NVMe: nvme_submit_async_admin_req() must use atomic rq allocation

We are called for async event notification issues, and the
nvmeq lock is already held. If we fail the request allocation,
we'll just retry next time.
Reported-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NJens Axboe <axboe@fb.com>

drivers/block/nvme-core.c

@@ -825,7 +825,7 @@ static int nvme_submit_async_admin_req(struct nvme_dev *dev)
 	struct nvme_cmd_info *cmd_info;
 	struct request *req;
 
-	req = blk_mq_alloc_request(dev->admin_q, WRITE, GFP_KERNEL, false);
+	req = blk_mq_alloc_request(dev->admin_q, WRITE, GFP_ATOMIC, false);
 	if (IS_ERR(req))
 		return PTR_ERR(req);