  50                          struct mvneta_tx_queue *txq)
  51  {
  52         int hdr_len, total_len, data_left;
  53 -       int desc_count = 0;
  54 +       int first_desc, desc_count = 0;
  55         struct mvneta_port *pp = netdev_priv(dev);
  56         struct tso_t tso;
  57 -       int i;
  58
  59         /* Count needed descriptors */
  60         if ((txq->count + tso_count_descs(skb)) >= txq->size)
  61 @@ -2665,6 +2691,8 @@ static int mvneta_tx_tso(struct sk_buff
  62                 return 0;
  63         }
  64
  65 +       first_desc = txq->txq_put_index;
  66 +
  67         /* Initialize the TSO handler, and prepare the first payload */
  68         hdr_len = tso_start(skb, &tso);
  69
  70 @@ -2705,15 +2733,7 @@ err_release:
  71         /* Release all used data descriptors; header descriptors must not
  72          * be DMA-unmapped.
  73          */
  74 -       for (i = desc_count - 1; i >= 0; i--) {
  75 -               struct mvneta_tx_desc *tx_desc = txq->descs + i;
  76 -               if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr))
  77 -                       dma_unmap_single(pp->dev->dev.parent,
  78 -                                        tx_desc->buf_phys_addr,
  79 -                                        tx_desc->data_size,
  80 -                                        DMA_TO_DEVICE);
  81 -               mvneta_txq_desc_put(txq);
  82 -       }
  83 +       mvneta_release_descs(pp, txq, first_desc, desc_count - 1);
  84         return 0;
  85  }
  86
  87 @@ -2723,6 +2743,7 @@ static int mvneta_tx_frag_process(struct
  88  {
  89         struct mvneta_tx_desc *tx_desc;
  90         int i, nr_frags = skb_shinfo(skb)->nr_frags;
  91 +       int first_desc = txq->txq_put_index;
  92
  93         for (i = 0; i < nr_frags; i++) {
  94                 struct mvneta_tx_buf *buf = &txq->buf[txq->txq_put_index];
  95 @@ -2761,15 +2782,7 @@ error:
  96         /* Release all descriptors that were used to map fragments of
  97          * this packet, as well as the corresponding DMA mappings
  98          */
  99 -       for (i = i - 1; i >= 0; i--) {
 100 -               tx_desc = txq->descs + i;
 101 -               dma_unmap_single(pp->dev->dev.parent,
 102 -                                tx_desc->buf_phys_addr,
 103 -                                tx_desc->data_size,
 104 -                                DMA_TO_DEVICE);
 105 -               mvneta_txq_desc_put(txq);
 106 -       }
 107 -
 108 +       mvneta_release_descs(pp, txq, first_desc, i - 1);
 109         return -ENOMEM;
 110  }
 111