qlcnic: protect resoruce cleanup by rtnl lock

o context resources can be in used, while resoruce cleanup is in progress,
  during fw recover.
o Null pointer execption can occur in send_cmd_desc, if fw recovery
  module frees tx ring without rtnl lock.
o Same applies to ethtool register dump and FW health registers should be dump
  in any case.
Signed-off-by: NAmit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/qlcnic/qlcnic_ethtool.c

@@ -326,12 +326,12 @@ qlcnic_get_regs(struct net_device *dev, struct ethtool_regs *regs, void *p)
 	regs->version = (1 << 24) | (adapter->ahw.revision_id << 16) |
 	    (adapter->pdev)->device;
 
-	if (adapter->is_up != QLCNIC_ADAPTER_UP_MAGIC)
-		return;
-
 	for (i = 0; diag_registers[i] != -1; i++)
 		regs_buff[i] = QLCRD32(adapter, diag_registers[i]);
 
+	if (adapter->is_up != QLCNIC_ADAPTER_UP_MAGIC)
+		return;
+
 	regs_buff[i++] = 0xFFEFCDAB; /* Marker btw regs and ring count*/
 
 	regs_buff[i++] = 1; /* No. of tx ring */

drivers/net/qlcnic/qlcnic_main.c

@@ -2051,7 +2051,9 @@ qlcnic_detach_work(struct work_struct *work)
 
 	qlcnic_down(adapter, netdev);
 
+	rtnl_lock();
 	qlcnic_detach(adapter);
+	rtnl_unlock();
 
 	status = QLCRD32(adapter, QLCNIC_PEG_HALT_STATUS1);