Patchwork [net-next,09/13] igb: Pull adapter out of main path in igb_xmit_frame_ring

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Submitter Jeff Kirsher
Date April 4, 2013, 11:37 a.m.
Message ID <1365075480-20183-10-git-send-email-jeffrey.t.kirsher@intel.com>
Download mbox | patch
Permalink /patch/233725/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Jeff Kirsher - April 4, 2013, 11:37 a.m.
From: Alexander Duyck <alexander.h.duyck@intel.com>

We only need the adapter pointer in the case of ptp.  As such we can pull the
adapter out of the main path and place it inside the if statement to avoid
the temptation of accessing the adapter pointer in the fast path.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)
Sergei Shtylyov - April 4, 2013, 2:15 p.m.
Hello.

On 04-04-2013 15:37, Jeff Kirsher wrote:

> From: Alexander Duyck <alexander.h.duyck@intel.com>

> We only need the adapter pointer in the case of ptp.  As such we can pull the
> adapter out of the main path and place it inside the if statement to avoid
> the temptation of accessing the adapter pointer in the fast path.

> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> Tested-by: Aaron Brown <aaron.f.brown@intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

   Two minor nits.

> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index 29facb5..6043245 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
[...]
> @@ -4628,15 +4627,17 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
>
>   	skb_tx_timestamp(skb);
>
> -	if (unlikely((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
> -		     !(adapter->ptp_tx_skb))) {
> -		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
> -		tx_flags |= IGB_TX_FLAGS_TSTAMP;
> +	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
> +		struct igb_adapter *adapter = netdev_priv(tx_ring->netdev);

    An empty line wouldn't hurt here.

> +		if (!(adapter->ptp_tx_skb)) {

    Parens not needed here.

WBR, Sergei

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Patch

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 29facb5..6043245 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4593,7 +4593,6 @@  static inline int igb_maybe_stop_tx(struct igb_ring *tx_ring, const u16 size)
 netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 				struct igb_ring *tx_ring)
 {
-	struct igb_adapter *adapter = netdev_priv(tx_ring->netdev);
 	struct igb_tx_buffer *first;
 	int tso;
 	u32 tx_flags = 0;
@@ -4628,15 +4627,17 @@  netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 
 	skb_tx_timestamp(skb);
 
-	if (unlikely((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
-		     !(adapter->ptp_tx_skb))) {
-		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
-		tx_flags |= IGB_TX_FLAGS_TSTAMP;
+	if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
+		struct igb_adapter *adapter = netdev_priv(tx_ring->netdev);
+		if (!(adapter->ptp_tx_skb)) {
+			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
+			tx_flags |= IGB_TX_FLAGS_TSTAMP;
 
-		adapter->ptp_tx_skb = skb_get(skb);
-		adapter->ptp_tx_start = jiffies;
-		if (adapter->hw.mac.type == e1000_82576)
-			schedule_work(&adapter->ptp_tx_work);
+			adapter->ptp_tx_skb = skb_get(skb);
+			adapter->ptp_tx_start = jiffies;
+			if (adapter->hw.mac.type == e1000_82576)
+				schedule_work(&adapter->ptp_tx_work);
+		}
 	}
 
 	if (vlan_tx_tag_present(skb)) {