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Date:	Tue, 13 Nov 2012 06:03:23 -0800
From:	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:	davem@...emloft.net
Cc:	Alexander Duyck <alexander.h.duyck@...el.com>,
	netdev@...r.kernel.org, gospo@...hat.com, sassmann@...hat.com,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 09/11] igb: Update igb Tx flags to improve code efficiency

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

This change is meant to improve the efficiency of the Tx flags in igb by
aligning them with the values that will later be written into either the
cmd_type or olinfo.  By doing this we are able to reduce most of these
functions to either just a simple shift followed by an or in the case of
cmd_type, or an and followed by an or in the case of olinfo.

In order to avoid type conversion errors I also adjusted the locations
where we were switching between CPU and little endian.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
Tested-by: Aaron Brown <aaron.f.brown@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
 drivers/net/ethernet/intel/igb/igb.h      | 17 ++++++---
 drivers/net/ethernet/intel/igb/igb_main.c | 61 +++++++++++++++++--------------
 2 files changed, 45 insertions(+), 33 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index b23a667..d8fd5b6 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -150,11 +150,18 @@ struct vf_data_storage {
 
 #define IGB_MNG_VLAN_NONE -1
 
-#define IGB_TX_FLAGS_CSUM		0x00000001
-#define IGB_TX_FLAGS_VLAN		0x00000002
-#define IGB_TX_FLAGS_TSO		0x00000004
-#define IGB_TX_FLAGS_IPV4		0x00000008
-#define IGB_TX_FLAGS_TSTAMP		0x00000010
+enum igb_tx_flags {
+	/* cmd_type flags */
+	IGB_TX_FLAGS_VLAN	= 0x01,
+	IGB_TX_FLAGS_TSO	= 0x02,
+	IGB_TX_FLAGS_TSTAMP	= 0x04,
+
+	/* olinfo flags */
+	IGB_TX_FLAGS_IPV4	= 0x10,
+	IGB_TX_FLAGS_CSUM	= 0x20,
+};
+
+/* VLAN info */
 #define IGB_TX_FLAGS_VLAN_MASK		0xffff0000
 #define IGB_TX_FLAGS_VLAN_SHIFT	16
 
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index b0730e9..0a0bd81 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4121,24 +4121,32 @@ static void igb_tx_csum(struct igb_ring *tx_ring, struct igb_tx_buffer *first)
 	igb_tx_ctxtdesc(tx_ring, vlan_macip_lens, type_tucmd, mss_l4len_idx);
 }
 
-static __le32 igb_tx_cmd_type(u32 tx_flags)
+#define IGB_SET_FLAG(_input, _flag, _result) \
+	((_flag <= _result) ? \
+	 ((u32)(_input & _flag) * (_result / _flag)) : \
+	 ((u32)(_input & _flag) / (_flag / _result)))
+
+static u32 igb_tx_cmd_type(struct sk_buff *skb, u32 tx_flags)
 {
 	/* set type for advanced descriptor with frame checksum insertion */
-	__le32 cmd_type = cpu_to_le32(E1000_ADVTXD_DTYP_DATA |
-				      E1000_ADVTXD_DCMD_IFCS |
-				      E1000_ADVTXD_DCMD_DEXT);
+	u32 cmd_type = E1000_ADVTXD_DTYP_DATA |
+		       E1000_ADVTXD_DCMD_DEXT |
+		       E1000_ADVTXD_DCMD_IFCS;
 
 	/* set HW vlan bit if vlan is present */
-	if (tx_flags & IGB_TX_FLAGS_VLAN)
-		cmd_type |= cpu_to_le32(E1000_ADVTXD_DCMD_VLE);
+	cmd_type |= IGB_SET_FLAG(tx_flags, IGB_TX_FLAGS_VLAN,
+				 (E1000_ADVTXD_DCMD_VLE));
+
+	/* set segmentation bits for TSO */
+	cmd_type |= IGB_SET_FLAG(tx_flags, IGB_TX_FLAGS_TSO,
+				 (E1000_ADVTXD_DCMD_TSE));
 
 	/* set timestamp bit if present */
-	if (unlikely(tx_flags & IGB_TX_FLAGS_TSTAMP))
-		cmd_type |= cpu_to_le32(E1000_ADVTXD_MAC_TSTAMP);
+	cmd_type |= IGB_SET_FLAG(tx_flags, IGB_TX_FLAGS_TSTAMP,
+				 (E1000_ADVTXD_MAC_TSTAMP));
 
