RDMA/rxe: Fix spinlock recursion deadlock on requester

The following deadlock is observed:

 Call Trace:
  <IRQ>
  _raw_spin_lock_bh+0x29/0x30
  check_type_state.constprop.0+0x4e/0xc0 [rdma_rxe]
  rxe_rcv+0x173/0x3d0 [rdma_rxe]
  rxe_udp_encap_recv+0x69/0xd0 [rdma_rxe]
  ? __pfx_rxe_udp_encap_recv+0x10/0x10 [rdma_rxe]
  udp_queue_rcv_one_skb+0x258/0x520
  udp_unicast_rcv_skb+0x75/0x90
  __udp4_lib_rcv+0x364/0x5c0
  ip_protocol_deliver_rcu+0xa7/0x160
  ip_local_deliver_finish+0x73/0xa0
  ip_sublist_rcv_finish+0x80/0x90
  ip_sublist_rcv+0x191/0x220
  ip_list_rcv+0x132/0x160
  __netif_receive_skb_list_core+0x297/0x2c0
  netif_receive_skb_list_internal+0x1c5/0x300
  napi_complete_done+0x6f/0x1b0
  virtnet_poll+0x1f4/0x2d0 [virtio_net]
  __napi_poll+0x2c/0x1b0
  net_rx_action+0x293/0x350
  ? __napi_schedule+0x79/0x90
  __do_softirq+0xcb/0x2ab
  __irq_exit_rcu+0xb9/0xf0
  common_interrupt+0x80/0xa0
  </IRQ>
  <TASK>
  asm_common_interrupt+0x22/0x40
  RIP: 0010:_raw_spin_lock+0x17/0x30
  rxe_requester+0xe4/0x8f0 [rdma_rxe]
  ? xas_load+0x9/0xa0
  ? xa_load+0x70/0xb0
  do_task+0x64/0x1f0 [rdma_rxe]
  rxe_post_send+0x54/0x110 [rdma_rxe]
  ib_uverbs_post_send+0x5f8/0x680 [ib_uverbs]
  ? netif_receive_skb_list_internal+0x1e3/0x300
  ib_uverbs_write+0x3c8/0x500 [ib_uverbs]
  vfs_write+0xc5/0x3b0
  ksys_write+0xab/0xe0
  ? syscall_trace_enter.constprop.0+0x126/0x1a0
  do_syscall_64+0x3b/0x90
  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  </TASK>

The deadlock is easily reproducible with perftest. Fix it by disabling
softirq when acquiring the lock in process context.

Fixes: f605f26 ("RDMA/rxe: Protect QP state with qp->state_lock")
Link: https://lore.kernel.org/r/20230418090642.1849358-1-matsuda-daisuke@fujitsu.com
Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
Acked-by: Zhu Yanjun <zyjzyj2000@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: ddmatsu

drivers/infiniband/sw/rxe/rxe_req.c

@@ -180,13 +180,13 @@ static struct rxe_send_wqe *req_next_wqe(struct rxe_qp *qp)
 	if (wqe == NULL)
 		return NULL;
 
-	spin_lock(&qp->state_lock);
+	spin_lock_bh(&qp->state_lock);
 	if (unlikely((qp_state(qp) == IB_QPS_SQD) &&
 		     (wqe->state != wqe_state_processing))) {
-		spin_unlock(&qp->state_lock);
+		spin_unlock_bh(&qp->state_lock);
 		return NULL;
 	}
-	spin_unlock(&qp->state_lock);
+	spin_unlock_bh(&qp->state_lock);
 
 	wqe->mask = wr_opcode_mask(wqe->wr.opcode, qp);
 	return wqe;