iwlagn: simplify iwlagn_tx_skb

We can simplify length calculation in iwlagn_tx_skb, that function
is enough complex, without fuzz it more than necessary.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-tx.c

@@ -522,7 +522,7 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	dma_addr_t phys_addr;
 	dma_addr_t txcmd_phys;
 	dma_addr_t scratch_phys;
-	u16 len, len_org, firstlen, secondlen;
+	u16 len, firstlen, secondlen;
 	u16 seq_number = 0;
 	__le16 fc;
 	u8 hdr_len;
@@ -687,30 +687,23 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	 */
 	len = sizeof(struct iwl_tx_cmd) +
 		sizeof(struct iwl_cmd_header) + hdr_len;
-
-	len_org = len;
-	firstlen = len = (len + 3) & ~3;
-
-	if (len_org != len)
-		len_org = 1;
-	else
-		len_org = 0;
+	firstlen = (len + 3) & ~3;
 
 	/* Tell NIC about any 2-byte padding after MAC header */
-	if (len_org)
+	if (firstlen != len)
 		tx_cmd->tx_flags |= TX_CMD_FLG_MH_PAD_MSK;
 
 	/* Physical address of this Tx command's header (not MAC header!),
 	 * within command buffer array. */
 	txcmd_phys = pci_map_single(priv->pci_dev,
-				    &out_cmd->hdr, len,
+				    &out_cmd->hdr, firstlen,
 				    PCI_DMA_BIDIRECTIONAL);
 	dma_unmap_addr_set(out_meta, mapping, txcmd_phys);
-	dma_unmap_len_set(out_meta, len, len);
+	dma_unmap_len_set(out_meta, len, firstlen);
 	/* Add buffer containing Tx command and MAC(!) header to TFD's
 	 * first entry */
 	priv->cfg->ops->lib->txq_attach_buf_to_tfd(priv, txq,
-						   txcmd_phys, len, 1, 0);
+						   txcmd_phys, firstlen, 1, 0);
 
 	if (!ieee80211_has_morefrags(hdr->frame_control)) {
 		txq->need_update = 1;
@@ -721,23 +714,21 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 
 	/* Set up TFD's 2nd entry to point directly to remainder of skb,
 	 * if any (802.11 null frames have no payload). */
-	secondlen = len = skb->len - hdr_len;
-	if (len) {
+	secondlen = skb->len - hdr_len;
+	if (secondlen > 0) {
 		phys_addr = pci_map_single(priv->pci_dev, skb->data + hdr_len,
-					   len, PCI_DMA_TODEVICE);
+					   secondlen, PCI_DMA_TODEVICE);
 		priv->cfg->ops->lib->txq_attach_buf_to_tfd(priv, txq,
-							   phys_addr, len,
+							   phys_addr, secondlen,
 							   0, 0);
 	}
 
 	scratch_phys = txcmd_phys + sizeof(struct iwl_cmd_header) +
 				offsetof(struct iwl_tx_cmd, scratch);
 
-	len = sizeof(struct iwl_tx_cmd) +
-		sizeof(struct iwl_cmd_header) + hdr_len;
 	/* take back ownership of DMA buffer to enable update */
 	pci_dma_sync_single_for_cpu(priv->pci_dev, txcmd_phys,
-				    len, PCI_DMA_BIDIRECTIONAL);
+				    firstlen, PCI_DMA_BIDIRECTIONAL);
 	tx_cmd->dram_lsb_ptr = cpu_to_le32(scratch_phys);
 	tx_cmd->dram_msb_ptr = iwl_get_dma_hi_addr(scratch_phys);
 
@@ -753,7 +744,7 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 						     le16_to_cpu(tx_cmd->len));
 
 	pci_dma_sync_single_for_device(priv->pci_dev, txcmd_phys,
-				       len, PCI_DMA_BIDIRECTIONAL);
+				       firstlen, PCI_DMA_BIDIRECTIONAL);
 
 	trace_iwlwifi_dev_tx(priv,
 			     &((struct iwl_tfd *)txq->tfds)[txq->q.write_ptr],