[net] ixgbe: simplify padding and length checks

From: Stephen Hemminger <redacted>

The check for length <= 0 is bogus because length is unsigned, and network
stack never sends zero length packets (unless it is totally broken).

The check for really small packets can be optimized (using unlikely)
and calling skb_pad directly.

Signed-off-by: Stephen Hemminger <redacted>
Tested-by: Phil Schmitt <redacted>
Signed-off-by: Jeff Kirsher <redacted>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index cbb05d6..9afe0cb 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -6383,17 +6383,12 @@ static netdev_tx_t ixgbe_xmit_frame(struct sk_buff *skb,
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 	struct ixgbe_ring *tx_ring;
 
-	if (skb->len <= 0) {
-		dev_kfree_skb_any(skb);
-		return NETDEV_TX_OK;
-	}
-
 	/*
 	 * The minimum packet size for olinfo paylen is 17 so pad the skb
 	 * in order to meet this minimum size requirement.
 	 */
-	if (skb->len < 17) {
-		if (skb_padto(skb, 17))
+	if (unlikely(skb->len < 17)) {
+		if (skb_pad(skb, 17 - skb->len))
 			return NETDEV_TX_OK;
 		skb->len = 17;
 	}

-- 
1.7.10.2

From: Jeff Kirsher <redacted>
Date: Thu, 21 Jun 2012 05:15:10 -0700

From: Stephen Hemminger <redacted>

The check for length <= 0 is bogus because length is unsigned, and network
stack never sends zero length packets (unless it is totally broken).

The check for really small packets can be optimized (using unlikely)
and calling skb_pad directly.

Signed-off-by: Stephen Hemminger <redacted>
Tested-by: Phil Schmitt <redacted>
Signed-off-by: Jeff Kirsher <redacted>

Not really fixing anything and more of a cleanup, so maybe 'net-next'
instead of 'net' for this guy instead?

On Thu, 2012-06-21 at 13:38 -0700, David Miller wrote:

From: Jeff Kirsher <redacted>
Date: Thu, 21 Jun 2012 05:15:10 -0700

quoted

From: Stephen Hemminger <redacted>

The check for length <= 0 is bogus because length is unsigned, and network
stack never sends zero length packets (unless it is totally broken).

The check for really small packets can be optimized (using unlikely)
and calling skb_pad directly.

Signed-off-by: Stephen Hemminger <redacted>
Tested-by: Phil Schmitt <redacted>
Signed-off-by: Jeff Kirsher <redacted>

Not really fixing anything and more of a cleanup, so maybe 'net-next'
instead of 'net' for this guy instead?

Yeah, net-next is fine.  I just verified that the patch applies cleanly
to net-next as well.

From: Jeff Kirsher <redacted>
Date: Thu, 21 Jun 2012 14:28:09 -0700

On Thu, 2012-06-21 at 13:38 -0700, David Miller wrote:

quoted

From: Jeff Kirsher <redacted>
Date: Thu, 21 Jun 2012 05:15:10 -0700

quoted

From: Stephen Hemminger <redacted>

The check for length <= 0 is bogus because length is unsigned, and network
stack never sends zero length packets (unless it is totally broken).

The check for really small packets can be optimized (using unlikely)
and calling skb_pad directly.

Signed-off-by: Stephen Hemminger <redacted>
Tested-by: Phil Schmitt <redacted>
Signed-off-by: Jeff Kirsher <redacted>

Not really fixing anything and more of a cleanup, so maybe 'net-next'
instead of 'net' for this guy instead?

Yeah, net-next is fine.  I just verified that the patch applies cleanly
to net-next as well.

Great, applied, thanks.