scsi: target: cxgbit: Remove tx flow control code

Firmware does tx flow control so remove tx flow control code from the
driver.
Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/iscsi/cxgbit/cxgbit.h

@@ -207,7 +207,6 @@ struct cxgbit_sock {
 	/* socket lock */
 	spinlock_t lock;
 	wait_queue_head_t waitq;
-	wait_queue_head_t ack_waitq;
 	bool lock_owner;
 	struct kref kref;
 	u32 max_iso_npdu;

drivers/target/iscsi/cxgbit/cxgbit_cm.c

@@ -1360,7 +1360,6 @@ cxgbit_pass_accept_req(struct cxgbit_device *cdev, struct sk_buff *skb)
 	cxgbit_sock_reset_wr_list(csk);
 	spin_lock_init(&csk->lock);
 	init_waitqueue_head(&csk->waitq);
-	init_waitqueue_head(&csk->ack_waitq);
 	csk->lock_owner = false;
 
 	if (cxgbit_alloc_csk_skb(csk)) {
@@ -1887,7 +1886,6 @@ static void cxgbit_fw4_ack(struct cxgbit_sock *csk, struct sk_buff *skb)
 		if (csk->snd_una != snd_una) {
 			csk->snd_una = snd_una;
 			dst_confirm(csk->dst);
-			wake_up(&csk->ack_waitq);
 		}
 	}
 

drivers/target/iscsi/cxgbit/cxgbit_target.c

@@ -284,18 +284,6 @@ void cxgbit_push_tx_frames(struct cxgbit_sock *csk)
 	}
 }
 
-static bool cxgbit_lock_sock(struct cxgbit_sock *csk)
-{
-	spin_lock_bh(&csk->lock);
-
-	if (before(csk->write_seq, csk->snd_una + csk->snd_win))
-		csk->lock_owner = true;
-
-	spin_unlock_bh(&csk->lock);
-
-	return csk->lock_owner;
-}
-
 static void cxgbit_unlock_sock(struct cxgbit_sock *csk)
 {
 	struct sk_buff_head backlogq;
@@ -325,20 +313,16 @@ static int cxgbit_queue_skb(struct cxgbit_sock *csk, struct sk_buff *skb)
 {
 	int ret = 0;
 
-	wait_event_interruptible(csk->ack_waitq, cxgbit_lock_sock(csk));
+	spin_lock_bh(&csk->lock);
+	csk->lock_owner = true;
+	spin_unlock_bh(&csk->lock);
 
 	if (unlikely((csk->com.state != CSK_STATE_ESTABLISHED) ||
 		     signal_pending(current))) {
 		__kfree_skb(skb);
 		__skb_queue_purge(&csk->ppodq);
 		ret = -1;
-		spin_lock_bh(&csk->lock);
-		if (csk->lock_owner) {
-			spin_unlock_bh(&csk->lock);
-			goto unlock;
-		}
-		spin_unlock_bh(&csk->lock);
-		return ret;
+		goto unlock;
 	}
 
 	csk->write_seq += skb->len +