ethernet: rocker: fix sleep in atomic context bug in neigh_timer_handler

The function neigh_timer_handler() is a timer handler that runs in an
atomic context. When used by rocker, neigh_timer_handler() calls
"kzalloc(.., GFP_KERNEL)" that may sleep. As a result, the sleep in
atomic context bug will happen. One of the processes is shown below:

ofdpa_fib4_add()
...
neigh_add_timer()

(wait a timer)

neigh_timer_handler()
neigh_release()
neigh_destroy()
rocker_port_neigh_destroy()
rocker_world_port_neigh_destroy()
ofdpa_port_neigh_destroy()
ofdpa_port_ipv4_neigh()
kzalloc(sizeof(.., GFP_KERNEL) //may sleep

This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to
GFP_ATOMIC in order to mitigate the bug.

Fixes: 00fc0c51e35b ("rocker: Change world_ops API and implementation to be switchdev independant")
Signed-off-by: Duoming Zhou <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/rocker/rocker_ofdpa.c

···
 	bool removing;
 	int err = 0;
 
-	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 	if (!entry)
 		return -ENOMEM;