From 0c8b26556c6f6abf84bca67ce2c2e010953bba81 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Wed, 14 Nov 2018 11:50:20 +0000 Subject: [PATCH] usbnet: smsc95xx: simplify tx_fixup code The smsc95xx_tx_fixup is doing multiple calls to skb_push() to put an 8-byte command header onto the packet. It would be easier to do one skb_push() and then copy the data in once the push is done. We also make the code smaller by using proper unaligned puts for the header. This merges in the CPU to LE32 conversion as well and makes the whole sequence easier to understand hopefully. Signed-off-by: Ben Dooks Signed-off-by: David S. Miller --- drivers/net/usb/smsc95xx.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index 6e971628bb50..924ca94d3495 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -2018,6 +2018,7 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev, bool csum = skb->ip_summed == CHECKSUM_PARTIAL; int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD; u32 tx_cmd_a, tx_cmd_b; + void *ptr; /* We do not advertise SG, so skbs should be already linearized */ BUG_ON(skb_shinfo(skb)->nr_frags); @@ -2031,6 +2032,9 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev, return NULL; } + tx_cmd_b = (u32)skb->len; + tx_cmd_a = tx_cmd_b | TX_CMD_A_FIRST_SEG_ | TX_CMD_A_LAST_SEG_; + if (csum) { if (skb->len <= 45) { /* workaround - hardware tx checksum does not work @@ -2044,24 +2048,18 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev, csum = false; } else { u32 csum_preamble = smsc95xx_calc_csum_preamble(skb); - skb_push(skb, 4); - cpu_to_le32s(&csum_preamble); - memcpy(skb->data, &csum_preamble, 4); + ptr = skb_push(skb, 4); + put_unaligned_le32(csum_preamble, ptr); + + tx_cmd_a += 4; + tx_cmd_b += 4; + tx_cmd_b |= TX_CMD_B_CSUM_ENABLE; } } - 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) | TX_CMD_A_FIRST_SEG_ | - TX_CMD_A_LAST_SEG_; - cpu_to_le32s(&tx_cmd_a); - memcpy(skb->data, &tx_cmd_a, 4); + ptr = skb_push(skb, 8); + put_unaligned_le32(tx_cmd_a, ptr); + put_unaligned_le32(tx_cmd_b, ptr+4); return skb; } -- 2.30.2