-	/* set segmentation bits for TSO */
-	if (tx_flags & IGB_TX_FLAGS_TSO)
-		cmd_type |= cpu_to_le32(E1000_ADVTXD_DCMD_TSE);
+	/* insert frame checksum */
+	cmd_type ^= IGB_SET_FLAG(skb->no_fcs, 1, E1000_ADVTXD_DCMD_IFCS);
 
 	return cmd_type;
 }
@@ -4149,19 +4157,19 @@ static void igb_tx_olinfo_status(struct igb_ring *tx_ring,
 {
 	u32 olinfo_status = paylen << E1000_ADVTXD_PAYLEN_SHIFT;
 
-	/* 82575 requires a unique index per ring if any offload is enabled */
-	if ((tx_flags & (IGB_TX_FLAGS_CSUM | IGB_TX_FLAGS_VLAN)) &&
-	    test_bit(IGB_RING_FLAG_TX_CTX_IDX, &tx_ring->flags))
+	/* 82575 requires a unique index per ring */
+	if (test_bit(IGB_RING_FLAG_TX_CTX_IDX, &tx_ring->flags))
 		olinfo_status |= tx_ring->reg_idx << 4;
 
 	/* insert L4 checksum */
-	if (tx_flags & IGB_TX_FLAGS_CSUM) {
-		olinfo_status |= E1000_TXD_POPTS_TXSM << 8;
+	olinfo_status |= IGB_SET_FLAG(tx_flags,
+				      IGB_TX_FLAGS_CSUM,
+				      (E1000_TXD_POPTS_TXSM << 8));
 
-		/* insert IPv4 checksum */
-		if (tx_flags & IGB_TX_FLAGS_IPV4)
-			olinfo_status |= E1000_TXD_POPTS_IXSM << 8;
-	}
+	/* insert IPv4 checksum */
+	olinfo_status |= IGB_SET_FLAG(tx_flags,
+				      IGB_TX_FLAGS_IPV4,
+				      (E1000_TXD_POPTS_IXSM << 8));
 
 	tx_desc->read.olinfo_status = cpu_to_le32(olinfo_status);
 }
@@ -4185,14 +4193,13 @@ static void igb_tx_map(struct igb_ring *tx_ring,
 	unsigned int data_len = skb->data_len;
 	unsigned int size = skb_headlen(skb);
 	unsigned int paylen = skb->len - hdr_len;
-	__le32 cmd_type;
 	u32 tx_flags = first->tx_flags;
+	u32 cmd_type = igb_tx_cmd_type(skb, tx_flags);
 	u16 i = tx_ring->next_to_use;
 
 	tx_desc = IGB_TX_DESC(tx_ring, i);
 
 	igb_tx_olinfo_status(tx_ring, tx_desc, tx_flags, paylen);
-	cmd_type = igb_tx_cmd_type(tx_flags);
 
 	dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);
 	if (dma_mapping_error(tx_ring->dev, dma))
@@ -4206,7 +4213,7 @@ static void igb_tx_map(struct igb_ring *tx_ring,
 	for (;;) {
 		while (unlikely(size > IGB_MAX_DATA_PER_TXD)) {
 			tx_desc->read.cmd_type_len =
-				cmd_type | cpu_to_le32(IGB_MAX_DATA_PER_TXD);
+				cpu_to_le32(cmd_type ^ IGB_MAX_DATA_PER_TXD);
 
 			i++;
 			tx_desc++;
@@ -4225,7 +4232,7 @@ static void igb_tx_map(struct igb_ring *tx_ring,
 		if (likely(!data_len))
 			break;
 
-		tx_desc->read.cmd_type_len = cmd_type | cpu_to_le32(size);
+		tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type ^ size);
 
 		i++;
 		tx_desc++;
@@ -4255,10 +4262,8 @@ static void igb_tx_map(struct igb_ring *tx_ring,
 	netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);
 
 	/* write last descriptor with RS and EOP bits */
-	cmd_type |= cpu_to_le32(size) | cpu_to_le32(IGB_TXD_DCMD);
-	if (unlikely(skb->no_fcs))
-		cmd_type &= ~(cpu_to_le32(E1000_ADVTXD_DCMD_IFCS));
-	tx_desc->read.cmd_type_len = cmd_type;
+	cmd_type |= size | IGB_TXD_DCMD;
+	tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
 
 	/* set the timestamp */
 	first->time_stamp = jiffies;
-- 
1.7.11.7

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