RDMA/siw: Fix duplicated reported IW_CM_EVENT_CONNECT_REPLY event

[ Upstream commit 3056fc6 ]

If siw_recv_mpa_rr returns -EAGAIN, it means that the MPA reply hasn't
been received completely, and should not report IW_CM_EVENT_CONNECT_REPLY
in this case. This may trigger a call trace in iw_cm. A simple way to
trigger this:
 server: ib_send_lat
 client: ib_send_lat -R <server_ip>

The call trace looks like this:

 kernel BUG at drivers/infiniband/core/iwcm.c:894!
 invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
 <...>
 Workqueue: iw_cm_wq cm_work_handler [iw_cm]
 Call Trace:
  <TASK>
  cm_work_handler+0x1dd/0x370 [iw_cm]
  process_one_work+0x1e2/0x3b0
  worker_thread+0x49/0x2e0
  ? rescuer_thread+0x370/0x370
  kthread+0xe5/0x110
  ? kthread_complete_and_exit+0x20/0x20
  ret_from_fork+0x1f/0x30
  </TASK>

Fixes: 6c52fdc ("rdma/siw: connection management")
Link: https://lore.kernel.org/r/dae34b5fd5c2ea2bd9744812c1d2653a34a94c67.1657706960.git.chengyou@linux.alibaba.com
Signed-off-by: Cheng Xu <chengyou@linux.alibaba.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/infiniband/sw/siw/siw_cm.c

@@ -725,11 +725,11 @@ static int siw_proc_mpareply(struct siw_cep *cep)
 	enum mpa_v2_ctrl mpa_p2p_mode = MPA_V2_RDMA_NO_RTR;
 
 	rv = siw_recv_mpa_rr(cep);
-	if (rv != -EAGAIN)
-		siw_cancel_mpatimer(cep);
 	if (rv)
 		goto out_err;
 
+	siw_cancel_mpatimer(cep);
+
 	rep = &cep->mpa.hdr;
 
 	if (__mpa_rr_revision(rep->params.bits) > MPA_REVISION_2) {
@@ -895,7 +895,8 @@ static int siw_proc_mpareply(struct siw_cep *cep)
 	}
 
 out_err:
-	siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY, -EINVAL);
+	if (rv != -EAGAIN)
+		siw_cm_upcall(cep, IW_CM_EVENT_CONNECT_REPLY, -EINVAL);
 
 	return rv;
 }