sparc: Use GFP_ATOMIC in ldc_alloc_exp_dring() as it can be called in softirq context

commit 0edfad59 upstream.

Since it is possible for vnet_event_napi to end up doing
vnet_control_pkt_engine -> ... -> vnet_send_attr ->
vnet_port_alloc_tx_ring -> ldc_alloc_exp_dring -> kzalloc()
(i.e., in softirq context), kzalloc() should be called with
GFP_ATOMIC from ldc_alloc_exp_dring.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

arch/sparc/kernel/ldc.c

@@ -2307,7 +2307,7 @@ void *ldc_alloc_exp_dring(struct ldc_channel *lp, unsigned int len,
 	if (len & (8UL - 1))
 		return ERR_PTR(-EINVAL);
 
-	buf = kzalloc(len, GFP_KERNEL);
+	buf = kzalloc(len, GFP_ATOMIC);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);