ibmvnic: Fix non-atomic memory allocation in IRQ context

ibmvnic_reset allocated new reset work item objects in a non-atomic
context. This can be called from a tasklet, generating the output below.
Allocate work items with the GFP_ATOMIC flag instead.

BUG: sleeping function called from invalid context at mm/slab.h:421
in_atomic(): 1, irqs_disabled(): 1, pid: 93, name: kworker/0:2
INFO: lockdep is turned off.
irq event stamp: 66049
hardirqs last  enabled at (66048): [<c000000000122468>] tasklet_action_common.isra.12+0x78/0x1c0
hardirqs last disabled at (66049): [<c000000000befce8>] _raw_spin_lock_irqsave+0x48/0xf0
softirqs last  enabled at (66044): [<c000000000a8ac78>] dev_deactivate_queue.constprop.28+0xc8/0x160
softirqs last disabled at (66045): [<c0000000000306e0>] call_do_softirq+0x14/0x24
CPU: 0 PID: 93 Comm: kworker/0:2 Kdump: loaded Not tainted 4.20.0-rc6-00001-g1b50a8f03706 #7
Workqueue: events linkwatch_event
Call Trace:
[c0000003fffe7ae0] [c000000000bc83e4] dump_stack+0xe8/0x164 (unreliable)
[c0000003fffe7b30] [c00000000015ba0c] ___might_sleep+0x2dc/0x320
[c0000003fffe7bb0] [c000000000391514] kmem_cache_alloc_trace+0x3e4/0x440
[c0000003fffe7c30] [d000000005b2309c] ibmvnic_reset+0x16c/0x360 [ibmvnic]
[c0000003fffe7cc0] [d000000005b29834] ibmvnic_tasklet+0x1054/0x2010 [ibmvnic]
[c0000003fffe7e00] [c0000000001224c8] tasklet_action_common.isra.12+0xd8/0x1c0
[c0000003fffe7e60] [c000000000bf1238] __do_softirq+0x1a8/0x64c
[c0000003fffe7f90] [c0000000000306e0] call_do_softirq+0x14/0x24
[c0000003f3967980] [c00000000001ba50] do_softirq_own_stack+0x60/0xb0
[c0000003f39679c0] [c0000000001218a8] do_softirq+0xa8/0x100
[c0000003f39679f0] [c000000000121a74] __local_bh_enable_ip+0x174/0x180
[c0000003f3967a60] [c000000000bf003c] _raw_spin_unlock_bh+0x5c/0x80
[c0000003f3967a90] [c000000000a8ac78] dev_deactivate_queue.constprop.28+0xc8/0x160
[c0000003f3967ad0] [c000000000a8c8b0] dev_deactivate_many+0xd0/0x520
[c0000003f3967b70] [c000000000a8cd40] dev_deactivate+0x40/0x60
[c0000003f3967ba0] [c000000000a5e0c4] linkwatch_do_dev+0x74/0xd0
[c0000003f3967bd0] [c000000000a5e694] __linkwatch_run_queue+0x1a4/0x1f0
[c0000003f3967c30] [c000000000a5e728] linkwatch_event+0x48/0x60
[c0000003f3967c50] [c0000000001444e8] process_one_work+0x238/0x710
[c0000003f3967d20] [c000000000144a48] worker_thread+0x88/0x4e0
[c0000003f3967db0] [c00000000014e3a8] kthread+0x178/0x1c0
[c0000003f3967e20] [c00000000000bfd0] ret_from_kernel_thread+0x5c/0x6c
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -2055,7 +2055,7 @@ static int ibmvnic_reset(struct ibmvnic_adapter *adapter,
 		}
 	}
 
-	rwi = kzalloc(sizeof(*rwi), GFP_KERNEL);
+	rwi = kzalloc(sizeof(*rwi), GFP_ATOMIC);
 	if (!rwi) {
 		spin_unlock_irqrestore(&adapter->rwi_lock, flags);
 		ibmvnic_close(netdev);