bnx2x: fix page fault following EEH recovery

In the last step of the EEH recovery process, the EEH driver calls into
bnx2x_io_resume() to re-initialize the NIC hardware via the function
bnx2x_nic_load(). If an error occurs during bnx2x_nic_load(), OS and
hardware resources are released and an error code is returned to the
caller. When called from bnx2x_io_resume(), the return code is ignored
and the network interface is brought up unconditionally. Later attempts
to send a packet via this interface result in a page fault due to a null
pointer reference.

This patch checks the return code of bnx2x_nic_load(), prints an error
message if necessary, and does not enable the interface.

Signed-off-by: David Christensen <[e-mail]>
Reviewed-by: Sridhar Samudrala <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c

···
 	bp->fw_seq = SHMEM_RD(bp, func_mb[BP_FW_MB_IDX(bp)].drv_mb_header) &
 							DRV_MSG_SEQ_NUMBER_MASK;
 
-	if (netif_running(dev))
-		bnx2x_nic_load(bp, LOAD_NORMAL);
+	if (netif_running(dev)) {
+		if (bnx2x_nic_load(bp, LOAD_NORMAL)) {
+			netdev_err(bp->dev, "Error during driver initialization, try unloading/reloading the driver\n");
+			goto done;
+		}
+	}
 
 	netif_device_attach(dev);
 
+done:
 	rtnl_unlock();
 }