iwlwifi: reduce sta_lock hold time in TX

When we TX, we hold the sta_lock for a long
time, a lot of which isn't needed. Reduce
the time we hold the lock. Note that this
doesn't really change anything as the code
is already under the other spinlock, but it
makes the code easier to read.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-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

@@ -341,13 +341,10 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	if (info->flags & IEEE80211_TX_CTL_AMPDU)
 		is_agg = true;
 
-	/* irqs already disabled/saved above when locking priv->shrd->lock */
-	spin_lock(&priv->shrd->sta_lock);
-
 	dev_cmd = kmem_cache_alloc(priv->tx_cmd_pool, GFP_ATOMIC);
 
 	if (unlikely(!dev_cmd))
-		goto drop_unlock_sta;
+		goto drop_unlock_priv;
 
 	memset(dev_cmd, 0, sizeof(*dev_cmd));
 	tx_cmd = (struct iwl_tx_cmd *) dev_cmd->payload;
@@ -372,6 +369,9 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	info->driver_data[0] = ctx;
 	info->driver_data[1] = dev_cmd;
 
+	/* irqs already disabled/saved above when locking priv->shrd->lock */
+	spin_lock(&priv->shrd->sta_lock);
+
 	if (ieee80211_is_data_qos(fc) && !ieee80211_is_qos_nullfunc(fc)) {
 		u8 *qc = NULL;
 		struct iwl_tid_data *tid_data;