Commit f35a1df8 authored by P33M's avatar P33M Committed by Phil Elwell
Browse files

Revert "smsc95xx: dynamically fix up TX buffer alignment with padding bytes" 

As reported in https://github.com/raspberrypi/linux/issues/2964 this
commit causes a regression corrupting non-option TCP ack packets.

This reverts commit 96b972dc.
parent 43f2cb3b

drivers/net/usb/smsc95xx.c

+5 −7
Original line number Diff line number Diff line
@@ -2082,9 +2082,7 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev, 
					 struct sk_buff *skb, gfp_t flags)

{

	bool csum = skb->ip_summed == CHECKSUM_PARTIAL;

	unsigned int align_bytes = -((uintptr_t)skb->data) & 0x3;

	int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM + align_bytes

				: SMSC95XX_TX_OVERHEAD + align_bytes;

	int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;

	u32 tx_cmd_a, tx_cmd_b;



	/* We do not advertise SG, so skbs should be already linearized */
@@ -2118,16 +2116,16 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev, 
		}

	}



	skb_push(skb, 4 + align_bytes);

	tx_cmd_b = (u32)(skb->len - 4 - align_bytes);

	skb_push(skb, 4);

	tx_cmd_b = (u32)(skb->len - 4);

	if (csum)

		tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;

	cpu_to_le32s(&tx_cmd_b);

	memcpy(skb->data, &tx_cmd_b, 4);



	skb_push(skb, 4);

	tx_cmd_a = (u32)(skb->len - 8 - align_bytes) | TX_CMD_A_FIRST_SEG_ |

		(align_bytes << 16) | TX_CMD_A_LAST_SEG_;

	tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |

		TX_CMD_A_LAST_SEG_;

	cpu_to_le32s(&tx_cmd_a);

	memcpy(skb->data, &tx_cmd_a, 4);

drivers/net/usb/smsc95xx.h

+1 −1
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ 
#define _SMSC95XX_H



/* Tx command words */

#define TX_CMD_A_DATA_OFFSET_	(0x00030000)	/* Data Start Offset */

#define TX_CMD_A_DATA_OFFSET_	(0x001F0000)	/* Data Start Offset */

#define TX_CMD_A_FIRST_SEG_	(0x00002000)	/* First Segment */

#define TX_CMD_A_LAST_SEG_	(0x00001000)	/* Last Segment */

#define TX_CMD_A_BUF_SIZE_	(0x000007FF)	/* Buffer Size */