[bug report] net: phylink: add suspend/resume support

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Russell King (Oracle),

This is a semi-automatic email about new static checker warnings.

The patch f97493657c63: "net: phylink: add suspend/resume support" 
from Sep 7, 2021, leads to the following Smatch complaint:

    drivers/net/phy/phylink.c:1336 phylink_suspend()
    error: we previously assumed 'pl->netdev' could be null (see line 1325)

drivers/net/phy/phylink.c
  1324	
  1325		if (mac_wol && (!pl->netdev || pl->netdev->wol_enabled)) {
                                 ^^^^^^^^^^
This checks for NULL

  1326			/* Wake-on-Lan enabled, MAC handling */
  1327			mutex_lock(&pl->state_mutex);
  1328	
  1329			/* Stop the resolver bringing the link up */
  1330			__set_bit(PHYLINK_DISABLE_MAC_WOL, &pl->phylink_disable_state);
  1331	
  1332			/* Disable the carrier, to prevent transmit timeouts,
  1333			 * but one would hope all packets have been sent. This
  1334			 * also means phylink_resolve() will do nothing.
  1335			 */
  1336			netif_carrier_off(pl->netdev);
                                          ^^^^^^^^^^
But there is an unchecked dereference inside the netif_carrier_off()
function.

  1337	
  1338			/* We do not call mac_link_down() here as we want the

regards,
dan carpenter