qed: qed ll2 race condition fixes

Avoiding qed ll2 race condition and NULL pointer dereference as part
of the remove and recovery flows.

Changes form V1:
- Change (!p_rx->set_prod_addr).
- qed_ll2.c checkpatch fixes.

Change from V2:
- Revert "qed_ll2.c checkpatch fixes".

Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: Shai Malin <smalin@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_ll2.c

@@ -327,6 +327,9 @@ static int qed_ll2_txq_completion(struct qed_hwfn *p_hwfn, void *p_cookie)
 	unsigned long flags;
 	int rc = -EINVAL;
 
+	if (!p_ll2_conn)
+		return rc;
+
 	spin_lock_irqsave(&p_tx->lock, flags);
 	if (p_tx->b_completing_packet) {
 		rc = -EBUSY;
@@ -500,7 +503,16 @@ static int qed_ll2_rxq_completion(struct qed_hwfn *p_hwfn, void *cookie)
 	unsigned long flags = 0;
 	int rc = 0;
 
+	if (!p_ll2_conn)
+		return rc;
+
 	spin_lock_irqsave(&p_rx->lock, flags);
+
+	if (!QED_LL2_RX_REGISTERED(p_ll2_conn)) {
+		spin_unlock_irqrestore(&p_rx->lock, flags);
+		return 0;
+	}
+
 	cq_new_idx = le16_to_cpu(*p_rx->p_fw_cons);
 	cq_old_idx = qed_chain_get_cons_idx(&p_rx->rcq_chain);
 
@@ -821,6 +833,9 @@ static int qed_ll2_lb_rxq_completion(struct qed_hwfn *p_hwfn, void *p_cookie)
 	struct qed_ll2_info *p_ll2_conn = (struct qed_ll2_info *)p_cookie;
 	int rc;
 
+	if (!p_ll2_conn)
+		return 0;
+
 	if (!QED_LL2_RX_REGISTERED(p_ll2_conn))
 		return 0;
 
@@ -844,6 +859,9 @@ static int qed_ll2_lb_txq_completion(struct qed_hwfn *p_hwfn, void *p_cookie)
 	u16 new_idx = 0, num_bds = 0;
 	int rc;
 
+	if (!p_ll2_conn)
+		return 0;
+
 	if (!QED_LL2_TX_REGISTERED(p_ll2_conn))
 		return 0;
 
@@ -1728,6 +1746,8 @@ int qed_ll2_post_rx_buffer(void *cxt,
 	if (!p_ll2_conn)
 		return -EINVAL;
 	p_rx = &p_ll2_conn->rx_queue;
+	if (!p_rx->set_prod_addr)
+		return -EIO;
 
 	spin_lock_irqsave(&p_rx->lock, flags);
 	if (!list_empty(&p_rx->free_descq))