target/linux/brcm2708/patches-4.19/950-0497-Revert-smsc95xx-dynamically-fix-up-TX-buffer-alignme.patch

   1 From fb13c1342c81bb0c06afdcfe1e8561e8a6e149d7 Mon Sep 17 00:00:00 2001
   2 From: P33M <p33m@github.com>
   3 Date: Tue, 14 May 2019 14:55:19 +0100
   4 Subject: [PATCH 497/703] Revert "smsc95xx: dynamically fix up TX buffer
   5  alignment with padding bytes"
   6
   7 As reported in https://github.com/raspberrypi/linux/issues/2964 this
   8 commit causes a regression corrupting non-option TCP ack packets.
   9
  10 This reverts commit 96b972dc736d943f371a16ccca452a053d83c65b.
  11 ---
  12  drivers/net/usb/smsc95xx.c | 12 +++++-------
  13  drivers/net/usb/smsc95xx.h |  2 +-
  14  2 files changed, 6 insertions(+), 8 deletions(-)
  15
  16 --- a/drivers/net/usb/smsc95xx.c
  17 +++ b/drivers/net/usb/smsc95xx.c
  18 @@ -2082,9 +2082,7 @@ static struct sk_buff *smsc95xx_tx_fixup
  19                                          struct sk_buff *skb, gfp_t flags)
  20  {
  21         bool csum = skb->ip_summed == CHECKSUM_PARTIAL;
  22 -       unsigned int align_bytes = -((uintptr_t)skb->data) & 0x3;
  23 -       int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM + align_bytes
  24 -                               : SMSC95XX_TX_OVERHEAD + align_bytes;
  25 +       int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
  26         u32 tx_cmd_a, tx_cmd_b;
  27
  28         /* We do not advertise SG, so skbs should be already linearized */
  29 @@ -2118,16 +2116,16 @@ static struct sk_buff *smsc95xx_tx_fixup
  30                 }
  31         }
  32
  33 -       skb_push(skb, 4 + align_bytes);
  34 -       tx_cmd_b = (u32)(skb->len - 4 - align_bytes);
  35 +       skb_push(skb, 4);
  36 +       tx_cmd_b = (u32)(skb->len - 4);
  37         if (csum)
  38                 tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
  39         cpu_to_le32s(&tx_cmd_b);
  40         memcpy(skb->data, &tx_cmd_b, 4);
  41
  42         skb_push(skb, 4);
  43 -       tx_cmd_a = (u32)(skb->len - 8 - align_bytes) | TX_CMD_A_FIRST_SEG_ |
  44 -               (align_bytes << 16) | TX_CMD_A_LAST_SEG_;
  45 +       tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |
  46 +               TX_CMD_A_LAST_SEG_;
  47         cpu_to_le32s(&tx_cmd_a);
  48         memcpy(skb->data, &tx_cmd_a, 4);
  49
  50 --- a/drivers/net/usb/smsc95xx.h
  51 +++ b/drivers/net/usb/smsc95xx.h
  52 @@ -21,7 +21,7 @@
  53  #define _SMSC95XX_H
  54
  55  /* Tx command words */
  56 -#define TX_CMD_A_DATA_OFFSET_  (0x00030000)    /* Data Start Offset */
  57 +#define TX_CMD_A_DATA_OFFSET_  (0x001F0000)    /* Data Start Offset */
  58  #define TX_CMD_A_FIRST_SEG_    (0x00002000)    /* First Segment */
  59  #define TX_CMD_A_LAST_SEG_     (0x00001000)    /* Last Segment */
  60  #define TX_CMD_A_BUF_SIZE_     (0x000007FF)    /* Buffer Size */